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/* 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
use api::{ColorF, YuvRangedColorSpace, YuvFormat, ImageRendering, ExternalImageId, ImageBufferKind};
use api::units::*;
use api::ColorDepth;
use crate::image_source::resolve_image;
use euclid::Box2D;
use crate::gpu_cache::GpuCache;
use crate::gpu_types::{ZBufferId, ZBufferIdGenerator};
use crate::internal_types::{FrameAllocator, FrameMemory, FrameVec, TextureSource};
use crate::picture::{ImageDependency, ResolvedSurfaceTexture, TileCacheInstance, TileId, TileSurface};
use crate::prim_store::DeferredResolve;
use crate::resource_cache::{ImageRequest, ResourceCache};
use crate::util::{Preallocator, ScaleOffset};
use crate::tile_cache::PictureCacheDebugInfo;
use crate::device::Device;
use crate::space::SpaceMapper;
use std::{ops, u64, os::raw::c_void};
/*
Types and definitions related to compositing picture cache tiles
and/or OS compositor integration.
*/
/// Which method is being used to draw a requested compositor surface
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Copy, Clone, MallocSizeOf, PartialEq)]
pub enum CompositorSurfaceKind {
/// Don't create a native compositor surface, blit it as a regular primitive
Blit,
/// Create a native surface, draw it under content (must be opaque)
Underlay,
/// Create a native surface, draw it between sub-slices (supports transparent)
Overlay,
}
/// Describes details of an operation to apply to a native surface
#[derive(Debug, Clone)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum NativeSurfaceOperationDetails {
CreateSurface {
id: NativeSurfaceId,
virtual_offset: DeviceIntPoint,
tile_size: DeviceIntSize,
is_opaque: bool,
},
CreateExternalSurface {
id: NativeSurfaceId,
is_opaque: bool,
},
CreateBackdropSurface {
id: NativeSurfaceId,
color: ColorF,
},
DestroySurface {
id: NativeSurfaceId,
},
CreateTile {
id: NativeTileId,
},
DestroyTile {
id: NativeTileId,
},
AttachExternalImage {
id: NativeSurfaceId,
external_image: ExternalImageId,
}
}
/// Describes an operation to apply to a native surface
#[derive(Debug, Clone)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct NativeSurfaceOperation {
pub details: NativeSurfaceOperationDetails,
}
/// Describes the source surface information for a tile to be composited. This
/// is the analog of the TileSurface type, with target surface information
/// resolved such that it can be used by the renderer.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Clone)]
pub enum CompositeTileSurface {
Texture {
surface: ResolvedSurfaceTexture,
},
Color {
color: ColorF,
},
Clear,
ExternalSurface {
external_surface_index: ResolvedExternalSurfaceIndex,
},
}
/// The surface format for a tile being composited.
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum CompositeSurfaceFormat {
Rgba,
Yuv,
}
bitflags! {
/// Optional features that can be opted-out of when compositing,
/// possibly allowing a fast path to be selected.
#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
pub struct CompositeFeatures: u8 {
// UV coordinates do not require clamping, for example because the
// entire texture is being composited.
const NO_UV_CLAMP = 1 << 0;
// The texture sample should not be modulated by a specified color.
const NO_COLOR_MODULATION = 1 << 1;
}
}
#[derive(Copy, Clone, Debug, PartialEq)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum TileKind {
Opaque,
Alpha,
Clear,
}
// Index in to the compositor transforms stored in `CompositeState`
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Copy, Clone)]
pub struct CompositorTransformIndex(usize);
impl CompositorTransformIndex {
pub const INVALID: CompositorTransformIndex = CompositorTransformIndex(!0);
}
/// Describes the geometry and surface of a tile to be composited
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Clone)]
pub struct CompositeTile {
pub surface: CompositeTileSurface,
pub local_rect: PictureRect,
pub local_valid_rect: PictureRect,
pub local_dirty_rect: PictureRect,
pub device_clip_rect: DeviceRect,
pub z_id: ZBufferId,
pub kind: TileKind,
pub transform_index: CompositorTransformIndex,
}
pub fn tile_kind(surface: &CompositeTileSurface, is_opaque: bool) -> TileKind {
match surface {
// Color tiles are, by definition, opaque. We might support non-opaque color
// tiles if we ever find pages that have a lot of these.
CompositeTileSurface::Color { .. } => TileKind::Opaque,
// Clear tiles have a special bucket
CompositeTileSurface::Clear => TileKind::Clear,
CompositeTileSurface::Texture { .. }
| CompositeTileSurface::ExternalSurface { .. } => {
// Texture surfaces get bucketed by opaque/alpha, for z-rejection
// on the Draw compositor mode.
if is_opaque {
TileKind::Opaque
} else {
TileKind::Alpha
}
}
}
}
pub enum ExternalSurfaceDependency {
Yuv {
image_dependencies: [ImageDependency; 3],
color_space: YuvRangedColorSpace,
format: YuvFormat,
channel_bit_depth: u32,
},
Rgb {
image_dependency: ImageDependency,
},
}
/// Describes information about drawing a primitive as a compositor surface.
/// For now, we support only YUV images as compositor surfaces, but in future
/// this will also support RGBA images.
pub struct ExternalSurfaceDescriptor {
// Normalized rectangle of this surface in local coordinate space
// TODO(gw): Fix up local_rect unit kinds in ExternalSurfaceDescriptor (many flow on effects)
pub local_surface_size: LayoutSize,
pub local_rect: PictureRect,
pub local_clip_rect: PictureRect,
pub clip_rect: DeviceRect,
pub transform_index: CompositorTransformIndex,
pub image_rendering: ImageRendering,
pub z_id: ZBufferId,
pub dependency: ExternalSurfaceDependency,
/// If native compositing is enabled, the native compositor surface handle.
