ignore glyph color data when doing fast shadows

webrender/res/ps_text_run.glsl

@@ -7,6 +7,7 @@
 flat varying vec4 vColor;
 varying vec3 vUv;
 flat varying vec4 vUvBorder;
+flat varying vec2 vMaskSwizzle;
 
 #ifdef WR_FEATURE_GLYPH_TRANSFORM
 varying vec4 vUvClip;
@@ -125,27 +126,29 @@ void main(void) {
 
     write_clip(vi.screen_pos, prim.clip_area);
 
-#ifdef WR_FEATURE_SUBPX_BG_PASS1
-    vColor = vec4(text.color.a) * text.bg_color;
-#else
     switch (uMode) {
         case MODE_ALPHA:
+        case MODE_BITMAP:
+            vMaskSwizzle = vec2(0.0, 1.0);
+            vColor = text.color;
+            break;
         case MODE_SUBPX_PASS1:
         case MODE_SUBPX_BG_PASS2:
-        case MODE_BITMAP:
+            vMaskSwizzle = vec2(1.0, 0.0);
             vColor = text.color;
             break;
         case MODE_SUBPX_CONST_COLOR:
         case MODE_SUBPX_PASS0:
         case MODE_SUBPX_BG_PASS0:
         case MODE_COLOR_BITMAP:
+            vMaskSwizzle = vec2(1.0, 0.0);
             vColor = vec4(text.color.a);
             break;
         case MODE_SUBPX_BG_PASS1:
-            // This should never be reached.
+            vMaskSwizzle = vec2(-1.0, 1.0);
+            vColor = vec4(text.color.a) * text.bg_color;
             break;
     }
-#endif
 
     vec2 texture_size = vec2(textureSize(sColor0, 0));
     vec2 st0 = res.uv_rect.xy / texture_size;
@@ -160,16 +163,13 @@ void main(void) {
 void main(void) {
     vec3 tc = vec3(clamp(vUv.xy, vUvBorder.xy, vUvBorder.zw), vUv.z);
     vec4 mask = texture(sColor0, tc);
+    mask.rgb = mask.rgb * vMaskSwizzle.x + mask.aaa * vMaskSwizzle.y;
 
     float alpha = do_clip();
 #ifdef WR_FEATURE_GLYPH_TRANSFORM
     alpha *= float(all(greaterThanEqual(vUvClip, vec4(0.0))));
 #endif
 
-#ifdef WR_FEATURE_SUBPX_BG_PASS1
-    mask.rgb = vec3(mask.a) - mask.rgb;
-#endif
-
     oFragColor = vColor * mask * alpha;
 }
 #endif

webrender/src/frame_builder.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use api::{BorderDetails, BorderDisplayItem, BuiltDisplayList};
-use api::{ClipAndScrollInfo, ClipId, ColorF, PropertyBinding};
+use api::{ClipAndScrollInfo, ClipId, ColorF, ColorU, PropertyBinding};
 use api::{DeviceUintPoint, DeviceUintRect, DeviceUintSize};
 use api::{DocumentLayer, ExtendMode, FontRenderMode, LayoutTransform};
 use api::{GlyphInstance, GlyphOptions, GradientStop, HitTestFlags, HitTestItem, HitTestResult};
@@ -1345,6 +1345,7 @@ impl FrameBuilder {
             glyph_gpu_blocks: Vec::new(),
             glyph_keys: Vec::new(),
             offset: run_offset,
+            shadow_color: ColorU::new(0, 0, 0, 0),
         };
 
         // Text shadows that have a blur radius of 0 need to be rendered as normal
@@ -1362,7 +1363,7 @@ impl FrameBuilder {
             match picture_prim.kind {
                 PictureKind::TextShadow { offset, color, blur_radius, .. } if blur_radius == 0.0 => {
                     let mut text_prim = prim.clone();
-                    text_prim.font.color = color.into();
+                    text_prim.shadow_color = color.into();
                     text_prim.offset += offset;
                     fast_shadow_prims.push((idx, text_prim));
                 }

webrender/src/glyph_rasterizer.rs

@@ -221,6 +221,17 @@ pub enum GlyphFormat {
     ColorBitmap,
 }
 
+impl GlyphFormat {
+    pub fn ignore_color(self) -> Self {
+        match self {
+            GlyphFormat::Subpixel => GlyphFormat::Alpha,
+            GlyphFormat::TransformedSubpixel => GlyphFormat::TransformedAlpha,
+            GlyphFormat::ColorBitmap => GlyphFormat::Bitmap,
+            _ => self,
+        }
+    }
+}
+
 pub struct RasterizedGlyph {
     pub top: f32,
     pub left: f32,

webrender/src/prim_store.rs

@@ -2,7 +2,7 @@
  * 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/. */
 
-use api::{BorderRadius, BuiltDisplayList, ClipAndScrollInfo, ClipId, ClipMode, ColorF};
+use api::{BorderRadius, BuiltDisplayList, ClipAndScrollInfo, ClipId, ClipMode, ColorF, ColorU};
 use api::{ComplexClipRegion, DeviceIntRect, DevicePoint, ExtendMode, FontRenderMode};
 use api::{GlyphInstance, GlyphKey, GradientStop, ImageKey, ImageRendering, ItemRange, ItemTag};
 use api::{LayerPoint, LayerRect, LayerSize, LayerToWorldTransform, LayerVector2D, LineOrientation};
@@ -740,9 +740,9 @@ pub struct TextRunPrimitiveCpu {
     pub glyph_count: usize,
     pub glyph_keys: Vec<GlyphKey>,
     pub glyph_gpu_blocks: Vec<GpuBlockData>,
+    pub shadow_color: ColorU,
 }
 
