Source code
Revision control
Copy as Markdown
Other Tools
/* 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
//! # Visibility pass
//!
//! TODO: document what this pass does!
//!
use api::{DebugFlags};
use api::units::*;
use std::{usize};
use crate::clip::ClipStore;
use crate::composite::CompositeState;
use crate::spatial_tree::{SpatialTree, SpatialNodeIndex};
use crate::clip::{ClipChainInstance, ClipTree};
use crate::frame_builder::FrameBuilderConfig;
use crate::gpu_cache::GpuCache;
use crate::picture::{PictureCompositeMode, ClusterFlags, SurfaceInfo, TileCacheInstance};
use crate::picture::{SurfaceIndex, RasterConfig, SubSliceIndex};
use crate::prim_store::{ClipTaskIndex, PictureIndex, PrimitiveInstanceKind};
use crate::prim_store::{PrimitiveStore, PrimitiveInstance};
use crate::render_backend::{DataStores, ScratchBuffer};
use crate::render_task_graph::RenderTaskGraphBuilder;
use crate::resource_cache::ResourceCache;
use crate::scene::SceneProperties;
use crate::space::SpaceMapper;
use crate::util::{MaxRect};
pub struct FrameVisibilityContext<'a> {
pub spatial_tree: &'a SpatialTree,
pub global_screen_world_rect: WorldRect,
pub global_device_pixel_scale: DevicePixelScale,
pub debug_flags: DebugFlags,
pub scene_properties: &'a SceneProperties,
pub config: FrameBuilderConfig,
pub root_spatial_node_index: SpatialNodeIndex,
}
pub struct FrameVisibilityState<'a> {
pub clip_store: &'a mut ClipStore,
pub resource_cache: &'a mut ResourceCache,
pub gpu_cache: &'a mut GpuCache,
pub scratch: &'a mut ScratchBuffer,
pub data_stores: &'a mut DataStores,
pub clip_tree: &'a mut ClipTree,
pub composite_state: &'a mut CompositeState,
pub rg_builder: &'a mut RenderTaskGraphBuilder,
/// A stack of currently active off-screen surfaces during the
/// visibility frame traversal.
pub surface_stack: Vec<(PictureIndex, SurfaceIndex)>,
}
impl<'a> FrameVisibilityState<'a> {
pub fn push_surface(
&mut self,
pic_index: PictureIndex,
surface_index: SurfaceIndex,
) {
self.surface_stack.push((pic_index, surface_index));
}
pub fn pop_surface(&mut self) {
self.surface_stack.pop().unwrap();
}
}
bitflags! {
/// A set of bitflags that can be set in the visibility information
/// for a primitive instance. This can be used to control how primitives
/// are treated during batching.
// TODO(gw): We should also move `is_compositor_surface` to be part of
// this flags struct.
#[cfg_attr(feature = "capture", derive(Serialize))]
#[derive(Debug, Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
pub struct PrimitiveVisibilityFlags: u8 {
/// Implies that this primitive covers the entire picture cache slice,
/// and can thus be dropped during batching and drawn with clear color.
const IS_BACKDROP = 1;
}
}
/// Contains the current state of the primitive's visibility.
#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
pub enum VisibilityState {
/// Uninitialized - this should never be encountered after prim reset
Unset,
/// Culled for being off-screen, or not possible to render (e.g. missing image resource)
Culled,
/// A picture that doesn't have a surface - primitives are composed into the
/// parent picture with a surface.
PassThrough,
/// A primitive that has been found to be visible
Visible {
/// A set of flags that define how this primitive should be handled
/// during batching of visible primitives.
vis_flags: PrimitiveVisibilityFlags,
/// Sub-slice within the picture cache that this prim exists on
sub_slice_index: SubSliceIndex,
},
}
/// Information stored for a visible primitive about the visible
/// rect and associated clip information.
#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
pub struct PrimitiveVisibility {
/// The clip chain instance that was built for this primitive.
pub clip_chain: ClipChainInstance,
/// Current visibility state of the primitive.