/// Otherwise, this will be None
pub native_surface_id: Option<NativeSurfaceId>,
/// If the native surface needs to be updated, this will contain the size
/// of the native surface as Some(size). If not dirty, this is None.
pub update_params: Option<DeviceIntSize>,
}
impl ExternalSurfaceDescriptor {
/// Calculate an optional occlusion rect for a given compositor surface
pub fn get_occluder_rect(
&self,
local_clip_rect: &PictureRect,
map_pic_to_world: &SpaceMapper<PicturePixel, WorldPixel>,
) -> Option<WorldRect> {
let local_surface_rect = self
.local_rect
.intersection(&self.local_clip_rect)
.and_then(|r| {
r.intersection(local_clip_rect)
});
local_surface_rect.map(|local_surface_rect| {
map_pic_to_world
.map(&local_surface_rect)
.expect("bug: unable to map external surface to world space")
})
}
}
/// Information about a plane in a YUV or RGB surface.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Copy, Clone)]
pub struct ExternalPlaneDescriptor {
pub texture: TextureSource,
pub uv_rect: TexelRect,
}
impl ExternalPlaneDescriptor {
fn invalid() -> Self {
ExternalPlaneDescriptor {
texture: TextureSource::Invalid,
uv_rect: TexelRect::invalid(),
}
}
}
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct ResolvedExternalSurfaceIndex(pub usize);
impl ResolvedExternalSurfaceIndex {
pub const INVALID: ResolvedExternalSurfaceIndex = ResolvedExternalSurfaceIndex(usize::MAX);
}
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum ResolvedExternalSurfaceColorData {
Yuv {
// YUV specific information
image_dependencies: [ImageDependency; 3],
planes: [ExternalPlaneDescriptor; 3],
color_space: YuvRangedColorSpace,
format: YuvFormat,
channel_bit_depth: u32,
},
Rgb {
image_dependency: ImageDependency,
plane: ExternalPlaneDescriptor,
},
}
/// An ExternalSurfaceDescriptor that has had image keys
/// resolved to texture handles. This contains all the
/// information that the compositor step in renderer
/// needs to know.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct ResolvedExternalSurface {
pub color_data: ResolvedExternalSurfaceColorData,
pub image_buffer_kind: ImageBufferKind,
// Update information for a native surface if it's dirty
pub update_params: Option<(NativeSurfaceId, DeviceIntSize)>,
}
/// Public interface specified in `WebRenderOptions` that configures
/// how WR compositing will operate.
pub enum CompositorConfig {
/// Let WR draw tiles via normal batching. This requires no special OS support.
Draw {
/// If this is zero, a full screen present occurs at the end of the
/// frame. This is the simplest and default mode. If this is non-zero,
/// then the operating system supports a form of 'partial present' where
/// only dirty regions of the framebuffer need to be updated.
max_partial_present_rects: usize,
/// If this is true, WR must draw the previous frames' dirty regions when
/// doing a partial present. This is used for EGL which requires the front
/// buffer to always be fully consistent.
draw_previous_partial_present_regions: bool,
/// A client provided interface to a compositor handling partial present.
/// Required if webrender must query the backbuffer's age.
partial_present: Option<Box<dyn PartialPresentCompositor>>,
},
/// Use a native OS compositor to draw tiles. This requires clients to implement
/// the Compositor trait, but can be significantly more power efficient on operating
/// systems that support it.
Native {
/// A client provided interface to a native / OS compositor.
compositor: Box<dyn Compositor>,
}
}
impl CompositorConfig {
pub fn compositor(&mut self) -> Option<&mut Box<dyn Compositor>> {
match self {
CompositorConfig::Native { ref mut compositor, .. } => {
Some(compositor)
}
CompositorConfig::Draw { .. } => {
None
}
}
}
pub fn partial_present(&mut self) -> Option<&mut Box<dyn PartialPresentCompositor>> {
match self {
CompositorConfig::Native { .. } => {
None
}
CompositorConfig::Draw { ref mut partial_present, .. } => {
partial_present.as_mut()
}
}
}
}
impl Default for CompositorConfig {
/// Default compositor config is full present without partial present.
fn default() -> Self {
CompositorConfig::Draw {
max_partial_present_rects: 0,
draw_previous_partial_present_regions: false,
partial_present: None,
}
}
}
/// This is a representation of `CompositorConfig` without the `Compositor` trait
/// present. This allows it to be freely copied to other threads, such as the render
/// backend where the frame builder can access it.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum CompositorKind {
/// WR handles compositing via drawing.
Draw {
/// Partial present support.
max_partial_present_rects: usize,
/// Draw previous regions when doing partial present.
draw_previous_partial_present_regions: bool,
},
/// Native OS compositor.
Native {
/// The capabilities of the underlying platform.
capabilities: CompositorCapabilities,
},
}
impl Default for CompositorKind {
/// Default compositor config is full present without partial present.
fn default() -> Self {
CompositorKind::Draw {
max_partial_present_rects: 0,
draw_previous_partial_present_regions: false,
}
}
}
impl CompositorKind {
pub fn get_virtual_surface_size(&self) -> i32 {
match self {
CompositorKind::Draw { .. } => 0,
CompositorKind::Native { capabilities, .. } => capabilities.virtual_surface_size,
}
}
pub fn should_redraw_on_invalidation(&self) -> bool {
match self {
CompositorKind::Draw { max_partial_present_rects, .. } => {
// When partial present is enabled, we need to force redraw.
*max_partial_present_rects > 0
}
CompositorKind::Native { capabilities, .. } => capabilities.redraw_on_invalidation,
}
}
}
/// The backing surface kind for a tile. Same as `TileSurface`, minus
/// the texture cache handles, visibility masks etc.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(PartialEq, Clone)]
pub enum TileSurfaceKind {
Texture,
Color {
color: ColorF,
},
Clear,
}
impl From<&TileSurface> for TileSurfaceKind {
fn from(surface: &TileSurface) -> Self {
match surface {
TileSurface::Texture { .. } => TileSurfaceKind::Texture,
TileSurface::Color { color } => TileSurfaceKind::Color { color: *color },
TileSurface::Clear => TileSurfaceKind::Clear,
}
}
}
/// Describes properties that identify a tile composition uniquely.