-
 impl TextRunPrimitiveCpu {
     pub fn get_font(
         &self,
@@ -762,6 +762,10 @@ impl TextRunPrimitiveCpu {
         font
     }
 
+    pub fn is_shadow(&self) -> bool {
+        self.shadow_color.a != 0
+    }
+
     fn prepare_for_render(
         &mut self,
         resource_cache: &mut ResourceCache,
@@ -813,7 +817,12 @@ impl TextRunPrimitiveCpu {
 
     fn write_gpu_blocks(&self, request: &mut GpuDataRequest) {
         let bg_color = ColorF::from(self.font.bg_color);
-        request.push(ColorF::from(self.font.color).premultiplied());
+        let color = ColorF::from(if self.is_shadow() {
+            self.shadow_color
+        } else {
+            self.font.color
+        });
+        request.push(color.premultiplied());
         // this is the only case where we need to provide plain color to GPU
         request.extend_from_slice(&[
             GpuBlockData { data: [bg_color.r, bg_color.g, bg_color.b, 1.0] }

webrender/src/renderer.rs

@@ -1597,7 +1597,6 @@ pub struct Renderer {
     // output, and the cache_image shader blits the results of
     // a cache shader (e.g. blur) to the screen.
     ps_text_run: TextShader,
-    ps_text_run_subpx_bg_pass1: TextShader,
     ps_image: Vec<Option<PrimitiveShader>>,
     ps_yuv_image: Vec<Option<PrimitiveShader>>,
     ps_border_corner: PrimitiveShader,
@@ -1863,13 +1862,6 @@ impl Renderer {
                            options.precache_shaders)
         };
 
-        let ps_text_run_subpx_bg_pass1 = try!{
-            TextShader::new("ps_text_run",
-                            &mut device,
-                            &["SUBPX_BG_PASS1"],
-                            options.precache_shaders)
-        };
-
         // All image configuration.
         let mut image_features = Vec::new();
         let mut ps_image: Vec<Option<PrimitiveShader>> = Vec::new();
@@ -2244,7 +2236,6 @@ impl Renderer {
             cs_clip_border,
             cs_clip_image,
             ps_text_run,
-            ps_text_run_subpx_bg_pass1,
             ps_image,
             ps_yuv_image,
             ps_border_corner,
@@ -3561,7 +3552,7 @@ impl Renderer {
 
                                 self.device.set_blend_mode_subpixel_with_bg_color_pass1();
 
-                                self.ps_text_run_subpx_bg_pass1.bind(
+                                self.ps_text_run.bind(
                                     &mut self.device,
                                     glyph_format,
                                     transform_kind,
@@ -4437,7 +4428,6 @@ impl Renderer {
         self.cs_clip_image.deinit(&mut self.device);
         self.cs_clip_border.deinit(&mut self.device);
         self.ps_text_run.deinit(&mut self.device);
-        self.ps_text_run_subpx_bg_pass1.deinit(&mut self.device);
         for shader in self.ps_image {
             if let Some(shader) = shader {
                 shader.deinit(&mut self.device);

webrender/src/tiling.rs

@@ -570,7 +570,7 @@ fn add_to_batch(
                 &text_cpu.glyph_keys,
                 glyph_fetch_buffer,
                 gpu_cache,
-                |texture_id, glyph_format, glyphs| {
+                |texture_id, mut glyph_format, glyphs| {
                     debug_assert_ne!(texture_id, SourceTexture::Invalid);
 
                     let textures = BatchTextures {
@@ -581,6 +581,11 @@ fn add_to_batch(
                         ],
                     };
 
+                    // Ignore color and only sample alpha when shadowing.
+                    if text_cpu.is_shadow() {
+                        glyph_format = glyph_format.ignore_color();
+                    }
+
                     let kind = BatchKind::Transformable(
                         transform_kind,
                         TransformBatchKind::TextRun(glyph_format),

wrench/reftests/text/Proggy-License.txt

@@ -1,5 +1,5 @@
-The "Proggy.fon" font was downloaded from https://proggyfonts.net/download/ on Dec 5, 2017.
-The following license applies to "Proggy.fon":
+The "Proggy.ttf" font was downloaded from https://proggyfonts.net/download/ on Dec 5, 2017.
+The following license applies to "Proggy.ttf":
 
 Copyright (c) 2004, 2005 Tristan Grimmer
 

wrench/reftests/text/embedded-bitmaps.yaml

@@ -5,5 +5,5 @@ root:
           origin: 20 30
           bounds: [0, 0, 710, 50]
           size: 8.25
-          font: "Proggy.fon"
+          font: "Proggy.ttf"
           embedded-bitmaps: true

wrench/reftests/text/reftest.list

@@ -21,7 +21,7 @@ fuzzy(1,100) == decorations-suite.yaml decorations-suite.png
 fuzzy(1,735) == shadow-grey.yaml shadow-grey-ref.yaml
 fuzzy(1,614) == shadow-grey-transparent.yaml shadow-grey-ref.yaml
 == subtle-shadow.yaml subtle-shadow-ref.yaml
-== shadow-atomic.yaml shadow-atomic-ref.yaml
+options(disable-aa) == shadow-atomic.yaml shadow-atomic-ref.yaml
 options(disable-aa) == shadow-ordering.yaml shadow-ordering-ref.yaml
 # enable when synthetic-italics implemented on mac
 platform(linux) != synthetic-italics.yaml synthetic-italics-ref.yaml