Bug 1621758 - Fix occlusion rect of clipped compositor surfaces. r=mstange

Differential Revision: https://phabricator.services.mozilla.com/D66506

--HG--
extra : moz-landing-system : lando

gfx/wr/webrender/src/composite.rs

@@ -94,6 +94,7 @@ pub struct ExternalSurfaceDescriptor {
     pub local_rect: PictureRect,
     pub world_rect: WorldRect,
     pub device_rect: DeviceRect,
+    pub local_clip_rect: PictureRect,
     pub clip_rect: DeviceRect,
     pub image_dependencies: [ImageDependency; 3],
     pub image_rendering: ImageRendering,

gfx/wr/webrender/src/picture.rs

@@ -3175,6 +3175,7 @@ impl TileCacheInstance {
                         self.external_surfaces.push(ExternalSurfaceDescriptor {
                             local_rect: prim_info.prim_clip_rect,
                             world_rect,
+                            local_clip_rect: prim_info.prim_clip_rect,
                             image_dependencies,
                             image_rendering: prim_data.kind.image_rendering,
                             device_rect,
@@ -3370,6 +3371,13 @@ impl TileCacheInstance {
             };
         }
 
+        let map_pic_to_world = SpaceMapper::new_with_target(
+            ROOT_SPATIAL_NODE_INDEX,
+            self.spatial_node_index,
+            frame_context.global_screen_world_rect,
+            frame_context.spatial_tree,
+        );
+
         // Register the opaque region of this tile cache as an occluder, which
         // is used later in the frame to occlude other tiles.
         if self.backdrop.rect.is_well_formed_and_nonempty() {
@@ -3380,13 +3388,6 @@ impl TileCacheInstance {
                 });
 
             if let Some(backdrop_rect) = backdrop_rect {
-                let map_pic_to_world = SpaceMapper::new_with_target(
-                    ROOT_SPATIAL_NODE_INDEX,
-                    self.spatial_node_index,
-                    frame_context.global_screen_world_rect,
-                    frame_context.spatial_tree,
-                );
-
                 let world_backdrop_rect = map_pic_to_world
                     .map(&backdrop_rect)
                     .expect("bug: unable to map backdrop to world space");
@@ -3405,10 +3406,22 @@ impl TileCacheInstance {
         // able to occlude every background tile (avoiding allocation, rasterizion
         // and compositing).
         for external_surface in &self.external_surfaces {
-            frame_state.composite_state.register_occluder(
-                external_surface.z_id,
-                external_surface.world_rect,
-            );
+            let local_surface_rect = external_surface.local_rect
+                .intersection(&external_surface.local_clip_rect)
+                .and_then(|r| {
+                    r.intersection(&self.local_clip_rect)
+                });
+
+            if let Some(local_surface_rect) = local_surface_rect {
+                let world_surface_rect = map_pic_to_world
+                    .map(&local_surface_rect)
+                    .expect("bug: unable to map external surface to world space");
+
+                frame_state.composite_state.register_occluder(
+                    external_surface.z_id,
+                    world_surface_rect,
+                );
+            }
         }
 
         // A simple GC of the native external surface cache, to remove and free any

gfx/wr/wrench/reftests/image/occlusion.yaml

@@ -0,0 +1,15 @@
+# Ensure that the clip rect of a primitive that is promoted to a compositor
+# surface is correctly applied when registering it as an occlusion plane.
+
+root:
+  items:
+    - type: rect
+      color: red
+      bounds: [50, 50, 200, 200]
+
+    - type: yuv-image
+      format: interleaved
+      src: spacex-yuv.png
+      bounds: [50, 50, 200, 200]
+      prefer-compositor-surface: true
+      clip-rect: [75, 75, 150, 150]

gfx/wr/wrench/reftests/image/reftest.list

@@ -9,3 +9,4 @@ platform(linux,mac) == yuv.yaml yuv.png
 skip_on(android,device) == tiled-clip-chain.yaml tiled-clip-chain-ref.yaml
 skip_on(android,device) == tiled-complex-clip.yaml tiled-complex-clip-ref.yaml
 platform(linux,mac) == texture-rect.yaml texture-rect-ref.yaml
+platform(linux) == occlusion.yaml occlusion.png

gfx/wr/wrench/reftests/mask/reftest.list

@@ -10,7 +10,7 @@ platform(linux,mac) == rounded-corners.yaml rounded-corners.png
 platform(linux,mac) fuzzy(1,17500) color_targets(3) alpha_targets(1) == mask-atomicity.yaml mask-atomicity-ref.yaml
 platform(linux,mac) fuzzy(1,17500) == mask-atomicity-tiling.yaml mask-atomicity-ref.yaml
 platform(linux,mac) == mask-perspective.yaml mask-perspective.png
-== fuzzy(1,7) mask-perspective-tiling.yaml mask-perspective.yaml
+== fuzzy(1,11) mask-perspective-tiling.yaml mask-perspective.yaml
 platform(linux,mac) == checkerboard.yaml checkerboard.png
 skip_on(android,device) == checkerboard.yaml checkerboard-tiling.yaml  # Fails on a Pixel2
 == missing-mask.yaml missing-mask-ref.yaml