Bug 1623791 - Remove segment gridding optimization. r=nical

This is no longer as important, with picture caching. Removing it
will simplify the planned changes to switch to a simpler segment
model based on nine-patch rectangles during scene building.

Differential Revision: https://phabricator.services.mozilla.com/D67792

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

gfx/wr/webrender/src/prim_store/mod.rs

@@ -82,7 +82,7 @@ pub fn register_prim_chase_id(id: PrimitiveDebugId) {
 pub fn register_prim_chase_id(_: PrimitiveDebugId) {
 }
 
-const MIN_BRUSH_SPLIT_AREA: f32 = 256.0 * 256.0;
+const MIN_BRUSH_SPLIT_AREA: f32 = 128.0 * 128.0;
 pub const VECS_PER_SEGMENT: usize = 2;
 
 #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq)]
@@ -3696,17 +3696,11 @@ impl<'a> GpuDataRequest<'a> {
         clip_store: &ClipStore,
         data_stores: &DataStores,
     ) -> bool {
-        // If the brush is small, we generally want to skip building segments
-        // and just draw it as a single primitive with clip mask. However,
-        // if the clips are purely rectangles that have no per-fragment
-        // clip masks, we will segment anyway. This allows us to completely
-        // skip allocating a clip mask in these cases.
-        let is_large = prim_local_rect.size.area() > MIN_BRUSH_SPLIT_AREA;
-
-        // TODO(gw): We should probably detect and store this on each
-        //           ClipSources instance, to avoid having to iterate
-        //           the clip sources here.
-        let mut rect_clips_only = true;
+        // If the brush is small, we want to skip building segments
+        // and just draw it as a single primitive with clip mask.
+        if prim_local_rect.size.area() < MIN_BRUSH_SPLIT_AREA {
+            return false;
+        }
 
         segment_builder.initialize(
             prim_local_rect,
@@ -3715,7 +3709,6 @@ impl<'a> GpuDataRequest<'a> {
         );
 
         // Segment the primitive on all the local-space clip sources that we can.
-        let mut local_clip_count = 0;
         for i in 0 .. clip_chain.clips_range.count {
             let clip_instance = clip_store
                 .get_instance_from_range(&clip_chain.clips_range, i);
@@ -3730,19 +3723,14 @@ impl<'a> GpuDataRequest<'a> {
                 continue;
             }
 
-            local_clip_count += 1;
-
             let (local_clip_rect, radius, mode) = match clip_node.item.kind {
                 ClipItemKind::RoundedRectangle { rect, radius, mode } => {
-                    rect_clips_only = false;
                     (rect, Some(radius), mode)
                 }
                 ClipItemKind::Rectangle { rect, mode } => {
                     (rect, None, mode)
                 }
                 ClipItemKind::BoxShadow { ref source } => {
-                    rect_clips_only = false;
-
                     // For inset box shadows, we can clip out any
                     // pixels that are inside the shadow region
                     // and are beyond the inner rect, as they can't
@@ -3781,43 +3769,7 @@ impl<'a> GpuDataRequest<'a> {
             segment_builder.push_clip_rect(local_clip_rect, radius, mode);
         }
 
-        if is_large || rect_clips_only {
-            // If there were no local clips, then we will subdivide the primitive into
-            // a uniform grid (up to 8x8 segments). This will typically result in
-            // a significant number of those segments either being completely clipped,
-            // or determined to not need a clip mask for that segment.
-            if local_clip_count == 0 && clip_chain.clips_range.count > 0 {
-                let x_clip_count = cmp::min(8, (prim_local_rect.size.width / 128.0).ceil() as i32);
-                let y_clip_count = cmp::min(8, (prim_local_rect.size.height / 128.0).ceil() as i32);
-
-                for y in 0 .. y_clip_count {
-                    let y0 = prim_local_rect.size.height * y as f32 / y_clip_count as f32;
-                    let y1 = prim_local_rect.size.height * (y+1) as f32 / y_clip_count as f32;
-
-                    for x in 0 .. x_clip_count {
-                        let x0 = prim_local_rect.size.width * x as f32 / x_clip_count as f32;
-                        let x1 = prim_local_rect.size.width * (x+1) as f32 / x_clip_count as f32;
-
-                        let rect = LayoutRect::new(
-                            LayoutPoint::new(
-                                x0 + prim_local_rect.origin.x,
-                                y0 + prim_local_rect.origin.y,
-                            ),
-                            LayoutSize::new(
-                                x1 - x0,
-                                y1 - y0,
-                            ),
-                        );
-
-                        segment_builder.push_mask_region(rect, LayoutRect::zero(), None);
-                    }
-                }
-            }
-
-            return true
-        }
-
-        false
+        true
     }
 
 impl PrimitiveInstance {

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

@@ -24,7 +24,7 @@ platform(linux,mac) fuzzy(1,283) == near-plane-clip.yaml near-plane-clip.png
 platform(linux,mac) == perspective-mask.yaml perspective-mask.png
 == rotate-clip.yaml rotate-clip-ref.yaml
 == clip-translate.yaml clip-translate-ref.yaml
-platform(linux,mac) == perspective-clip.yaml perspective-clip.png
+platform(linux,mac) fuzzy(1,1) == perspective-clip.yaml perspective-clip.png
 platform(linux,mac) fuzzy(1,2) == perspective-clip-1.yaml perspective-clip-1.png
 platform(linux,mac) fuzzy(1,2) == perspective-shadow.yaml perspective-shadow.png
 # The ref YAML here produces significantly worse quality

layout/reftests/box-shadow/reftest.list

@@ -29,7 +29,7 @@ fuzzy(0-2,0-440) == boxshadow-skiprect.html boxshadow-skiprect-ref.html
 fuzzy(0-3,0-500) fuzzy-if(d2d,0-2,0-1080) == boxshadow-border-radius-int.html boxshadow-border-radius-int-ref.html
 == boxshadow-inset-neg-spread.html about:blank
 == boxshadow-inset-neg-spread2.html boxshadow-inset-neg-spread2-ref.html
-fuzzy(0-26,0-3610) fuzzy-if(d2d,0-26,0-5910) fuzzy-if(webrender,18-19,4184-4342) == boxshadow-rotated.html boxshadow-rotated-ref.html # Bug 1211264
+fuzzy(0-26,0-3610) fuzzy-if(d2d,0-26,0-5910) fuzzy-if(webrender,4-6,4184-4250) == boxshadow-rotated.html boxshadow-rotated-ref.html # Bug 1211264
 == boxshadow-inset-large-border-radius.html boxshadow-inset-large-border-radius-ref.html
 
 # fuzzy due to blur going inside, but as long as it's essentially black instead of a light gray its ok.