Introduced ClipVertexInfo

webrender/res/clip_shared.glsl

@@ -34,12 +34,21 @@ CacheClipInstance fetch_clip_item(int index) {
     return cci;
 }
 
+struct ClipVertexInfo {
+    vec3 local_pos;
+    vec2 screen_pos;
+    RectWithSize clipped_local_rect;
+};
+
 // The transformed vertex function that always covers the whole clip area,
 // which is the intersection of all clip instances of a given primitive
-TransformVertexInfo write_clip_tile_vertex(RectWithSize local_clip_rect,
-                                           Layer layer,
-                                           ClipArea area,
-                                           int segment_index) {
+ClipVertexInfo write_clip_tile_vertex(RectWithSize local_clip_rect,
+                                      Layer layer,
+                                      ClipArea area,
+                                      int segment_index) {
+
+    RectWithSize clipped_local_rect = intersect_rect(local_clip_rect,
+                                                     layer.local_clip_rect);
 
     vec2 outer_p0 = area.screen_origin_target_index.xy;
     vec2 outer_p1 = outer_p0 + area.task_bounds.zw - area.task_bounds.xy;
@@ -79,7 +88,7 @@ TransformVertexInfo write_clip_tile_vertex(RectWithSize local_clip_rect,
 
     gl_Position = uTransform * vec4(vertex_pos, 0.0, 1);
 
-    return TransformVertexInfo(layer_pos.xyw, actual_pos);
+    return ClipVertexInfo(layer_pos.xyw, actual_pos, clipped_local_rect);
 }
 
 #endif //WR_VERTEX_SHADER

webrender/res/cs_clip_image.vs.glsl

@@ -29,12 +29,12 @@ void main(void) {
     ImageMaskData mask = fetch_mask_data(cci.data_index);
     RectWithSize local_rect = mask.local_rect;
 
-    TransformVertexInfo vi = write_clip_tile_vertex(local_rect,
-                                                    layer,
-                                                    area,
-                                                    cci.segment_index);
+    ClipVertexInfo vi = write_clip_tile_vertex(local_rect,
+                                               layer,
+                                               area,
+                                               cci.segment_index);
 
-    vLocalRect = local_rect;
+    vLocalRect = vi.clipped_local_rect;
     vPos = vi.local_pos;
 
     vClipMaskUv = vec3((vPos.xy / vPos.z - local_rect.p0) / local_rect.size, 0.0);

webrender/res/cs_clip_rectangle.vs.glsl

@@ -64,11 +64,11 @@ void main(void) {
     ClipData clip = fetch_clip(cci.data_index);
     RectWithSize local_rect = clip.rect.rect;
 
-    TransformVertexInfo vi = write_clip_tile_vertex(local_rect,
-                                                    layer,
-                                                    area,
-                                                    cci.segment_index);
-    vLocalRect = local_rect;
+    ClipVertexInfo vi = write_clip_tile_vertex(local_rect,
+                                               layer,
+                                               area,
+                                               cci.segment_index);
+    vLocalRect = vi.clipped_local_rect;
     vPos = vi.local_pos;
 
     vClipMode = clip.rect.mode.x;

webrender/res/prim_shared.glsl

@@ -472,14 +472,6 @@ struct VertexInfo {
     vec2 screen_pos;
 };
 
-RectWithSize compute_clip_rect(RectWithSize local_rect,
-                               RectWithSize local_clip_rect,
-                               Layer layer) {
-    // intersect all 3 clip rectangles
-    return intersect_rect(layer.local_clip_rect,
-                          intersect_rect(local_clip_rect, local_rect));
-}
-
 VertexInfo write_vertex(RectWithSize instance_rect,
                         RectWithSize local_clip_rect,
                         float z,