/// The backing surface for this tile.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(PartialEq, Clone)]
pub struct CompositeTileDescriptor {
pub tile_id: TileId,
pub surface_kind: TileSurfaceKind,
}
// Whether a compositor surface / swapchain is being used
// by WR to render content, or is an external swapchain for video
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, PartialEq, Copy, Clone)]
pub enum CompositorSurfaceUsage {
Content,
External,
}
/// Describes the properties that identify a surface composition uniquely.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(PartialEq, Clone)]
pub struct CompositeSurfaceDescriptor {
pub surface_id: Option<NativeSurfaceId>,
pub clip_rect: DeviceRect,
pub transform: CompositorSurfaceTransform,
// A list of image keys and generations that this compositor surface
// depends on. This avoids composites being skipped when the only
// thing that has changed is the generation of an compositor surface
// image dependency.
pub image_dependencies: [ImageDependency; 3],
pub image_rendering: ImageRendering,
// List of the surface information for each tile added to this virtual surface
pub tile_descriptors: Vec<CompositeTileDescriptor>,
}
/// Describes surface properties used to composite a frame. This
/// is used to compare compositions between frames.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(PartialEq, Clone)]
pub struct CompositeDescriptor {
pub surfaces: Vec<CompositeSurfaceDescriptor>,
pub external_surfaces_rect: DeviceRect,
}
impl CompositeDescriptor {
/// Construct an empty descriptor.
pub fn empty() -> Self {
CompositeDescriptor {
surfaces: Vec::new(),
external_surfaces_rect: DeviceRect::zero(),
}
}
}
pub struct CompositeStatePreallocator {
tiles: Preallocator,
external_surfaces: Preallocator,
occluders: Preallocator,
occluders_events: Preallocator,
occluders_active: Preallocator,
descriptor_surfaces: Preallocator,
}
impl CompositeStatePreallocator {
pub fn record(&mut self, state: &CompositeState) {
self.tiles.record_vec(&state.tiles);
self.external_surfaces.record_vec(&state.external_surfaces);
self.occluders.record_vec(&state.occluders.occluders);
self.occluders_events.record_vec(&state.occluders.scratch.events);
self.occluders_active.record_vec(&state.occluders.scratch.active);
self.descriptor_surfaces.record_vec(&state.descriptor.surfaces);
}
pub fn preallocate(&self, state: &mut CompositeState) {
self.tiles.preallocate_framevec(&mut state.tiles);
self.external_surfaces.preallocate_framevec(&mut state.external_surfaces);
self.occluders.preallocate_framevec(&mut state.occluders.occluders);
self.occluders_events.preallocate_framevec(&mut state.occluders.scratch.events);
self.occluders_active.preallocate_framevec(&mut state.occluders.scratch.active);
self.descriptor_surfaces.preallocate_vec(&mut state.descriptor.surfaces);
}
}
impl Default for CompositeStatePreallocator {
fn default() -> Self {
CompositeStatePreallocator {
tiles: Preallocator::new(56),
external_surfaces: Preallocator::new(0),
occluders: Preallocator::new(16),
occluders_events: Preallocator::new(32),
occluders_active: Preallocator::new(16),
descriptor_surfaces: Preallocator::new(8),
}
}
}
/// A transform for either a picture cache or external compositor surface, stored
/// in the `CompositeState` structure. This allows conversions from local rects
/// to raster or device rects, without access to the spatial tree (e.g. during
/// the render step where dirty rects are calculated). Since we know that we only
/// handle scale and offset transforms for these types, we can store a single
/// ScaleOffset rather than 4x4 matrix here for efficiency.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct CompositorTransform {
// Map from local rect of a composite tile to the real backing surface coords
local_to_raster: ScaleOffset,
// Map from surface coords to the final device space position
raster_to_device: ScaleOffset,
// Combined local -> surface -> device transform
local_to_device: ScaleOffset,
}
/// The list of tiles to be drawn this frame
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct CompositeState {
// TODO(gw): Consider splitting up CompositeState into separate struct types depending
// on the selected compositing mode. Many of the fields in this state struct
// are only applicable to either Native or Draw compositing mode.
/// List of tiles to be drawn by the Draw compositor.
/// Tiles are accumulated in this vector and sorted from front to back at the end of the
/// frame.
pub tiles: FrameVec<CompositeTile>,
/// List of primitives that were promoted to be compositor surfaces.
pub external_surfaces: FrameVec<ResolvedExternalSurface>,
/// Used to generate z-id values for tiles in the Draw compositor mode.
pub z_generator: ZBufferIdGenerator,
// If false, we can't rely on the dirty rects in the CompositeTile
// instances. This currently occurs during a scroll event, as a
// signal to refresh the whole screen. This is only a temporary
// measure until we integrate with OS compositors. In the meantime
// it gives us the ability to partial present for any non-scroll
// case as a simple win (e.g. video, animation etc).
pub dirty_rects_are_valid: bool,
/// The kind of compositor for picture cache tiles (e.g. drawn by WR, or OS compositor)
pub compositor_kind: CompositorKind,
/// List of registered occluders
pub occluders: Occluders,
/// Description of the surfaces and properties that are being composited.
pub descriptor: CompositeDescriptor,
/// Debugging information about the state of the pictures cached for regression testing.
pub picture_cache_debug: PictureCacheDebugInfo,
/// List of registered transforms used by picture cache or external surfaces
pub transforms: FrameVec<CompositorTransform>,
/// Whether we have low quality pinch zoom enabled
low_quality_pinch_zoom: bool,
}
impl CompositeState {
/// Construct a new state for compositing picture tiles. This is created
/// during each frame construction and passed to the renderer.
