1 files changed, 72 insertions, 0 deletions
diff --git a/dom/canvas/WebGLVertexArrayFake.cpp b/dom/canvas/WebGLVertexArrayFake.cpp
new file mode 100644
index 0000000000..3a498ea209
--- /dev/null
+++ b/dom/canvas/WebGLVertexArrayFake.cpp
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WebGLVertexArrayFake.h"
+
+#include "GLContext.h"
+#include "WebGLBuffer.h"
+#include "WebGLContext.h"
+
+namespace mozilla {
+
+static void BindBuffer(gl::GLContext* const gl, const GLenum target,
+                       WebGLBuffer* const buffer) {
+  gl->fBindBuffer(target, buffer ? buffer->mGLName : 0);
+}
+
+WebGLVertexArrayFake::WebGLVertexArrayFake(WebGLContext* webgl)
+    : WebGLVertexArray(webgl) {}
+
+void WebGLVertexArray::DoVertexAttrib(const uint32_t index,
+                                      const uint32_t vertOffset) const {
+  const auto& gl = mContext->gl;
+
+  const bool useDivisor =
+      mContext->IsWebGL2() ||
+      mContext->IsExtensionEnabled(WebGLExtensionID::ANGLE_instanced_arrays);
+
+  const auto& binding = mBindings.at(index);
+  const auto& desc = mDescs.at(index);
+
+  if (binding.layout.isArray) {
+    gl->fEnableVertexAttribArray(index);
+  } else {
+    gl->fDisableVertexAttribArray(index);
+  }
+
+  if (useDivisor) {
+    gl->fVertexAttribDivisor(index, binding.layout.divisor);
+  }
+
+  static_assert(IsBufferTargetLazilyBound(LOCAL_GL_ARRAY_BUFFER));
+  BindBuffer(gl, LOCAL_GL_ARRAY_BUFFER, binding.buffer);
+
+  auto desc2 = desc;
+  if (!binding.layout.divisor) {
+    desc2.byteOffset += binding.layout.byteStride * vertOffset;
+  }
+  DoVertexAttribPointer(*gl, index, desc2);
+
+  BindBuffer(gl, LOCAL_GL_ARRAY_BUFFER, nullptr);
+}
+
+void WebGLVertexArrayFake::BindVertexArray() {
+  // Go through and re-bind all buffers and setup all
+  // vertex attribute pointers
+  const auto& gl = mContext->gl;
+
+  mContext->mBoundVertexArray = this;
+
+  static_assert(IsBufferTargetLazilyBound(LOCAL_GL_ARRAY_BUFFER));
+  static_assert(!IsBufferTargetLazilyBound(LOCAL_GL_ELEMENT_ARRAY_BUFFER));
+
+  BindBuffer(gl, LOCAL_GL_ELEMENT_ARRAY_BUFFER, mElementArrayBuffer);
+
+  for (const auto i : IntegerRange(mContext->MaxVertexAttribs())) {
+    DoVertexAttrib(i);
+  }
+}
+
+}  // namespace mozilla