Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

12 files changed, 5810 insertions, 0 deletions

diff --git a/third_party/rust/gleam/.cargo-checksum.json b/third_party/rust/gleam/.cargo-checksum.json
new file mode 100644
index 0000000000..651bf11aab
--- /dev/null
+++ b/third_party/rust/gleam/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"COPYING":"ec82b96487e9e778ee610c7ab245162464782cfa1f555c2299333f8dbe5c036a","Cargo.toml":"6dce42dfad850b93a2d4a2d29ab4c8de9c7bd783e6870ceec5fd8dccb960e50f","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"62065228e42caebca7e7d7db1204cbb867033de5982ca4009928915e4095f3a3","README.md":"1acb12040be43a3582d5897f11870b3ffdcd7ce0f4f32de158175bb6b33ec0b7","build.rs":"cf4ed31d33c2dcc3cb16648ce60c6ac69a7959fbd2491aa3565237f601a1ef18","rustfmt.toml":"e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855","src/gl.rs":"c10739f5382209a4a4715a9e38b3a263f750f52a7b5131c31683f0fd221e8d00","src/gl_fns.rs":"03c0232de8e1ffb8db3b4669cefe00f8e8c4ba49504276b0b84c88804cc01d13","src/gles_fns.rs":"7101fd4dbc354c2b375a8a525623d29ee5ac0e6cd13bf78c93a264fc50c0b589","src/lib.rs":"16610c19b45a3f26d56b379a3591aa2e4fc9477e7bd88f86b31c6ea32e834861"},"package":"0173481f2bb6e809bf4985de2e86c83876d84d2805830e3301cd37355e897f0f"}
\ No newline at end of file
diff --git a/third_party/rust/gleam/COPYING b/third_party/rust/gleam/COPYING
new file mode 100644
index 0000000000..8b7291ad28
--- /dev/null
+++ b/third_party/rust/gleam/COPYING
@@ -0,0 +1,5 @@
+Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+<LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+option. All files in the project carrying such notice may not be
+copied, modified, or distributed except according to those terms.
diff --git a/third_party/rust/gleam/Cargo.toml b/third_party/rust/gleam/Cargo.toml
new file mode 100644
index 0000000000..7cc789b302
--- /dev/null
+++ b/third_party/rust/gleam/Cargo.toml
@@ -0,0 +1,24 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+name = "gleam"
+version = "0.15.0"
+authors = ["The Servo Project Developers"]
+build = "build.rs"
+description = "Generated OpenGL bindings and wrapper for Servo."
+documentation = "https://doc.servo.org/gleam/"
+readme = "README.md"
+license = "Apache-2.0/MIT"
+repository = "https://github.com/servo/gleam"
+
+[build-dependencies.gl_generator]
+version = "0.14"
diff --git a/third_party/rust/gleam/LICENSE-APACHE b/third_party/rust/gleam/LICENSE-APACHE
new file mode 100644
index 0000000000..16fe87b06e
--- /dev/null
+++ b/third_party/rust/gleam/LICENSE-APACHE
@@ -0,0 +1,201 @@
+                              Apache License
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diff --git a/third_party/rust/gleam/LICENSE-MIT b/third_party/rust/gleam/LICENSE-MIT
new file mode 100644
index 0000000000..807526f57f
--- /dev/null
+++ b/third_party/rust/gleam/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2012-2013 Mozilla Foundation
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/third_party/rust/gleam/README.md b/third_party/rust/gleam/README.md
new file mode 100644
index 0000000000..1eaa2128fd
--- /dev/null
+++ b/third_party/rust/gleam/README.md
@@ -0,0 +1,6 @@
+servo-gl
+========
+
+[Documentation](https://doc.servo.org/gleam/)
+
+OpenGL bindings for Servo
diff --git a/third_party/rust/gleam/build.rs b/third_party/rust/gleam/build.rs
new file mode 100644
index 0000000000..12fd38e373
--- /dev/null
+++ b/third_party/rust/gleam/build.rs
@@ -0,0 +1,88 @@
+extern crate gl_generator;
+
+use gl_generator::{Api, Fallbacks, Profile, Registry};
+use std::env;
+use std::fs::File;
+use std::path::Path;
+
+fn main() {
+    let dest = env::var("OUT_DIR").unwrap();
+    let mut file_gl_and_gles =
+        File::create(&Path::new(&dest).join("gl_and_gles_bindings.rs")).unwrap();
+    let mut file_gl = File::create(&Path::new(&dest).join("gl_bindings.rs")).unwrap();
+    let mut file_gles = File::create(&Path::new(&dest).join("gles_bindings.rs")).unwrap();
+
+    // OpenGL 3.3 bindings
+    let gl_extensions = [
+        "GL_APPLE_client_storage",
+        "GL_APPLE_fence",
+        "GL_APPLE_texture_range",
+        "GL_APPLE_vertex_array_object",
+        "GL_ARB_blend_func_extended",
+        "GL_ARB_buffer_storage",
+        "GL_ARB_copy_image",
+        "GL_ARB_get_program_binary",
+        "GL_ARB_invalidate_subdata",
+        "GL_ARB_texture_rectangle",
+        "GL_ARB_texture_storage",
+        "GL_ARB_vertex_attrib_binding",
+        "GL_EXT_debug_marker",
+        "GL_EXT_texture_filter_anisotropic",
+        "GL_KHR_debug",
+        "GL_KHR_blend_equation_advanced",
+        "GL_KHR_blend_equation_advanced_coherent",
+        "GL_KHR_blend_equation_advanced_coherent",
+        "GL_ARB_shader_storage_buffer_object",
+    ];
+    let gl_reg = Registry::new(
+        Api::Gl,
+        (3, 3),
+        Profile::Compatibility,
+        Fallbacks::All,
+        gl_extensions,
+    );
+    gl_reg
+        .write_bindings(gl_generator::StructGenerator, &mut file_gl)
+        .unwrap();
+
+    // GLES 3.0 bindings
+    let gles_extensions = [
+        "GL_EXT_buffer_storage",
+        "GL_EXT_copy_image",
+        "GL_EXT_debug_marker",
+        "GL_EXT_disjoint_timer_query",
+        "GL_EXT_shader_texture_lod",
+        "GL_EXT_texture_filter_anisotropic",
+        "GL_EXT_texture_format_BGRA8888",
+        "GL_EXT_texture_storage",
+        "GL_OES_EGL_image_external",
+        "GL_OES_EGL_image",
+        "GL_OES_texture_half_float",
+        "GL_EXT_shader_pixel_local_storage",
+        "GL_ANGLE_provoking_vertex",
+        "GL_ANGLE_texture_usage",
+        "GL_CHROMIUM_copy_texture",
+        "GL_KHR_debug",
+        "GL_KHR_blend_equation_advanced",
+        "GL_KHR_blend_equation_advanced_coherent",
+        "GL_ANGLE_copy_texture_3d",
+        "GL_QCOM_tiled_rendering",
+    ];
+    let gles_reg = Registry::new(
+        Api::Gles2,
+        // using 3.1 to get SSBO support
+        (3, 1),
+        Profile::Core,
+        Fallbacks::All,
+        gles_extensions,
+    );
+    gles_reg
+        .write_bindings(gl_generator::StructGenerator, &mut file_gles)
+        .unwrap();
+
+    // OpenGL 3.3 + GLES 3.0 bindings. Used to get all enums
+    let gl_reg = gl_reg + gles_reg;
+    gl_reg
+        .write_bindings(gl_generator::StructGenerator, &mut file_gl_and_gles)
+        .unwrap();
+}
diff --git a/third_party/rust/gleam/rustfmt.toml b/third_party/rust/gleam/rustfmt.toml
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/third_party/rust/gleam/rustfmt.toml
diff --git a/third_party/rust/gleam/src/gl.rs b/third_party/rust/gleam/src/gl.rs
new file mode 100644
index 0000000000..6293d81100
--- /dev/null
+++ b/third_party/rust/gleam/src/gl.rs
@@ -0,0 +1,841 @@
+// Copyright 2014 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use ffi;
+use std::ffi::{CStr, CString};
+use std::mem;
+use std::mem::size_of;
+use std::os::raw::{c_char, c_int, c_void};
+use std::ptr;
+use std::rc::Rc;
+use std::str;
+use std::time::{Duration, Instant};
+
+pub use ffi::types::*;
+pub use ffi::*;
+
+pub use ffi_gl::Gl as GlFfi;
+pub use ffi_gles::Gles2 as GlesFfi;
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum GlType {
+    Gl,
+    Gles,
+}
+
+impl Default for GlType {
+    #[cfg(any(target_os = "android", target_os = "ios"))]
+    fn default() -> GlType {
+        GlType::Gles
+    }
+    #[cfg(not(any(target_os = "android", target_os = "ios")))]
+    fn default() -> GlType {
+        GlType::Gl
+    }
+}
+
+fn bpp(format: GLenum, pixel_type: GLenum) -> GLsizei {
+    let colors = match format {
+        ffi::RED => 1,
+        ffi::RGB => 3,
+        ffi::BGR => 3,
+
+        ffi::RGBA => 4,
+        ffi::BGRA => 4,
+
+        ffi::ALPHA => 1,
+        ffi::R16 => 1,
+        ffi::LUMINANCE => 1,
+        ffi::DEPTH_COMPONENT => 1,
+        _ => panic!("unsupported format for read_pixels: {:?}", format),
+    };
+    let depth = match pixel_type {
+        ffi::UNSIGNED_BYTE => 1,
+        ffi::UNSIGNED_SHORT => 2,
+        ffi::SHORT => 2,
+        ffi::FLOAT => 4,
+        ffi::UNSIGNED_INT_8_8_8_8_REV => return 4,
+        _ => panic!("unsupported pixel_type for read_pixels: {:?}", pixel_type),
+    };
+    colors * depth
+}
+
+fn calculate_length(width: GLsizei, height: GLsizei, format: GLenum, pixel_type: GLenum) -> usize {
+    (width * height * bpp(format, pixel_type)) as usize
+}
+
+pub struct DebugMessage {
+    pub message: String,
+    pub source: GLenum,
+    pub ty: GLenum,
+    pub id: GLenum,
+    pub severity: GLenum,
+}
+
+macro_rules! declare_gl_apis {
+    // garbo is a hack to handle unsafe methods.
+    ($($(unsafe $([$garbo:expr])*)* fn $name:ident(&self $(, $arg:ident: $t:ty)* $(,)*) $(-> $retty:ty)* ;)+) => {
+        pub trait Gl {
+            $($(unsafe $($garbo)*)* fn $name(&self $(, $arg:$t)*) $(-> $retty)* ;)+
+        }
+
+        impl Gl for ErrorCheckingGl {
+            $($(unsafe $($garbo)*)* fn $name(&self $(, $arg:$t)*) $(-> $retty)* {
+                let rv = self.gl.$name($($arg,)*);
+                assert_eq!(self.gl.get_error(), 0);
+                rv
+            })+
+        }
+
+        impl<F: Fn(&dyn Gl, &str, GLenum)> Gl for ErrorReactingGl<F> {
+            $($(unsafe $($garbo)*)* fn $name(&self $(, $arg:$t)*) $(-> $retty)* {
+                let rv = self.gl.$name($($arg,)*);
+                let error = self.gl.get_error();
+                if error != 0 {
+                    (self.callback)(&*self.gl, stringify!($name), error);
+                }
+                rv
+            })+
+        }
+
+        impl<F: Fn(&str, Duration)> Gl for ProfilingGl<F> {
+            $($(unsafe $($garbo)*)* fn $name(&self $(, $arg:$t)*) $(-> $retty)* {
+                let start = Instant::now();
+                let rv = self.gl.$name($($arg,)*);
+                let duration = Instant::now() - start;
+                if duration > self.threshold {
+                    (self.callback)(stringify!($name), duration);
+                }
+                rv
+            })+
+        }
+    }
+}
+
+declare_gl_apis! {
+    fn get_type(&self) -> GlType;
+    fn buffer_data_untyped(
+        &self,
+        target: GLenum,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+        usage: GLenum,
+    );
+    fn buffer_sub_data_untyped(
+        &self,
+        target: GLenum,
+        offset: isize,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+    );
+    fn map_buffer(&self, target: GLenum, access: GLbitfield) -> *mut c_void;
+    fn map_buffer_range(
+        &self,
+        target: GLenum,
+        offset: GLintptr,
+        length: GLsizeiptr,
+        access: GLbitfield,
+    ) -> *mut c_void;
+    fn unmap_buffer(&self, target: GLenum) -> GLboolean;
+    fn tex_buffer(&self, target: GLenum, internal_format: GLenum, buffer: GLuint);
+    fn shader_source(&self, shader: GLuint, strings: &[&[u8]]);
+    fn read_buffer(&self, mode: GLenum);
+    fn read_pixels_into_buffer(
+        &self,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        pixel_type: GLenum,
+        dst_buffer: &mut [u8],
+    );
+    fn read_pixels(
+        &self,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        pixel_type: GLenum,
+    ) -> Vec<u8>;
+    unsafe fn read_pixels_into_pbo(
+        &self,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        pixel_type: GLenum,
+    );
+    fn sample_coverage(&self, value: GLclampf, invert: bool);
+    fn polygon_offset(&self, factor: GLfloat, units: GLfloat);
+    fn pixel_store_i(&self, name: GLenum, param: GLint);
+    fn gen_buffers(&self, n: GLsizei) -> Vec<GLuint>;
+    fn gen_renderbuffers(&self, n: GLsizei) -> Vec<GLuint>;
+    fn gen_framebuffers(&self, n: GLsizei) -> Vec<GLuint>;
+    fn gen_textures(&self, n: GLsizei) -> Vec<GLuint>;
+    fn gen_vertex_arrays(&self, n: GLsizei) -> Vec<GLuint>;
+    fn gen_vertex_arrays_apple(&self, n: GLsizei) -> Vec<GLuint>;
+    fn gen_queries(&self, n: GLsizei) -> Vec<GLuint>;
+    fn begin_query(&self, target: GLenum, id: GLuint);
+    fn end_query(&self, target: GLenum);
+    fn query_counter(&self, id: GLuint, target: GLenum);
+    fn get_query_object_iv(&self, id: GLuint, pname: GLenum) -> i32;
+    fn get_query_object_uiv(&self, id: GLuint, pname: GLenum) -> u32;
+    fn get_query_object_i64v(&self, id: GLuint, pname: GLenum) -> i64;
+    fn get_query_object_ui64v(&self, id: GLuint, pname: GLenum) -> u64;
+    fn delete_queries(&self, queries: &[GLuint]);
+    fn delete_vertex_arrays(&self, vertex_arrays: &[GLuint]);
+    fn delete_vertex_arrays_apple(&self, vertex_arrays: &[GLuint]);
+    fn delete_buffers(&self, buffers: &[GLuint]);
+    fn delete_renderbuffers(&self, renderbuffers: &[GLuint]);
+    fn delete_framebuffers(&self, framebuffers: &[GLuint]);
+    fn delete_textures(&self, textures: &[GLuint]);
+    fn framebuffer_renderbuffer(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        renderbuffertarget: GLenum,
+        renderbuffer: GLuint,
+    );
+    fn renderbuffer_storage(
+        &self,
+        target: GLenum,
+        internalformat: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+    );
+    fn depth_func(&self, func: GLenum);
+    fn active_texture(&self, texture: GLenum);
+    fn attach_shader(&self, program: GLuint, shader: GLuint);
+    fn bind_attrib_location(&self, program: GLuint, index: GLuint, name: &str);
+    unsafe fn get_uniform_iv(&self, program: GLuint, location: GLint, result: &mut [GLint]);
+    unsafe fn get_uniform_fv(&self, program: GLuint, location: GLint, result: &mut [GLfloat]);
+    fn get_uniform_block_index(&self, program: GLuint, name: &str) -> GLuint;
+    fn get_uniform_indices(&self, program: GLuint, names: &[&str]) -> Vec<GLuint>;
+    fn bind_buffer_base(&self, target: GLenum, index: GLuint, buffer: GLuint);
+    fn bind_buffer_range(
+        &self,
+        target: GLenum,
+        index: GLuint,
+        buffer: GLuint,
+        offset: GLintptr,
+        size: GLsizeiptr,
+    );
+    fn uniform_block_binding(
+        &self,
+        program: GLuint,
+        uniform_block_index: GLuint,
+        uniform_block_binding: GLuint,
+    );
+    fn bind_buffer(&self, target: GLenum, buffer: GLuint);
+    fn bind_vertex_array(&self, vao: GLuint);
+    fn bind_vertex_array_apple(&self, vao: GLuint);
+    fn bind_renderbuffer(&self, target: GLenum, renderbuffer: GLuint);
+    fn bind_framebuffer(&self, target: GLenum, framebuffer: GLuint);
+    fn bind_texture(&self, target: GLenum, texture: GLuint);
+    fn bind_vertex_buffer(&self, binding_index: GLuint, buffer: GLuint, offset: GLintptr, stride: GLint);
+    fn draw_buffers(&self, bufs: &[GLenum]);
+    fn tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+        format: GLenum,
+        ty: GLenum,
+        opt_data: Option<&[u8]>,
+    );
+    fn compressed_tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+        data: &[u8],
+    );
+    fn compressed_tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        data: &[u8],
+    );
+    fn tex_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        border: GLint,
+        format: GLenum,
+        ty: GLenum,
+        opt_data: Option<&[u8]>,
+    );
+    fn copy_tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLenum,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+    );
+    fn copy_tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    );
+    fn copy_tex_sub_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    );
+    fn tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        data: &[u8],
+    );
+    fn tex_sub_image_2d_pbo(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        offset: usize,
+    );
+    fn tex_sub_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        data: &[u8],
+    );
