1 files changed, 436 insertions, 0 deletions
diff --git a/gfx/wr/webrender/src/command_buffer.rs b/gfx/wr/webrender/src/command_buffer.rs
new file mode 100644
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+++ b/gfx/wr/webrender/src/command_buffer.rs
@@ -0,0 +1,436 @@
+/* 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/. */
+
+use api::units::PictureRect;
+use crate::{spatial_tree::SpatialNodeIndex, render_task_graph::RenderTaskId, surface::SurfaceTileDescriptor, picture::TileKey, renderer::GpuBufferAddress, FastHashMap, prim_store::PrimitiveInstanceIndex, gpu_cache::GpuCacheAddress};
+use crate::gpu_types::{QuadSegment, TransformPaletteId};
+use crate::segment::EdgeAaSegmentMask;
+
+/// A tightly packed command stored in a command buffer
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+#[derive(Debug, Copy, Clone)]
+pub struct Command(u32);
+
+impl Command {
+    /// Draw a simple primitive that needs prim instance index only.
+    const CMD_DRAW_SIMPLE_PRIM: u32 = 0x00000000;
+    /// Change the current spatial node.
+    const CMD_SET_SPATIAL_NODE: u32 = 0x10000000;
+    /// Draw a complex (3d-split) primitive, that has multiple GPU cache addresses.
+    const CMD_DRAW_COMPLEX_PRIM: u32 = 0x20000000;
+    /// Draw a primitive, that has a single GPU buffer addresses.
+    const CMD_DRAW_INSTANCE: u32 = 0x30000000;
+    /// Draw a generic quad primitive
+    const CMD_DRAW_QUAD: u32 = 0x40000000;
+    /// Set a list of variable-length segments
+    const CMD_SET_SEGMENTS: u32 = 0x50000000;
+
+    /// Bitmask for command bits of the command.
+    const CMD_MASK: u32 = 0xf0000000;
+    /// Bitmask for param bits of the command.
+    const PARAM_MASK: u32 = 0x0fffffff;
+
+    /// Encode drawing a simple primitive.
+    fn draw_simple_prim(prim_instance_index: PrimitiveInstanceIndex) -> Self {
+        Command(Command::CMD_DRAW_SIMPLE_PRIM | prim_instance_index.0)
+    }
+
+    /// Encode changing spatial node.
+    fn set_spatial_node(spatial_node_index: SpatialNodeIndex) -> Self {
+        Command(Command::CMD_SET_SPATIAL_NODE | spatial_node_index.0)
+    }
+
+    /// Encode a list of segments that follow
+    fn set_segments(count: usize) -> Self {
+        Command(Command::CMD_SET_SEGMENTS | count as u32)
+    }
+
+    /// Encode drawing a complex prim.
+    fn draw_complex_prim(prim_instance_index: PrimitiveInstanceIndex) -> Self {
+        Command(Command::CMD_DRAW_COMPLEX_PRIM | prim_instance_index.0)
+    }
+
+    fn draw_instance(prim_instance_index: PrimitiveInstanceIndex) -> Self {
+        Command(Command::CMD_DRAW_INSTANCE | prim_instance_index.0)
+    }
+
+    /// Encode arbitrary data word.
+    fn data(data: u32) -> Self {
+        Command(data)
+    }
+
+    fn draw_quad(prim_instance_index: PrimitiveInstanceIndex) -> Self {
+        Command(Command::CMD_DRAW_QUAD | prim_instance_index.0)
+    }
+}
+
+bitflags! {
+    /// Flags related to quad primitives
+    #[repr(transparent)]
+    #[cfg_attr(feature = "capture", derive(Serialize))]
+    #[cfg_attr(feature = "replay", derive(Deserialize))]
+    pub struct QuadFlags : u8 {
+        const IS_OPAQUE = 1 << 0;
+
+        /// If true, the prim is 2d and we can apply a clip to the task rect in vertex shader
+        const APPLY_DEVICE_CLIP = 1 << 1;
+
+        /// If true, the device-pixel scale is already applied, so ignore in vertex shaders
+        const IGNORE_DEVICE_PIXEL_SCALE = 1 << 2;
+    }
+}
+
+bitflags! {
+    /// Defines the space that a quad primitive is drawn in
+    #[repr(transparent)]
+    #[cfg_attr(feature = "capture", derive(Serialize))]
+    #[cfg_attr(feature = "replay", derive(Deserialize))]
+    pub struct MaskFlags : i32 {
+        const PRIM_SPACE = 1 << 0;
+    }
+}
+
+/// The unpacked equivalent to a `Command`.