// TODO(gw): Move more of the fields from this struct into
// the state enum.
pub state: VisibilityState,
/// An index into the clip task instances array in the primitive
/// store. If this is ClipTaskIndex::INVALID, then the primitive
/// has no clip mask. Otherwise, it may store the offset of the
/// global clip mask task for this primitive, or the first of
/// a list of clip task ids (one per segment).
pub clip_task_index: ClipTaskIndex,
}
impl PrimitiveVisibility {
pub fn new() -> Self {
PrimitiveVisibility {
state: VisibilityState::Unset,
clip_chain: ClipChainInstance::empty(),
clip_task_index: ClipTaskIndex::INVALID,
}
}
pub fn reset(&mut self) {
self.state = VisibilityState::Culled;
self.clip_task_index = ClipTaskIndex::INVALID;
}
}
pub fn update_prim_visibility(
pic_index: PictureIndex,
parent_surface_index: Option<SurfaceIndex>,
world_culling_rect: &WorldRect,
store: &PrimitiveStore,
prim_instances: &mut [PrimitiveInstance],
surfaces: &mut [SurfaceInfo],
is_root_tile_cache: bool,
frame_context: &FrameVisibilityContext,
frame_state: &mut FrameVisibilityState,
tile_cache: &mut TileCacheInstance,
) {
let pic = &store.pictures[pic_index.0];
let (surface_index, pop_surface) = match pic.raster_config {
Some(RasterConfig { surface_index, composite_mode: PictureCompositeMode::TileCache { .. }, .. }) => {
(surface_index, false)
}
Some(ref raster_config) => {
frame_state.push_surface(
pic_index,
raster_config.surface_index,
);
let surface_local_rect = surfaces[raster_config.surface_index.0]
.unclipped_local_rect
.cast_unit();
// Let the picture cache know that we are pushing an off-screen
// surface, so it can treat dependencies of surface atomically.
tile_cache.push_surface(
surface_local_rect,
pic.spatial_node_index,
frame_context.spatial_tree,
);
(raster_config.surface_index, true)
}
None => {
(parent_surface_index.expect("bug: pass-through with no parent"), false)
}
};
let surface = &surfaces[surface_index.0 as usize];
let device_pixel_scale = surface.device_pixel_scale;
let mut map_local_to_surface = surface.map_local_to_surface.clone();
let map_surface_to_world = SpaceMapper::new_with_target(
frame_context.root_spatial_node_index,
surface.surface_spatial_node_index,
frame_context.global_screen_world_rect,
frame_context.spatial_tree,
);
for cluster in &pic.prim_list.clusters {
profile_scope!("cluster");
// Each prim instance must have reset called each frame, to clear
// indices into various scratch buffers. If this doesn't occur,
// the primitive may incorrectly be considered visible, which can
// cause unexpected conditions to occur later during the frame.
// Primitive instances are normally reset in the main loop below,
// but we must also reset them in the rare case that the cluster
// visibility has changed (due to an invalid transform and/or
// backface visibility changing for this cluster).
// TODO(gw): This is difficult to test for in CI - as a follow up,
// we should add a debug flag that validates the prim
// instance is always reset every frame to catch similar
// issues in future.
for prim_instance in &mut prim_instances[cluster.prim_range()] {
prim_instance.reset();
}
// Get the cluster and see if is visible
if !cluster.flags.contains(ClusterFlags::IS_VISIBLE) {
continue;
}
map_local_to_surface.set_target_spatial_node(
cluster.spatial_node_index,
frame_context.spatial_tree,
);
for prim_instance_index in cluster.prim_range() {
if let PrimitiveInstanceKind::Picture { pic_index, .. } = prim_instances[prim_instance_index].kind {
if !store.pictures[pic_index.0].is_visible(frame_context.spatial_tree) {
continue;
}
let is_passthrough = match store.pictures[pic_index.0].raster_config {
Some(..) => false,
None => true,
};
if !is_passthrough {
let clip_root = store
.pictures[pic_index.0]
.clip_root
.unwrap_or_else(|| {
// If we couldn't find a common ancestor then just use the
// clip node of the picture primitive itself
let leaf_id = prim_instances[prim_instance_index].clip_leaf_id;
frame_state.clip_tree.get_leaf(leaf_id).node_id
}
);
frame_state.clip_tree.push_clip_root_node(clip_root);
}
update_prim_visibility(
pic_index,
Some(surface_index),
world_culling_rect,
store,
prim_instances,
surfaces,
false,
frame_context,
frame_state,
tile_cache,
);
if is_passthrough {
// Pass through pictures are always considered visible in all dirty tiles.