+    fn tex_sub_image_3d_pbo(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        offset: usize,
+    );
+    fn tex_storage_2d(
+        &self,
+        target: GLenum,
+        levels: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+    );
+    fn tex_storage_3d(
+        &self,
+        target: GLenum,
+        levels: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+    );
+    fn get_tex_image_into_buffer(
+        &self,
+        target: GLenum,
+        level: GLint,
+        format: GLenum,
+        ty: GLenum,
+        output: &mut [u8],
+    );
+    unsafe fn copy_image_sub_data(
+        &self,
+        src_name: GLuint,
+        src_target: GLenum,
+        src_level: GLint,
+        src_x: GLint,
+        src_y: GLint,
+        src_z: GLint,
+        dst_name: GLuint,
+        dst_target: GLenum,
+        dst_level: GLint,
+        dst_x: GLint,
+        dst_y: GLint,
+        dst_z: GLint,
+        src_width: GLsizei,
+        src_height: GLsizei,
+        src_depth: GLsizei,
+    );
+
+    fn invalidate_framebuffer(&self, target: GLenum, attachments: &[GLenum]);
+    fn invalidate_sub_framebuffer(
+        &self,
+        target: GLenum,
+        attachments: &[GLenum],
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    );
+
+    unsafe fn get_integer_v(&self, name: GLenum, result: &mut [GLint]);
+    unsafe fn get_integer_64v(&self, name: GLenum, result: &mut [GLint64]);
+    unsafe fn get_integer_iv(&self, name: GLenum, index: GLuint, result: &mut [GLint]);
+    unsafe fn get_integer_64iv(&self, name: GLenum, index: GLuint, result: &mut [GLint64]);
+    unsafe fn get_boolean_v(&self, name: GLenum, result: &mut [GLboolean]);
+    unsafe fn get_float_v(&self, name: GLenum, result: &mut [GLfloat]);
+
+    fn get_framebuffer_attachment_parameter_iv(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        pname: GLenum,
+    ) -> GLint;
+    fn get_renderbuffer_parameter_iv(&self, target: GLenum, pname: GLenum) -> GLint;
+    fn get_tex_parameter_iv(&self, target: GLenum, name: GLenum) -> GLint;
+    fn get_tex_parameter_fv(&self, target: GLenum, name: GLenum) -> GLfloat;
+    fn tex_parameter_i(&self, target: GLenum, pname: GLenum, param: GLint);
+    fn tex_parameter_f(&self, target: GLenum, pname: GLenum, param: GLfloat);
+    fn framebuffer_texture_2d(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        textarget: GLenum,
+        texture: GLuint,
+        level: GLint,
+    );
+    fn framebuffer_texture_layer(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        texture: GLuint,
+        level: GLint,
+        layer: GLint,
+    );
+    fn blit_framebuffer(
+        &self,
+        src_x0: GLint,
+        src_y0: GLint,
+        src_x1: GLint,
+        src_y1: GLint,
+        dst_x0: GLint,
+        dst_y0: GLint,
+        dst_x1: GLint,
+        dst_y1: GLint,
+        mask: GLbitfield,
+        filter: GLenum,
+    );
+    fn vertex_attrib_4f(&self, index: GLuint, x: GLfloat, y: GLfloat, z: GLfloat, w: GLfloat);
+    fn vertex_attrib_binding(&self, attrib_index: GLuint, binding_index: GLuint);
+    fn vertex_attrib_pointer_f32(
+        &self,
+        index: GLuint,
+        size: GLint,
+        normalized: bool,
+        stride: GLsizei,
+        offset: GLuint,
+    );
+    fn vertex_attrib_pointer(
+        &self,
+        index: GLuint,
+        size: GLint,
+        type_: GLenum,
+        normalized: bool,
+        stride: GLsizei,
+        offset: GLuint,
+    );
+    fn vertex_attrib_i_pointer(
+        &self,
+        index: GLuint,
+        size: GLint,
+        type_: GLenum,
+        stride: GLsizei,
+        offset: GLuint,
+    );
+    fn vertex_attrib_divisor(&self, index: GLuint, divisor: GLuint);
+    fn vertex_attrib_format(&self, attrib_index: GLuint, size: GLint, type_: GLenum, normalized: bool, relative_offset: GLuint);
+    fn vertex_attrib_i_format(&self, attrib_index: GLuint, size: GLint, type_: GLenum, relative_offset: GLuint);
+    fn vertex_binding_divisor(&self, binding_index: GLuint, divisor: GLuint);
+    fn viewport(&self, x: GLint, y: GLint, width: GLsizei, height: GLsizei);
+    fn scissor(&self, x: GLint, y: GLint, width: GLsizei, height: GLsizei);
+    fn line_width(&self, width: GLfloat);
+    fn use_program(&self, program: GLuint);
+    fn validate_program(&self, program: GLuint);
+    fn draw_arrays(&self, mode: GLenum, first: GLint, count: GLsizei);
+    fn draw_arrays_instanced(&self, mode: GLenum, first: GLint, count: GLsizei, primcount: GLsizei);
+    fn draw_elements(
+        &self,
+        mode: GLenum,
+        count: GLsizei,
+        element_type: GLenum,
+        indices_offset: GLuint,
+    );
+    fn draw_elements_instanced(
+        &self,
+        mode: GLenum,
+        count: GLsizei,
+        element_type: GLenum,
+        indices_offset: GLuint,
+        primcount: GLsizei,
+    );
+    fn blend_color(&self, r: f32, g: f32, b: f32, a: f32);
+    fn blend_func(&self, sfactor: GLenum, dfactor: GLenum);
+    fn blend_func_separate(
+        &self,
+        src_rgb: GLenum,
+        dest_rgb: GLenum,
+        src_alpha: GLenum,
+        dest_alpha: GLenum,
+    );
+    fn blend_equation(&self, mode: GLenum);
+    fn blend_equation_separate(&self, mode_rgb: GLenum, mode_alpha: GLenum);
+    fn color_mask(&self, r: bool, g: bool, b: bool, a: bool);
+    fn cull_face(&self, mode: GLenum);
+    fn front_face(&self, mode: GLenum);
+    fn enable(&self, cap: GLenum);
+    fn disable(&self, cap: GLenum);
+    fn hint(&self, param_name: GLenum, param_val: GLenum);
+    fn is_enabled(&self, cap: GLenum) -> GLboolean;
+    fn is_shader(&self, shader: GLuint) -> GLboolean;
+    fn is_texture(&self, texture: GLenum) -> GLboolean;
+    fn is_framebuffer(&self, framebuffer: GLenum) -> GLboolean;
+    fn is_renderbuffer(&self, renderbuffer: GLenum) -> GLboolean;
+    fn check_frame_buffer_status(&self, target: GLenum) -> GLenum;
+    fn enable_vertex_attrib_array(&self, index: GLuint);
+    fn disable_vertex_attrib_array(&self, index: GLuint);
+    fn uniform_1f(&self, location: GLint, v0: GLfloat);
+    fn uniform_1fv(&self, location: GLint, values: &[f32]);
+    fn uniform_1i(&self, location: GLint, v0: GLint);
+    fn uniform_1iv(&self, location: GLint, values: &[i32]);
+    fn uniform_1ui(&self, location: GLint, v0: GLuint);
+    fn uniform_2f(&self, location: GLint, v0: GLfloat, v1: GLfloat);
+    fn uniform_2fv(&self, location: GLint, values: &[f32]);
+    fn uniform_2i(&self, location: GLint, v0: GLint, v1: GLint);
+    fn uniform_2iv(&self, location: GLint, values: &[i32]);
+    fn uniform_2ui(&self, location: GLint, v0: GLuint, v1: GLuint);
+    fn uniform_3f(&self, location: GLint, v0: GLfloat, v1: GLfloat, v2: GLfloat);
+    fn uniform_3fv(&self, location: GLint, values: &[f32]);
+    fn uniform_3i(&self, location: GLint, v0: GLint, v1: GLint, v2: GLint);
+    fn uniform_3iv(&self, location: GLint, values: &[i32]);
+    fn uniform_3ui(&self, location: GLint, v0: GLuint, v1: GLuint, v2: GLuint);
+    fn uniform_4f(&self, location: GLint, x: GLfloat, y: GLfloat, z: GLfloat, w: GLfloat);
+    fn uniform_4i(&self, location: GLint, x: GLint, y: GLint, z: GLint, w: GLint);
+    fn uniform_4iv(&self, location: GLint, values: &[i32]);
+    fn uniform_4ui(&self, location: GLint, x: GLuint, y: GLuint, z: GLuint, w: GLuint);
+    fn uniform_4fv(&self, location: GLint, values: &[f32]);
+    fn uniform_matrix_2fv(&self, location: GLint, transpose: bool, value: &[f32]);
+    fn uniform_matrix_3fv(&self, location: GLint, transpose: bool, value: &[f32]);
+    fn uniform_matrix_4fv(&self, location: GLint, transpose: bool, value: &[f32]);
+    fn depth_mask(&self, flag: bool);
+    fn depth_range(&self, near: f64, far: f64);
+    fn get_active_attrib(&self, program: GLuint, index: GLuint) -> (i32, u32, String);
+    fn get_active_uniform(&self, program: GLuint, index: GLuint) -> (i32, u32, String);
+    fn get_active_uniforms_iv(
+        &self,
+        program: GLuint,
+        indices: Vec<GLuint>,
+        pname: GLenum,
+    ) -> Vec<GLint>;
+    fn get_active_uniform_block_i(&self, program: GLuint, index: GLuint, pname: GLenum) -> GLint;
+    fn get_active_uniform_block_iv(
+        &self,
+        program: GLuint,
+        index: GLuint,
+        pname: GLenum,
+    ) -> Vec<GLint>;
+    fn get_active_uniform_block_name(&self, program: GLuint, index: GLuint) -> String;
+    fn get_attrib_location(&self, program: GLuint, name: &str) -> c_int;
+    fn get_frag_data_location(&self, program: GLuint, name: &str) -> c_int;
+    fn get_uniform_location(&self, program: GLuint, name: &str) -> c_int;
+    fn get_program_info_log(&self, program: GLuint) -> String;
+    unsafe fn get_program_iv(&self, program: GLuint, pname: GLenum, result: &mut [GLint]);
+    fn get_program_binary(&self, program: GLuint) -> (Vec<u8>, GLenum);
+    fn program_binary(&self, program: GLuint, format: GLenum, binary: &[u8]);
+    fn program_parameter_i(&self, program: GLuint, pname: GLenum, value: GLint);
+    unsafe fn get_vertex_attrib_iv(&self, index: GLuint, pname: GLenum, result: &mut [GLint]);
+    unsafe fn get_vertex_attrib_fv(&self, index: GLuint, pname: GLenum, result: &mut [GLfloat]);
+    fn get_vertex_attrib_pointer_v(&self, index: GLuint, pname: GLenum) -> GLsizeiptr;
+    fn get_buffer_parameter_iv(&self, target: GLuint, pname: GLenum) -> GLint;
+    fn get_shader_info_log(&self, shader: GLuint) -> String;
+    fn get_string(&self, which: GLenum) -> String;
+    fn get_string_i(&self, which: GLenum, index: GLuint) -> String;
+    unsafe fn get_shader_iv(&self, shader: GLuint, pname: GLenum, result: &mut [GLint]);
+    fn get_shader_precision_format(
+        &self,
+        shader_type: GLuint,
+        precision_type: GLuint,
+    ) -> (GLint, GLint, GLint);
+    fn compile_shader(&self, shader: GLuint);
+    fn create_program(&self) -> GLuint;
+    fn delete_program(&self, program: GLuint);
+    fn create_shader(&self, shader_type: GLenum) -> GLuint;
+    fn delete_shader(&self, shader: GLuint);
+    fn detach_shader(&self, program: GLuint, shader: GLuint);
+    fn link_program(&self, program: GLuint);
+    fn clear_color(&self, r: f32, g: f32, b: f32, a: f32);
+    fn clear(&self, buffer_mask: GLbitfield);
+    fn clear_depth(&self, depth: f64);
+    fn clear_stencil(&self, s: GLint);
+    fn flush(&self);
+    fn finish(&self);
+    fn get_error(&self) -> GLenum;
+    fn stencil_mask(&self, mask: GLuint);
+    fn stencil_mask_separate(&self, face: GLenum, mask: GLuint);
+    fn stencil_func(&self, func: GLenum, ref_: GLint, mask: GLuint);
+    fn stencil_func_separate(&self, face: GLenum, func: GLenum, ref_: GLint, mask: GLuint);
+    fn stencil_op(&self, sfail: GLenum, dpfail: GLenum, dppass: GLenum);
+    fn stencil_op_separate(&self, face: GLenum, sfail: GLenum, dpfail: GLenum, dppass: GLenum);
+    fn egl_image_target_texture2d_oes(&self, target: GLenum, image: GLeglImageOES);
+    fn egl_image_target_renderbuffer_storage_oes(&self, target: GLenum, image: GLeglImageOES);
+    fn generate_mipmap(&self, target: GLenum);
+    fn insert_event_marker_ext(&self, message: &str);
+    fn push_group_marker_ext(&self, message: &str);
+    fn pop_group_marker_ext(&self);
+    fn debug_message_insert_khr(
+        &self,
+        source: GLenum,
+        type_: GLenum,
+        id: GLuint,
+        severity: GLenum,
+        message: &str,
+    );
+    fn push_debug_group_khr(&self, source: GLenum, id: GLuint, message: &str);
+    fn pop_debug_group_khr(&self);
+    fn fence_sync(&self, condition: GLenum, flags: GLbitfield) -> GLsync;
+    fn client_wait_sync(&self, sync: GLsync, flags: GLbitfield, timeout: GLuint64) -> GLenum;
+    fn wait_sync(&self, sync: GLsync, flags: GLbitfield, timeout: GLuint64);
+    fn delete_sync(&self, sync: GLsync);
+    fn texture_range_apple(&self, target: GLenum, data: &[u8]);
+    fn gen_fences_apple(&self, n: GLsizei) -> Vec<GLuint>;
+    fn delete_fences_apple(&self, fences: &[GLuint]);
+    fn set_fence_apple(&self, fence: GLuint);
+    fn finish_fence_apple(&self, fence: GLuint);
+    fn test_fence_apple(&self, fence: GLuint);
+    fn test_object_apple(&self, object: GLenum, name: GLuint) -> GLboolean;
+    fn finish_object_apple(&self, object: GLenum, name: GLuint);
+    // GL_KHR_blend_equation_advanced
+    fn blend_barrier_khr(&self);
+
+    // GL_ARB_blend_func_extended
+    fn bind_frag_data_location_indexed(
+        &self,
+        program: GLuint,
+        color_number: GLuint,
+        index: GLuint,
+        name: &str,
+    );
+    fn get_frag_data_index(&self, program: GLuint, name: &str) -> GLint;
+
+    // GL_KHR_debug
+    fn get_debug_messages(&self) -> Vec<DebugMessage>;
+
+    // GL_ANGLE_provoking_vertex
+    fn provoking_vertex_angle(&self, mode: GLenum);
+
+    // GL_CHROMIUM_copy_texture
+    fn copy_texture_chromium(
+        &self,
+        source_id: GLuint,
+        source_level: GLint,
+        dest_target: GLenum,
+        dest_id: GLuint,
+        dest_level: GLint,
+        internal_format: GLint,
+        dest_type: GLenum,
+        unpack_flip_y: GLboolean,
+        unpack_premultiply_alpha: GLboolean,
+        unpack_unmultiply_alpha: GLboolean,
+    );
+    fn copy_sub_texture_chromium(
+        &self,
+        source_id: GLuint,
+        source_level: GLint,
+        dest_target: GLenum,
+        dest_id: GLuint,
+        dest_level: GLint,
+        x_offset: GLint,
+        y_offset: GLint,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        unpack_flip_y: GLboolean,
+        unpack_premultiply_alpha: GLboolean,
+        unpack_unmultiply_alpha: GLboolean,
+    );
+
+    // GL_ANGLE_copy_texture_3d
+    fn copy_texture_3d_angle(
+        &self,
+        source_id: GLuint,
+        source_level: GLint,
+        dest_target: GLenum,
+        dest_id: GLuint,
+        dest_level: GLint,
+        internal_format: GLint,
+        dest_type: GLenum,
+        unpack_flip_y: GLboolean,
+        unpack_premultiply_alpha: GLboolean,
+        unpack_unmultiply_alpha: GLboolean,
+    );
+
+    fn copy_sub_texture_3d_angle(
+        &self,
+        source_id: GLuint,
+        source_level: GLint,
+        dest_target: GLenum,
+        dest_id: GLuint,
+        dest_level: GLint,
+        x_offset: GLint,
+        y_offset: GLint,
+        z_offset: GLint,
+        x: GLint,
+        y: GLint,
+        z: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        unpack_flip_y: GLboolean,
+        unpack_premultiply_alpha: GLboolean,
+        unpack_unmultiply_alpha: GLboolean,
+    );
+
+    fn buffer_storage(
+        &self,
+        target: GLenum,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+        flags: GLbitfield,
+    );
+
+    fn flush_mapped_buffer_range(&self, target: GLenum, offset: GLintptr, length: GLsizeiptr);
+
+    fn start_tiling_qcom(&self, x: GLuint, y: GLuint, width: GLuint, height: GLuint, preserve_mask: GLbitfield);
+    fn end_tiling_qcom(&self, preserve_mask: GLbitfield);
+}
+
+//#[deprecated(since = "0.6.11", note = "use ErrorReactingGl instead")]
+pub struct ErrorCheckingGl {
+    gl: Rc<dyn Gl>,
+}
+
+impl ErrorCheckingGl {
+    pub fn wrap(fns: Rc<dyn Gl>) -> Rc<dyn Gl> {
+        Rc::new(ErrorCheckingGl { gl: fns }) as Rc<dyn Gl>
+    }
+}
+
+/// A wrapper around GL context that calls a specified callback on each GL error.
+pub struct ErrorReactingGl<F> {
+    gl: Rc<dyn Gl>,
+    callback: F,
+}
+
+impl<F: 'static + Fn(&dyn Gl, &str, GLenum)> ErrorReactingGl<F> {
+    pub fn wrap(fns: Rc<dyn Gl>, callback: F) -> Rc<dyn Gl> {
+        Rc::new(ErrorReactingGl { gl: fns, callback }) as Rc<dyn Gl>
+    }
+}
+
+/// A wrapper around GL context that times each call and invokes the callback
+/// if the call takes longer than the threshold.