+#[cfg_attr(feature = "capture", derive(Serialize))]
+pub enum PrimitiveCommand {
+    Simple {
+        prim_instance_index: PrimitiveInstanceIndex,
+    },
+    Complex {
+        prim_instance_index: PrimitiveInstanceIndex,
+        gpu_address: GpuCacheAddress,
+    },
+    Instance {
+        prim_instance_index: PrimitiveInstanceIndex,
+        gpu_buffer_address: GpuBufferAddress,
+    },
+    Quad {
+        // TODO(gw): Used for bounding rect only, could possibly remove
+        prim_instance_index: PrimitiveInstanceIndex,
+        gpu_buffer_address: GpuBufferAddress,
+        transform_id: TransformPaletteId,
+        quad_flags: QuadFlags,
+        edge_flags: EdgeAaSegmentMask,
+    },
+}
+
+impl PrimitiveCommand {
+    pub fn simple(
+        prim_instance_index: PrimitiveInstanceIndex,
+    ) -> Self {
+        PrimitiveCommand::Simple {
+            prim_instance_index,
+        }
+    }
+
+    pub fn complex(
+        prim_instance_index: PrimitiveInstanceIndex,
+        gpu_address: GpuCacheAddress,
+    ) -> Self {
+        PrimitiveCommand::Complex {
+            prim_instance_index,
+            gpu_address,
+        }
+    }
+
+    pub fn quad(
+        prim_instance_index: PrimitiveInstanceIndex,
+        gpu_buffer_address: GpuBufferAddress,
+        transform_id: TransformPaletteId,
+        quad_flags: QuadFlags,
+        edge_flags: EdgeAaSegmentMask,
+    ) -> Self {
+        PrimitiveCommand::Quad {
+            prim_instance_index,
+            gpu_buffer_address,
+            transform_id,
+            quad_flags,
+            edge_flags,
+        }
+    }
+
+    pub fn instance(
+        prim_instance_index: PrimitiveInstanceIndex,
+        gpu_buffer_address: GpuBufferAddress,
+    ) -> Self {
+        PrimitiveCommand::Instance {
+            prim_instance_index,
+            gpu_buffer_address,
+        }
+    }
+}
+
+
+/// A list of commands describing how to draw a primitive list.
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+pub struct CommandBuffer {
+    /// The encoded drawing commands.
+    commands: Vec<Command>,
+    /// Cached current spatial node.
+    current_spatial_node_index: SpatialNodeIndex,
+}
+
+impl CommandBuffer {
+    /// Construct a new cmd buffer.
+    pub fn new() -> Self {
+        CommandBuffer {
+            commands: Vec::new(),
+            current_spatial_node_index: SpatialNodeIndex::INVALID,
+        }
+    }
+
+    /// Push a list of segments in to the cmd buffer
+    pub fn set_segments(
+        &mut self,
+        segments: &[QuadSegment],
+    ) {
+        self.commands.push(Command::set_segments(segments.len()));
+        for segment in segments {
+            self.commands.push(Command::data(segment.task_id.index));
+        }
+    }
+
+    /// Add a primitive to the command buffer.
+    pub fn add_prim(
+        &mut self,
+        prim_cmd: &PrimitiveCommand,
+        spatial_node_index: SpatialNodeIndex,
+    ) {
+        if self.current_spatial_node_index != spatial_node_index {
+            self.commands.push(Command::set_spatial_node(spatial_node_index));
+            self.current_spatial_node_index = spatial_node_index;
+        }
+
+        self.add_cmd(prim_cmd);
+    }
+
+    /// Add a cmd to the command buffer.