pub fn new(
compositor_kind: CompositorKind,
max_depth_ids: i32,
dirty_rects_are_valid: bool,
low_quality_pinch_zoom: bool,
memory: &FrameMemory,
) -> Self {
CompositeState {
tiles: memory.new_vec(),
z_generator: ZBufferIdGenerator::new(max_depth_ids),
dirty_rects_are_valid,
compositor_kind,
occluders: Occluders::new(memory),
descriptor: CompositeDescriptor::empty(),
external_surfaces: memory.new_vec(),
picture_cache_debug: PictureCacheDebugInfo::new(),
transforms: memory.new_vec(),
low_quality_pinch_zoom,
}
}
/// Register use of a transform for a picture cache tile or external surface
pub fn register_transform(
&mut self,
local_to_raster: ScaleOffset,
raster_to_device: ScaleOffset,
) -> CompositorTransformIndex {
let index = CompositorTransformIndex(self.transforms.len());
let local_to_device = local_to_raster.then(&raster_to_device);
self.transforms.push(CompositorTransform {
local_to_raster,
raster_to_device,
local_to_device,
});
index
}
/// Calculate the device-space rect of a local compositor surface rect
pub fn get_device_rect(
&self,
local_rect: &PictureRect,
transform_index: CompositorTransformIndex,
) -> DeviceRect {
let transform = &self.transforms[transform_index.0];
transform.local_to_device.map_rect(&local_rect).round()
}
/// Calculate the device-space rect of a local compositor surface rect, normalized
/// to the origin of a given point
pub fn get_surface_rect<T>(
&self,
local_sub_rect: &Box2D<f32, T>,
local_bounds: &Box2D<f32, T>,
transform_index: CompositorTransformIndex,
) -> DeviceRect {
let transform = &self.transforms[transform_index.0];
let surface_bounds = transform.local_to_raster.map_rect(&local_bounds);
let surface_rect = transform.local_to_raster.map_rect(&local_sub_rect);
surface_rect
.round_out()
.translate(-surface_bounds.min.to_vector())
.round_out()
.intersection(&surface_bounds.size().round().into())
.unwrap_or_else(DeviceRect::zero)
}
/// Get the local -> device compositor transform
pub fn get_device_transform(
&self,
transform_index: CompositorTransformIndex,
) -> ScaleOffset {
let transform = &self.transforms[transform_index.0];
transform.local_to_device
}
/// Get the surface -> device compositor transform
pub fn get_compositor_transform(
&self,
transform_index: CompositorTransformIndex,
) -> ScaleOffset {
let transform = &self.transforms[transform_index.0];
transform.raster_to_device
}
/// Register an occluder during picture cache updates that can be
/// used during frame building to occlude tiles.
pub fn register_occluder(
&mut self,
z_id: ZBufferId,
rect: WorldRect,
) {
let world_rect = rect.round().to_i32();
self.occluders.push(world_rect, z_id);
}
/// Push a compositor surface on to the list of tiles to be passed to the compositor
fn push_compositor_surface(
&mut self,
external_surface: &ExternalSurfaceDescriptor,
is_opaque: bool,
device_clip_rect: DeviceRect,
resource_cache: &ResourceCache,
gpu_cache: &mut GpuCache,
deferred_resolves: &mut FrameVec<DeferredResolve>,
) {
let clip_rect = external_surface
.clip_rect
.intersection(&device_clip_rect)
.unwrap_or_else(DeviceRect::zero);
// Skip compositor surfaces with empty clip rects.
if clip_rect.is_empty() {
return;
}
let required_plane_count =
match external_surface.dependency {
ExternalSurfaceDependency::Yuv { format, .. } => {
format.get_plane_num()
},
ExternalSurfaceDependency::Rgb { .. } => {
1
}
};
let mut image_dependencies = [ImageDependency::INVALID; 3];
for i in 0 .. required_plane_count {
let dependency = match external_surface.dependency {
ExternalSurfaceDependency::Yuv { image_dependencies, .. } => {
image_dependencies[i]
},
ExternalSurfaceDependency::Rgb { image_dependency, .. } => {
image_dependency
}
};
image_dependencies[i] = dependency;
}
// Get a new z_id for each compositor surface, to ensure correct ordering
// when drawing with the simple (Draw) compositor, and to schedule compositing
// of any required updates into the surfaces.
let needs_external_surface_update = match self.compositor_kind {
CompositorKind::Draw { .. } => true,
_ => external_surface.update_params.is_some(),
};
let external_surface_index = if needs_external_surface_update {
let external_surface_index = self.compute_external_surface_dependencies(
&external_surface,
&image_dependencies,
required_plane_count,
resource_cache,
gpu_cache,
deferred_resolves,
);
if external_surface_index == ResolvedExternalSurfaceIndex::INVALID {
return;
}
external_surface_index
} else {
ResolvedExternalSurfaceIndex::INVALID
};
let surface = CompositeTileSurface::ExternalSurface { external_surface_index };
let local_rect = external_surface.local_surface_size.cast_unit().into();
let tile = CompositeTile {
kind: tile_kind(&surface, is_opaque),
surface,
local_rect,
local_valid_rect: local_rect,
local_dirty_rect: local_rect,
device_clip_rect: clip_rect,
z_id: external_surface.z_id,
transform_index: external_surface.transform_index,
};
// Add a surface descriptor for each compositor surface. For the Draw
// compositor, this is used to avoid composites being skipped by adding
// a dependency on the compositor surface external image keys / generations.
self.descriptor.surfaces.push(
CompositeSurfaceDescriptor {
surface_id: external_surface.native_surface_id,
clip_rect,
transform: self.get_compositor_transform(external_surface.transform_index),
image_dependencies: image_dependencies,
image_rendering: external_surface.image_rendering,
tile_descriptors: Vec::new(),
}
);
let device_rect =
self.get_device_rect(&local_rect, external_surface.transform_index);
self.descriptor.external_surfaces_rect =
self.descriptor.external_surfaces_rect.union(&device_rect);
self.tiles.push(tile);
}
/// Add a picture cache to be composited
pub fn push_surface(
&mut self,
tile_cache: &TileCacheInstance,
device_clip_rect: DeviceRect,
resource_cache: &ResourceCache,
gpu_cache: &mut GpuCache,
deferred_resolves: &mut FrameVec<DeferredResolve>,
) {
let slice_transform = self.get_compositor_transform(tile_cache.transform_index);
let image_rendering = if self.low_quality_pinch_zoom {
ImageRendering::Auto
} else {
ImageRendering::CrispEdges
};
if let Some(backdrop_surface) = &tile_cache.backdrop_surface {
// Use the backdrop native surface we created and add that to the composite state.
self.descriptor.surfaces.push(
CompositeSurfaceDescriptor {
surface_id: Some(backdrop_surface.id),
clip_rect: backdrop_surface.device_rect,
transform: slice_transform,
image_dependencies: [ImageDependency::INVALID; 3],
image_rendering,
tile_descriptors: Vec::new(),
}
);
}
// Add any underlay surfaces to the compositing tree
for underlay in &tile_cache.underlays {
self.push_compositor_surface(
underlay,
true,
device_clip_rect,
resource_cache,
gpu_cache,
deferred_resolves,
);
}
for sub_slice in &tile_cache.sub_slices {
let mut surface_device_rect = DeviceRect::zero();
for tile in sub_slice.tiles.values() {
if !tile.is_visible {
// This can occur when a tile is found to be occluded during frame building.
continue;
}
// Accumulate this tile into the overall surface bounds. This is used below
// to clamp the size of the supplied clip rect to a reasonable value.