+pub struct ProfilingGl<F> {
+    gl: Rc<dyn Gl>,
+    threshold: Duration,
+    callback: F,
+}
+
+impl<F: 'static + Fn(&str, Duration)> ProfilingGl<F> {
+    pub fn wrap(fns: Rc<dyn Gl>, threshold: Duration, callback: F) -> Rc<dyn Gl> {
+        Rc::new(ProfilingGl {
+            gl: fns,
+            threshold,
+            callback,
+        }) as Rc<dyn Gl>
+    }
+}
+
+#[inline]
+pub fn buffer_data<T>(gl_: &dyn Gl, target: GLenum, data: &[T], usage: GLenum) {
+    gl_.buffer_data_untyped(
+        target,
+        (data.len() * size_of::<T>()) as GLsizeiptr,
+        data.as_ptr() as *const GLvoid,
+        usage,
+    )
+}
+
+#[inline]
+pub fn buffer_data_raw<T>(gl_: &dyn Gl, target: GLenum, data: &T, usage: GLenum) {
+    gl_.buffer_data_untyped(
+        target,
+        size_of::<T>() as GLsizeiptr,
+        data as *const T as *const GLvoid,
+        usage,
+    )
+}
+
+#[inline]
+pub fn buffer_sub_data<T>(gl_: &dyn Gl, target: GLenum, offset: isize, data: &[T]) {
+    gl_.buffer_sub_data_untyped(
+        target,
+        offset,
+        (data.len() * size_of::<T>()) as GLsizeiptr,
+        data.as_ptr() as *const GLvoid,
+    );
+}
+
+include!("gl_fns.rs");
+include!("gles_fns.rs");
diff --git a/third_party/rust/gleam/src/gl_fns.rs b/third_party/rust/gleam/src/gl_fns.rs
new file mode 100644
index 0000000000..8e00c7e563
--- /dev/null
+++ b/third_party/rust/gleam/src/gl_fns.rs
@@ -0,0 +1,2293 @@
+// Copyright 2014 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub struct GlFns {
+    ffi_gl_: GlFfi,
+}
+
+impl GlFns {
+    pub unsafe fn load_with<'a, F>(loadfn: F) -> Rc<dyn Gl>
+    where
+        F: FnMut(&str) -> *const c_void,
+    {
+        let ffi_gl_ = GlFfi::load_with(loadfn);
+        Rc::new(GlFns { ffi_gl_: ffi_gl_ }) as Rc<dyn Gl>
+    }
+}
+
+impl Gl for GlFns {
+    fn get_type(&self) -> GlType {
+        GlType::Gl
+    }
+
+    fn buffer_data_untyped(
+        &self,
+        target: GLenum,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+        usage: GLenum,
+    ) {
+        unsafe {
+            self.ffi_gl_.BufferData(target, size, data, usage);
+        }
+    }
+
+    fn buffer_sub_data_untyped(
+        &self,
+        target: GLenum,
+        offset: isize,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+    ) {
+        unsafe {
+            self.ffi_gl_.BufferSubData(target, offset, size, data);
+        }
+    }
+
+    fn map_buffer(&self,
+                  target: GLenum,
+                  access: GLbitfield) -> *mut c_void {
+        unsafe {
+            return self.ffi_gl_.MapBuffer(target, access);
+        }
+    }
+
+    fn map_buffer_range(&self,
+                        target: GLenum,
+                        offset: GLintptr,
+                        length: GLsizeiptr,
+                        access: GLbitfield) -> *mut c_void {
+        unsafe {
+            return self.ffi_gl_.MapBufferRange(target, offset, length, access);
+        }
+    }
+
+    fn unmap_buffer(&self, target: GLenum) -> GLboolean {
+        unsafe {
+            return self.ffi_gl_.UnmapBuffer(target);
+        }
+    }
+
+    fn shader_source(&self, shader: GLuint, strings: &[&[u8]]) {
+        let pointers: Vec<*const u8> = strings.iter().map(|string| (*string).as_ptr()).collect();
+        let lengths: Vec<GLint> = strings.iter().map(|string| string.len() as GLint).collect();
+        unsafe {
+            self.ffi_gl_.ShaderSource(
+                shader,
+                pointers.len() as GLsizei,
+                pointers.as_ptr() as *const *const GLchar,
+                lengths.as_ptr(),
+            );
+        }
+        drop(lengths);
+        drop(pointers);
+    }
+
+    fn tex_buffer(&self, target: GLenum, internal_format: GLenum, buffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.TexBuffer(target, internal_format, buffer);
+        }
+    }
+
+    fn read_buffer(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.ReadBuffer(mode);
+        }
+    }
+
+    fn read_pixels_into_buffer(
+        &self,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        pixel_type: GLenum,
+        dst_buffer: &mut [u8],
+    ) {
+        // Assumes that the user properly allocated the size for dst_buffer.
+        let mut row_length = 0;
+        unsafe {
+            self.ffi_gl_.GetIntegerv(ffi::PACK_ROW_LENGTH, &mut row_length as _);
+        }
+        if row_length == 0 {
+            row_length = width;
+        } else {
+            assert!(row_length >= width);
+        }
+        assert_eq!(calculate_length(row_length, height, format, pixel_type), dst_buffer.len());
+
+        unsafe {
+            // We don't want any alignment padding on pixel rows.
+            self.ffi_gl_.PixelStorei(ffi::PACK_ALIGNMENT, 1);
+            self.ffi_gl_.ReadPixels(
+                x,
+                y,
+                width,
+                height,
+                format,
+                pixel_type,
+                dst_buffer.as_mut_ptr() as *mut c_void,
+            );
+        }
+    }
+
+    fn read_pixels(
+        &self,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        pixel_type: GLenum,
+    ) -> Vec<u8> {
+        let len = calculate_length(width, height, format, pixel_type);
+        let mut pixels: Vec<u8> = Vec::new();
+        pixels.reserve(len);
+        unsafe {
+            pixels.set_len(len);
+        }
+
+        self.read_pixels_into_buffer(
+            x,
+            y,
+            width,
+            height,
+            format,
+            pixel_type,
+            pixels.as_mut_slice(),
+        );
+
+        pixels
+    }
+
+    unsafe fn read_pixels_into_pbo(&self,
+                            x: GLint,
+                            y: GLint,
+                            width: GLsizei,
+                            height: GLsizei,
+                            format: GLenum,
+                            pixel_type: GLenum) {
+        self.ffi_gl_.ReadPixels(x, y, width, height, format, pixel_type, ptr::null_mut());
+    }
+
+    fn sample_coverage(&self, value: GLclampf, invert: bool) {
+        unsafe {
+            self.ffi_gl_.SampleCoverage(value, invert as GLboolean);
+        }
+    }
+
+    fn polygon_offset(&self, factor: GLfloat, units: GLfloat) {
+        unsafe {
+            self.ffi_gl_.PolygonOffset(factor, units);
+        }
+    }
+
+    fn pixel_store_i(&self, name: GLenum, param: GLint) {
+        unsafe {
+            self.ffi_gl_.PixelStorei(name, param);
+        }
+    }
+
+    fn gen_buffers(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenBuffers(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_renderbuffers(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenRenderbuffers(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_framebuffers(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenFramebuffers(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_textures(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenTextures(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_vertex_arrays(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenVertexArrays(n, result.as_mut_ptr())
+        }
+        result
+    }
+
+    fn gen_vertex_arrays_apple(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenVertexArraysAPPLE(n, result.as_mut_ptr())
+        }
+        result
+    }
+
+    fn gen_queries(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenQueries(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn begin_query(&self, target: GLenum, id: GLuint) {
+        unsafe {
+            self.ffi_gl_.BeginQuery(target, id);
+        }
+    }
+
+    fn end_query(&self, target: GLenum) {
+        unsafe {
+            self.ffi_gl_.EndQuery(target);
+        }
+    }
+
+    fn query_counter(&self, id: GLuint, target: GLenum) {
+        unsafe {
+            self.ffi_gl_.QueryCounter(id, target);
+        }
+    }
+
+    fn get_query_object_iv(&self, id: GLuint, pname: GLenum) -> i32 {
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjectiv(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_query_object_uiv(&self, id: GLuint, pname: GLenum) -> u32 {
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjectuiv(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_query_object_i64v(&self, id: GLuint, pname: GLenum) -> i64 {
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjecti64v(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_query_object_ui64v(&self, id: GLuint, pname: GLenum) -> u64 {
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjectui64v(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn delete_queries(&self, queries: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteQueries(queries.len() as GLsizei, queries.as_ptr());
+        }
+    }
+
+    fn delete_vertex_arrays(&self, vertex_arrays: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteVertexArrays(vertex_arrays.len() as GLsizei, vertex_arrays.as_ptr());
+        }
+    }
+
+    fn delete_vertex_arrays_apple(&self, vertex_arrays: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteVertexArraysAPPLE(vertex_arrays.len() as GLsizei, vertex_arrays.as_ptr());
+        }
+    }
+
+    fn delete_buffers(&self, buffers: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteBuffers(buffers.len() as GLsizei, buffers.as_ptr());
+        }
+    }
+
+    fn delete_renderbuffers(&self, renderbuffers: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteRenderbuffers(renderbuffers.len() as GLsizei, renderbuffers.as_ptr());
+        }
+    }
+
+    fn delete_framebuffers(&self, framebuffers: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteFramebuffers(framebuffers.len() as GLsizei, framebuffers.as_ptr());
+        }
+    }
+
+    fn delete_textures(&self, textures: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteTextures(textures.len() as GLsizei, textures.as_ptr());
+        }
+    }
+
+    fn framebuffer_renderbuffer(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        renderbuffertarget: GLenum,
+        renderbuffer: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_.FramebufferRenderbuffer(
+                target,
+                attachment,
+                renderbuffertarget,
+                renderbuffer,
+            );
+        }
+    }
+
+    fn renderbuffer_storage(
+        &self,
+        target: GLenum,
+        internalformat: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .RenderbufferStorage(target, internalformat, width, height);
+        }
+    }
+
+    fn depth_func(&self, func: GLenum) {
+        unsafe {
+            self.ffi_gl_.DepthFunc(func);
+        }
+    }
+
+    fn active_texture(&self, texture: GLenum) {
+        unsafe {
+            self.ffi_gl_.ActiveTexture(texture);
+        }
+    }
+
+    fn attach_shader(&self, program: GLuint, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.AttachShader(program, shader);
+        }
+    }
+
+    fn bind_attrib_location(&self, program: GLuint, index: GLuint, name: &str) {
+        let c_string = CString::new(name).unwrap();
+        unsafe {
+            self.ffi_gl_
+                .BindAttribLocation(program, index, c_string.as_ptr())
+        }
+    }
+
+    // https://www.khronos.org/registry/OpenGL-Refpages/es2.0/xhtml/glGetUniform.xml
+    unsafe fn get_uniform_iv(&self, program: GLuint, location: GLint, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetUniformiv(program, location, result.as_mut_ptr());
+    }
+
+    // https://www.khronos.org/registry/OpenGL-Refpages/es2.0/xhtml/glGetUniform.xml
+    unsafe fn get_uniform_fv(&self, program: GLuint, location: GLint, result: &mut [GLfloat]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetUniformfv(program, location, result.as_mut_ptr());
+    }
+
+    fn get_uniform_block_index(&self, program: GLuint, name: &str) -> GLuint {
+        let c_string = CString::new(name).unwrap();
+        unsafe {
+            self.ffi_gl_
+                .GetUniformBlockIndex(program, c_string.as_ptr())
+        }
+    }
+
+    fn get_uniform_indices(&self, program: GLuint, names: &[&str]) -> Vec<GLuint> {
+        let c_strings: Vec<CString> = names.iter().map(|n| CString::new(*n).unwrap()).collect();
+        let pointers: Vec<*const GLchar> = c_strings.iter().map(|string| string.as_ptr()).collect();
+        let mut result = Vec::with_capacity(c_strings.len());
+        unsafe {
+            result.set_len(c_strings.len());
+            self.ffi_gl_.GetUniformIndices(
+                program,
+                pointers.len() as GLsizei,
+                pointers.as_ptr(),
+                result.as_mut_ptr(),
+            );
+        }
+        result
+    }
+
+    fn bind_buffer_base(&self, target: GLenum, index: GLuint, buffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindBufferBase(target, index, buffer);
+        }
+    }
+
+    fn bind_buffer_range(
+        &self,
+        target: GLenum,
+        index: GLuint,
+        buffer: GLuint,
+        offset: GLintptr,
+        size: GLsizeiptr,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .BindBufferRange(target, index, buffer, offset, size);
+        }
+    }
+
+    fn uniform_block_binding(
+        &self,
+        program: GLuint,
+        uniform_block_index: GLuint,
+        uniform_block_binding: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .UniformBlockBinding(program, uniform_block_index, uniform_block_binding);
+        }
+    }
+
+    fn bind_buffer(&self, target: GLenum, buffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindBuffer(target, buffer);
+        }
+    }
+
+    fn bind_vertex_array(&self, vao: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindVertexArray(vao);
+        }
+    }
+
+    fn bind_vertex_array_apple(&self, vao: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindVertexArrayAPPLE(vao)
+        }
+    }
+
+    fn bind_renderbuffer(&self, target: GLenum, renderbuffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindRenderbuffer(target, renderbuffer);
+        }
+    }
+
+    fn bind_framebuffer(&self, target: GLenum, framebuffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindFramebuffer(target, framebuffer);
+        }
+    }
+
+    fn bind_texture(&self, target: GLenum, texture: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindTexture(target, texture);
+        }
+    }
+
+    fn bind_vertex_buffer(&self, binding_index: GLuint, buffer: GLuint, offset: GLintptr, stride: GLint) {
+        unsafe { self.ffi_gl_.BindVertexBuffer(binding_index, buffer, offset, stride) }
+    }
+
+    fn draw_buffers(&self, bufs: &[GLenum]) {
+        unsafe {
+            self.ffi_gl_
+                .DrawBuffers(bufs.len() as GLsizei, bufs.as_ptr());
+        }
+    }
+
+    // FIXME: Does not verify buffer size -- unsafe!
+    fn tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+        format: GLenum,
+        ty: GLenum,
+        opt_data: Option<&[u8]>,
+    ) {
+        match opt_data {
+            Some(data) => unsafe {
+                self.ffi_gl_.TexImage2D(
+                    target,
+                    level,
+                    internal_format,
+                    width,
+                    height,
+                    border,
+                    format,
+                    ty,
+                    data.as_ptr() as *const GLvoid,
+                );
+            },
+            None => unsafe {
+                self.ffi_gl_.TexImage2D(
+                    target,
+                    level,
+                    internal_format,
+                    width,
+                    height,
+                    border,
+                    format,
+                    ty,
+                    ptr::null(),
+                );
+            },
+        }
+    }
+
+    fn compressed_tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.CompressedTexImage2D(
+                target,
+                level,
+                internal_format,
+                width,
+                height,
+                border,
+                data.len() as GLsizei,
+                data.as_ptr() as *const GLvoid,
+            );
+        }
+    }
+
+    fn compressed_tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.CompressedTexSubImage2D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                width,
+                height,
+                format,
+                data.len() as GLsizei,
+                data.as_ptr() as *const GLvoid,
+            );
+        }
+    }
+
+    // FIXME: Does not verify buffer size -- unsafe!
+    fn tex_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        border: GLint,
+        format: GLenum,
+        ty: GLenum,
+        opt_data: Option<&[u8]>,
+    ) {
+        unsafe {
+            let pdata = match opt_data {
+                Some(data) => mem::transmute(data.as_ptr()),
+                None => ptr::null(),
+            };
+            self.ffi_gl_.TexImage3D(
+                target,
+                level,
+                internal_format,
+                width,
+                height,
+                depth,
+                border,
+                format,
+                ty,
+                pdata,
+            );
+        }
+    }
+
+    fn copy_tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLenum,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+    ) {
+        unsafe {
+            self.ffi_gl_.CopyTexImage2D(
+                target,
+                level,
+                internal_format,
+                x,
+                y,
+                width,
+                height,
+                border,
+            );
+        }
+    }
+
+    fn copy_tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .CopyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
+        }
+    }
+
+    fn copy_tex_sub_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_.CopyTexSubImage3D(
+                target, level, xoffset, yoffset, zoffset, x, y, width, height,
+            );
+        }
+    }
+
+    fn tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage2D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                width,
+                height,
+                format,
+                ty,
+                data.as_ptr() as *const c_void,
+            );
+        }
+    }
+
+    fn tex_sub_image_2d_pbo(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        offset: usize,
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage2D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                width,
+                height,
+                format,
+                ty,
+                offset as *const c_void,
+            );
+        }
+    }
+
+    fn tex_sub_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage3D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                zoffset,
+                width,
+                height,
+                depth,
+                format,
+                ty,
+                data.as_ptr() as *const c_void,
+            );
+        }
+    }
+
+    fn tex_sub_image_3d_pbo(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        offset: usize,
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage3D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                zoffset,
+                width,
+                height,
+                depth,
+                format,
+                ty,
+                offset as *const c_void,
+            );
+        }
+    }
+
+    fn tex_storage_2d(
+        &self,
+        target: GLenum,
+        levels: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        if self.ffi_gl_.TexStorage2D.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .TexStorage2D(target, levels, internal_format, width, height);
+            }
+        }
+    }
+
+    fn tex_storage_3d(
+        &self,
+        target: GLenum,
+        levels: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+    ) {
+        if self.ffi_gl_.TexStorage3D.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .TexStorage3D(target, levels, internal_format, width, height, depth);
+            }
+        }
+    }
+
+    fn get_tex_image_into_buffer(
+        &self,
+        target: GLenum,
+        level: GLint,
+        format: GLenum,
+        ty: GLenum,
+        output: &mut [u8],
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .GetTexImage(target, level, format, ty, output.as_mut_ptr() as *mut _);
+        }
+    }
+
+    unsafe fn copy_image_sub_data(
+        &self,
+        src_name: GLuint,
+        src_target: GLenum,
+        src_level: GLint,
+        src_x: GLint,
+        src_y: GLint,
+        src_z: GLint,
+        dst_name: GLuint,
+        dst_target: GLenum,
+        dst_level: GLint,
+        dst_x: GLint,
+        dst_y: GLint,
+        dst_z: GLint,
+        src_width: GLsizei,
+        src_height: GLsizei,
+        src_depth: GLsizei,
+    ) {
+        self.ffi_gl_.CopyImageSubData(
+            src_name, src_target, src_level, src_x, src_y, src_z, dst_name, dst_target, dst_level,
+            dst_x, dst_y, dst_z, src_width, src_height, src_depth,
+        );
+    }
+
+    fn invalidate_framebuffer(&self, target: GLenum, attachments: &[GLenum]) {
+        if self.ffi_gl_.InvalidateFramebuffer.is_loaded() {
+            unsafe {
+                self.ffi_gl_.InvalidateFramebuffer(
+                    target,
+                    attachments.len() as GLsizei,
+                    attachments.as_ptr(),
+                );
+            }
+        }
+    }
+
+    fn invalidate_sub_framebuffer(
+        &self,
+        target: GLenum,
+        attachments: &[GLenum],
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        if self.ffi_gl_.InvalidateSubFramebuffer.is_loaded() {
+            unsafe {
+                self.ffi_gl_.InvalidateSubFramebuffer(
+                    target,
+                    attachments.len() as GLsizei,
+                    attachments.as_ptr(),
+                    xoffset,
+                    yoffset,
+                    width,
+                    height,
+                );
+            }
+        }
+    }
+
+    #[inline]
+    unsafe fn get_integer_v(&self, name: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetIntegerv(name, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_integer_64v(&self, name: GLenum, result: &mut [GLint64]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetInteger64v(name, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_integer_iv(&self, name: GLenum, index: GLuint, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetIntegeri_v(name, index, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_integer_64iv(&self, name: GLenum, index: GLuint, result: &mut [GLint64]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetInteger64i_v(name, index, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_boolean_v(&self, name: GLenum, result: &mut [GLboolean]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetBooleanv(name, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_float_v(&self, name: GLenum, result: &mut [GLfloat]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetFloatv(name, result.as_mut_ptr());
+    }
+
+    fn get_framebuffer_attachment_parameter_iv(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        pname: GLenum,
+    ) -> GLint {
+        let mut result: GLint = 0;
+        unsafe {
+            self.ffi_gl_.GetFramebufferAttachmentParameteriv(
+                target,
+                attachment,
+                pname,
+                &mut result,
+            );
+        }
+        result
+    }
+