+    pub fn add_cmd(
+        &mut self,
+        prim_cmd: &PrimitiveCommand,
+    ) {
+        match *prim_cmd {
+            PrimitiveCommand::Simple { prim_instance_index } => {
+                self.commands.push(Command::draw_simple_prim(prim_instance_index));
+            }
+            PrimitiveCommand::Complex { prim_instance_index, gpu_address } => {
+                self.commands.push(Command::draw_complex_prim(prim_instance_index));
+                self.commands.push(Command::data((gpu_address.u as u32) << 16 | gpu_address.v as u32));
+            }
+            PrimitiveCommand::Instance { prim_instance_index, gpu_buffer_address } => {
+                self.commands.push(Command::draw_instance(prim_instance_index));
+                self.commands.push(Command::data((gpu_buffer_address.u as u32) << 16 | gpu_buffer_address.v as u32));
+            }
+            PrimitiveCommand::Quad { prim_instance_index, gpu_buffer_address, transform_id, quad_flags, edge_flags } => {
+                self.commands.push(Command::draw_quad(prim_instance_index));
+                self.commands.push(Command::data((gpu_buffer_address.u as u32) << 16 | gpu_buffer_address.v as u32));
+                self.commands.push(Command::data(transform_id.0));
+                self.commands.push(Command::data((quad_flags.bits as u32) << 16 | edge_flags.bits() as u32));
+            }
+        }
+    }
+
+    /// Iterate the command list, calling a provided closure for each primitive draw command.
+    pub fn iter_prims<F>(
+        &self,
+        f: &mut F,
+    ) where F: FnMut(&PrimitiveCommand, SpatialNodeIndex, &[RenderTaskId]) {
+        let mut current_spatial_node_index = SpatialNodeIndex::INVALID;
+        let mut cmd_iter = self.commands.iter();
+        // TODO(gw): Consider pre-allocating this / Smallvec if it shows up in profiles.
+        let mut segments = Vec::new();
+
+        while let Some(cmd) = cmd_iter.next() {
+            let command = cmd.0 & Command::CMD_MASK;
+            let param = cmd.0 & Command::PARAM_MASK;
+
+            match command {
+                Command::CMD_DRAW_SIMPLE_PRIM => {
+                    let prim_instance_index = PrimitiveInstanceIndex(param);
+                    let cmd = PrimitiveCommand::simple(prim_instance_index);
+                    f(&cmd, current_spatial_node_index, &[]);
+                }
+                Command::CMD_SET_SPATIAL_NODE => {
+                    current_spatial_node_index = SpatialNodeIndex(param);
+                }
+                Command::CMD_DRAW_COMPLEX_PRIM => {
+                    let prim_instance_index = PrimitiveInstanceIndex(param);
+                    let data = cmd_iter.next().unwrap();
+                    let gpu_address = GpuCacheAddress {
+                        u: (data.0 >> 16) as u16,
+                        v: (data.0 & 0xffff) as u16,
+                    };
+                    let cmd = PrimitiveCommand::complex(
+                        prim_instance_index,
+                        gpu_address,
+                    );
+                    f(&cmd, current_spatial_node_index, &[]);
+                }
+                Command::CMD_DRAW_QUAD => {
+                    let prim_instance_index = PrimitiveInstanceIndex(param);
+                    let data = cmd_iter.next().unwrap();
+                    let transform_id = TransformPaletteId(cmd_iter.next().unwrap().0);
+                    let bits = cmd_iter.next().unwrap().0;
+                    let quad_flags = QuadFlags::from_bits((bits >> 16) as u8).unwrap();
+                    let edge_flags = EdgeAaSegmentMask::from_bits((bits & 0xff) as u8).unwrap();
+                    let gpu_buffer_address = GpuBufferAddress {
+                        u: (data.0 >> 16) as u16,
+                        v: (data.0 & 0xffff) as u16,
+                    };
+                    let cmd = PrimitiveCommand::quad(
+                        prim_instance_index,
+                        gpu_buffer_address,
+                        transform_id,
+                        quad_flags,
+                        edge_flags,
+                    );
+                    f(&cmd, current_spatial_node_index, &segments);
+                    segments.clear()
+                }
+                Command::CMD_DRAW_INSTANCE => {
+                    let prim_instance_index = PrimitiveInstanceIndex(param);
+                    let data = cmd_iter.next().unwrap();
+                    let gpu_buffer_address = GpuBufferAddress {
+                        u: (data.0 >> 16) as u16,
+                        v: (data.0 & 0xffff) as u16,
+                    };
+                    let cmd = PrimitiveCommand::instance(
+                        prim_instance_index,
+                        gpu_buffer_address,
+                    );
+                    f(&cmd, current_spatial_node_index, &[]);
+                }
+                Command::CMD_SET_SEGMENTS => {
+                    let count = param;
+                    for _ in 0 .. count {
+                        segments.push(RenderTaskId { index: cmd_iter.next().unwrap().0 });
+                    }
+                }
+                _ => {
+                    unreachable!();
+                }
+            }
+        }
+    }
+}
+
+/// Abstracts whether a command buffer is being built for a tiled (picture cache)
+/// or simple (child surface).
