Bug 2068160 - Part 10 - Flag a failed culling rect projection explicitly. r=gw

The fallback counter inferred a failed projection from the culling rect being
max_rect, which the snapshot surface also produces legitimately by passing an
unbounded screen rect. Record whether the projection actually failed instead.

Differential Revision: https://phabricator.services.mozilla.com/D322978

gfx/wr/webrender/src/picture.rs

@@ -2909,6 +2909,7 @@ fn test_large_surface_scale_1() {
             is_opaque: true,
             clipping_rect: PictureRect::max_rect(),
             culling_rect: VisRect::max_rect(),
+            culling_rect_projection_failed: false,
             map_local_to_picture: map_local_to_picture.clone(),
             raster_spatial_node_index: root_reference_frame_index,
             surface_spatial_node_index: root_reference_frame_index,
@@ -2930,6 +2931,7 @@ fn test_large_surface_scale_1() {
             is_opaque: true,
             clipping_rect: PictureRect::max_rect(),
             culling_rect: VisRect::max_rect(),
+            culling_rect_projection_failed: false,
             map_local_to_picture,
             raster_spatial_node_index: root_reference_frame_index,
             surface_spatial_node_index: root_reference_frame_index,
@@ -3024,6 +3026,7 @@ fn test_drop_filter_dirty_region_outside_prim() {
             force_scissor_rect: false,
             svgfe_source_map: ScaleOffset::identity(),
             culling_rect: VisRect::max_rect(),
+            culling_rect_projection_failed: false,
         },
         SurfaceInfo {
             unclipped_local_rect: PictureRect::new(
@@ -3048,6 +3051,7 @@ fn test_drop_filter_dirty_region_outside_prim() {
             force_scissor_rect: false,
             svgfe_source_map: ScaleOffset::identity(),
             culling_rect: VisRect::max_rect(),
+            culling_rect_projection_failed: false,
         },
     ];
 
@@ -3144,6 +3148,7 @@ fn test_drop_filter_partial_dirty_content_inflate() {
             force_scissor_rect: false,
             svgfe_source_map: ScaleOffset::identity(),
             culling_rect: VisRect::max_rect(),
+            culling_rect_projection_failed: false,
         },
         SurfaceInfo {
             unclipped_local_rect: PictureRect::new(
@@ -3168,6 +3173,7 @@ fn test_drop_filter_partial_dirty_content_inflate() {
             force_scissor_rect: false,
             svgfe_source_map: ScaleOffset::identity(),
             culling_rect: VisRect::max_rect(),
+            culling_rect_projection_failed: false,
         },
     ];
 

gfx/wr/webrender/src/surface.rs

@@ -216,6 +216,10 @@ pub struct SurfaceInfo {
     /// rect culls the whole surface, so any projection that cannot be computed
     /// falls back to `max_rect` (cull nothing) instead.
     pub culling_rect: VisRect,
+    /// Whether `culling_rect` is the `max_rect` fallback rather than a real
+    /// projection of the screen. Instrumentation only: a `max_rect` culling rect
+    /// is also legitimate for a surface handed an unbounded screen rect.
+    pub culling_rect_projection_failed: bool,
     /// Helper structs for mapping local rects in different
     /// coordinate systems into the picture coordinates.
     pub map_local_to_picture: SpaceMapper<LayoutPixel, PicturePixel>,
@@ -307,9 +311,11 @@ impl SurfaceInfo {
             spatial_tree,
         );
 
+        let mut culling_rect_projection_failed = false;
         let culling_rect = match map_vis_to_root.unmap(&global_culling_rect) {
             Some(rect) => rect,
             None => {
+                culling_rect_projection_failed = true;
                 // Cull nothing rather than everything; see `culling_rect`.
                 // Only reachable for a vis node outside the root coordinate
                 // system, where the screen rect need not have an axis-aligned
@@ -359,6 +365,7 @@ impl SurfaceInfo {
             force_scissor_rect,
             svgfe_source_map: ScaleOffset::identity(),
             culling_rect,
+            culling_rect_projection_failed,
         }
     }
 

gfx/wr/webrender/src/visibility.rs

@@ -312,9 +312,7 @@ pub fn update_prim_visibility(
 
     let visibility_spatial_node_index = surface.visibility_spatial_node_index;
 
-    if surface_culling_rect == VisRect::max_rect() {
-        // `SurfaceInfo::new` could not project the screen into vis space, so this
-        // surface culls nothing at all.
+    if surface.culling_rect_projection_failed {
         frame_state.profile.add(profiler::VIS_CULLING_RECT_FALLBACKS, 1);
     }