Mask generation in the off-screen cache textures with support for multiple rounded cornered rectangles.

Removal of the _clip shader variants.

Author: kvark

replay/src/main.rs

@@ -79,6 +79,7 @@ fn main() {
     let resource_path = &args[1];
     let ref dir = args[2];
     let window = glutin::WindowBuilder::new()
+        .with_title("WebRender Replay")
         .with_gl(glutin::GlRequest::Specific(glutin::Api::OpenGl, (3,2)))
         .build()
         .unwrap();

sample/src/main.rs

@@ -63,6 +63,7 @@ fn main() {
     let res_path = &args[1];
 
     let window = glutin::WindowBuilder::new()
+                .with_title("WebRender Sample")
                 .with_gl(glutin::GlRequest::Specific(glutin::Api::OpenGl, (3, 2)))
                 .build()
                 .unwrap();
@@ -133,14 +134,15 @@ fn main() {
                                                &mut auxiliary_lists_builder));
 
     let clip_region = {
-        let rect = Rect::new(Point2D::new(100.0, 100.0), Size2D::new(100.0, 100.0));
         let mask = webrender_traits::ImageMask {
             image: api.add_image(2, 2, None, ImageFormat::A8, vec![0,80, 180, 255]),
-            rect: rect,
+            rect: Rect::new(Point2D::new(75.0, 75.0), Size2D::new(100.0, 100.0)),
             repeat: false,
         };
         let radius = webrender_traits::BorderRadius::uniform(20.0);
-        let complex = webrender_traits::ComplexClipRegion::new(rect, radius);
+        let complex = webrender_traits::ComplexClipRegion::new(
+            Rect::new(Point2D::new(50.0, 50.0), Size2D::new(100.0, 100.0)),
+            radius);
 
         webrender_traits::ClipRegion::new(&bounds,
                                           vec![complex],

webrender/res/clip_shared.glsl

@@ -3,63 +3,49 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-flat varying vec4 vClipRect;
-flat varying vec4 vClipRadius;
-flat varying vec4 vClipMaskUvRect;
-flat varying vec4 vClipMaskLocalRect;
-
 #ifdef WR_VERTEX_SHADER
-void write_clip(ClipData clip) {
-    vClipRect = vec4(clip.rect.rect.xy, clip.rect.rect.xy + clip.rect.rect.zw);
-    vClipRadius = vec4(clip.top_left.outer_inner_radius.x,
-                       clip.top_right.outer_inner_radius.x,
-                       clip.bottom_right.outer_inner_radius.x,
-                       clip.bottom_left.outer_inner_radius.x);
-    //TODO: interpolate the final mask UV
-    vec2 texture_size = textureSize(sMask, 0);
-    vClipMaskUvRect = clip.mask_data.uv_rect / texture_size.xyxy;
-    vClipMaskLocalRect = clip.mask_data.local_rect; //TODO: transform
-}
-#endif
 
-#ifdef WR_FRAGMENT_SHADER
-float do_clip(vec2 pos) {
-    vec2 ref_tl = vClipRect.xy + vec2( vClipRadius.x,  vClipRadius.x);
-    vec2 ref_tr = vClipRect.zy + vec2(-vClipRadius.y,  vClipRadius.y);
-    vec2 ref_br = vClipRect.zw + vec2(-vClipRadius.z, -vClipRadius.z);
-    vec2 ref_bl = vClipRect.xw + vec2( vClipRadius.w, -vClipRadius.w);
+struct CacheClipInstance {
+    int render_task_index;
+    int layer_index;
+    int data_index;
+};
 
-    float d_tl = distance(pos, ref_tl);
-    float d_tr = distance(pos, ref_tr);
-    float d_br = distance(pos, ref_br);
-    float d_bl = distance(pos, ref_bl);
+CacheClipInstance fetch_clip_item(int index) {
+    CacheClipInstance cci;
 
-    float pixels_per_fragment = length(fwidth(pos.xy));
-    float nudge = 0.5 * pixels_per_fragment;
-    vec4 distances = vec4(d_tl, d_tr, d_br, d_bl) - vClipRadius + nudge;
+    int offset = index * 1;
 
-    bvec4 is_out = bvec4(pos.x < ref_tl.x && pos.y < ref_tl.y,
-                         pos.x > ref_tr.x && pos.y < ref_tr.y,
-                         pos.x > ref_br.x && pos.y > ref_br.y,
-                         pos.x < ref_bl.x && pos.y > ref_bl.y);
+    ivec4 data0 = int_data[offset + 0];
 