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+pub enum CommandBufferBuilderKind {
+    Tiled {
+        // TODO(gw): It might be worth storing this as a 2d-array instead
+        //           of a hash map if it ever shows up in profiles. This is
+        //           slightly complicated by the sub_slice_index in the
+        //           TileKey structure - could have a 2 level array?
+        tiles: FastHashMap<TileKey, SurfaceTileDescriptor>,
+    },
+    Simple {
+        render_task_id: RenderTaskId,
+        root_task_id: Option<RenderTaskId>,
+        dirty_rect: PictureRect,
+    },
+    Invalid,
+}
+
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+pub struct CommandBufferBuilder {
+    pub kind: CommandBufferBuilderKind,
+
+    /// If a command buffer establishes a sub-graph, then at the end of constructing
+    /// the surface, the parent surface is supplied as an input dependency, and the
+    /// parent surface gets a duplicated (existing) task with the same location, and
+    /// with the sub-graph output as an input dependency.
+    pub establishes_sub_graph: bool,
+
+    /// If this surface builds a sub-graph, it will mark a task in the filter sub-graph
+    /// as a resolve source for the input from the parent surface.
+    pub resolve_source: Option<RenderTaskId>,
+
+    /// List of render tasks that depend on the task that will be created for this builder.
+    pub extra_dependencies: Vec<RenderTaskId>,
+}
+
+impl CommandBufferBuilder {
+    pub fn empty() -> Self {
+        CommandBufferBuilder {
+            kind: CommandBufferBuilderKind::Invalid,
+            establishes_sub_graph: false,
+            resolve_source: None,
+            extra_dependencies: Vec::new(),
+        }
+    }
+
+    /// Construct a tiled command buffer builder.
+    pub fn new_tiled(
+        tiles: FastHashMap<TileKey, SurfaceTileDescriptor>,
+    ) -> Self {
+        CommandBufferBuilder {
+            kind: CommandBufferBuilderKind::Tiled {
+                tiles,
+            },
+            establishes_sub_graph: false,
+            resolve_source: None,
+            extra_dependencies: Vec::new(),
+        }
+    }
+
+    /// Construct a simple command buffer builder.
+    pub fn new_simple(
+        render_task_id: RenderTaskId,
+        establishes_sub_graph: bool,
+        root_task_id: Option<RenderTaskId>,
+        dirty_rect: PictureRect,
+    ) -> Self {
+        CommandBufferBuilder {
+            kind: CommandBufferBuilderKind::Simple {
+                render_task_id,
+                root_task_id,
+                dirty_rect,
+            },
+            establishes_sub_graph,
+            resolve_source: None,
+            extra_dependencies: Vec::new(),
+        }
+    }
+}
+
+// Index into a command buffer stored in a `CommandBufferList`.
+#[cfg_attr(feature = "capture", derive(Serialize))]
+#[cfg_attr(feature = "replay", derive(Deserialize))]
+#[derive(Debug, Copy, Clone)]
+pub struct CommandBufferIndex(pub u32);
+
+// Container for a list of command buffers that are built for a frame.
+pub struct CommandBufferList {
+    cmd_buffers: Vec<CommandBuffer>,
+}
+
+impl CommandBufferList {
+    pub fn new() -> Self {
+        CommandBufferList {
+            cmd_buffers: Vec::new(),
+        }
+    }
+
+    pub fn create_cmd_buffer(
+        &mut self,
+    ) -> CommandBufferIndex {
+        let index = CommandBufferIndex(self.cmd_buffers.len() as u32);
+        self.cmd_buffers.push(CommandBuffer::new());
+        index
+    }
+
+    pub fn get(&self, index: CommandBufferIndex) -> &CommandBuffer {
+        &self.cmd_buffers[index.0 as usize]
+    }
+
+    pub fn get_mut(&mut self, index: CommandBufferIndex) -> &mut CommandBuffer {
+        &mut self.cmd_buffers[index.0 as usize]
+    }
+}