+    fn get_renderbuffer_parameter_iv(&self, target: GLenum, pname: GLenum) -> GLint {
+        let mut result: GLint = 0;
+        unsafe {
+            self.ffi_gl_
+                .GetRenderbufferParameteriv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_tex_parameter_iv(&self, target: GLenum, pname: GLenum) -> GLint {
+        let mut result: GLint = 0;
+        unsafe {
+            self.ffi_gl_.GetTexParameteriv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_tex_parameter_fv(&self, target: GLenum, pname: GLenum) -> GLfloat {
+        let mut result: GLfloat = 0.0;
+        unsafe {
+            self.ffi_gl_.GetTexParameterfv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn tex_parameter_i(&self, target: GLenum, pname: GLenum, param: GLint) {
+        unsafe {
+            self.ffi_gl_.TexParameteri(target, pname, param);
+        }
+    }
+
+    fn tex_parameter_f(&self, target: GLenum, pname: GLenum, param: GLfloat) {
+        unsafe {
+            self.ffi_gl_.TexParameterf(target, pname, param);
+        }
+    }
+
+    fn framebuffer_texture_2d(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        textarget: GLenum,
+        texture: GLuint,
+        level: GLint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .FramebufferTexture2D(target, attachment, textarget, texture, level);
+        }
+    }
+
+    fn framebuffer_texture_layer(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        texture: GLuint,
+        level: GLint,
+        layer: GLint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .FramebufferTextureLayer(target, attachment, texture, level, layer);
+        }
+    }
+
+    fn blit_framebuffer(
+        &self,
+        src_x0: GLint,
+        src_y0: GLint,
+        src_x1: GLint,
+        src_y1: GLint,
+        dst_x0: GLint,
+        dst_y0: GLint,
+        dst_x1: GLint,
+        dst_y1: GLint,
+        mask: GLbitfield,
+        filter: GLenum,
+    ) {
+        unsafe {
+            self.ffi_gl_.BlitFramebuffer(
+                src_x0, src_y0, src_x1, src_y1, dst_x0, dst_y0, dst_x1, dst_y1, mask, filter,
+            );
+        }
+    }
+
+    fn vertex_attrib_4f(&self, index: GLuint, x: GLfloat, y: GLfloat, z: GLfloat, w: GLfloat) {
+        unsafe { self.ffi_gl_.VertexAttrib4f(index, x, y, z, w) }
+    }
+
+    fn vertex_attrib_binding(&self, attrib_index: GLuint, binding_index: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribBinding(attrib_index, binding_index) }
+    }
+
+    fn vertex_attrib_pointer_f32(
+        &self,
+        index: GLuint,
+        size: GLint,
+        normalized: bool,
+        stride: GLsizei,
+        offset: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_.VertexAttribPointer(
+                index,
+                size,
+                ffi::FLOAT,
+                normalized as GLboolean,
+                stride,
+                offset as *const GLvoid,
+            )
+        }
+    }
+
+    fn vertex_attrib_pointer(
+        &self,
+        index: GLuint,
+        size: GLint,
+        type_: GLenum,
+        normalized: bool,
+        stride: GLsizei,
+        offset: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_.VertexAttribPointer(
+                index,
+                size,
+                type_,
+                normalized as GLboolean,
+                stride,
+                offset as *const GLvoid,
+            )
+        }
+    }
+
+    fn vertex_attrib_i_pointer(
+        &self,
+        index: GLuint,
+        size: GLint,
+        type_: GLenum,
+        stride: GLsizei,
+        offset: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .VertexAttribIPointer(index, size, type_, stride, offset as *const GLvoid)
+        }
+    }
+
+    fn vertex_attrib_divisor(&self, index: GLuint, divisor: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribDivisor(index, divisor) }
+    }
+
+    fn vertex_attrib_format(&self, attrib_index: GLuint, size: GLint, type_: GLenum, normalized: bool, relative_offset: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribFormat(attrib_index, size, type_, normalized as GLboolean, relative_offset) }
+    }
+
+    fn vertex_attrib_i_format(&self, attrib_index: GLuint, size: GLint, type_: GLenum, relative_offset: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribIFormat(attrib_index, size, type_, relative_offset) }
+    }
+
+    fn vertex_binding_divisor(&self, binding_index: GLuint, divisor: GLuint) {
+        unsafe { self.ffi_gl_.VertexBindingDivisor(binding_index, divisor) }
+    }
+
+    fn viewport(&self, x: GLint, y: GLint, width: GLsizei, height: GLsizei) {
+        unsafe {
+            self.ffi_gl_.Viewport(x, y, width, height);
+        }
+    }
+
+    fn scissor(&self, x: GLint, y: GLint, width: GLsizei, height: GLsizei) {
+        unsafe {
+            self.ffi_gl_.Scissor(x, y, width, height);
+        }
+    }
+
+    fn line_width(&self, width: GLfloat) {
+        unsafe {
+            self.ffi_gl_.LineWidth(width);
+        }
+    }
+
+    fn use_program(&self, program: GLuint) {
+        unsafe {
+            self.ffi_gl_.UseProgram(program);
+        }
+    }
+
+    fn validate_program(&self, program: GLuint) {
+        unsafe {
+            self.ffi_gl_.ValidateProgram(program);
+        }
+    }
+
+    fn draw_arrays(&self, mode: GLenum, first: GLint, count: GLsizei) {
+        unsafe {
+            return self.ffi_gl_.DrawArrays(mode, first, count);
+        }
+    }
+
+    fn draw_arrays_instanced(
+        &self,
+        mode: GLenum,
+        first: GLint,
+        count: GLsizei,
+        primcount: GLsizei,
+    ) {
+        unsafe {
+            return self
+                .ffi_gl_
+                .DrawArraysInstanced(mode, first, count, primcount);
+        }
+    }
+
+    fn draw_elements(
+        &self,
+        mode: GLenum,
+        count: GLsizei,
+        element_type: GLenum,
+        indices_offset: GLuint,
+    ) {
+        unsafe {
+            return self.ffi_gl_.DrawElements(
+                mode,
+                count,
+                element_type,
+                indices_offset as *const c_void,
+            );
+        }
+    }
+
+    fn draw_elements_instanced(
+        &self,
+        mode: GLenum,
+        count: GLsizei,
+        element_type: GLenum,
+        indices_offset: GLuint,
+        primcount: GLsizei,
+    ) {
+        unsafe {
+            return self.ffi_gl_.DrawElementsInstanced(
+                mode,
+                count,
+                element_type,
+                indices_offset as *const c_void,
+                primcount,
+            );
+        }
+    }
+
+    fn blend_color(&self, r: f32, g: f32, b: f32, a: f32) {
+        unsafe {
+            self.ffi_gl_.BlendColor(r, g, b, a);
+        }
+    }
+
+    fn blend_func(&self, sfactor: GLenum, dfactor: GLenum) {
+        unsafe {
+            self.ffi_gl_.BlendFunc(sfactor, dfactor);
+        }
+    }
+
+    fn blend_func_separate(
+        &self,
+        src_rgb: GLenum,
+        dest_rgb: GLenum,
+        src_alpha: GLenum,
+        dest_alpha: GLenum,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .BlendFuncSeparate(src_rgb, dest_rgb, src_alpha, dest_alpha);
+        }
+    }
+
+    fn blend_equation(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.BlendEquation(mode);
+        }
+    }
+
+    fn blend_equation_separate(&self, mode_rgb: GLenum, mode_alpha: GLenum) {
+        unsafe {
+            self.ffi_gl_.BlendEquationSeparate(mode_rgb, mode_alpha);
+        }
+    }
+
+    fn color_mask(&self, r: bool, g: bool, b: bool, a: bool) {
+        unsafe {
+            self.ffi_gl_.ColorMask(
+                r as GLboolean,
+                g as GLboolean,
+                b as GLboolean,
+                a as GLboolean,
+            );
+        }
+    }
+
+    fn cull_face(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.CullFace(mode);
+        }
+    }
+
+    fn front_face(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.FrontFace(mode);
+        }
+    }
+
+    fn enable(&self, cap: GLenum) {
+        unsafe {
+            self.ffi_gl_.Enable(cap);
+        }
+    }
+
+    fn disable(&self, cap: GLenum) {
+        unsafe {
+            self.ffi_gl_.Disable(cap);
+        }
+    }
+
+    fn hint(&self, param_name: GLenum, param_val: GLenum) {
+        unsafe {
+            self.ffi_gl_.Hint(param_name, param_val);
+        }
+    }
+
+    fn is_enabled(&self, cap: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsEnabled(cap) }
+    }
+
+    fn is_shader(&self, shader: GLuint) -> GLboolean {
+        unsafe { self.ffi_gl_.IsShader(shader) }
+    }
+
+    fn is_texture(&self, texture: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsTexture(texture) }
+    }
+
+    fn is_framebuffer(&self, framebuffer: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsFramebuffer(framebuffer) }
+    }
+
+    fn is_renderbuffer(&self, renderbuffer: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsRenderbuffer(renderbuffer) }
+    }
+
+    fn check_frame_buffer_status(&self, target: GLenum) -> GLenum {
+        unsafe { self.ffi_gl_.CheckFramebufferStatus(target) }
+    }
+
+    fn enable_vertex_attrib_array(&self, index: GLuint) {
+        unsafe {
+            self.ffi_gl_.EnableVertexAttribArray(index);
+        }
+    }
+
+    fn disable_vertex_attrib_array(&self, index: GLuint) {
+        unsafe {
+            self.ffi_gl_.DisableVertexAttribArray(index);
+        }
+    }
+
+    fn uniform_1f(&self, location: GLint, v0: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform1f(location, v0);
+        }
+    }
+
+    fn uniform_1fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform1fv(location, values.len() as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_1i(&self, location: GLint, v0: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform1i(location, v0);
+        }
+    }
+
+    fn uniform_1iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform1iv(location, values.len() as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_1ui(&self, location: GLint, v0: GLuint) {
+        unsafe {
+            self.ffi_gl_.Uniform1ui(location, v0);
+        }
+    }
+
+    fn uniform_2f(&self, location: GLint, v0: GLfloat, v1: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform2f(location, v0, v1);
+        }
+    }
+
+    fn uniform_2fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform2fv(location, (values.len() / 2) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_2i(&self, location: GLint, v0: GLint, v1: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform2i(location, v0, v1);
+        }
+    }
+
+    fn uniform_2iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform2iv(location, (values.len() / 2) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_2ui(&self, location: GLint, v0: GLuint, v1: GLuint) {
+        unsafe {
+            self.ffi_gl_.Uniform2ui(location, v0, v1);
+        }
+    }
+
+    fn uniform_3f(&self, location: GLint, v0: GLfloat, v1: GLfloat, v2: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform3f(location, v0, v1, v2);
+        }
+    }
+
+    fn uniform_3fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform3fv(location, (values.len() / 3) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_3i(&self, location: GLint, v0: GLint, v1: GLint, v2: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform3i(location, v0, v1, v2);
+        }
+    }
+
+    fn uniform_3iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform3iv(location, (values.len() / 3) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_3ui(&self, location: GLint, v0: GLuint, v1: GLuint, v2: GLuint) {
+        unsafe {
+            self.ffi_gl_.Uniform3ui(location, v0, v1, v2);
+        }
+    }
+
+    fn uniform_4f(&self, location: GLint, x: GLfloat, y: GLfloat, z: GLfloat, w: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform4f(location, x, y, z, w);
+        }
+    }
+
+    fn uniform_4i(&self, location: GLint, x: GLint, y: GLint, z: GLint, w: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform4i(location, x, y, z, w);
+        }
+    }
+
+    fn uniform_4iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform4iv(location, (values.len() / 4) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_4ui(&self, location: GLint, x: GLuint, y: GLuint, z: GLuint, w: GLuint) {
+        unsafe {
+            self.ffi_gl_.Uniform4ui(location, x, y, z, w);
+        }
+    }
+
+    fn uniform_4fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform4fv(location, (values.len() / 4) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_matrix_2fv(&self, location: GLint, transpose: bool, value: &[f32]) {
+        unsafe {
+            self.ffi_gl_.UniformMatrix2fv(
+                location,
+                (value.len() / 4) as GLsizei,
+                transpose as GLboolean,
+                value.as_ptr(),
+            );
+        }
+    }
+
+    fn uniform_matrix_3fv(&self, location: GLint, transpose: bool, value: &[f32]) {
+        unsafe {
+            self.ffi_gl_.UniformMatrix3fv(
+                location,
+                (value.len() / 9) as GLsizei,
+                transpose as GLboolean,
+                value.as_ptr(),
+            );
+        }
+    }
+
+    fn uniform_matrix_4fv(&self, location: GLint, transpose: bool, value: &[f32]) {
+        unsafe {
+            self.ffi_gl_.UniformMatrix4fv(
+                location,
+                (value.len() / 16) as GLsizei,
+                transpose as GLboolean,
+                value.as_ptr(),
+            );
+        }
+    }
+
+    fn depth_mask(&self, flag: bool) {
+        unsafe {
+            self.ffi_gl_.DepthMask(flag as GLboolean);
+        }
+    }
+
+    fn depth_range(&self, near: f64, far: f64) {
+        unsafe {
+            self.ffi_gl_.DepthRange(near as GLclampd, far as GLclampd);
+        }
+    }
+
+    fn get_active_attrib(&self, program: GLuint, index: GLuint) -> (i32, u32, String) {
+        let mut buf_size = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::ACTIVE_ATTRIBUTE_MAX_LENGTH, &mut buf_size);
+        }
+        let mut name = vec![0u8; buf_size[0] as usize];
+        let mut length = 0 as GLsizei;
+        let mut size = 0 as i32;
+        let mut type_ = 0 as u32;
+        unsafe {
+            self.ffi_gl_.GetActiveAttrib(
+                program,
+                index,
+                buf_size[0],
+                &mut length,
+                &mut size,
+                &mut type_,
+                name.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        name.truncate(if length > 0 { length as usize } else { 0 });
+        (size, type_, String::from_utf8(name).unwrap())
+    }
+
+    fn get_active_uniform(&self, program: GLuint, index: GLuint) -> (i32, u32, String) {
+        let mut buf_size = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::ACTIVE_UNIFORM_MAX_LENGTH, &mut buf_size);
+        }
+        let mut name = vec![0 as u8; buf_size[0] as usize];
+        let mut length: GLsizei = 0;
+        let mut size: i32 = 0;
+        let mut type_: u32 = 0;
+
+        unsafe {
+            self.ffi_gl_.GetActiveUniform(
+                program,
+                index,
+                buf_size[0],
+                &mut length,
+                &mut size,
+                &mut type_,
+                name.as_mut_ptr() as *mut GLchar,
+            );
+        }
+
+        name.truncate(if length > 0 { length as usize } else { 0 });
+
+        (size, type_, String::from_utf8(name).unwrap())
+    }
+
+    fn get_active_uniforms_iv(
+        &self,
+        program: GLuint,
+        indices: Vec<GLuint>,
+        pname: GLenum,
+    ) -> Vec<GLint> {
+        let mut result = Vec::with_capacity(indices.len());
+        unsafe {
+            result.set_len(indices.len());
+            self.ffi_gl_.GetActiveUniformsiv(
+                program,
+                indices.len() as GLsizei,
+                indices.as_ptr(),
+                pname,
+                result.as_mut_ptr(),
+            );
+        }
+        result
+    }
+
+    fn get_active_uniform_block_i(&self, program: GLuint, index: GLuint, pname: GLenum) -> GLint {
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_
+                .GetActiveUniformBlockiv(program, index, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_active_uniform_block_iv(
+        &self,
+        program: GLuint,
+        index: GLuint,
+        pname: GLenum,
+    ) -> Vec<GLint> {
+        let count =
+            self.get_active_uniform_block_i(program, index, ffi::UNIFORM_BLOCK_ACTIVE_UNIFORMS);
+        let mut result = Vec::with_capacity(count as usize);
+        unsafe {
+            result.set_len(count as usize);
+            self.ffi_gl_
+                .GetActiveUniformBlockiv(program, index, pname, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn get_active_uniform_block_name(&self, program: GLuint, index: GLuint) -> String {
+        let buf_size =
+            self.get_active_uniform_block_i(program, index, ffi::UNIFORM_BLOCK_NAME_LENGTH);
+        let mut name = vec![0 as u8; buf_size as usize];
+        let mut length: GLsizei = 0;
+        unsafe {
+            self.ffi_gl_.GetActiveUniformBlockName(
+                program,
+                index,
+                buf_size,
+                &mut length,
+                name.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        name.truncate(if length > 0 { length as usize } else { 0 });
+
+        String::from_utf8(name).unwrap()
+    }
+
+    fn get_attrib_location(&self, program: GLuint, name: &str) -> c_int {
+        let name = CString::new(name).unwrap();
+        unsafe { self.ffi_gl_.GetAttribLocation(program, name.as_ptr()) }
+    }
+
+    fn get_frag_data_location(&self, program: GLuint, name: &str) -> c_int {
+        let name = CString::new(name).unwrap();
+        unsafe { self.ffi_gl_.GetFragDataLocation(program, name.as_ptr()) }
+    }
+
+    fn get_uniform_location(&self, program: GLuint, name: &str) -> c_int {
+        let name = CString::new(name).unwrap();
+        unsafe { self.ffi_gl_.GetUniformLocation(program, name.as_ptr()) }
+    }
+
+    fn get_program_info_log(&self, program: GLuint) -> String {
+        let mut max_len = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::INFO_LOG_LENGTH, &mut max_len);
+        }
+        if max_len[0] == 0 {
+            return String::new();
+        }
+        let mut result = vec![0u8; max_len[0] as usize];
+        let mut result_len = 0 as GLsizei;
+        unsafe {
+            self.ffi_gl_.GetProgramInfoLog(
+                program,
+                max_len[0] as GLsizei,
+                &mut result_len,
+                result.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        result.truncate(if result_len > 0 {
+            result_len as usize
+        } else {
+            0
+        });
+        String::from_utf8(result).unwrap()
+    }
+
+    #[inline]
+    unsafe fn get_program_iv(&self, program: GLuint, pname: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetProgramiv(program, pname, result.as_mut_ptr());
+    }
+
+    fn get_program_binary(&self, program: GLuint) -> (Vec<u8>, GLenum) {
+        if !self.ffi_gl_.GetProgramBinary.is_loaded() {
+            return (Vec::new(), NONE);
+        }
+        let mut len = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::PROGRAM_BINARY_LENGTH, &mut len);
+        }
+        if len[0] <= 0 {
+            return (Vec::new(), NONE);
+        }
+        let mut binary: Vec<u8> = Vec::with_capacity(len[0] as usize);
+        let mut format = NONE;
+        let mut out_len = 0;
+        unsafe {
+            binary.set_len(len[0] as usize);
+            self.ffi_gl_.GetProgramBinary(
+                program,
+                len[0],
+                &mut out_len as *mut GLsizei,
+                &mut format,
+                binary.as_mut_ptr() as *mut c_void,
+            );
+        }
+        if len[0] != out_len {
+            return (Vec::new(), NONE);
+        }
+
+        (binary, format)
+    }
+
+    fn program_binary(&self, program: GLuint, format: GLenum, binary: &[u8]) {
+        if !self.ffi_gl_.ProgramBinary.is_loaded() {
+            return;
+        }
+        unsafe {
+            self.ffi_gl_.ProgramBinary(
+                program,
+                format,
+                binary.as_ptr() as *const c_void,
+                binary.len() as GLsizei,
+            );
+        }
+    }
+
+    fn program_parameter_i(&self, program: GLuint, pname: GLenum, value: GLint) {
+        if !self.ffi_gl_.ProgramParameteri.is_loaded() {
+            return;
+        }
+        unsafe {
+            self.ffi_gl_.ProgramParameteri(program, pname, value);
+        }
+    }
+
+    #[inline]
+    unsafe fn get_vertex_attrib_iv(&self, index: GLuint, pname: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetVertexAttribiv(index, pname, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_vertex_attrib_fv(&self, index: GLuint, pname: GLenum, result: &mut [GLfloat]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetVertexAttribfv(index, pname, result.as_mut_ptr());
+    }
+
+    fn get_vertex_attrib_pointer_v(&self, index: GLuint, pname: GLenum) -> GLsizeiptr {
+        let mut result = 0 as *mut GLvoid;
+        unsafe {
+            self.ffi_gl_
+                .GetVertexAttribPointerv(index, pname, &mut result)
+        }
+        result as GLsizeiptr
+    }
+
+    fn get_buffer_parameter_iv(&self, target: GLuint, pname: GLenum) -> GLint {
+        let mut result = 0 as GLint;
+        unsafe {
+            self.ffi_gl_
+                .GetBufferParameteriv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_shader_info_log(&self, shader: GLuint) -> String {
+        let mut max_len = [0];
+        unsafe {
+            self.get_shader_iv(shader, ffi::INFO_LOG_LENGTH, &mut max_len);
+        }
+        if max_len[0] == 0 {
+            return String::new();
+        }
+        let mut result = vec![0u8; max_len[0] as usize];
+        let mut result_len = 0 as GLsizei;
+        unsafe {
+            self.ffi_gl_.GetShaderInfoLog(
+                shader,
+                max_len[0] as GLsizei,
+                &mut result_len,
+                result.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        result.truncate(if result_len > 0 {
+            result_len as usize
+        } else {
+            0
+        });
+        String::from_utf8(result).unwrap()
+    }
+
+    fn get_string(&self, which: GLenum) -> String {
+        unsafe {
+            let llstr = self.ffi_gl_.GetString(which);
+            if !llstr.is_null() {
+                return str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
+                    .to_string();
+            } else {
+                return "".to_string();
+            }
+        }
+    }
+
+    fn get_string_i(&self, which: GLenum, index: GLuint) -> String {
+        unsafe {
+            let llstr = self.ffi_gl_.GetStringi(which, index);
+            if !llstr.is_null() {
+                str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
+                    .to_string()
+            } else {
+                "".to_string()
+            }
+        }
+    }
+
+    unsafe fn get_shader_iv(&self, shader: GLuint, pname: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetShaderiv(shader, pname, result.as_mut_ptr());
+    }
+
+    fn get_shader_precision_format(
+        &self,
+        _shader_type: GLuint,
+        precision_type: GLuint,
+    ) -> (GLint, GLint, GLint) {
+        // gl.GetShaderPrecisionFormat is not available until OpenGL 4.1.