prim_instances[prim_instance_index].vis.state = VisibilityState::PassThrough;
continue;
} else {
frame_state.clip_tree.pop_clip_root();
}
}
let prim_instance = &mut prim_instances[prim_instance_index];
let local_coverage_rect = frame_state.data_stores.get_local_prim_coverage_rect(
prim_instance,
&store.pictures,
surfaces,
);
frame_state.clip_store.set_active_clips(
cluster.spatial_node_index,
map_local_to_surface.ref_spatial_node_index,
prim_instance.clip_leaf_id,
&frame_context.spatial_tree,
&frame_state.data_stores.clip,
frame_state.clip_tree,
);
let clip_chain = frame_state
.clip_store
.build_clip_chain_instance(
local_coverage_rect,
&map_local_to_surface,
&map_surface_to_world,
&frame_context.spatial_tree,
frame_state.gpu_cache,
frame_state.resource_cache,
device_pixel_scale,
&world_culling_rect,
&mut frame_state.data_stores.clip,
frame_state.rg_builder,
true,
);
prim_instance.vis.clip_chain = match clip_chain {
Some(clip_chain) => clip_chain,
None => {
continue;
}
};
tile_cache.update_prim_dependencies(
prim_instance,
cluster.spatial_node_index,
// It's OK to pass the local_coverage_rect here as it's only used by primitives
// (for compositor surfaces) that don't have inflation anyway.
local_coverage_rect,
frame_context,
frame_state.data_stores,
frame_state.clip_store,
&store.pictures,
frame_state.resource_cache,
&store.color_bindings,
&frame_state.surface_stack,
&mut frame_state.composite_state,
&mut frame_state.gpu_cache,
&mut frame_state.scratch.primitive,
is_root_tile_cache,
surfaces,
);
}
}
if pop_surface {
frame_state.pop_surface();
}
if let Some(ref rc) = pic.raster_config {
match rc.composite_mode {
PictureCompositeMode::TileCache { .. } => {}
_ => {
// Pop the off-screen surface from the picture cache stack
tile_cache.pop_surface();
}
}
}
}
pub fn compute_conservative_visible_rect(
clip_chain: &ClipChainInstance,
world_culling_rect: WorldRect,
prim_spatial_node_index: SpatialNodeIndex,
spatial_tree: &SpatialTree,
) -> LayoutRect {
let root_spatial_node_index = spatial_tree.root_reference_frame_index();
// Mapping from picture space -> world space
let map_pic_to_world: SpaceMapper<PicturePixel, WorldPixel> = SpaceMapper::new_with_target(
root_spatial_node_index,
clip_chain.pic_spatial_node_index,
world_culling_rect,
spatial_tree,
);
// Mapping from local space -> picture space
let map_local_to_pic: SpaceMapper<LayoutPixel, PicturePixel> = SpaceMapper::new_with_target(
clip_chain.pic_spatial_node_index,
prim_spatial_node_index,
PictureRect::max_rect(),
spatial_tree,
);
// Unmap the world culling rect from world -> picture space. If this mapping fails due
// to matrix weirdness, best we can do is use the clip chain's local clip rect.
let pic_culling_rect = match map_pic_to_world.unmap(&world_culling_rect) {
Some(rect) => rect,
None => return clip_chain.local_clip_rect,
};
// Intersect the unmapped world culling rect with the primitive's clip chain rect that
// is in picture space (the clip-chain already takes into account the bounds of the
// primitive local_rect and local_clip_rect). If there is no intersection here, the
// primitive is not visible at all.
let pic_culling_rect = match pic_culling_rect.intersection(&clip_chain.pic_coverage_rect) {
Some(rect) => rect,
None => return LayoutRect::zero(),
};
// Unmap the picture culling rect from picture -> local space. If this mapping fails due
// to matrix weirdness, best we can do is use the clip chain's local clip rect.
match map_local_to_pic.unmap(&pic_culling_rect) {
Some(rect) => rect,
None => clip_chain.local_clip_rect,
}
}