// NOTE: This clip rect must include the device_valid_rect rather than
// the tile device rect. This ensures that in the case of a picture
// cache slice that is smaller than a single tile, the clip rect in
// the composite descriptor will change if the position of that slice
// is changed. Otherwise, WR may conclude that no composite is needed
// if the tile itself was not invalidated due to changing content.
// See bug #1675414 for more detail.
surface_device_rect = surface_device_rect.union(&tile.device_valid_rect);
}
// Append the visible tiles from this sub-slice
self.tiles.extend_from_slice(&sub_slice.composite_tiles);
// If the clip rect is too large, it can cause accuracy and correctness problems
// for some native compositors (specifically, CoreAnimation in this case). To
// work around that, intersect the supplied clip rect with the current bounds
// of the native surface, which ensures it is a reasonable size.
let surface_clip_rect = device_clip_rect
.intersection(&surface_device_rect)
.unwrap_or(DeviceRect::zero());
// Only push tiles if they have valid clip rects.
if !surface_clip_rect.is_empty() {
// Add opaque surface before any compositor surfaces
if !sub_slice.opaque_tile_descriptors.is_empty() {
self.descriptor.surfaces.push(
CompositeSurfaceDescriptor {
surface_id: sub_slice.native_surface.as_ref().map(|s| s.opaque),
clip_rect: surface_clip_rect,
transform: slice_transform,
image_dependencies: [ImageDependency::INVALID; 3],
image_rendering,
tile_descriptors: sub_slice.opaque_tile_descriptors.clone(),
}
);
}
// Add alpha tiles after opaque surfaces
if !sub_slice.alpha_tile_descriptors.is_empty() {
self.descriptor.surfaces.push(
CompositeSurfaceDescriptor {
surface_id: sub_slice.native_surface.as_ref().map(|s| s.alpha),
clip_rect: surface_clip_rect,
transform: slice_transform,
image_dependencies: [ImageDependency::INVALID; 3],
image_rendering,
tile_descriptors: sub_slice.alpha_tile_descriptors.clone(),
}
);
}
}
// For each compositor surface that was promoted, build the
// information required for the compositor to draw it
for compositor_surface in &sub_slice.compositor_surfaces {
self.push_compositor_surface(
&compositor_surface.descriptor,
compositor_surface.is_opaque,
device_clip_rect,
resource_cache,
gpu_cache,
deferred_resolves,
);
}
}
}
/// Compare this state vs. a previous frame state, and invalidate dirty rects if
/// the surface count has changed
pub fn update_dirty_rect_validity(
&mut self,
old_descriptor: &CompositeDescriptor,
) {
// TODO(gw): Make this more robust in other cases - there are other situations where
// the surface count may be the same but we still need to invalidate the
// dirty rects (e.g. if the surface ordering changed, or the external
// surface itself is animated?)
if old_descriptor.surfaces.len() != self.descriptor.surfaces.len() {
self.dirty_rects_are_valid = false;
return;
}
// The entire area of external surfaces are treated as dirty, however,
// if a surface has moved or shrunk that is no longer valid, as we
// additionally need to ensure the area the surface used to occupy is
// composited.
if !self
.descriptor
.external_surfaces_rect
.contains_box(&old_descriptor.external_surfaces_rect)
{
self.dirty_rects_are_valid = false;
return;
}
}
fn compute_external_surface_dependencies(
&mut self,
external_surface: &ExternalSurfaceDescriptor,
image_dependencies: &[ImageDependency; 3],
required_plane_count: usize,
resource_cache: &ResourceCache,
gpu_cache: &mut GpuCache,
deferred_resolves: &mut FrameVec<DeferredResolve>,
) -> ResolvedExternalSurfaceIndex {
let mut planes = [
ExternalPlaneDescriptor::invalid(),
ExternalPlaneDescriptor::invalid(),
ExternalPlaneDescriptor::invalid(),
];
let mut valid_plane_count = 0;
for i in 0 .. required_plane_count {
let request = ImageRequest {
key: image_dependencies[i].key,
rendering: external_surface.image_rendering,
tile: None,
};
let cache_item = resolve_image(
request,
resource_cache,
gpu_cache,
deferred_resolves,
);
if cache_item.texture_id != TextureSource::Invalid {
valid_plane_count += 1;
let plane = &mut planes[i];
*plane = ExternalPlaneDescriptor {
texture: cache_item.texture_id,
uv_rect: cache_item.uv_rect.into(),
};
}
}
// Check if there are valid images added for each YUV plane
if valid_plane_count < required_plane_count {
warn!("Warnings: skip a YUV/RGB compositor surface, found {}/{} valid images",
valid_plane_count,
required_plane_count,
);
return ResolvedExternalSurfaceIndex::INVALID;
}
let external_surface_index = ResolvedExternalSurfaceIndex(self.external_surfaces.len());
// If the external surface descriptor reports that the native surface
// needs to be updated, create an update params tuple for the renderer
// to use.
let update_params = external_surface.update_params.map(|surface_size| {
(
external_surface.native_surface_id.expect("bug: no native surface!"),
surface_size
)
});
match external_surface.dependency {
ExternalSurfaceDependency::Yuv{ color_space, format, channel_bit_depth, .. } => {
let image_buffer_kind = planes[0].texture.image_buffer_kind();
self.external_surfaces.push(ResolvedExternalSurface {
color_data: ResolvedExternalSurfaceColorData::Yuv {
image_dependencies: *image_dependencies,
planes,
color_space,
format,
channel_bit_depth,
},
image_buffer_kind,
update_params,
});
},
ExternalSurfaceDependency::Rgb { .. } => {
let image_buffer_kind = planes[0].texture.image_buffer_kind();
self.external_surfaces.push(ResolvedExternalSurface {
color_data: ResolvedExternalSurfaceColorData::Rgb {
image_dependency: image_dependencies[0],
plane: planes[0],
},
image_buffer_kind,
update_params,
});
},
}
external_surface_index
}
pub fn end_frame(&mut self) {
// Sort tiles from front to back.