+        // Fallback to OpenGL standard precissions that most desktop hardware support.
+        match precision_type {
+            ffi::LOW_FLOAT | ffi::MEDIUM_FLOAT | ffi::HIGH_FLOAT => {
+                // Fallback to IEEE 754 single precision
+                // Range: from -2^127 to 2^127
+                // Significand precision: 23 bits
+                (127, 127, 23)
+            }
+            ffi::LOW_INT | ffi::MEDIUM_INT | ffi::HIGH_INT => {
+                // Fallback to single precision integer
+                // Range: from -2^24 to 2^24
+                // Precision: For integer formats this value is always 0
+                (24, 24, 0)
+            }
+            _ => (0, 0, 0),
+        }
+    }
+
+    fn compile_shader(&self, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.CompileShader(shader);
+        }
+    }
+
+    fn create_program(&self) -> GLuint {
+        unsafe {
+            return self.ffi_gl_.CreateProgram();
+        }
+    }
+
+    fn delete_program(&self, program: GLuint) {
+        unsafe {
+            self.ffi_gl_.DeleteProgram(program);
+        }
+    }
+
+    fn create_shader(&self, shader_type: GLenum) -> GLuint {
+        unsafe {
+            return self.ffi_gl_.CreateShader(shader_type);
+        }
+    }
+
+    fn delete_shader(&self, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.DeleteShader(shader);
+        }
+    }
+
+    fn detach_shader(&self, program: GLuint, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.DetachShader(program, shader);
+        }
+    }
+
+    fn link_program(&self, program: GLuint) {
+        unsafe {
+            return self.ffi_gl_.LinkProgram(program);
+        }
+    }
+
+    fn clear_color(&self, r: f32, g: f32, b: f32, a: f32) {
+        unsafe {
+            self.ffi_gl_.ClearColor(r, g, b, a);
+        }
+    }
+
+    fn clear(&self, buffer_mask: GLbitfield) {
+        unsafe {
+            self.ffi_gl_.Clear(buffer_mask);
+        }
+    }
+
+    fn clear_depth(&self, depth: f64) {
+        unsafe {
+            self.ffi_gl_.ClearDepth(depth as GLclampd);
+        }
+    }
+
+    fn clear_stencil(&self, s: GLint) {
+        unsafe {
+            self.ffi_gl_.ClearStencil(s);
+        }
+    }
+
+    fn flush(&self) {
+        unsafe {
+            self.ffi_gl_.Flush();
+        }
+    }
+
+    fn finish(&self) {
+        unsafe {
+            self.ffi_gl_.Finish();
+        }
+    }
+
+    fn get_error(&self) -> GLenum {
+        unsafe { self.ffi_gl_.GetError() }
+    }
+
+    fn stencil_mask(&self, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilMask(mask) }
+    }
+
+    fn stencil_mask_separate(&self, face: GLenum, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilMaskSeparate(face, mask) }
+    }
+
+    fn stencil_func(&self, func: GLenum, ref_: GLint, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilFunc(func, ref_, mask) }
+    }
+
+    fn stencil_func_separate(&self, face: GLenum, func: GLenum, ref_: GLint, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilFuncSeparate(face, func, ref_, mask) }
+    }
+
+    fn stencil_op(&self, sfail: GLenum, dpfail: GLenum, dppass: GLenum) {
+        unsafe { self.ffi_gl_.StencilOp(sfail, dpfail, dppass) }
+    }
+
+    fn stencil_op_separate(&self, face: GLenum, sfail: GLenum, dpfail: GLenum, dppass: GLenum) {
+        unsafe { self.ffi_gl_.StencilOpSeparate(face, sfail, dpfail, dppass) }
+    }
+
+    #[allow(unused_variables)]
+    fn egl_image_target_texture2d_oes(&self, target: GLenum, image: GLeglImageOES) {
+        panic!("not supported")
+    }
+
+    #[allow(unused_variables)]
+    fn egl_image_target_renderbuffer_storage_oes(&self, target: GLenum, image: GLeglImageOES) {
+        panic!("not supported")
+    }
+
+    fn generate_mipmap(&self, target: GLenum) {
+        unsafe { self.ffi_gl_.GenerateMipmap(target) }
+    }
+
+    fn insert_event_marker_ext(&self, message: &str) {
+        if self.ffi_gl_.InsertEventMarkerEXT.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .InsertEventMarkerEXT(message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn push_group_marker_ext(&self, message: &str) {
+        if self.ffi_gl_.PushGroupMarkerEXT.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .PushGroupMarkerEXT(message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn pop_group_marker_ext(&self) {
+        if self.ffi_gl_.PopGroupMarkerEXT.is_loaded() {
+            unsafe {
+                self.ffi_gl_.PopGroupMarkerEXT();
+            }
+        }
+    }
+
+    fn debug_message_insert_khr(&self, source: GLenum, type_: GLenum, id: GLuint, severity: GLenum, message: &str) {
+        if self.ffi_gl_.DebugMessageInsertKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .DebugMessageInsertKHR(source, type_, id, severity, message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn push_debug_group_khr(&self, source: GLenum, id: GLuint, message: &str) {
+        if self.ffi_gl_.PushDebugGroupKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .PushDebugGroupKHR(source, id, message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn pop_debug_group_khr(&self) {
+        if self.ffi_gl_.PopDebugGroupKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_.PopDebugGroupKHR();
+            }
+        }
+    }
+
+    fn fence_sync(&self, condition: GLenum, flags: GLbitfield) -> GLsync {
+        unsafe { self.ffi_gl_.FenceSync(condition, flags) as *const _ }
+    }
+
+    fn client_wait_sync(&self, sync: GLsync, flags: GLbitfield, timeout: GLuint64) -> GLenum {
+        unsafe {
+            self.ffi_gl_
+                .ClientWaitSync(sync as *const _, flags, timeout)
+        }
+    }
+
+    fn wait_sync(&self, sync: GLsync, flags: GLbitfield, timeout: GLuint64) {
+        unsafe {
+            self.ffi_gl_.WaitSync(sync as *const _, flags, timeout);
+        }
+    }
+
+    fn texture_range_apple(&self, target: GLenum, data: &[u8]) {
+        unsafe {
+            self.ffi_gl_.TextureRangeAPPLE(
+                target,
+                data.len() as GLsizei,
+                data.as_ptr() as *const c_void,
+            );
+        }
+    }
+
+    fn delete_sync(&self, sync: GLsync) {
+        unsafe {
+            self.ffi_gl_.DeleteSync(sync as *const _);
+        }
+    }
+
+    fn gen_fences_apple(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenFencesAPPLE(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn delete_fences_apple(&self, fences: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteFencesAPPLE(fences.len() as GLsizei, fences.as_ptr());
+        }
+    }
+
+    fn set_fence_apple(&self, fence: GLuint) {
+        unsafe {
+            self.ffi_gl_.SetFenceAPPLE(fence);
+        }
+    }
+
+    fn finish_fence_apple(&self, fence: GLuint) {
+        unsafe {
+            self.ffi_gl_.FinishFenceAPPLE(fence);
+        }
+    }
+
+    fn test_fence_apple(&self, fence: GLuint) {
+        unsafe {
+            self.ffi_gl_.TestFenceAPPLE(fence);
+        }
+    }
+
+    fn test_object_apple(&self, object: GLenum, name: GLuint) -> GLboolean {
+        unsafe {
+            self.ffi_gl_.TestObjectAPPLE(object, name)
+        }
+    }
+
+    fn finish_object_apple(&self, object: GLenum, name: GLuint) {
+        unsafe {
+            // the spec has a typo for name as GLint instead of GLuint
+            self.ffi_gl_.FinishObjectAPPLE(object, name as GLint);
+        }
+    }
+
+    // GL_ARB_blend_func_extended
+    fn bind_frag_data_location_indexed(
+        &self,
+        program: GLuint,
+        color_number: GLuint,
+        index: GLuint,
+        name: &str,
+    ) {
+        if !self.ffi_gl_.BindFragDataLocationIndexed.is_loaded() {
+            return;
+        }
+
+        let c_string = CString::new(name).unwrap();
+
+        unsafe {
+            self.ffi_gl_.BindFragDataLocationIndexed(
+                program,
+                color_number,
+                index,
+                c_string.as_ptr(),
+            )
+        }
+    }
+
+    fn get_frag_data_index(&self, program: GLuint, name: &str) -> GLint {
+        if !self.ffi_gl_.GetFragDataIndex.is_loaded() {
+            return -1;
+        }
+
+        let c_string = CString::new(name).unwrap();
+
+        unsafe { self.ffi_gl_.GetFragDataIndex(program, c_string.as_ptr()) }
+    }
+
+    // GL_KHR_debug
+    fn get_debug_messages(&self) -> Vec<DebugMessage> {
+        if !self.ffi_gl_.GetDebugMessageLog.is_loaded() {
+            return Vec::new();
+        }
+
+        let mut max_message_len = 0;
+        unsafe {
+            self.ffi_gl_
+                .GetIntegerv(ffi::MAX_DEBUG_MESSAGE_LENGTH, &mut max_message_len)
+        }
+
+        let mut output = Vec::new();
+        const CAPACITY: usize = 4;
+
+        let mut msg_data = vec![0u8; CAPACITY * max_message_len as usize];
+        let mut sources = [0 as GLenum; CAPACITY];
+        let mut types = [0 as GLenum; CAPACITY];
+        let mut severities = [0 as GLenum; CAPACITY];
+        let mut ids = [0 as GLuint; CAPACITY];
+        let mut lengths = [0 as GLsizei; CAPACITY];
+
+        loop {
+            let count = unsafe {
+                self.ffi_gl_.GetDebugMessageLog(
+                    CAPACITY as _,
+                    msg_data.len() as _,
+                    sources.as_mut_ptr(),
+                    types.as_mut_ptr(),
+                    ids.as_mut_ptr(),
+                    severities.as_mut_ptr(),
+                    lengths.as_mut_ptr(),
+                    msg_data.as_mut_ptr() as *mut _,
+                )
+            };
+
+            let mut offset = 0;
+            output.extend((0..count as usize).map(|i| {
+                let len = lengths[i] as usize;
+                let slice = &msg_data[offset..offset + len];
+                offset += len;
+                DebugMessage {
+                    message: String::from_utf8_lossy(slice).to_string(),
+                    source: sources[i],
+                    ty: types[i],
+                    id: ids[i],
+                    severity: severities[i],
+                }
+            }));
+
+            if (count as usize) < CAPACITY {
+                return output;
+            }
+        }
+    }
+
+    fn provoking_vertex_angle(&self, _mode: GLenum) {
+        unimplemented!("This extension is GLES only");
+    }
+
+    // GL_KHR_blend_equation_advanced
+    fn blend_barrier_khr(&self) {
+        if self.ffi_gl_.BlendBarrierKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_.BlendBarrierKHR();
+            }
+        }
+    }
+
+    // GL_CHROMIUM_copy_texture
+    fn copy_texture_chromium(&self,
+        _source_id: GLuint, _source_level: GLint,
+        _dest_target: GLenum, _dest_id: GLuint, _dest_level: GLint,
+        _internal_format: GLint, _dest_type: GLenum,
+        _unpack_flip_y: GLboolean, _unpack_premultiply_alpha: GLboolean, _unpack_unmultiply_alpha: GLboolean)
+    {
+        unimplemented!("This extension is GLES only");
+    }
+    fn copy_sub_texture_chromium(&self,
+        _source_id: GLuint, _source_level: GLint,
+        _dest_target: GLenum, _dest_id: GLuint, _dest_level: GLint,
+        _x_offset: GLint, _y_offset: GLint, _x: GLint, _y: GLint, _width: GLsizei, _height: GLsizei,
+        _unpack_flip_y: GLboolean, _unpack_premultiply_alpha: GLboolean, _unpack_unmultiply_alpha: GLboolean)
+    {
+        unimplemented!("This extension is GLES only");
+    }
+
+    // GL_ANGLE_copy_texture_3d
+    fn copy_texture_3d_angle(
+        &self,
+        _source_id: GLuint,
+        _source_level: GLint,
+        _dest_target: GLenum,
+        _dest_id: GLuint,
+        _dest_level: GLint,
+        _internal_format: GLint,
+        _dest_type: GLenum,
+        _unpack_flip_y: GLboolean,
+        _unpack_premultiply_alpha: GLboolean,
+        _unpack_unmultiply_alpha: GLboolean,
+    ) {
+        unimplemented!("This extension is ANGLE only");
+    }
+
+    fn copy_sub_texture_3d_angle(
+        &self,
+        _source_id: GLuint,
+        _source_level: GLint,
+        _dest_target: GLenum,
+        _dest_id: GLuint,
+        _dest_level: GLint,
+        _x_offset: GLint,
+        _y_offset: GLint,
+        _z_offset: GLint,
+        _x: GLint,
+        _y: GLint,
+        _z: GLint,
+        _width: GLsizei,
+        _height: GLsizei,
+        _depth: GLsizei,
+        _unpack_flip_y: GLboolean,
+        _unpack_premultiply_alpha: GLboolean,
+        _unpack_unmultiply_alpha: GLboolean,
+    ) {
+        unimplemented!("This extension is ANGLE only");
+    }
+
+    fn buffer_storage(
+        &self,
+        target: GLenum,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+        flags: GLbitfield,
+    ) {
+        unsafe {
+            self.ffi_gl_.BufferStorage(target, size, data, flags);
+        }
+    }
+
+    fn flush_mapped_buffer_range(&self, target: GLenum, offset: GLintptr, length: GLsizeiptr) {
+        unsafe {
+            self.ffi_gl_.FlushMappedBufferRange(target, offset, length);
+        }
+    }
+
+    fn start_tiling_qcom(&self, _x: GLuint, _y: GLuint, _width: GLuint, _height: GLuint, _preserve_mask: GLbitfield) {
+    }
+
+    fn end_tiling_qcom(&self, _preserve_mask: GLbitfield) {
+    }
+}
diff --git a/third_party/rust/gleam/src/gles_fns.rs b/third_party/rust/gleam/src/gles_fns.rs
new file mode 100644
index 0000000000..ee7ea70265
--- /dev/null
+++ b/third_party/rust/gleam/src/gles_fns.rs
@@ -0,0 +1,2301 @@
+// Copyright 2014 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+pub struct GlesFns {
+    ffi_gl_: GlesFfi,
+}
+
+impl GlesFns {
+    pub unsafe fn load_with<'a, F>(loadfn: F) -> Rc<dyn Gl>
+    where
+        F: FnMut(&str) -> *const c_void,
+    {
+        let ffi_gl_ = GlesFfi::load_with(loadfn);
+        Rc::new(GlesFns { ffi_gl_: ffi_gl_ }) as Rc<dyn Gl>
+    }
+}
+
+impl Gl for GlesFns {
+    fn get_type(&self) -> GlType {
+        GlType::Gles
+    }
+
+    fn buffer_data_untyped(
+        &self,
+        target: GLenum,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+        usage: GLenum,
+    ) {
+        unsafe {
+            self.ffi_gl_.BufferData(target, size, data, usage);
+        }
+    }
+
+    fn tex_buffer(&self, _target: GLenum, _internal_format: GLenum, _buffer: GLuint) {
+        panic!("not supported")
+    }
+
+    fn buffer_sub_data_untyped(
+        &self,
+        target: GLenum,
+        offset: isize,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+    ) {
+        unsafe {
+            self.ffi_gl_.BufferSubData(target, offset, size, data);
+        }
+    }
+
+    fn map_buffer(&self,
+                  _target: GLenum,
+                  _access: GLbitfield) -> *mut c_void {
+        panic!("not supported")
+    }
+
+    fn map_buffer_range(&self,
+                        target: GLenum,
+                        offset: GLintptr,
+                        length: GLsizeiptr,
+                        access: GLbitfield) -> *mut c_void {
+        unsafe {
+            return self.ffi_gl_.MapBufferRange(target, offset, length, access);
+        }
+    }
+
+    fn unmap_buffer(&self, target: GLenum) -> GLboolean {
+        unsafe {
+            return self.ffi_gl_.UnmapBuffer(target);
+        }
+    }
+
+    fn shader_source(&self, shader: GLuint, strings: &[&[u8]]) {
+        let pointers: Vec<*const u8> = strings.iter().map(|string| (*string).as_ptr()).collect();
+        let lengths: Vec<GLint> = strings.iter().map(|string| string.len() as GLint).collect();
+        unsafe {
+            self.ffi_gl_.ShaderSource(
+                shader,
+                pointers.len() as GLsizei,
+                pointers.as_ptr() as *const *const GLchar,
+                lengths.as_ptr(),
+            );
+        }
+        drop(lengths);
+        drop(pointers);
+    }
+
+    #[allow(unused_variables)]
+    fn read_buffer(&self, mode: GLenum) {
+        panic!("not supported")
+    }
+
+    fn read_pixels_into_buffer(
+        &self,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        pixel_type: GLenum,
+        dst_buffer: &mut [u8],
+    ) {
+        // Assumes that the user properly allocated the size for dst_buffer.