-    float distance_from_border = dot(vec4(is_out),
-                                     max(vec4(0.0, 0.0, 0.0, 0.0), distances));
+    cci.render_task_index = data0.x;
+    cci.layer_index = data0.y;
+    cci.data_index = data0.z;
+
+    return cci;
+}
 
-    // Move the distance back into pixels.
-    distance_from_border /= pixels_per_fragment;
-    // Apply a more gradual fade out to transparent.
-    //distance_from_border -= 0.5;
+// The transformed vertex function that always covers the whole whole clip area,
+// which is the intersection of all clip instances of a given primitive
+TransformVertexInfo write_clip_tile_vertex(vec4 local_clip_rect,
+                                           Layer layer,
+                                           ClipArea area) {
+    vec2 lp0_base = local_clip_rect.xy;
+    vec2 lp1_base = local_clip_rect.xy + local_clip_rect.zw;
 
-    float border_alpha = 1.0 - smoothstep(0.0, 1.0, distance_from_border);
+    vec2 lp0 = clamp_rect(lp0_base, layer.local_clip_rect);
+    vec2 lp1 = clamp_rect(lp1_base, layer.local_clip_rect);
+    vec4 clipped_local_rect = vec4(lp0, lp1 - lp0);
 
-    bool repeat_mask = false; //TODO
-    vec2 vMaskUv = (pos - vClipMaskLocalRect.xy) / vClipMaskLocalRect.zw;
-    vec2 clamped_mask_uv = repeat_mask ? fract(vMaskUv) :
-        clamp(vMaskUv, vec2(0.0, 0.0), vec2(1.0, 1.0));
-    vec2 source_uv = clamped_mask_uv * vClipMaskUvRect.zw + vClipMaskUvRect.xy;
-    float mask_alpha = texture(sMask, source_uv).r; //careful: texture has type A8
+    vec2 final_pos = mix(area.task_bounds.xy, area.task_bounds.zw, aPosition.xy);
 
-    return border_alpha * mask_alpha;
+    // compute the point position in side the layer, in CSS space
+    vec2 clamped_pos = final_pos + area.screen_origin_target_index.xy - area.task_bounds.xy;
+    vec4 layer_pos = get_layer_pos(clamped_pos / uDevicePixelRatio, layer);
+
+    gl_Position = uTransform * vec4(final_pos, 0.0, 1);
+
+    return TransformVertexInfo(layer_pos.xyw, clamped_pos, clipped_local_rect);
 }
-#endif
+
+#endif //WR_VERTEX_SHADER

webrender/res/cs_clip_clear.fs.glsl

@@ -0,0 +1,7 @@
+/* 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+void main(void) {
+    oFragColor = vec4(1.0, 1.0, 1.0, 1.0);
+}

webrender/res/cs_clip_clear.vs.glsl

@@ -0,0 +1,13 @@
+#line 1
+/* 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+void main(void) {
+    CacheClipInstance cci = fetch_clip_item(gl_InstanceID);
+    ClipArea area = fetch_clip_area(cci.render_task_index);
+
+    vec2 final_pos = mix(area.task_bounds.xy, area.task_bounds.zw, aPosition.xy);
+
+    gl_Position = uTransform * vec4(final_pos, 0.0, 1.0);
+}

webrender/res/cs_clip_image.fs.glsl

@@ -0,0 +1,16 @@
+/* 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+void main(void) {
+    float alpha = 1.f;
+    vec2 local_pos = init_transform_fs(vPos, vLocalRect, alpha);
+
+    bool repeat_mask = false; //TODO
+    vec2 clamped_mask_uv = repeat_mask ? fract(vClipMaskUv.xy) :
+        clamp(vClipMaskUv.xy, vec2(0.0, 0.0), vec2(1.0, 1.0));
+    vec2 source_uv = clamped_mask_uv * vClipMaskUvRect.zw + vClipMaskUvRect.xy;
+    float clip_alpha = texture(sMask, source_uv).r; //careful: texture has type A8
+
+    oFragColor = vec4(1.0, 1.0, 1.0, min(alpha, clip_alpha));
+}

