1 files changed, 121 insertions, 0 deletions
diff --git a/gfx/wr/webrender/res/brush_blend.glsl b/gfx/wr/webrender/res/brush_blend.glsl
new file mode 100644
index 0000000000..49f047edbd
--- /dev/null
+++ b/gfx/wr/webrender/res/brush_blend.glsl
@@ -0,0 +1,121 @@
+/* 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/. */
+
+#define VECS_PER_SPECIFIC_BRUSH 3
+#define WR_FEATURE_TEXTURE_2D
+
+#include shared,prim_shared,brush,blend
+
+// Interpolated UV coordinates to sample.
+varying highp vec2 v_uv;
+
+// Normalized bounds of the source image in the texture, adjusted to avoid
+// sampling artifacts.
+flat varying highp vec4 v_uv_sample_bounds;
+
+// x: Flag to allow perspective interpolation of UV.
+// y: Filter-dependent "amount" parameter.
+// Packed in to a vector to work around bug 1630356.
+flat varying mediump vec2 v_perspective_amount;
+#define v_perspective v_perspective_amount.x
+#define v_amount v_perspective_amount.y
+
+// x: Blend op, y: Lookup table GPU cache address.
+// Packed in to a vector to work around bug 1630356.
+// Must be explicitly marked as highp, as the default integer precision in
+// fragment shaders is mediump which may only be 16 bits in ESSL 3, and GPU
+// cache address can exceed that maximum representable value.
+flat varying highp ivec2 v_op_table_address_vec;
+#define v_op v_op_table_address_vec.x
+#define v_table_address v_op_table_address_vec.y
+
+// We must keep this as highp as we encoutered shader compilation crashes on
+// Mali-T devices when mediump.
+flat varying highp mat4 v_color_mat;
+// The function to use for each component of a component transfer filter. Using a int[4]
+// or ivec4 (with each element or component containing the function for each component) has
+// ran in to bugs 1695912 and 1731758, so instead use a vec4 and cast the values to/from floats.
+flat varying mediump vec4 v_funcs;
+flat varying mediump vec4 v_color_offset;
+
+#ifdef WR_VERTEX_SHADER
+void brush_vs(
+    VertexInfo vi,
+    int prim_address,
+    RectWithEndpoint local_rect,
+    RectWithEndpoint segment_rect,
+    ivec4 prim_user_data,
+    int specific_resource_address,
+    mat4 transform,
+    PictureTask pic_task,
+    int brush_flags,
+    vec4 unused
+) {
+    ImageSource res = fetch_image_source(prim_user_data.x);
+    vec2 uv0 = res.uv_rect.p0;
+    vec2 uv1 = res.uv_rect.p1;
+
+    vec2 inv_texture_size = vec2(1.0) / vec2(TEX_SIZE(sColor0).xy);
+    vec2 f = (vi.local_pos - local_rect.p0) / rect_size(local_rect);
+    f = get_image_quad_uv(prim_user_data.x, f);
+    vec2 uv = mix(uv0, uv1, f);
+    float perspective_interpolate = (brush_flags & BRUSH_FLAG_PERSPECTIVE_INTERPOLATION) != 0 ? 1.0 : 0.0;
+
+    v_uv = uv * inv_texture_size * mix(vi.world_pos.w, 1.0, perspective_interpolate);
+    v_perspective = perspective_interpolate;
+
+    v_uv_sample_bounds = vec4(uv0 + vec2(0.5), uv1 - vec2(0.5)) * inv_texture_size.xyxy;
+
+    float amount = float(prim_user_data.z) / 65536.0;
+
+    v_op = prim_user_data.y & 0xffff;
+    v_amount = amount;
+
+    v_funcs.r = float((prim_user_data.y >> 28) & 0xf);
+    v_funcs.g = float((prim_user_data.y >> 24) & 0xf);
+    v_funcs.b = float((prim_user_data.y >> 20) & 0xf);
+    v_funcs.a = float((prim_user_data.y >> 16) & 0xf);
+
+    SetupFilterParams(
+        v_op,
+        amount,
+        prim_user_data.z,
+        v_color_offset,
+        v_color_mat,
+        v_table_address
+    );
+}
+#endif
+
+#ifdef WR_FRAGMENT_SHADER
+Fragment brush_fs() {
+    float perspective_divisor = mix(gl_FragCoord.w, 1.0, v_perspective);
+    vec2 uv = v_uv * perspective_divisor;
+    // Clamp the uvs to avoid sampling artifacts.
+    uv = clamp(uv, v_uv_sample_bounds.xy, v_uv_sample_bounds.zw);
+
+    vec4 Cs = texture(sColor0, uv);
+
+    float alpha;
+    vec3 color;
+    CalculateFilter(
+        Cs,
+        v_op,
+        v_amount,
+        v_table_address,
+        v_color_offset,
+        v_color_mat,
+        v_funcs,
+        color,
+        alpha
+    );
+
+    #ifdef WR_FEATURE_ALPHA_PASS
+        alpha *= antialias_brush();
+    #endif
+
+    // Pre-multiply the alpha into the output value.
+    return Fragment(alpha * vec4(color, 1.0));
+}
+#endif