+        let mut row_length = 0;
+        unsafe {
+            self.ffi_gl_.GetIntegerv(ffi::PACK_ROW_LENGTH, &mut row_length as _);
+        }
+        if row_length == 0 {
+            row_length = width;
+        } else {
+            assert!(row_length >= width);
+        }
+        assert_eq!(calculate_length(row_length, height, format, pixel_type), dst_buffer.len());
+
+        unsafe {
+            // We don't want any alignment padding on pixel rows.
+            self.ffi_gl_.PixelStorei(ffi::PACK_ALIGNMENT, 1);
+            self.ffi_gl_.ReadPixels(
+                x,
+                y,
+                width,
+                height,
+                format,
+                pixel_type,
+                dst_buffer.as_mut_ptr() as *mut c_void,
+            );
+        }
+    }
+
+    fn read_pixels(
+        &self,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        pixel_type: GLenum,
+    ) -> Vec<u8> {
+        let len = calculate_length(width, height, format, pixel_type);
+        let mut pixels: Vec<u8> = Vec::new();
+        pixels.reserve(len);
+        unsafe {
+            pixels.set_len(len);
+        }
+
+        self.read_pixels_into_buffer(
+            x,
+            y,
+            width,
+            height,
+            format,
+            pixel_type,
+            pixels.as_mut_slice(),
+        );
+
+        pixels
+    }
+
+    unsafe fn read_pixels_into_pbo(&self,
+                                   x: GLint,
+                                   y: GLint,
+                                   width: GLsizei,
+                                   height: GLsizei,
+                                   format: GLenum,
+                                   pixel_type: GLenum) {
+        self.ffi_gl_.ReadPixels(x, y, width, height, format, pixel_type, ptr::null_mut());
+    }
+
+    fn sample_coverage(&self, value: GLclampf, invert: bool) {
+        unsafe {
+            self.ffi_gl_.SampleCoverage(value, invert as GLboolean);
+        }
+    }
+
+    fn polygon_offset(&self, factor: GLfloat, units: GLfloat) {
+        unsafe {
+            self.ffi_gl_.PolygonOffset(factor, units);
+        }
+    }
+
+    fn pixel_store_i(&self, name: GLenum, param: GLint) {
+        unsafe {
+            self.ffi_gl_.PixelStorei(name, param);
+        }
+    }
+
+    fn gen_buffers(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenBuffers(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_renderbuffers(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenRenderbuffers(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_framebuffers(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenFramebuffers(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_textures(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenTextures(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_vertex_arrays(&self, n: GLsizei) -> Vec<GLuint> {
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenVertexArrays(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn gen_vertex_arrays_apple(&self, _n: GLsizei) -> Vec<GLuint> {
+        panic!("not supported")
+    }
+
+    fn gen_queries(&self, n: GLsizei) -> Vec<GLuint> {
+        if !self.ffi_gl_.GenQueriesEXT.is_loaded() {
+            return Vec::new();
+        }
+        let mut result = vec![0 as GLuint; n as usize];
+        unsafe {
+            self.ffi_gl_.GenQueriesEXT(n, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn begin_query(&self, target: GLenum, id: GLuint) {
+        if !self.ffi_gl_.BeginQueryEXT.is_loaded() {
+            return;
+        }
+        unsafe {
+            self.ffi_gl_.BeginQueryEXT(target, id);
+        }
+    }
+
+    fn end_query(&self, target: GLenum) {
+        if !self.ffi_gl_.EndQueryEXT.is_loaded() {
+            return;
+        }
+        unsafe {
+            self.ffi_gl_.EndQueryEXT(target);
+        }
+    }
+
+    fn query_counter(&self, id: GLuint, target: GLenum) {
+        if !self.ffi_gl_.QueryCounterEXT.is_loaded() {
+            return;
+        }
+        unsafe {
+            self.ffi_gl_.QueryCounterEXT(id, target);
+        }
+    }
+
+    fn get_query_object_iv(&self, id: GLuint, pname: GLenum) -> i32 {
+        if !self.ffi_gl_.GetQueryObjectivEXT.is_loaded() {
+            return 0;
+        }
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjectivEXT(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_query_object_uiv(&self, id: GLuint, pname: GLenum) -> u32 {
+        if !self.ffi_gl_.GetQueryObjectuivEXT.is_loaded() {
+            return 0;
+        }
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjectuivEXT(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_query_object_i64v(&self, id: GLuint, pname: GLenum) -> i64 {
+        if !self.ffi_gl_.GetQueryObjecti64vEXT.is_loaded() {
+            return 0;
+        }
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjecti64vEXT(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_query_object_ui64v(&self, id: GLuint, pname: GLenum) -> u64 {
+        if !self.ffi_gl_.GetQueryObjectui64vEXT.is_loaded() {
+            return 0;
+        }
+        let mut result = 0;
+        unsafe {
+            self.ffi_gl_.GetQueryObjectui64vEXT(id, pname, &mut result);
+        }
+        result
+    }
+
+    fn delete_queries(&self, queries: &[GLuint]) {
+        if !self.ffi_gl_.DeleteQueriesEXT.is_loaded() {
+            return;
+        }
+        unsafe {
+            self.ffi_gl_
+                .DeleteQueriesEXT(queries.len() as GLsizei, queries.as_ptr());
+        }
+    }
+
+    fn delete_vertex_arrays(&self, vertex_arrays: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteVertexArrays(vertex_arrays.len() as GLsizei, vertex_arrays.as_ptr());
+        }
+    }
+
+    fn delete_vertex_arrays_apple(&self, _vertex_arrays: &[GLuint]) {
+        panic!("not supported")
+    }
+
+    fn delete_buffers(&self, buffers: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteBuffers(buffers.len() as GLsizei, buffers.as_ptr());
+        }
+    }
+
+    fn delete_renderbuffers(&self, renderbuffers: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteRenderbuffers(renderbuffers.len() as GLsizei, renderbuffers.as_ptr());
+        }
+    }
+
+    fn delete_framebuffers(&self, framebuffers: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteFramebuffers(framebuffers.len() as GLsizei, framebuffers.as_ptr());
+        }
+    }
+
+    fn delete_textures(&self, textures: &[GLuint]) {
+        unsafe {
+            self.ffi_gl_
+                .DeleteTextures(textures.len() as GLsizei, textures.as_ptr());
+        }
+    }
+
+    fn framebuffer_renderbuffer(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        renderbuffertarget: GLenum,
+        renderbuffer: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_.FramebufferRenderbuffer(
+                target,
+                attachment,
+                renderbuffertarget,
+                renderbuffer,
+            );
+        }
+    }
+
+    fn renderbuffer_storage(
+        &self,
+        target: GLenum,
+        internalformat: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .RenderbufferStorage(target, internalformat, width, height);
+        }
+    }
+
+    fn depth_func(&self, func: GLenum) {
+        unsafe {
+            self.ffi_gl_.DepthFunc(func);
+        }
+    }
+
+    fn active_texture(&self, texture: GLenum) {
+        unsafe {
+            self.ffi_gl_.ActiveTexture(texture);
+        }
+    }
+
+    fn attach_shader(&self, program: GLuint, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.AttachShader(program, shader);
+        }
+    }
+
+    fn bind_attrib_location(&self, program: GLuint, index: GLuint, name: &str) {
+        let c_string = CString::new(name).unwrap();
+        unsafe {
+            self.ffi_gl_
+                .BindAttribLocation(program, index, c_string.as_ptr())
+        }
+    }
+
+    // https://www.khronos.org/registry/OpenGL-Refpages/es2.0/xhtml/glGetUniform.xml
+    unsafe fn get_uniform_iv(&self, program: GLuint, location: GLint, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetUniformiv(program, location, result.as_mut_ptr());
+    }
+
+    // https://www.khronos.org/registry/OpenGL-Refpages/es2.0/xhtml/glGetUniform.xml
+    unsafe fn get_uniform_fv(&self, program: GLuint, location: GLint, result: &mut [GLfloat]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetUniformfv(program, location, result.as_mut_ptr());
+    }
+
+    fn get_uniform_block_index(&self, program: GLuint, name: &str) -> GLuint {
+        let c_string = CString::new(name).unwrap();
+        unsafe {
+            self.ffi_gl_
+                .GetUniformBlockIndex(program, c_string.as_ptr())
+        }
+    }
+
+    fn get_uniform_indices(&self, program: GLuint, names: &[&str]) -> Vec<GLuint> {
+        let c_strings: Vec<CString> = names.iter().map(|n| CString::new(*n).unwrap()).collect();
+        let pointers: Vec<*const GLchar> = c_strings.iter().map(|string| string.as_ptr()).collect();
+        let mut result = Vec::with_capacity(c_strings.len());
+        unsafe {
+            result.set_len(c_strings.len());
+            self.ffi_gl_.GetUniformIndices(
+                program,
+                pointers.len() as GLsizei,
+                pointers.as_ptr(),
+                result.as_mut_ptr(),
+            );
+        }
+        result
+    }
+
+    fn bind_buffer_base(&self, target: GLenum, index: GLuint, buffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindBufferBase(target, index, buffer);
+        }
+    }
+
+    fn bind_buffer_range(
+        &self,
+        target: GLenum,
+        index: GLuint,
+        buffer: GLuint,
+        offset: GLintptr,
+        size: GLsizeiptr,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .BindBufferRange(target, index, buffer, offset, size);
+        }
+    }
+
+    fn uniform_block_binding(
+        &self,
+        program: GLuint,
+        uniform_block_index: GLuint,
+        uniform_block_binding: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .UniformBlockBinding(program, uniform_block_index, uniform_block_binding);
+        }
+    }
+
+    fn bind_buffer(&self, target: GLenum, buffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindBuffer(target, buffer);
+        }
+    }
+
+    fn bind_vertex_array(&self, vao: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindVertexArray(vao);
+        }
+    }
+
+    fn bind_vertex_array_apple(&self, _vao: GLuint) {
+        panic!("not supported")
+    }
+
+    fn bind_renderbuffer(&self, target: GLenum, renderbuffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindRenderbuffer(target, renderbuffer);
+        }
+    }
+
+    fn bind_framebuffer(&self, target: GLenum, framebuffer: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindFramebuffer(target, framebuffer);
+        }
+    }
+
+    fn bind_texture(&self, target: GLenum, texture: GLuint) {
+        unsafe {
+            self.ffi_gl_.BindTexture(target, texture);
+        }
+    }
+
+    fn bind_vertex_buffer(&self, binding_index: GLuint, buffer: GLuint, offset: GLintptr, stride: GLint) {
+        unsafe { self.ffi_gl_.BindVertexBuffer(binding_index, buffer, offset, stride) }
+    }
+
+    fn draw_buffers(&self, bufs: &[GLenum]) {
+        unsafe {
+            self.ffi_gl_
+                .DrawBuffers(bufs.len() as GLsizei, bufs.as_ptr());
+        }
+    }
+
+    // FIXME: Does not verify buffer size -- unsafe!
+    fn tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+        format: GLenum,
+        ty: GLenum,
+        opt_data: Option<&[u8]>,
+    ) {
+        match opt_data {
+            Some(data) => unsafe {
+                self.ffi_gl_.TexImage2D(
+                    target,
+                    level,
+                    internal_format,
+                    width,
+                    height,
+                    border,
+                    format,
+                    ty,
+                    data.as_ptr() as *const GLvoid,
+                );
+            },
+            None => unsafe {
+                self.ffi_gl_.TexImage2D(
+                    target,
+                    level,
+                    internal_format,
+                    width,
+                    height,
+                    border,
+                    format,
+                    ty,
+                    ptr::null(),
+                );
+            },
+        }
+    }
+
+    fn compressed_tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.CompressedTexImage2D(
+                target,
+                level,
+                internal_format,
+                width,
+                height,
+                border,
+                data.len() as GLsizei,
+                data.as_ptr() as *const GLvoid,
+            );
+        }
+    }
+
+    fn compressed_tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.CompressedTexSubImage2D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                width,
+                height,
+                format,
+                data.len() as GLsizei,
+                data.as_ptr() as *const GLvoid,
+            );
+        }
+    }
+
+    // FIXME: Does not verify buffer size -- unsafe!
+    fn tex_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        border: GLint,
+        format: GLenum,
+        ty: GLenum,
+        opt_data: Option<&[u8]>,
+    ) {
+        unsafe {
+            let pdata = match opt_data {
+                Some(data) => mem::transmute(data.as_ptr()),
+                None => ptr::null(),
+            };
+            self.ffi_gl_.TexImage3D(
+                target,
+                level,
+                internal_format,
+                width,
+                height,
+                depth,
+                border,
+                format,
+                ty,
+                pdata,
+            );
+        }
+    }
+
+    fn copy_tex_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        internal_format: GLenum,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        border: GLint,
+    ) {
+        unsafe {
+            self.ffi_gl_.CopyTexImage2D(
+                target,
+                level,
+                internal_format,
+                x,
+                y,
+                width,
+                height,
+                border,
+            );
+        }
+    }
+
+    fn copy_tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .CopyTexSubImage2D(target, level, xoffset, yoffset, x, y, width, height);
+        }
+    }
+
+    fn copy_tex_sub_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        x: GLint,
+        y: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_.CopyTexSubImage3D(
+                target, level, xoffset, yoffset, zoffset, x, y, width, height,
+            );
+        }
+    }
+
+    fn tex_sub_image_2d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage2D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                width,
+                height,
+                format,
+                ty,
+                data.as_ptr() as *const c_void,
+            );
+        }
+    }
+
+    fn tex_sub_image_2d_pbo(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        offset: usize,
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage2D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                width,
+                height,
+                format,
+                ty,
+                offset as *const c_void,
+            );
+        }
+    }
+
+    fn tex_sub_image_3d(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        data: &[u8],
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage3D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                zoffset,
+                width,
+                height,
+                depth,
+                format,
+                ty,
+                data.as_ptr() as *const c_void,
+            );
+        }
+    }
+
+    fn tex_sub_image_3d_pbo(
+        &self,
+        target: GLenum,
+        level: GLint,
+        xoffset: GLint,
+        yoffset: GLint,
+        zoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        format: GLenum,
+        ty: GLenum,
+        offset: usize,
+    ) {
+        unsafe {
+            self.ffi_gl_.TexSubImage3D(
+                target,
+                level,
+                xoffset,
+                yoffset,
+                zoffset,
+                width,
+                height,
+                depth,
+                format,
+                ty,
+                offset as *const c_void,
+            );
+        }
+    }
+
+    fn tex_storage_2d(
+        &self,
+        target: GLenum,
+        levels: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .TexStorage2D(target, levels, internal_format, width, height);
+        }
+    }
+
+    fn tex_storage_3d(
+        &self,
+        target: GLenum,
+        levels: GLint,
+        internal_format: GLenum,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .TexStorage3D(target, levels, internal_format, width, height, depth);
+        }
+    }
+
+    #[allow(unused_variables)]
+    fn get_tex_image_into_buffer(
+        &self,
+        target: GLenum,
+        level: GLint,
+        format: GLenum,
+        ty: GLenum,
+        output: &mut [u8],
+    ) {
+        panic!("not supported");
+    }
+
+    unsafe fn copy_image_sub_data(
+        &self,
+        src_name: GLuint,
+        src_target: GLenum,
+        src_level: GLint,
+        src_x: GLint,
+        src_y: GLint,
+        src_z: GLint,
+        dst_name: GLuint,
+        dst_target: GLenum,
+        dst_level: GLint,
+        dst_x: GLint,
+        dst_y: GLint,
+        dst_z: GLint,
+        src_width: GLsizei,
+        src_height: GLsizei,
+        src_depth: GLsizei,
+    ) {
+        self.ffi_gl_.CopyImageSubDataEXT(
+            src_name, src_target, src_level, src_x, src_y, src_z, dst_name, dst_target, dst_level,
+            dst_x, dst_y, dst_z, src_width, src_height, src_depth,
+        );
+    }
+
+    fn invalidate_framebuffer(&self, target: GLenum, attachments: &[GLenum]) {
+        unsafe {
+            self.ffi_gl_.InvalidateFramebuffer(
+                target,
+                attachments.len() as GLsizei,
+                attachments.as_ptr(),
+            );
+        }
+    }
+
+    fn invalidate_sub_framebuffer(
+        &self,
+        target: GLenum,
+        attachments: &[GLenum],
+        xoffset: GLint,
+        yoffset: GLint,
+        width: GLsizei,
+        height: GLsizei,
+    ) {
+        unsafe {
+            self.ffi_gl_.InvalidateSubFramebuffer(
+                target,
+                attachments.len() as GLsizei,
+                attachments.as_ptr(),
+                xoffset,
+                yoffset,
+                width,
+                height,
+            );
+        }
+    }
+
+    #[inline]
+    unsafe fn get_integer_v(&self, name: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetIntegerv(name, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_integer_64v(&self, name: GLenum, result: &mut [GLint64]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetInteger64v(name, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_integer_iv(&self, name: GLenum, index: GLuint, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetIntegeri_v(name, index, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_integer_64iv(&self, name: GLenum, index: GLuint, result: &mut [GLint64]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetInteger64i_v(name, index, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_boolean_v(&self, name: GLenum, result: &mut [GLboolean]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetBooleanv(name, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_float_v(&self, name: GLenum, result: &mut [GLfloat]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetFloatv(name, result.as_mut_ptr());
+    }
+
+    fn get_renderbuffer_parameter_iv(&self, target: GLenum, pname: GLenum) -> GLint {
+        let mut result: GLint = 0;
+        unsafe {
+            self.ffi_gl_
+                .GetRenderbufferParameteriv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_framebuffer_attachment_parameter_iv(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        pname: GLenum,
+    ) -> GLint {
+        let mut result: GLint = 0;
+        unsafe {
+            self.ffi_gl_.GetFramebufferAttachmentParameteriv(
+                target,
+                attachment,
+                pname,
+                &mut result,
+            );
+        }
+        result
+    }
+
+    fn get_tex_parameter_iv(&self, target: GLenum, pname: GLenum) -> GLint {
+        let mut result: GLint = 0;
+        unsafe {
+            self.ffi_gl_.GetTexParameteriv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_tex_parameter_fv(&self, target: GLenum, pname: GLenum) -> GLfloat {
+        let mut result: GLfloat = 0.0;
+        unsafe {
+            self.ffi_gl_.GetTexParameterfv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn tex_parameter_i(&self, target: GLenum, pname: GLenum, param: GLint) {
+        unsafe {
+            self.ffi_gl_.TexParameteri(target, pname, param);
+        }
+    }
+
+    fn tex_parameter_f(&self, target: GLenum, pname: GLenum, param: GLfloat) {
+        unsafe {
+            self.ffi_gl_.TexParameterf(target, pname, param);
+        }
+    }
+
+    fn framebuffer_texture_2d(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        textarget: GLenum,
+        texture: GLuint,
+        level: GLint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .FramebufferTexture2D(target, attachment, textarget, texture, level);
+        }
+    }
+
+    fn framebuffer_texture_layer(
+        &self,
+        target: GLenum,
+        attachment: GLenum,
+        texture: GLuint,
+        level: GLint,
+        layer: GLint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .FramebufferTextureLayer(target, attachment, texture, level, layer);
+        }
