1 files changed, 354 insertions, 0 deletions
diff --git a/gfx/wr/webrender/res/ps_text_run.glsl b/gfx/wr/webrender/res/ps_text_run.glsl
new file mode 100644
index 0000000000..9c5f34e3a6
--- /dev/null
+++ b/gfx/wr/webrender/res/ps_text_run.glsl
@@ -0,0 +1,354 @@
+/* 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/. */
+
+#include shared,prim_shared
+
+flat varying mediump vec4 v_color;
+flat varying mediump vec3 v_mask_swizzle;
+// Normalized bounds of the source image in the texture.
+flat varying highp vec4 v_uv_bounds;
+
+// Interpolated UV coordinates to sample.
+varying highp vec2 v_uv;
+
+
+#if defined(WR_FEATURE_GLYPH_TRANSFORM) && !defined(SWGL_CLIP_DIST)
+varying highp vec4 v_uv_clip;
+#endif
+
+#ifdef WR_VERTEX_SHADER
+
+#define VECS_PER_TEXT_RUN           2
+#define GLYPHS_PER_GPU_BLOCK        2U
+
+#ifdef WR_FEATURE_GLYPH_TRANSFORM
+RectWithEndpoint transform_rect(RectWithEndpoint rect, mat2 transform) {
+    vec2 size = rect_size(rect);
+    vec2 center = transform * (rect.p0 + size * 0.5);
+    vec2 radius = mat2(abs(transform[0]), abs(transform[1])) * (size * 0.5);
+    return RectWithEndpoint(center - radius, center + radius);
+}
+
+bool rect_inside_rect(RectWithEndpoint little, RectWithEndpoint big) {
+    return all(lessThanEqual(vec4(big.p0, little.p1), vec4(little.p0, big.p1)));
+}
+#endif //WR_FEATURE_GLYPH_TRANSFORM
+
+struct Glyph {
+    vec2 offset;
+};
+
+Glyph fetch_glyph(int specific_prim_address,
+                  int glyph_index) {
+    // Two glyphs are packed in each texel in the GPU cache.
+    int glyph_address = specific_prim_address +
+                        VECS_PER_TEXT_RUN +
+                        int(uint(glyph_index) / GLYPHS_PER_GPU_BLOCK);
+    vec4 data = fetch_from_gpu_cache_1(glyph_address);
+    // Select XY or ZW based on glyph index.
+    vec2 glyph = mix(data.xy, data.zw,
+                     bvec2(uint(glyph_index) % GLYPHS_PER_GPU_BLOCK == 1U));
+
+    return Glyph(glyph);
+}
+
+struct GlyphResource {
+    vec4 uv_rect;
+    vec2 offset;
+    float scale;
+};
+
+GlyphResource fetch_glyph_resource(int address) {
+    vec4 data[2] = fetch_from_gpu_cache_2(address);
+    return GlyphResource(data[0], data[1].xy, data[1].z);
+}
+
+struct TextRun {
+    vec4 color;
+    vec4 bg_color;
+};
+
+TextRun fetch_text_run(int address) {
+    vec4 data[2] = fetch_from_gpu_cache_2(address);
+    return TextRun(data[0], data[1]);
+}
+
+vec2 get_snap_bias(int subpx_dir) {
+    // In subpixel mode, the subpixel offset has already been
+    // accounted for while rasterizing the glyph. However, we
+    // must still round with a subpixel bias rather than rounding
+    // to the nearest whole pixel, depending on subpixel direciton.
+    switch (subpx_dir) {
+        case SUBPX_DIR_NONE:
+        default:
+            return vec2(0.5);
+        case SUBPX_DIR_HORIZONTAL:
+            // Glyphs positioned [-0.125, 0.125] get a
+            // subpx position of zero. So include that
+            // offset in the glyph position to ensure
+            // we round to the correct whole position.