webrender/res/ps_rectangle_clip.glsl renamed to webrender/res/cs_clip_image.glsl

@@ -4,11 +4,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-varying vec4 vColor;
-
-#ifdef WR_FEATURE_TRANSFORM
 varying vec3 vPos;
 flat varying vec4 vLocalRect;
-#else
-varying vec2 vPos;
-#endif
+flat varying vec4 vClipMaskUvRect;

webrender/res/cs_clip_image.vs.glsl

@@ -0,0 +1,38 @@
+#line 1
+/* 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+struct ImageMaskData {
+    vec4 uv_rect;
+    vec4 local_rect;
+};
+
+ImageMaskData fetch_mask_data(int index) {
+    ImageMaskData info;
+
+    ivec2 uv = get_fetch_uv_2(index);
+
+    info.uv_rect = texelFetchOffset(sData32, uv, 0, ivec2(0, 0));
+    info.local_rect = texelFetchOffset(sData32, uv, 0, ivec2(1, 0));
+
+    return info;
+}
+
+void main(void) {
+    CacheClipInstance cci = fetch_clip_item(gl_InstanceID);
+    ClipArea area = fetch_clip_area(cci.render_task_index);
+    Layer layer = fetch_layer(cci.layer_index);
+    ImageMaskData mask = fetch_mask_data(cci.data_index);
+    vec4 local_rect = mask.local_rect;
+
+    TransformVertexInfo vi = write_clip_tile_vertex(local_rect,
+                                                    layer,
+                                                    area);
+    vLocalRect = vi.clipped_local_rect;
+    vPos = vi.local_pos;
+
+    vClipMaskUv = vec3((vPos.xy / vPos.z - local_rect.xy) / local_rect.zw, 0.0);
+    vec2 texture_size = textureSize(sMask, 0);
+    vClipMaskUvRect = mask.uv_rect / texture_size.xyxy;
+}

webrender/res/cs_clip_rectangle.fs.glsl

@@ -0,0 +1,44 @@
+/* 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+float rounded_rect(vec2 pos) {
+    vec2 ref_tl = vClipRect.xy + vec2( vClipRadius.x,  vClipRadius.x);
+    vec2 ref_tr = vClipRect.zy + vec2(-vClipRadius.y,  vClipRadius.y);
+    vec2 ref_br = vClipRect.zw + vec2(-vClipRadius.z, -vClipRadius.z);
+    vec2 ref_bl = vClipRect.xw + vec2( vClipRadius.w, -vClipRadius.w);
+
+    float d_tl = distance(pos, ref_tl);
+    float d_tr = distance(pos, ref_tr);
+    float d_br = distance(pos, ref_br);
+    float d_bl = distance(pos, ref_bl);
+
+    float pixels_per_fragment = length(fwidth(pos.xy));
+    float nudge = 0.5 * pixels_per_fragment;
+    vec4 distances = vec4(d_tl, d_tr, d_br, d_bl) - vClipRadius + nudge;
+
+    bvec4 is_out = bvec4(pos.x < ref_tl.x && pos.y < ref_tl.y,
+                         pos.x > ref_tr.x && pos.y < ref_tr.y,
+                         pos.x > ref_br.x && pos.y > ref_br.y,
+                         pos.x < ref_bl.x && pos.y > ref_bl.y);
+
+    float distance_from_border = dot(vec4(is_out),
+                                     max(vec4(0.0, 0.0, 0.0, 0.0), distances));
+
+    // Move the distance back into pixels.
+    distance_from_border /= pixels_per_fragment;
+    // Apply a more gradual fade out to transparent.
+    //distance_from_border -= 0.5;
+
+    return 1.0 - smoothstep(0.0, 1.0, distance_from_border);
+}
+
+
+void main(void) {
+    float alpha = 1.f;
+    vec2 local_pos = init_transform_fs(vPos, vLocalRect, alpha);
+
+    float clip_alpha = rounded_rect(local_pos);
+
+    oFragColor = vec4(1.0, 1.0, 1.0, min(alpha, clip_alpha));
+}

webrender/res/ps_gradient_clip.glsl renamed to webrender/res/cs_clip_rectangle.glsl

@@ -1,12 +1,10 @@
+#line 1
+
 /* 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
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-varying vec4 vColor;
-
-#ifdef WR_FEATURE_TRANSFORM
-varying vec3 vLocalPos;
+varying vec3 vPos;
 flat varying vec4 vLocalRect;
-#else
-varying vec2 vPos;
-#endif
+flat varying vec4 vClipRect;
+flat varying vec4 vClipRadius;