+    }
+
+    fn blit_framebuffer(
+        &self,
+        src_x0: GLint,
+        src_y0: GLint,
+        src_x1: GLint,
+        src_y1: GLint,
+        dst_x0: GLint,
+        dst_y0: GLint,
+        dst_x1: GLint,
+        dst_y1: GLint,
+        mask: GLbitfield,
+        filter: GLenum,
+    ) {
+        unsafe {
+            self.ffi_gl_.BlitFramebuffer(
+                src_x0, src_y0, src_x1, src_y1, dst_x0, dst_y0, dst_x1, dst_y1, mask, filter,
+            );
+        }
+    }
+
+    fn vertex_attrib_4f(&self, index: GLuint, x: GLfloat, y: GLfloat, z: GLfloat, w: GLfloat) {
+        unsafe { self.ffi_gl_.VertexAttrib4f(index, x, y, z, w) }
+    }
+
+    fn vertex_attrib_binding(&self, attrib_index: GLuint, binding_index: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribBinding(attrib_index, binding_index) }
+    }
+
+    fn vertex_attrib_pointer_f32(
+        &self,
+        index: GLuint,
+        size: GLint,
+        normalized: bool,
+        stride: GLsizei,
+        offset: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_.VertexAttribPointer(
+                index,
+                size,
+                ffi::FLOAT,
+                normalized as GLboolean,
+                stride,
+                offset as *const GLvoid,
+            )
+        }
+    }
+
+    fn vertex_attrib_pointer(
+        &self,
+        index: GLuint,
+        size: GLint,
+        type_: GLenum,
+        normalized: bool,
+        stride: GLsizei,
+        offset: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_.VertexAttribPointer(
+                index,
+                size,
+                type_,
+                normalized as GLboolean,
+                stride,
+                offset as *const GLvoid,
+            )
+        }
+    }
+
+    fn vertex_attrib_i_pointer(
+        &self,
+        index: GLuint,
+        size: GLint,
+        type_: GLenum,
+        stride: GLsizei,
+        offset: GLuint,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .VertexAttribIPointer(index, size, type_, stride, offset as *const GLvoid)
+        }
+    }
+
+    fn vertex_attrib_divisor(&self, index: GLuint, divisor: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribDivisor(index, divisor) }
+    }
+
+    fn vertex_attrib_format(&self, attrib_index: GLuint, size: GLint, type_: GLenum, normalized: bool, relative_offset: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribFormat(attrib_index, size, type_, normalized as GLboolean, relative_offset) }
+    }
+
+    fn vertex_attrib_i_format(&self, attrib_index: GLuint, size: GLint, type_: GLenum, relative_offset: GLuint) {
+        unsafe { self.ffi_gl_.VertexAttribIFormat(attrib_index, size, type_, relative_offset) }
+    }
+
+    fn vertex_binding_divisor(&self, binding_index: GLuint, divisor: GLuint) {
+        unsafe { self.ffi_gl_.VertexBindingDivisor(binding_index, divisor) }
+    }
+
+    fn viewport(&self, x: GLint, y: GLint, width: GLsizei, height: GLsizei) {
+        unsafe {
+            self.ffi_gl_.Viewport(x, y, width, height);
+        }
+    }
+
+    fn scissor(&self, x: GLint, y: GLint, width: GLsizei, height: GLsizei) {
+        unsafe {
+            self.ffi_gl_.Scissor(x, y, width, height);
+        }
+    }
+
+    fn line_width(&self, width: GLfloat) {
+        unsafe {
+            self.ffi_gl_.LineWidth(width);
+        }
+    }
+
+    fn use_program(&self, program: GLuint) {
+        unsafe {
+            self.ffi_gl_.UseProgram(program);
+        }
+    }
+
+    fn validate_program(&self, program: GLuint) {
+        unsafe {
+            self.ffi_gl_.ValidateProgram(program);
+        }
+    }
+
+    fn draw_arrays(&self, mode: GLenum, first: GLint, count: GLsizei) {
+        unsafe {
+            return self.ffi_gl_.DrawArrays(mode, first, count);
+        }
+    }
+
+    fn draw_arrays_instanced(
+        &self,
+        mode: GLenum,
+        first: GLint,
+        count: GLsizei,
+        primcount: GLsizei,
+    ) {
+        unsafe {
+            return self
+                .ffi_gl_
+                .DrawArraysInstanced(mode, first, count, primcount);
+        }
+    }
+
+    fn draw_elements(
+        &self,
+        mode: GLenum,
+        count: GLsizei,
+        element_type: GLenum,
+        indices_offset: GLuint,
+    ) {
+        unsafe {
+            return self.ffi_gl_.DrawElements(
+                mode,
+                count,
+                element_type,
+                indices_offset as *const c_void,
+            );
+        }
+    }
+
+    fn draw_elements_instanced(
+        &self,
+        mode: GLenum,
+        count: GLsizei,
+        element_type: GLenum,
+        indices_offset: GLuint,
+        primcount: GLsizei,
+    ) {
+        unsafe {
+            return self.ffi_gl_.DrawElementsInstanced(
+                mode,
+                count,
+                element_type,
+                indices_offset as *const c_void,
+                primcount,
+            );
+        }
+    }
+
+    fn blend_color(&self, r: f32, g: f32, b: f32, a: f32) {
+        unsafe {
+            self.ffi_gl_.BlendColor(r, g, b, a);
+        }
+    }
+
+    fn blend_func(&self, sfactor: GLenum, dfactor: GLenum) {
+        unsafe {
+            self.ffi_gl_.BlendFunc(sfactor, dfactor);
+        }
+    }
+
+    fn blend_func_separate(
+        &self,
+        src_rgb: GLenum,
+        dest_rgb: GLenum,
+        src_alpha: GLenum,
+        dest_alpha: GLenum,
+    ) {
+        unsafe {
+            self.ffi_gl_
+                .BlendFuncSeparate(src_rgb, dest_rgb, src_alpha, dest_alpha);
+        }
+    }
+
+    fn blend_equation(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.BlendEquation(mode);
+        }
+    }
+
+    fn blend_equation_separate(&self, mode_rgb: GLenum, mode_alpha: GLenum) {
+        unsafe {
+            self.ffi_gl_.BlendEquationSeparate(mode_rgb, mode_alpha);
+        }
+    }
+
+    fn color_mask(&self, r: bool, g: bool, b: bool, a: bool) {
+        unsafe {
+            self.ffi_gl_.ColorMask(
+                r as GLboolean,
+                g as GLboolean,
+                b as GLboolean,
+                a as GLboolean,
+            );
+        }
+    }
+
+    fn cull_face(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.CullFace(mode);
+        }
+    }
+
+    fn front_face(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.FrontFace(mode);
+        }
+    }
+
+    fn enable(&self, cap: GLenum) {
+        unsafe {
+            self.ffi_gl_.Enable(cap);
+        }
+    }
+
+    fn disable(&self, cap: GLenum) {
+        unsafe {
+            self.ffi_gl_.Disable(cap);
+        }
+    }
+
+    fn hint(&self, param_name: GLenum, param_val: GLenum) {
+        unsafe {
+            self.ffi_gl_.Hint(param_name, param_val);
+        }
+    }
+
+    fn is_enabled(&self, cap: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsEnabled(cap) }
+    }
+
+    fn is_shader(&self, shader: GLuint) -> GLboolean {
+        unsafe { self.ffi_gl_.IsShader(shader) }
+    }
+
+    fn is_texture(&self, texture: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsTexture(texture) }
+    }
+
+    fn is_framebuffer(&self, framebuffer: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsFramebuffer(framebuffer) }
+    }
+
+    fn is_renderbuffer(&self, renderbuffer: GLenum) -> GLboolean {
+        unsafe { self.ffi_gl_.IsRenderbuffer(renderbuffer) }
+    }
+
+    fn check_frame_buffer_status(&self, target: GLenum) -> GLenum {
+        unsafe { self.ffi_gl_.CheckFramebufferStatus(target) }
+    }
+
+    fn enable_vertex_attrib_array(&self, index: GLuint) {
+        unsafe {
+            self.ffi_gl_.EnableVertexAttribArray(index);
+        }
+    }
+
+    fn disable_vertex_attrib_array(&self, index: GLuint) {
+        unsafe {
+            self.ffi_gl_.DisableVertexAttribArray(index);
+        }
+    }
+
+    fn uniform_1f(&self, location: GLint, v0: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform1f(location, v0);
+        }
+    }
+
+    fn uniform_1fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform1fv(location, values.len() as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_1i(&self, location: GLint, v0: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform1i(location, v0);
+        }
+    }
+
+    fn uniform_1iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform1iv(location, values.len() as GLsizei, values.as_ptr());
+        }
+    }
+
+    #[allow(unused_variables)]
+    fn uniform_1ui(&self, location: GLint, v0: GLuint) {
+        panic!("not supported")
+    }
+
+    fn uniform_2f(&self, location: GLint, v0: GLfloat, v1: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform2f(location, v0, v1);
+        }
+    }
+
+    fn uniform_2fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform2fv(location, (values.len() / 2) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_2i(&self, location: GLint, v0: GLint, v1: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform2i(location, v0, v1);
+        }
+    }
+
+    fn uniform_2iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform2iv(location, (values.len() / 2) as GLsizei, values.as_ptr());
+        }
+    }
+
+    #[allow(unused_variables)]
+    fn uniform_2ui(&self, location: GLint, v0: GLuint, v1: GLuint) {
+        panic!("not supported")
+    }
+
+    fn uniform_3f(&self, location: GLint, v0: GLfloat, v1: GLfloat, v2: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform3f(location, v0, v1, v2);
+        }
+    }
+
+    fn uniform_3fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform3fv(location, (values.len() / 3) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_3i(&self, location: GLint, v0: GLint, v1: GLint, v2: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform3i(location, v0, v1, v2);
+        }
+    }
+
+    fn uniform_3iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform3iv(location, (values.len() / 3) as GLsizei, values.as_ptr());
+        }
+    }
+
+    #[allow(unused_variables)]
+    fn uniform_3ui(&self, location: GLint, v0: GLuint, v1: GLuint, v2: GLuint) {
+        panic!("not supported")
+    }
+
+    fn uniform_4f(&self, location: GLint, x: GLfloat, y: GLfloat, z: GLfloat, w: GLfloat) {
+        unsafe {
+            self.ffi_gl_.Uniform4f(location, x, y, z, w);
+        }
+    }
+
+    fn uniform_4i(&self, location: GLint, x: GLint, y: GLint, z: GLint, w: GLint) {
+        unsafe {
+            self.ffi_gl_.Uniform4i(location, x, y, z, w);
+        }
+    }
+
+    fn uniform_4iv(&self, location: GLint, values: &[i32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform4iv(location, (values.len() / 4) as GLsizei, values.as_ptr());
+        }
+    }
+
+    #[allow(unused_variables)]
+    fn uniform_4ui(&self, location: GLint, x: GLuint, y: GLuint, z: GLuint, w: GLuint) {
+        panic!("not supported")
+    }
+
+    fn uniform_4fv(&self, location: GLint, values: &[f32]) {
+        unsafe {
+            self.ffi_gl_
+                .Uniform4fv(location, (values.len() / 4) as GLsizei, values.as_ptr());
+        }
+    }
+
+    fn uniform_matrix_2fv(&self, location: GLint, transpose: bool, value: &[f32]) {
+        unsafe {
+            self.ffi_gl_.UniformMatrix2fv(
+                location,
+                (value.len() / 4) as GLsizei,
+                transpose as GLboolean,
+                value.as_ptr(),
+            );
+        }
+    }
+
+    fn uniform_matrix_3fv(&self, location: GLint, transpose: bool, value: &[f32]) {
+        unsafe {
+            self.ffi_gl_.UniformMatrix3fv(
+                location,
+                (value.len() / 9) as GLsizei,
+                transpose as GLboolean,
+                value.as_ptr(),
+            );
+        }
+    }
+
+    fn uniform_matrix_4fv(&self, location: GLint, transpose: bool, value: &[f32]) {
+        unsafe {
+            self.ffi_gl_.UniformMatrix4fv(
+                location,
+                (value.len() / 16) as GLsizei,
+                transpose as GLboolean,
+                value.as_ptr(),
+            );
+        }
+    }
+
+    fn depth_mask(&self, flag: bool) {
+        unsafe {
+            self.ffi_gl_.DepthMask(flag as GLboolean);
+        }
+    }
+
+    fn depth_range(&self, near: f64, far: f64) {
+        unsafe {
+            self.ffi_gl_.DepthRangef(near as GLclampf, far as GLclampf);
+        }
+    }
+
+    fn get_active_attrib(&self, program: GLuint, index: GLuint) -> (i32, u32, String) {
+        let mut buf_size = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::ACTIVE_ATTRIBUTE_MAX_LENGTH, &mut buf_size);
+        }
+        let mut name = vec![0u8; buf_size[0] as usize];
+        let mut length = 0 as GLsizei;
+        let mut size = 0 as i32;
+        let mut type_ = 0 as u32;
+        unsafe {
+            self.ffi_gl_.GetActiveAttrib(
+                program,
+                index,
+                buf_size[0],
+                &mut length,
+                &mut size,
+                &mut type_,
+                name.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        name.truncate(if length > 0 { length as usize } else { 0 });
+        (size, type_, String::from_utf8(name).unwrap())
+    }
+
+    fn get_active_uniform(&self, program: GLuint, index: GLuint) -> (i32, u32, String) {
+        let mut buf_size = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::ACTIVE_UNIFORM_MAX_LENGTH, &mut buf_size);
+        }
+        let mut name = vec![0 as u8; buf_size[0] as usize];
+        let mut length: GLsizei = 0;
+        let mut size: i32 = 0;
+        let mut type_: u32 = 0;
+
+        unsafe {
+            self.ffi_gl_.GetActiveUniform(
+                program,
+                index,
+                buf_size[0],
+                &mut length,
+                &mut size,
+                &mut type_,
+                name.as_mut_ptr() as *mut GLchar,
+            );
+        }
+
+        name.truncate(if length > 0 { length as usize } else { 0 });
+
+        (size, type_, String::from_utf8(name).unwrap())
+    }
+
+    fn get_active_uniforms_iv(
+        &self,
+        program: GLuint,
+        indices: Vec<GLuint>,
+        pname: GLenum,
+    ) -> Vec<GLint> {
+        let mut result = Vec::with_capacity(indices.len());
+        unsafe {
+            result.set_len(indices.len());
+            self.ffi_gl_.GetActiveUniformsiv(
+                program,
+                indices.len() as GLsizei,
+                indices.as_ptr(),
+                pname,
+                result.as_mut_ptr(),
+            );
+        }
+        result
+    }
+
+    fn get_active_uniform_block_i(&self, program: GLuint, index: GLuint, pname: GLenum) -> GLint {
+        let mut result = 0 as GLint;
+        unsafe {
+            self.ffi_gl_
+                .GetActiveUniformBlockiv(program, index, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_active_uniform_block_iv(
+        &self,
+        program: GLuint,
+        index: GLuint,
+        pname: GLenum,
+    ) -> Vec<GLint> {
+        let count =
+            self.get_active_uniform_block_i(program, index, ffi::UNIFORM_BLOCK_ACTIVE_UNIFORMS);
+        let mut result = Vec::with_capacity(count as usize);
+        unsafe {
+            result.set_len(count as usize);
+            self.ffi_gl_
+                .GetActiveUniformBlockiv(program, index, pname, result.as_mut_ptr());
+        }
+        result
+    }
+
+    fn get_active_uniform_block_name(&self, program: GLuint, index: GLuint) -> String {
+        let buf_size =
+            self.get_active_uniform_block_i(program, index, ffi::UNIFORM_BLOCK_NAME_LENGTH);
+        let mut name = vec![0 as u8; buf_size as usize];
+        let mut length: GLsizei = 0;
+        unsafe {
+            self.ffi_gl_.GetActiveUniformBlockName(
+                program,
+                index,
+                buf_size,
+                &mut length,
+                name.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        name.truncate(if length > 0 { length as usize } else { 0 });
+
+        String::from_utf8(name).unwrap()
+    }
+
+    fn get_attrib_location(&self, program: GLuint, name: &str) -> c_int {
+        let name = CString::new(name).unwrap();
+        unsafe { self.ffi_gl_.GetAttribLocation(program, name.as_ptr()) }
+    }
+
+    #[allow(unused_variables)]
+    fn get_frag_data_location(&self, program: GLuint, name: &str) -> c_int {
+        panic!("not supported")
+    }
+
+    fn get_uniform_location(&self, program: GLuint, name: &str) -> c_int {
+        let name = CString::new(name).unwrap();
+        unsafe { self.ffi_gl_.GetUniformLocation(program, name.as_ptr()) }
+    }
+
+    fn get_program_info_log(&self, program: GLuint) -> String {
+        let mut max_len = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::INFO_LOG_LENGTH, &mut max_len);
+        }
+        if max_len[0] == 0 {
+            return String::new();
+        }
+        let mut result = vec![0u8; max_len[0] as usize];
+        let mut result_len = 0 as GLsizei;
+        unsafe {
+            self.ffi_gl_.GetProgramInfoLog(
+                program,
+                max_len[0] as GLsizei,
+                &mut result_len,
+                result.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        result.truncate(if result_len > 0 {
+            result_len as usize
+        } else {
+            0
+        });
+        String::from_utf8(result).unwrap()
+    }
+
+    #[inline]
+    unsafe fn get_program_iv(&self, program: GLuint, pname: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetProgramiv(program, pname, result.as_mut_ptr());
+    }
+
+    fn get_program_binary(&self, program: GLuint) -> (Vec<u8>, GLenum) {
+        let mut len = [0];
+        unsafe {
+            self.get_program_iv(program, ffi::PROGRAM_BINARY_LENGTH, &mut len);
+        }
+        if len[0] <= 0 {
+            return (Vec::new(), NONE);
+        }
+        let mut binary: Vec<u8> = Vec::with_capacity(len[0] as usize);
+        let mut format = NONE;
+        let mut out_len = 0;
+        unsafe {
+            binary.set_len(len[0] as usize);
+            self.ffi_gl_.GetProgramBinary(
+                program,
+                len[0],
+                &mut out_len as *mut GLsizei,
+                &mut format,
+                binary.as_mut_ptr() as *mut c_void,
+            );
+        }
+        if len[0] != out_len {
+            return (Vec::new(), NONE);
+        }
+
+        (binary, format)
+    }
+
+    fn program_binary(&self, program: GLuint, format: GLenum, binary: &[u8]) {
+        unsafe {
+            self.ffi_gl_.ProgramBinary(
+                program,
+                format,
+                binary.as_ptr() as *const c_void,
+                binary.len() as GLsizei,
+            );
+        }
+    }
+
+    fn program_parameter_i(&self, program: GLuint, pname: GLenum, value: GLint) {
+        unsafe {
+            self.ffi_gl_.ProgramParameteri(program, pname, value);
+        }
+    }
+
+    #[inline]
+    unsafe fn get_vertex_attrib_iv(&self, index: GLuint, pname: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetVertexAttribiv(index, pname, result.as_mut_ptr());
+    }
+
+    #[inline]
+    unsafe fn get_vertex_attrib_fv(&self, index: GLuint, pname: GLenum, result: &mut [GLfloat]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_
+            .GetVertexAttribfv(index, pname, result.as_mut_ptr());
+    }
+
+    fn get_vertex_attrib_pointer_v(&self, index: GLuint, pname: GLenum) -> GLsizeiptr {
+        let mut result = 0 as *mut GLvoid;
+        unsafe {
+            self.ffi_gl_
+                .GetVertexAttribPointerv(index, pname, &mut result)
+        }
+        result as GLsizeiptr
+    }
+
+    fn get_buffer_parameter_iv(&self, target: GLuint, pname: GLenum) -> GLint {
+        let mut result = 0 as GLint;
+        unsafe {
+            self.ffi_gl_
+                .GetBufferParameteriv(target, pname, &mut result);
+        }
+        result
+    }
+
+    fn get_shader_info_log(&self, shader: GLuint) -> String {
+        let mut max_len = [0];
+        unsafe {
+            self.get_shader_iv(shader, ffi::INFO_LOG_LENGTH, &mut max_len);
+        }
+        if max_len[0] == 0 {
+            return String::new();
+        }
+        let mut result = vec![0u8; max_len[0] as usize];
+        let mut result_len = 0 as GLsizei;
+        unsafe {
+            self.ffi_gl_.GetShaderInfoLog(
+                shader,
+                max_len[0] as GLsizei,
+                &mut result_len,
+                result.as_mut_ptr() as *mut GLchar,
+            );
+        }
+        result.truncate(if result_len > 0 {
+            result_len as usize
+        } else {
+            0
+        });
+        String::from_utf8(result).unwrap()
+    }
+
+    fn get_string(&self, which: GLenum) -> String {
+        unsafe {
+            let llstr = self.ffi_gl_.GetString(which);
+            if !llstr.is_null() {
+                return str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
+                    .to_string();
+            } else {
+                return "".to_string();
+            }
+        }
+    }
+
+    fn get_string_i(&self, which: GLenum, index: GLuint) -> String {
+        unsafe {
+            let llstr = self.ffi_gl_.GetStringi(which, index);
+            if !llstr.is_null() {
+                str::from_utf8_unchecked(CStr::from_ptr(llstr as *const c_char).to_bytes())
+                    .to_string()
+            } else {
+                "".to_string()
+            }
+        }
+    }
+
+    unsafe fn get_shader_iv(&self, shader: GLuint, pname: GLenum, result: &mut [GLint]) {
+        assert!(!result.is_empty());
+        self.ffi_gl_.GetShaderiv(shader, pname, result.as_mut_ptr());
+    }
+
+    fn get_shader_precision_format(
+        &self,
+        shader_type: GLuint,
+        precision_type: GLuint,
+    ) -> (GLint, GLint, GLint) {
+        let (mut range, mut precision) = match precision_type {
+            // These values are for a 32-bit twos-complement integer format.