+            return vec2(0.125, 0.5);
+        case SUBPX_DIR_VERTICAL:
+            return vec2(0.5, 0.125);
+        case SUBPX_DIR_MIXED:
+            return vec2(0.125);
+    }
+}
+
+void main() {
+    Instance instance = decode_instance_attributes();
+    PrimitiveHeader ph = fetch_prim_header(instance.prim_header_address);
+    Transform transform = fetch_transform(ph.transform_id);
+    ClipArea clip_area = fetch_clip_area(instance.clip_address);
+    PictureTask task = fetch_picture_task(instance.picture_task_address);
+
+    int glyph_index = instance.segment_index;
+    int subpx_dir = (instance.flags >> 8) & 0xff;
+    int color_mode = instance.flags & 0xff;
+
+    // Note that the reference frame relative offset is stored in the prim local
+    // rect size during batching, instead of the actual size of the primitive.
+    TextRun text = fetch_text_run(ph.specific_prim_address);
+    vec2 text_offset = ph.local_rect.p1;
+
+    if (color_mode == COLOR_MODE_FROM_PASS) {
+        color_mode = uMode;
+    }
+
+    // Note that the unsnapped reference frame relative offset has already
+    // been subtracted from the prim local rect origin during batching.
+    // It was done this way to avoid pushing both the snapped and the
+    // unsnapped offsets to the shader.
+    Glyph glyph = fetch_glyph(ph.specific_prim_address, glyph_index);
+    glyph.offset += ph.local_rect.p0;
+
+    GlyphResource res = fetch_glyph_resource(instance.resource_address);
+
+    vec2 snap_bias = get_snap_bias(subpx_dir);
+
+    // Glyph space refers to the pixel space used by glyph rasterization during frame
+    // building. If a non-identity transform was used, WR_FEATURE_GLYPH_TRANSFORM will
+    // be set. Otherwise, regardless of whether the raster space is LOCAL or SCREEN,
+    // we ignored the transform during glyph rasterization, and need to snap just using
+    // the device pixel scale and the raster scale.
+#ifdef WR_FEATURE_GLYPH_TRANSFORM
+    // Transform from local space to glyph space.
+    mat2 glyph_transform = mat2(transform.m) * task.device_pixel_scale;
+    vec2 glyph_translation = transform.m[3].xy * task.device_pixel_scale;
+
+    // Transform from glyph space back to local space.
+    mat2 glyph_transform_inv = inverse(glyph_transform);
+
+    // Glyph raster pixels include the impact of the transform. This path can only be
+    // entered for 3d transforms that can be coerced into a 2d transform; they have no
+    // perspective, and have a 2d inverse. This is a looser condition than axis aligned
+    // transforms because it also allows 2d rotations.
+    vec2 raster_glyph_offset = floor(glyph_transform * glyph.offset + snap_bias);
+
+    // We want to eliminate any subpixel translation in device space to ensure glyph
+    // snapping is stable for equivalent glyph subpixel positions. Note that we must take
+    // into account the translation from the transform for snapping purposes.
+    vec2 raster_text_offset = floor(glyph_transform * text_offset + glyph_translation + 0.5) - glyph_translation;
+
+    vec2 glyph_origin = res.offset + raster_glyph_offset + raster_text_offset;
+    // Compute the glyph rect in glyph space.
+    RectWithEndpoint glyph_rect = RectWithEndpoint(
+        glyph_origin,
+        glyph_origin + res.uv_rect.zw - res.uv_rect.xy
+    );
+
+    // The glyph rect is in glyph space, so transform it back to local space.
+    RectWithEndpoint local_rect = transform_rect(glyph_rect, glyph_transform_inv);
+
+    // Select the corner of the glyph's local space rect that we are processing.
+    vec2 local_pos = mix(local_rect.p0, local_rect.p1, aPosition.xy);
+
+    // If the glyph's local rect would fit inside the local clip rect, then select a corner from
+    // the device space glyph rect to reduce overdraw of clipped pixels in the fragment shader.
+    // Otherwise, fall back to clamping the glyph's local rect to the local clip rect.