self.tiles.sort_by_key(|tile| tile.z_id.0);
}
}
/// An arbitrary identifier for a native (OS compositor) surface
#[repr(C)]
#[derive(Debug, Copy, Clone, Hash, Eq, PartialEq)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct NativeSurfaceId(pub u64);
impl NativeSurfaceId {
/// A special id for the native surface that is used for debug / profiler overlays.
pub const DEBUG_OVERLAY: NativeSurfaceId = NativeSurfaceId(u64::MAX);
}
#[repr(C)]
#[derive(Debug, Copy, Clone, Hash, Eq, PartialEq)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct NativeTileId {
pub surface_id: NativeSurfaceId,
pub x: i32,
pub y: i32,
}
impl NativeTileId {
/// A special id for the native surface that is used for debug / profiler overlays.
pub const DEBUG_OVERLAY: NativeTileId = NativeTileId {
surface_id: NativeSurfaceId::DEBUG_OVERLAY,
x: 0,
y: 0,
};
}
/// Information about a bound surface that the native compositor
/// returns to WR.
#[repr(C)]
#[derive(Copy, Clone)]
pub struct NativeSurfaceInfo {
/// An offset into the surface that WR should draw. Some compositing
/// implementations (notably, DirectComposition) use texture atlases
/// when the surface sizes are small. In this case, an offset can
/// be returned into the larger texture where WR should draw. This
/// can be (0, 0) if texture atlases are not used.
pub origin: DeviceIntPoint,
/// The ID of the FBO that WR should bind to, in order to draw to
/// the bound surface. On Windows (ANGLE) this will always be 0,
/// since creating a p-buffer sets the default framebuffer to
/// be the DirectComposition surface. On Mac, this will be non-zero,
/// since it identifies the IOSurface that has been bound to draw to.
// TODO(gw): This may need to be a larger / different type for WR
// backends that are not GL.
pub fbo_id: u32,
}
#[repr(C)]
#[derive(Debug, Copy, Clone, PartialEq)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct CompositorCapabilities {
/// The virtual surface size used by the underlying platform.
pub virtual_surface_size: i32,
/// Whether the compositor requires redrawing on invalidation.
pub redraw_on_invalidation: bool,
/// The maximum number of dirty rects that can be provided per compositor
/// surface update. If this is zero, the entire compositor surface for
/// a given tile will be drawn if it's dirty.
pub max_update_rects: usize,
/// Whether or not this compositor will create surfaces for backdrops.
pub supports_surface_for_backdrop: bool,
/// Whether external compositor surface supports negative scaling.
pub supports_external_compositor_surface_negative_scaling: bool,
}
impl Default for CompositorCapabilities {
fn default() -> Self {
// The default set of compositor capabilities for a given platform.
// These should only be modified if a compositor diverges specifically
// from the default behavior so that compositors don't have to track
// which changes to this structure unless necessary.
CompositorCapabilities {
virtual_surface_size: 0,
redraw_on_invalidation: false,
// Assume compositors can do at least partial update of surfaces. If not,
// the native compositor should override this to be 0.
max_update_rects: 1,
supports_surface_for_backdrop: false,
supports_external_compositor_surface_negative_scaling: true,
}
}
}
#[repr(C)]
#[derive(Copy, Clone, Debug)]
pub struct WindowVisibility {
pub is_fully_occluded: bool,
}
impl Default for WindowVisibility {
fn default() -> Self {
WindowVisibility {
is_fully_occluded: false,
}
}
}
/// The transform type to apply to Compositor surfaces.
// TODO: Should transform from CompositorSurfacePixel instead, but this requires a cleanup of the
// Compositor API to use CompositorSurface-space geometry instead of Device-space where necessary
// to avoid a bunch of noisy cast_unit calls and make it actually type-safe. May be difficult due
// to pervasive use of Device-space nomenclature inside WR.
// pub struct CompositorSurfacePixel;
pub type CompositorSurfaceTransform = ScaleOffset;
/// Defines an interface to a native (OS level) compositor. If supplied
/// by the client application, then picture cache slices will be
/// composited by the OS compositor, rather than drawn via WR batches.
pub trait Compositor {
/// Create a new OS compositor surface with the given properties.
fn create_surface(
&mut self,
device: &mut Device,
id: NativeSurfaceId,
virtual_offset: DeviceIntPoint,
tile_size: DeviceIntSize,
is_opaque: bool,
);
/// Create a new OS compositor surface that can be used with an
/// existing ExternalImageId, instead of being drawn to by WebRender.
/// Surfaces created by this can only be used with attach_external_image,
/// and not create_tile/destroy_tile/bind/unbind.
fn create_external_surface(
&mut self,
device: &mut Device,
id: NativeSurfaceId,
is_opaque: bool,
);
/// Create a new OS backdrop surface that will display a color.
fn create_backdrop_surface(
&mut self,
device: &mut Device,
id: NativeSurfaceId,
color: ColorF,
);
/// Destroy the surface with the specified id. WR may call this
/// at any time the surface is no longer required (including during
/// renderer deinit). It's the responsibility of the embedder
/// to ensure that the surface is only freed once the GPU is
/// no longer using the surface (if this isn't already handled
/// by the operating system).
fn destroy_surface(
&mut self,
device: &mut Device,
id: NativeSurfaceId,
);
/// Create a new OS compositor tile with the given properties.
fn create_tile(
&mut self,
device: &mut Device,
id: NativeTileId,
);
/// Destroy an existing compositor tile.
fn destroy_tile(
&mut self,
device: &mut Device,
id: NativeTileId,
);
/// Attaches an ExternalImageId to an OS compositor surface created
/// by create_external_surface, and uses that as the contents of
/// the surface. It is expected that a single surface will have
/// many different images attached (like one for each video frame).
fn attach_external_image(
&mut self,
device: &mut Device,
id: NativeSurfaceId,
external_image: ExternalImageId
);
/// Mark a tile as invalid before any surfaces are queued for
/// composition and before it is updated with bind. This is useful
/// for early composition, allowing for dependency tracking of which
/// surfaces can be composited early while others are still updating.
