1 files changed, 117 insertions, 0 deletions
diff --git a/gfx/wr/webrender/res/cs_clip_image.glsl b/gfx/wr/webrender/res/cs_clip_image.glsl
new file mode 100644
index 0000000000..24ba1dab8e
--- /dev/null
+++ b/gfx/wr/webrender/res/cs_clip_image.glsl
@@ -0,0 +1,117 @@
+/* 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,clip_shared
+
+varying highp vec2 vLocalPos;
+varying highp vec2 vClipMaskImageUv;
+
+flat varying highp vec4 vClipMaskUvInnerRect;
+
+#ifdef WR_VERTEX_SHADER
+
+PER_INSTANCE in vec4 aClipTileRect;
+PER_INSTANCE in ivec2 aClipDataResourceAddress;
+PER_INSTANCE in vec4 aClipLocalRect;
+
+struct ClipMaskInstanceImage {
+    ClipMaskInstanceCommon base;
+    RectWithEndpoint tile_rect;
+    ivec2 resource_address;
+    RectWithEndpoint local_rect;
+};
+
+ClipMaskInstanceImage fetch_clip_item() {
+    ClipMaskInstanceImage cmi;
+
+    cmi.base = fetch_clip_item_common();
+
+    cmi.tile_rect = RectWithEndpoint(aClipTileRect.xy, aClipTileRect.zw);
+    cmi.resource_address = aClipDataResourceAddress;
+    cmi.local_rect = RectWithEndpoint(aClipLocalRect.xy, aClipLocalRect.zw);
+
+    return cmi;
+}
+
+struct ClipImageVertexInfo {
+    vec2 local_pos;
+    vec4 world_pos;
+};
+
+// This differs from write_clip_tile_vertex in that we forward transform the
+// primitive's local-space tile rect into the target space. We use scissoring
+// to ensure that the primitive does not draw outside the target bounds.
+ClipImageVertexInfo write_clip_image_vertex(RectWithEndpoint tile_rect,
+                                            RectWithEndpoint local_clip_rect,
+                                            Transform prim_transform,
+                                            Transform clip_transform,
+                                            RectWithEndpoint sub_rect,
+                                            vec2 task_origin,
+                                            vec2 screen_origin,
+                                            float device_pixel_scale) {
+    vec2 local_pos = rect_clamp(local_clip_rect, mix(tile_rect.p0, tile_rect.p1, aPosition.xy));
+    vec4 world_pos = prim_transform.m * vec4(local_pos, 0.0, 1.0);
+    vec4 final_pos = vec4(
+        world_pos.xy * device_pixel_scale + (task_origin - screen_origin) * world_pos.w,
+        0.0,
+        world_pos.w
+    );
+    gl_Position = uTransform * final_pos;
+
+    init_transform_vs(
+        clip_transform.is_axis_aligned
+            ? vec4(vec2(-1.0e16), vec2(1.0e16))
+            : vec4(local_clip_rect.p0, local_clip_rect.p1));
+
+    ClipImageVertexInfo vi = ClipImageVertexInfo(local_pos, world_pos);
+    return vi;
+}
+
+void main(void) {
+    ClipMaskInstanceImage cmi = fetch_clip_item();
+    Transform clip_transform = fetch_transform(cmi.base.clip_transform_id);
+    Transform prim_transform = fetch_transform(cmi.base.prim_transform_id);
+    ImageSource res = fetch_image_source_direct(cmi.resource_address);
+
+    ClipImageVertexInfo vi = write_clip_image_vertex(
+        cmi.tile_rect,
+        cmi.local_rect,
+        prim_transform,
+        clip_transform,
+        cmi.base.sub_rect,
+        cmi.base.task_origin,
+        cmi.base.screen_origin,
+        cmi.base.device_pixel_scale
+    );
+    vLocalPos = vi.local_pos;
+    vec2 uv = (vi.local_pos - cmi.tile_rect.p0) / rect_size(cmi.tile_rect);
+
+    vec2 texture_size = vec2(TEX_SIZE(sColor0));
+    vec4 uv_rect = vec4(res.uv_rect.p0, res.uv_rect.p1);
+    vClipMaskImageUv = mix(uv_rect.xy, uv_rect.zw, uv) / texture_size;
+
+    // applying a half-texel offset to the UV boundaries to prevent linear samples from the outside
+    vClipMaskUvInnerRect = (uv_rect + vec4(0.5, 0.5, -0.5, -0.5)) / texture_size.xyxy;
+}
+#endif
+
+#ifdef WR_FRAGMENT_SHADER
+void main(void) {
+    float alpha = init_transform_rough_fs(vLocalPos);
+    vec2 source_uv = clamp(vClipMaskImageUv, vClipMaskUvInnerRect.xy, vClipMaskUvInnerRect.zw);
+    float clip_alpha = texture(sColor0, source_uv).r; //careful: texture has type A8
+    oFragColor = vec4(mix(1.0, clip_alpha, alpha), 0.0, 0.0, 1.0);
+}
+
+#ifdef SWGL_DRAW_SPAN
+void swgl_drawSpanR8() {
+    if (has_valid_transform_bounds()) {
+        return;
+    }
+
+    swgl_commitTextureLinearR8(sColor0, vClipMaskImageUv, vClipMaskUvInnerRect);
+}
+#endif
+
+#endif