+    if (rect_inside_rect(local_rect, ph.local_clip_rect)) {
+        local_pos = glyph_transform_inv * mix(glyph_rect.p0, glyph_rect.p1, aPosition.xy);
+    }
+#else
+    float raster_scale = float(ph.user_data.x) / 65535.0;
+
+    // Scale in which the glyph is snapped when rasterized.
+    float glyph_raster_scale = raster_scale * task.device_pixel_scale;
+
+    // Scale from glyph space to local space.
+    float glyph_scale_inv = res.scale / glyph_raster_scale;
+
+    // Glyph raster pixels do not include the impact of the transform. Instead it was
+    // replaced with an identity transform during glyph rasterization. As such only the
+    // impact of the raster scale (if in local space) and the device pixel scale (for both
+    // local and screen space) are included.
+    //
+    // This implies one or more of the following conditions:
+    // - The transform is an identity. In that case, setting WR_FEATURE_GLYPH_TRANSFORM
+    //   should have the same output result as not. We just distingush which path to use
+    //   based on the transform used during glyph rasterization. (Screen space).
+    // - The transform contains an animation. We will imply local raster space in such
+    //   cases to avoid constantly rerasterizing the glyphs.
+    // - The transform has perspective or does not have a 2d inverse (Screen or local space).
+    // - The transform's scale will result in result in very large rasterized glyphs and
+    //   we clamped the size. This will imply local raster space.
+    vec2 raster_glyph_offset = floor(glyph.offset * glyph_raster_scale + snap_bias) / res.scale;
+
+    // Compute the glyph rect in local space.
+    //
+    // The transform may be animated, so we don't want to do any snapping here for the
+    // text offset to avoid glyphs wiggling. The text offset should have been snapped
+    // already for axis aligned transforms excluding any animations during frame building.
+    vec2 glyph_origin = glyph_scale_inv * (res.offset + raster_glyph_offset) + text_offset;
+    RectWithEndpoint glyph_rect = RectWithEndpoint(
+        glyph_origin,
+        glyph_origin + glyph_scale_inv * (res.uv_rect.zw - res.uv_rect.xy)
+    );
+
+    // Select the corner of the glyph rect that we are processing.
+    vec2 local_pos = mix(glyph_rect.p0, glyph_rect.p1, aPosition.xy);
+#endif
+
+    VertexInfo vi = write_vertex(
+        local_pos,
+        ph.local_clip_rect,
+        ph.z,
+        transform,
+        task
+    );
+
+#ifdef WR_FEATURE_GLYPH_TRANSFORM
+    vec2 f = (glyph_transform * vi.local_pos - glyph_rect.p0) / rect_size(glyph_rect);
+    #ifdef SWGL_CLIP_DIST
+        gl_ClipDistance[0] = f.x;
+        gl_ClipDistance[1] = f.y;
+        gl_ClipDistance[2] = 1.0 - f.x;
+        gl_ClipDistance[3] = 1.0 - f.y;
+    #else
+        v_uv_clip = vec4(f, 1.0 - f);
+    #endif
+#else
+    vec2 f = (vi.local_pos - glyph_rect.p0) / rect_size(glyph_rect);
+#endif
+
+    write_clip(vi.world_pos, clip_area, task);
+
+    switch (color_mode) {
+        case COLOR_MODE_ALPHA:
+            v_mask_swizzle = vec3(0.0, 1.0, 1.0);
+            v_color = text.color;
+            break;
+        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);
+            v_color = text.color;
