Bug 1700434 - Store mono bitmaps and alpha glyphs with same texture format. r=jrmuizel

Differential Revision: https://phabricator.services.mozilla.com/D115511

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/0a38ce1f4c59f60ce0fbe66c3bce3be551069071

Author: lsalzman

webrender/res/brush_image.glsl

@@ -246,7 +246,7 @@ void brush_vs(
 
     switch (color_mode) {
         case COLOR_MODE_ALPHA:
-        case COLOR_MODE_BITMAP:
+        case COLOR_MODE_BITMAP_SHADOW:
             #ifdef SWGL_BLEND
                 swgl_blendDropShadow(image_data.color);
                 v_mask_swizzle = vec2(1.0, 0.0);

webrender/res/prim_shared.glsl

@@ -32,7 +32,7 @@ varying vec2 vClipMaskUv;
 #define COLOR_MODE_SUBPX_BG_PASS1       4
 #define COLOR_MODE_SUBPX_BG_PASS2       5
 #define COLOR_MODE_SUBPX_DUAL_SOURCE    6
-#define COLOR_MODE_BITMAP               7
+#define COLOR_MODE_BITMAP_SHADOW        7
 #define COLOR_MODE_COLOR_BITMAP         8
 #define COLOR_MODE_IMAGE                9
 #define COLOR_MODE_MULTIPLY_DUAL_SOURCE 10

webrender/res/ps_text_run.glsl

@@ -233,9 +233,15 @@ void main() {
             v_mask_swizzle = vec3(0.0, 1.0, 1.0);
             v_color = text.color;
             break;
-        case COLOR_MODE_BITMAP:
-            v_mask_swizzle = vec3(0.0, 1.0, 0.0);
-            v_color = text.color;
+        case COLOR_MODE_BITMAP_SHADOW:
+            #ifdef SWGL_BLEND
+                swgl_blendDropShadow(text.color);
+                v_mask_swizzle = vec3(1.0, 0.0, 0.0);
+                v_color = vec4(1.0);
+            #else
+                v_mask_swizzle = vec3(0.0, 1.0, 0.0);
+                v_color = text.color;
+            #endif
             break;
         case COLOR_MODE_SUBPX_BG_PASS2:
             v_mask_swizzle = vec3(1.0, 0.0, 0.0);

webrender/src/batch.rs

@@ -1271,14 +1271,9 @@ impl BatchBuilder {
                     &glyph_keys,
                     &mut self.glyph_fetch_buffer,
                     gpu_cache,
-                    |texture_id, mut glyph_format, glyphs| {
+                    |texture_id, glyph_format, glyphs| {
                         debug_assert_ne!(texture_id, TextureSource::Invalid);
 
-                        // Ignore color and only sample alpha when shadowing.
-                        if run.shadow {
-                            glyph_format = glyph_format.ignore_color();
-                        }
-
                         let subpx_dir = subpx_dir.limit_by(glyph_format);
 
                         let textures = BatchTextures::prim_textured(
@@ -1309,22 +1304,22 @@ impl BatchBuilder {
                                 }
                             }
                             GlyphFormat::Alpha |
-                            GlyphFormat::TransformedAlpha => {
-                                (
-                                    BlendMode::PremultipliedAlpha,
-                                    ShaderColorMode::Alpha,
-                                )
-                            }
+                            GlyphFormat::TransformedAlpha |
                             GlyphFormat::Bitmap => {
                                 (
                                     BlendMode::PremultipliedAlpha,
-                                    ShaderColorMode::Bitmap,
+                                    ShaderColorMode::Alpha,
                                 )
                             }
                             GlyphFormat::ColorBitmap => {
                                 (
                                     BlendMode::PremultipliedAlpha,
-                                    ShaderColorMode::ColorBitmap,
+                                    if run.shadow {
+                                        // Ignore color and only sample alpha when shadowing.
+                                        ShaderColorMode::BitmapShadow
+                                    } else {
+                                        ShaderColorMode::ColorBitmap
+                                    },
                                 )
                             }
                         };

webrender/src/glyph_rasterizer/mod.rs

@@ -759,22 +759,14 @@ pub enum GlyphFormat {
 }
 
 impl GlyphFormat {
-    pub fn ignore_color(self) -> Self {
-        match self {
-            GlyphFormat::ColorBitmap => GlyphFormat::Bitmap,
-            _ => self,
-        }
-    }
-
     /// Returns the ImageFormat that a glyph should be stored as in the texture cache.
     /// can_use_r8_format should be set false on platforms where we have encountered
     /// issues with R8 textures, so that we do not use them for glyphs.
     pub fn image_format(&self, can_use_r8_format: bool) -> ImageFormat {
         match *self {
-            // GlyphFormat::Bitmap glyphs could be stored in an R8 texture. However, we currently
-            // support drawing ColorBitmap glyphs (stored in a BGRA8 texture) in Bitmap mode, and
-            // currently the text shader cannot differentiate between the two cases.
-            GlyphFormat::Alpha | GlyphFormat::TransformedAlpha => {
+            GlyphFormat::Alpha |
+            GlyphFormat::TransformedAlpha |
+            GlyphFormat::Bitmap => {
                 if can_use_r8_format {
                     ImageFormat::R8
                 } else {
@@ -783,7 +775,6 @@ impl GlyphFormat {
             }
             GlyphFormat::Subpixel |
             GlyphFormat::TransformedSubpixel |
-            GlyphFormat::Bitmap |
             GlyphFormat::ColorBitmap => ImageFormat::BGRA8,
         }
     }

webrender/src/renderer/mod.rs

@@ -312,7 +312,7 @@ pub enum ShaderColorMode {
     SubpixelWithBgColorPass1 = 4,
     SubpixelWithBgColorPass2 = 5,
     SubpixelDualSource = 6,
-    Bitmap = 7,
+    BitmapShadow = 7,
     ColorBitmap = 8,
     Image = 9,
     MultiplyDualSource = 10,
@@ -321,11 +321,12 @@ pub enum ShaderColorMode {
 impl From<GlyphFormat> for ShaderColorMode {
     fn from(format: GlyphFormat) -> ShaderColorMode {
         match format {
-            GlyphFormat::Alpha | GlyphFormat::TransformedAlpha => ShaderColorMode::Alpha,
+            GlyphFormat::Alpha |
+            GlyphFormat::TransformedAlpha |
+            GlyphFormat::Bitmap => ShaderColorMode::Alpha,
             GlyphFormat::Subpixel | GlyphFormat::TransformedSubpixel => {
                 panic!("Subpixel glyph formats must be handled separately.");
             }
-            GlyphFormat::Bitmap => ShaderColorMode::Bitmap,
             GlyphFormat::ColorBitmap => ShaderColorMode::ColorBitmap,
         }
     }