fn invalidate_tile(
&mut self,
_device: &mut Device,
_id: NativeTileId,
_valid_rect: DeviceIntRect
) {}
/// Bind this surface such that WR can issue OpenGL commands
/// that will target the surface. Returns an (x, y) offset
/// where WR should draw into the surface. This can be set
/// to (0, 0) if the OS doesn't use texture atlases. The dirty
/// rect is a local surface rect that specifies which part
/// of the surface needs to be updated. If max_update_rects
/// in CompositeConfig is 0, this will always be the size
/// of the entire surface. The returned offset is only
/// relevant to compositors that store surfaces in a texture
/// atlas (that is, WR expects that the dirty rect doesn't
/// affect the coordinates of the returned origin).
fn bind(
&mut self,
device: &mut Device,
id: NativeTileId,
dirty_rect: DeviceIntRect,
valid_rect: DeviceIntRect,
) -> NativeSurfaceInfo;
/// Unbind the surface. This is called by WR when it has
/// finished issuing OpenGL commands on the current surface.
fn unbind(
&mut self,
device: &mut Device,
);
/// Begin the frame
fn begin_frame(&mut self, device: &mut Device);
/// Add a surface to the visual tree to be composited. Visuals must
/// be added every frame, between the begin/end transaction call. The
/// z-order of the surfaces is determined by the order they are added
/// to the visual tree.
// TODO(gw): Adding visuals every frame makes the interface simple,
// but may have performance implications on some compositors?
// We might need to change the interface to maintain a visual
// tree that can be mutated?
// TODO(gw): We might need to add a concept of a hierachy in future.
fn add_surface(
&mut self,
device: &mut Device,
id: NativeSurfaceId,
transform: CompositorSurfaceTransform,
clip_rect: DeviceIntRect,
image_rendering: ImageRendering,
);
/// Notify the compositor that all tiles have been invalidated and all
/// native surfaces have been added, thus it is safe to start compositing
/// valid surfaces. The dirty rects array allows native compositors that
/// support partial present to skip copying unchanged areas.
/// Optionally provides a set of rectangles for the areas known to be
/// opaque, this is currently only computed if the caller is SwCompositor.
fn start_compositing(
&mut self,
_device: &mut Device,
_clear_color: ColorF,
_dirty_rects: &[DeviceIntRect],
_opaque_rects: &[DeviceIntRect],
) {}
/// Commit any changes in the compositor tree for this frame. WR calls
/// this once when all surface and visual updates are complete, to signal
/// that the OS composite transaction should be applied.
fn end_frame(&mut self, device: &mut Device);
/// Enable/disable native compositor usage
fn enable_native_compositor(&mut self, device: &mut Device, enable: bool);
/// Safely deinitialize any remaining resources owned by the compositor.
fn deinit(&mut self, device: &mut Device);
/// Get the capabilities struct for this compositor. This is used to
/// specify what features a compositor supports, depending on the
/// underlying platform
fn get_capabilities(&self, device: &mut Device) -> CompositorCapabilities;
fn get_window_visibility(&self, device: &mut Device) -> WindowVisibility;
}
// Describes the configuration for an input layer that the compositor
// implemention should prepare
pub struct CompositorInputLayer {
// Device space location and size of the layer
pub rect: DeviceIntRect,
// Whether a content or external surface
pub usage: CompositorSurfaceUsage,
// If true, layer is opaque, blend can be disabled
pub is_opaque: bool,
}
// Provides the parameters about the frame to the compositor implementation.
// TODO(gw): Include information about picture cache slices and external surfaces.
pub struct CompositorInputConfig<'a> {
pub layers: &'a [CompositorInputLayer],
pub framebuffer_size: DeviceIntSize,
}
// Skeleton trait for implementors of swapchain based compositing. For now
// the implementation simply binds a framebuffer-sized surface that can
// be presented by the native compositor.
// TODO(gw): Extend to handle external surfaces, layers, swgl, etc.
pub trait Compositor2 {
// Prepare to composite a frame. Ensure that layers are constructed
// to match the input config
fn begin_frame(
&mut self,
input: &CompositorInputConfig,
);
// Bind a layer (by index in the input config) to begin rendering
// content to it.
fn bind_layer(&mut self, index: usize);
// Complete rendering of a layer and present / swap buffers
fn present_layer(&mut self, index: usize);
fn add_surface(
&mut self,
index: usize,
clip_rect: DeviceIntRect,
image_rendering: ImageRendering,
);
// Finish compositing this frame - commit the visual tree to the OS
fn end_frame(&mut self);
}
/// Information about the underlying data buffer of a mapped tile.
#[repr(C)]
#[derive(Copy, Clone)]
pub struct MappedTileInfo {
pub data: *mut c_void,
pub stride: i32,
}
/// Descriptor for a locked surface that will be directly composited by SWGL.
#[repr(C)]
pub struct SWGLCompositeSurfaceInfo {
/// The number of YUV planes in the surface. 0 indicates non-YUV BGRA.
/// 1 is interleaved YUV. 2 is NV12. 3 is planar YUV.
pub yuv_planes: u32,
/// Textures for planes of the surface, or 0 if not applicable.
pub textures: [u32; 3],
/// Color space of surface if using a YUV format.
pub color_space: YuvRangedColorSpace,
/// Color depth of surface if using a YUV format.
pub color_depth: ColorDepth,
/// The actual source surface size before transformation.
pub size: DeviceIntSize,
}
/// A Compositor variant that supports mapping tiles into CPU memory.
pub trait MappableCompositor: Compositor {
/// Map a tile's underlying buffer so it can be used as the backing for
/// a SWGL framebuffer. This is intended to be a replacement for 'bind'
/// in any compositors that intend to directly interoperate with SWGL
/// while supporting some form of native layers.
fn map_tile(
&mut self,
device: &mut Device,
id: NativeTileId,
dirty_rect: DeviceIntRect,
valid_rect: DeviceIntRect,
) -> Option<MappedTileInfo>;
/// Unmap a tile that was was previously mapped via map_tile to signal
/// that SWGL is done rendering to the buffer.
fn unmap_tile(&mut self, device: &mut Device);
fn lock_composite_surface(
&mut self,
device: &mut Device,
ctx: *mut c_void,
external_image_id: ExternalImageId,
composite_info: *mut SWGLCompositeSurfaceInfo,
) -> bool;
fn unlock_composite_surface(&mut self, device: &mut Device, ctx: *mut c_void, external_image_id: ExternalImageId);
}
/// Defines an interface to a non-native (application-level) Compositor which handles
/// partial present. This is required if webrender must query the backbuffer's age.