+            break;
+        case COLOR_MODE_SUBPX_BG_PASS0:
+        case COLOR_MODE_COLOR_BITMAP:
+            v_mask_swizzle = vec3(1.0, 0.0, 0.0);
+            v_color = vec4(text.color.a);
+            break;
+        case COLOR_MODE_SUBPX_BG_PASS1:
+            v_mask_swizzle = vec3(-1.0, 1.0, 0.0);
+            v_color = vec4(text.color.a) * text.bg_color;
+            break;
+        case COLOR_MODE_SUBPX_DUAL_SOURCE:
+            #ifdef SWGL_BLEND
+                swgl_blendSubpixelText(text.color);
+                v_mask_swizzle = vec3(1.0, 0.0, 0.0);
+                v_color = vec4(1.0);
+            #else
+                v_mask_swizzle = vec3(text.color.a, 0.0, 0.0);
+                v_color = text.color;
+            #endif
+            break;
+        default:
+            v_mask_swizzle = vec3(0.0, 0.0, 0.0);
+            v_color = vec4(1.0);
+    }
+
+    vec2 texture_size = vec2(TEX_SIZE(sColor0));
+    vec2 st0 = res.uv_rect.xy / texture_size;
+    vec2 st1 = res.uv_rect.zw / texture_size;
+
+    v_uv = mix(st0, st1, f);
+    v_uv_bounds = (res.uv_rect + vec4(0.5, 0.5, -0.5, -0.5)) / texture_size.xyxy;
+}
+
+#endif // WR_VERTEX_SHADER
+
+#ifdef WR_FRAGMENT_SHADER
+
+Fragment text_fs(void) {
+    Fragment frag;
+
+    vec2 tc = clamp(v_uv, v_uv_bounds.xy, v_uv_bounds.zw);
+    vec4 mask = texture(sColor0, tc);
+    // v_mask_swizzle.z != 0 means we are using an R8 texture as alpha,
+    // and therefore must swizzle from the r channel to all channels.
+    mask = mix(mask, mask.rrrr, bvec4(v_mask_swizzle.z != 0.0));
+    #ifndef WR_FEATURE_DUAL_SOURCE_BLENDING
+        mask.rgb = mask.rgb * v_mask_swizzle.x + mask.aaa * v_mask_swizzle.y;
+    #endif
+
+    #if defined(WR_FEATURE_GLYPH_TRANSFORM) && !defined(SWGL_CLIP_DIST)
+        mask *= float(all(greaterThanEqual(v_uv_clip, vec4(0.0))));
+    #endif
+
+    frag.color = v_color * mask;
+
+    #if defined(WR_FEATURE_DUAL_SOURCE_BLENDING) && !defined(SWGL_BLEND)
+        frag.blend = mask * v_mask_swizzle.x + mask.aaaa * v_mask_swizzle.y;
+    #endif
+
+    return frag;
+}
+
+
+void main() {
+    Fragment frag = text_fs();
+
+    float clip_mask = do_clip();
+    frag.color *= clip_mask;
+
+    #if defined(WR_FEATURE_DEBUG_OVERDRAW)
+        oFragColor = WR_DEBUG_OVERDRAW_COLOR;
+    #elif defined(WR_FEATURE_DUAL_SOURCE_BLENDING) && !defined(SWGL_BLEND)
+        oFragColor = frag.color;
+        oFragBlend = frag.blend * clip_mask;
+    #else
+        write_output(frag.color);
+    #endif
+}
+
+#if defined(SWGL_DRAW_SPAN) && defined(SWGL_BLEND) && defined(SWGL_CLIP_DIST)
+void swgl_drawSpanRGBA8() {
+    // Only support simple swizzles for now. More complex swizzles must either
+    // be handled by blend overrides or the slow path.
+    if (v_mask_swizzle.x != 0.0 && v_mask_swizzle.x != 1.0) {
+        return;
+    }
+
+    #ifdef WR_FEATURE_DUAL_SOURCE_BLENDING
+        swgl_commitTextureLinearRGBA8(sColor0, v_uv, v_uv_bounds);
+    #else
+        if (swgl_isTextureR8(sColor0)) {
+            swgl_commitTextureLinearColorR8ToRGBA8(sColor0, v_uv, v_uv_bounds, v_color);
+        } else {
+            swgl_commitTextureLinearColorRGBA8(sColor0, v_uv, v_uv_bounds, v_color);
+        }
+    #endif
+}
+#endif
+
+#endif // WR_FRAGMENT_SHADER