+            ffi::LOW_INT | ffi::MEDIUM_INT | ffi::HIGH_INT => ([31, 30], 0),
+
+            // These values are for an IEEE single-precision floating-point format.
+            ffi::LOW_FLOAT | ffi::MEDIUM_FLOAT | ffi::HIGH_FLOAT => ([127, 127], 23),
+
+            _ => unreachable!("invalid precision"),
+        };
+        // This function is sometimes defined even though it's really just
+        // a stub, so we need to set range and precision as if it weren't
+        // defined before calling it. Suppress any error that might occur.
+        unsafe {
+            self.ffi_gl_.GetShaderPrecisionFormat(
+                shader_type,
+                precision_type,
+                range.as_mut_ptr(),
+                &mut precision,
+            );
+            let _ = self.ffi_gl_.GetError();
+        }
+
+        (range[0], range[1], precision)
+    }
+
+    fn compile_shader(&self, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.CompileShader(shader);
+        }
+    }
+
+    fn create_program(&self) -> GLuint {
+        unsafe {
+            return self.ffi_gl_.CreateProgram();
+        }
+    }
+
+    fn delete_program(&self, program: GLuint) {
+        unsafe {
+            self.ffi_gl_.DeleteProgram(program);
+        }
+    }
+
+    fn create_shader(&self, shader_type: GLenum) -> GLuint {
+        unsafe {
+            return self.ffi_gl_.CreateShader(shader_type);
+        }
+    }
+
+    fn delete_shader(&self, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.DeleteShader(shader);
+        }
+    }
+
+    fn detach_shader(&self, program: GLuint, shader: GLuint) {
+        unsafe {
+            self.ffi_gl_.DetachShader(program, shader);
+        }
+    }
+
+    fn link_program(&self, program: GLuint) {
+        unsafe {
+            return self.ffi_gl_.LinkProgram(program);
+        }
+    }
+
+    fn clear_color(&self, r: f32, g: f32, b: f32, a: f32) {
+        unsafe {
+            self.ffi_gl_.ClearColor(r, g, b, a);
+        }
+    }
+
+    fn clear(&self, buffer_mask: GLbitfield) {
+        unsafe {
+            self.ffi_gl_.Clear(buffer_mask);
+        }
+    }
+
+    fn clear_depth(&self, depth: f64) {
+        unsafe {
+            self.ffi_gl_.ClearDepthf(depth as GLclampf);
+        }
+    }
+
+    fn clear_stencil(&self, s: GLint) {
+        unsafe {
+            self.ffi_gl_.ClearStencil(s);
+        }
+    }
+
+    fn flush(&self) {
+        unsafe {
+            self.ffi_gl_.Flush();
+        }
+    }
+
+    fn finish(&self) {
+        unsafe {
+            self.ffi_gl_.Finish();
+        }
+    }
+
+    fn get_error(&self) -> GLenum {
+        unsafe { self.ffi_gl_.GetError() }
+    }
+
+    fn stencil_mask(&self, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilMask(mask) }
+    }
+
+    fn stencil_mask_separate(&self, face: GLenum, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilMaskSeparate(face, mask) }
+    }
+
+    fn stencil_func(&self, func: GLenum, ref_: GLint, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilFunc(func, ref_, mask) }
+    }
+
+    fn stencil_func_separate(&self, face: GLenum, func: GLenum, ref_: GLint, mask: GLuint) {
+        unsafe { self.ffi_gl_.StencilFuncSeparate(face, func, ref_, mask) }
+    }
+
+    fn stencil_op(&self, sfail: GLenum, dpfail: GLenum, dppass: GLenum) {
+        unsafe { self.ffi_gl_.StencilOp(sfail, dpfail, dppass) }
+    }
+
+    fn stencil_op_separate(&self, face: GLenum, sfail: GLenum, dpfail: GLenum, dppass: GLenum) {
+        unsafe { self.ffi_gl_.StencilOpSeparate(face, sfail, dpfail, dppass) }
+    }
+
+    fn egl_image_target_texture2d_oes(&self, target: GLenum, image: GLeglImageOES) {
+        unsafe {
+            self.ffi_gl_.EGLImageTargetTexture2DOES(target, image);
+        }
+    }
+
+    fn egl_image_target_renderbuffer_storage_oes(&self, target: GLenum, image: GLeglImageOES) {
+        unsafe {
+            self.ffi_gl_.EGLImageTargetRenderbufferStorageOES(target, image);
+        }
+    }
+
+    fn generate_mipmap(&self, target: GLenum) {
+        unsafe { self.ffi_gl_.GenerateMipmap(target) }
+    }
+
+    fn insert_event_marker_ext(&self, message: &str) {
+        if self.ffi_gl_.InsertEventMarkerEXT.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .InsertEventMarkerEXT(message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn push_group_marker_ext(&self, message: &str) {
+        if self.ffi_gl_.PushGroupMarkerEXT.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .PushGroupMarkerEXT(message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn pop_group_marker_ext(&self) {
+        if self.ffi_gl_.PopGroupMarkerEXT.is_loaded() {
+            unsafe {
+                self.ffi_gl_.PopGroupMarkerEXT();
+            }
+        }
+    }
+
+    fn debug_message_insert_khr(&self, source: GLenum, type_: GLenum, id: GLuint, severity: GLenum, message: &str) {
+        if self.ffi_gl_.DebugMessageInsertKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .DebugMessageInsertKHR(source, type_, id, severity, message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn push_debug_group_khr(&self, source: GLenum, id: GLuint, message: &str) {
+        if self.ffi_gl_.PushDebugGroupKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_
+                    .PushDebugGroupKHR(source, id, message.len() as GLsizei, message.as_ptr() as *const _);
+            }
+        }
+    }
+
+    fn pop_debug_group_khr(&self) {
+        if self.ffi_gl_.PopDebugGroupKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_.PopDebugGroupKHR();
+            }
+        }
+    }
+
+    fn fence_sync(&self, condition: GLenum, flags: GLbitfield) -> GLsync {
+        unsafe { self.ffi_gl_.FenceSync(condition, flags) as *const _ }
+    }
+
+    fn client_wait_sync(&self, sync: GLsync, flags: GLbitfield, timeout: GLuint64) -> GLenum {
+        unsafe {
+            self.ffi_gl_
+                .ClientWaitSync(sync as *const _, flags, timeout)
+        }
+    }
+
+    fn wait_sync(&self, sync: GLsync, flags: GLbitfield, timeout: GLuint64) {
+        unsafe {
+            self.ffi_gl_.WaitSync(sync as *const _, flags, timeout);
+        }
+    }
+
+    fn delete_sync(&self, sync: GLsync) {
+        unsafe {
+            self.ffi_gl_.DeleteSync(sync as *const _);
+        }
+    }
+
+    fn texture_range_apple(&self, _target: GLenum, _data: &[u8]) {
+        panic!("not supported")
+    }
+
+    fn gen_fences_apple(&self, _n: GLsizei) -> Vec<GLuint> {
+        panic!("not supported")
+    }
+
+    fn delete_fences_apple(&self, _fences: &[GLuint]) {
+        panic!("not supported")
+    }
+
+    fn set_fence_apple(&self, _fence: GLuint) {
+        panic!("not supported")
+    }
+
+    fn finish_fence_apple(&self, _fence: GLuint) {
+        panic!("not supported")
+    }
+
+    fn test_fence_apple(&self, _fence: GLuint) {
+        panic!("not supported")
+    }
+
+    fn test_object_apple(&self, _object: GLenum, _name: GLuint) -> GLboolean {
+        panic!("not supported")
+    }
+
+    fn finish_object_apple(&self, _object: GLenum, _name: GLuint) {
+        panic!("not supported")
+    }
+
+
+
+    // GL_ARB_blend_func_extended
+    fn bind_frag_data_location_indexed(
+        &self,
+        _program: GLuint,
+        _color_number: GLuint,
+        _index: GLuint,
+        _name: &str,
+    ) {
+        panic!("not supported");
+    }
+
+    fn get_frag_data_index(&self, _program: GLuint, _name: &str) -> GLint {
+        panic!("not supported");
+    }
+
+    // GL_KHR_debug
+    fn get_debug_messages(&self) -> Vec<DebugMessage> {
+        if !self.ffi_gl_.GetDebugMessageLog.is_loaded() {
+            return Vec::new();
+        }
+
+        let mut max_message_len = 0;
+        unsafe {
+            self.ffi_gl_
+                .GetIntegerv(ffi::MAX_DEBUG_MESSAGE_LENGTH, &mut max_message_len)
+        }
+
+        let mut output = Vec::new();
+        const CAPACITY: usize = 4;
+
+        let mut msg_data = vec![0u8; CAPACITY * max_message_len as usize];
+        let mut sources = [0 as GLenum; CAPACITY];
+        let mut types = [0 as GLenum; CAPACITY];
+        let mut severities = [0 as GLenum; CAPACITY];
+        let mut ids = [0 as GLuint; CAPACITY];
+        let mut lengths = [0 as GLsizei; CAPACITY];
+
+        loop {
+            let count = unsafe {
+                self.ffi_gl_.GetDebugMessageLog(
+                    CAPACITY as _,
+                    msg_data.len() as _,
+                    sources.as_mut_ptr(),
+                    types.as_mut_ptr(),
+                    ids.as_mut_ptr(),
+                    severities.as_mut_ptr(),
+                    lengths.as_mut_ptr(),
+                    msg_data.as_mut_ptr() as *mut _,
+                )
+            };
+
+            let mut offset = 0;
+            output.extend((0..count as usize).map(|i| {
+                let len = lengths[i] as usize;
+                let slice = &msg_data[offset..offset + len];
+                offset += len;
+                DebugMessage {
+                    message: String::from_utf8_lossy(slice).to_string(),
+                    source: sources[i],
+                    ty: types[i],
+                    id: ids[i],
+                    severity: severities[i],
+                }
+            }));
+
+            if (count as usize) < CAPACITY {
+                return output;
+            }
+        }
+    }
+
+    fn provoking_vertex_angle(&self, mode: GLenum) {
+        unsafe {
+            self.ffi_gl_.ProvokingVertexANGLE(mode);
+        }
+    }
+
+    // GL_KHR_blend_equation_advanced
+    fn blend_barrier_khr(&self) {
+        if self.ffi_gl_.BlendBarrierKHR.is_loaded() {
+            unsafe {
+                self.ffi_gl_.BlendBarrierKHR();
+            }
+        }
+    }
+
+    // GL_CHROMIUM_copy_texture
+    fn copy_texture_chromium(&self,
+        source_id: GLuint, source_level: GLint,
+        dest_target: GLenum, dest_id: GLuint, dest_level: GLint,
+        internal_format: GLint, dest_type: GLenum,
+        unpack_flip_y: GLboolean, unpack_premultiply_alpha: GLboolean, unpack_unmultiply_alpha: GLboolean)
+    {
+        unsafe {
+            self.ffi_gl_.CopyTextureCHROMIUM(source_id, source_level, dest_target, dest_id, dest_level,
+                internal_format, dest_type,
+                unpack_flip_y, unpack_premultiply_alpha, unpack_unmultiply_alpha,
+            );
+        }
+    }
+    fn copy_sub_texture_chromium(&self,
+        source_id: GLuint, source_level: GLint,
+        dest_target: GLenum, dest_id: GLuint, dest_level: GLint,
+        x_offset: GLint, y_offset: GLint, x: GLint, y: GLint, width: GLsizei, height: GLsizei,
+        unpack_flip_y: GLboolean, unpack_premultiply_alpha: GLboolean, unpack_unmultiply_alpha: GLboolean)
+    {
+        unsafe {
+            self.ffi_gl_.CopySubTextureCHROMIUM(source_id, source_level, dest_target, dest_id, dest_level,
+                x_offset, y_offset, x, y, width, height,
+                unpack_flip_y, unpack_premultiply_alpha, unpack_unmultiply_alpha,
+            );
+        }
+    }
+
+    // GL_ANGLE_copy_texture_3d
+    fn copy_texture_3d_angle(
+        &self,
+        source_id: GLuint,
+        source_level: GLint,
+        dest_target: GLenum,
+        dest_id: GLuint,
+        dest_level: GLint,
+        internal_format: GLint,
+        dest_type: GLenum,
+        unpack_flip_y: GLboolean,
+        unpack_premultiply_alpha: GLboolean,
+        unpack_unmultiply_alpha: GLboolean,
+    ) {
+        unsafe {
+            self.ffi_gl_.CopyTexture3DANGLE(
+                source_id,
+                source_level,
+                dest_target,
+                dest_id,
+                dest_level,
+                internal_format,
+                dest_type,
+                unpack_flip_y,
+                unpack_premultiply_alpha,
+                unpack_unmultiply_alpha,
+            );
+        }
+    }
+
+    fn copy_sub_texture_3d_angle(
+        &self,
+        source_id: GLuint,
+        source_level: GLint,
+        dest_target: GLenum,
+        dest_id: GLuint,
+        dest_level: GLint,
+        x_offset: GLint,
+        y_offset: GLint,
+        z_offset: GLint,
+        x: GLint,
+        y: GLint,
+        z: GLint,
+        width: GLsizei,
+        height: GLsizei,
+        depth: GLsizei,
+        unpack_flip_y: GLboolean,
+        unpack_premultiply_alpha: GLboolean,
+        unpack_unmultiply_alpha: GLboolean,
+    ) {
+        unsafe {
+            self.ffi_gl_.CopySubTexture3DANGLE(
+                source_id,
+                source_level,
+                dest_target,
+                dest_id,
+                dest_level,
+                x_offset,
+                y_offset,
+                z_offset,
+                x,
+                y,
+                z,
+                width,
+                height,
+                depth,
+                unpack_flip_y,
+                unpack_premultiply_alpha,
+                unpack_unmultiply_alpha,
+            );
+        }
+    }
+
+    fn buffer_storage(
+        &self,
+        target: GLenum,
+        size: GLsizeiptr,
+        data: *const GLvoid,
+        flags: GLbitfield,
+    ) {
+        unsafe {
+            self.ffi_gl_.BufferStorageEXT(target, size, data, flags);
+        }
+    }
+
+    fn flush_mapped_buffer_range(&self, target: GLenum, offset: GLintptr, length: GLsizeiptr) {
+        unsafe {
+            self.ffi_gl_.FlushMappedBufferRange(target, offset, length);
+        }
+    }
+
+    fn start_tiling_qcom(&self, x: GLuint, y: GLuint, width: GLuint, height: GLuint, preserve_mask: GLbitfield) {
+        unsafe {
+            self.ffi_gl_.StartTilingQCOM(x, y, width, height, preserve_mask);
+        }
+    }
+
+    fn end_tiling_qcom(&self, preserve_mask: GLbitfield) {
+        unsafe {
+            self.ffi_gl_.EndTilingQCOM(preserve_mask);
+        }
+    }
+}
diff --git a/third_party/rust/gleam/src/lib.rs b/third_party/rust/gleam/src/lib.rs
new file mode 100644
index 0000000000..aebb612368
--- /dev/null
+++ b/third_party/rust/gleam/src/lib.rs
@@ -0,0 +1,25 @@
+// Copyright 2014 The Servo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![crate_name = "gleam"]
+#![crate_type = "lib"]
+
+pub mod gl;
+
+mod ffi {
+    include!(concat!(env!("OUT_DIR"), "/gl_and_gles_bindings.rs"));
+}
+
+mod ffi_gl {
+    include!(concat!(env!("OUT_DIR"), "/gl_bindings.rs"));
+}
+
+mod ffi_gles {
+    include!(concat!(env!("OUT_DIR"), "/gles_bindings.rs"));
+}