/// TODO: Use the Compositor trait for native and non-native compositors, and integrate
/// this functionality there.
pub trait PartialPresentCompositor {
/// Allows webrender to specify the total region that will be rendered to this frame,
/// ie the frame's dirty region and some previous frames' dirty regions, if applicable
/// (calculated using the buffer age). Must be called before anything has been rendered
/// to the main framebuffer.
fn set_buffer_damage_region(&mut self, rects: &[DeviceIntRect]);
}
/// Information about an opaque surface used to occlude tiles.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
struct Occluder {
z_id: ZBufferId,
world_rect: WorldIntRect,
}
// Whether this event is the start or end of a rectangle
#[derive(Debug)]
enum OcclusionEventKind {
Begin,
End,
}
// A list of events on the y-axis, with the rectangle range that it affects on the x-axis
#[derive(Debug)]
struct OcclusionEvent {
y: i32,
x_range: ops::Range<i32>,
kind: OcclusionEventKind,
}
impl OcclusionEvent {
fn new(y: i32, kind: OcclusionEventKind, x0: i32, x1: i32) -> Self {
OcclusionEvent {
y,
x_range: ops::Range {
start: x0,
end: x1,
},
kind,
}
}
}
/// This struct exists to provide a Default impl and allow #[serde(skip)]
/// on the two frame vectors. Unfortunately FrameVec does not have a Default
/// implementation (vectors only implement it with the global allocator).
pub struct OccludersScratchBuffers {
events: FrameVec<OcclusionEvent>,
active: FrameVec<ops::Range<i32>>,
}
impl Default for OccludersScratchBuffers {
fn default() -> Self {
OccludersScratchBuffers {
events: FrameVec::new_in(FrameAllocator::fallback()),
active: FrameVec::new_in(FrameAllocator::fallback()),
}
}
}
/// List of registered occluders.
///
/// Also store a couple of vectors for reuse.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct Occluders {
occluders: FrameVec<Occluder>,
// The two vectors in scratch are kept to avoid unnecessary reallocations in area().
#[cfg_attr(any(feature = "capture", feature = "replay"), serde(skip))]
scratch: OccludersScratchBuffers,
}
impl Occluders {
fn new(memory: &FrameMemory) -> Self {
Occluders {
occluders: memory.new_vec(),
scratch: OccludersScratchBuffers {
events: memory.new_vec(),
active: memory.new_vec(),
}
}
}
fn push(&mut self, world_rect: WorldIntRect, z_id: ZBufferId) {
self.occluders.push(Occluder { world_rect, z_id });
}
/// Returns true if a tile with the specified rectangle and z_id
/// is occluded by an opaque surface in front of it.
pub fn is_tile_occluded(
&mut self,
z_id: ZBufferId,
world_rect: WorldRect,
) -> bool {
// It's often the case that a tile is only occluded by considering multiple
// picture caches in front of it (for example, the background tiles are
// often occluded by a combination of the content slice + the scrollbar slices).
// The basic algorithm is:
// For every occluder:
// If this occluder is in front of the tile we are querying:
// Clip the occluder rectangle to the query rectangle.
// Calculate the total non-overlapping area of those clipped occluders.
// If the cumulative area of those occluders is the same as the area of the query tile,
// Then the entire tile must be occluded and can be skipped during rasterization and compositing.
// Get the reference area we will compare against.
let world_rect = world_rect.round().to_i32();
let ref_area = world_rect.area();
// Calculate the non-overlapping area of the valid occluders.
let cover_area = self.area(z_id, &world_rect);
debug_assert!(cover_area <= ref_area);
// Check if the tile area is completely covered
ref_area == cover_area
}
/// Return the total area covered by a set of occluders, accounting for
/// overlapping areas between those rectangles.
fn area(
&mut self,
z_id: ZBufferId,
clip_rect: &WorldIntRect,
) -> i32 {
// This is not a particularly efficient implementation (it skips building segment trees), however
// we typically use this where the length of the rectangles array is < 10, so simplicity is more important.
self.scratch.events.clear();
self.scratch.active.clear();
let mut area = 0;
// Step through each rectangle and build the y-axis event list
for occluder in &self.occluders {
// Only consider occluders in front of this rect
if occluder.z_id.0 < z_id.0 {
// Clip the source rect to the rectangle we care about, since we only
// want to record area for the tile we are comparing to.
if let Some(rect) = occluder.world_rect.intersection(clip_rect) {
let x0 = rect.min.x;
let x1 = x0 + rect.width();
self.scratch.events.push(OcclusionEvent::new(rect.min.y, OcclusionEventKind::Begin, x0, x1));
self.scratch.events.push(OcclusionEvent::new(rect.min.y + rect.height(), OcclusionEventKind::End, x0, x1));
}
}
}
// If we didn't end up with any valid events, the area must be 0
if self.scratch.events.is_empty() {
return 0;
}
// Sort the events by y-value
self.scratch.events.sort_by_key(|e| e.y);
let mut cur_y = self.scratch.events[0].y;
// Step through each y interval
for event in &self.scratch.events {
// This is the dimension of the y-axis we are accumulating areas for
let dy = event.y - cur_y;
// If we have active events covering x-ranges in this y-interval, process them
if dy != 0 && !self.scratch.active.is_empty() {
assert!(dy > 0);
// Step through the x-ranges, ordered by x0 of each event
self.scratch.active.sort_by_key(|i| i.start);
let mut query = 0;
let mut cur = self.scratch.active[0].start;
// Accumulate the non-overlapping x-interval that contributes to area for this y-interval.
for interval in &self.scratch.active {
cur = interval.start.max(cur);
query += (interval.end - cur).max(0);
cur = cur.max(interval.end);
}
// Accumulate total area for this y-interval
area += query * dy;
}
// Update the active events list
match event.kind {
OcclusionEventKind::Begin => {
self.scratch.active.push(event.x_range.clone());
}
OcclusionEventKind::End => {
let index = self.scratch.active.iter().position(|i| *i == event.x_range).unwrap();
self.scratch.active.remove(index);
}
}
cur_y = event.y;
}
area
}
}