1 files changed, 110 insertions, 0 deletions
diff --git a/src/effects/GrAlphaThresholdFragmentProcessor.fp b/src/effects/GrAlphaThresholdFragmentProcessor.fp
new file mode 100644
index 0000000000..a7010a712a
--- /dev/null
+++ b/src/effects/GrAlphaThresholdFragmentProcessor.fp
@@ -0,0 +1,110 @@
+in uniform sampler2D image;
+in uniform colorSpaceXform colorXform;
+in uniform sampler2D mask;
+in uniform float innerThreshold;
+in uniform float outerThreshold;
+
+@class {
+    inline OptimizationFlags optFlags(float outerThreshold);
+}
+
+@constructorParams {
+    const SkIRect& bounds
+}
+
+@make {
+    static sk_sp<GrFragmentProcessor> Make(sk_sp<GrTextureProxy> image,
+                                           sk_sp<GrColorSpaceXform> colorXform,
+                                           sk_sp<GrTextureProxy> mask,
+                                           float innerThreshold,
+                                           float outerThreshold,
+                                           const SkIRect& bounds) {
+        return sk_sp<GrFragmentProcessor>(new GrAlphaThresholdFragmentProcessor(image,
+                                                                                colorXform,
+                                                                                mask,
+                                                                                innerThreshold,
+                                                                                outerThreshold,
+                                                                                bounds));
+    }
+}
+
+@fields {
+    GrCoordTransform fImageCoordTransform;
+    GrCoordTransform fMaskCoordTransform;
+}
+
+@initializers {
+    fImageCoordTransform(SkMatrix::I(), image.get()),
+    fMaskCoordTransform(SkMatrix::MakeTrans(SkIntToScalar(-bounds.x()), SkIntToScalar(-bounds.y())),
+                        mask.get())
+}
+
+@constructorCode {
+    this->addCoordTransform(&fImageCoordTransform);
+    this->addCoordTransform(&fMaskCoordTransform);
+}
+
+@header {
+    #include "SkTypes.h"
+    #if SK_SUPPORT_GPU
+}
+
+@headerEnd {
+    #endif
+}
+
+@cpp {
+    #if SK_SUPPORT_GPU
+    inline GrFragmentProcessor::OptimizationFlags GrAlphaThresholdFragmentProcessor::optFlags(
+                                                                             float outerThreshold) {
+        if (outerThreshold >= 1.0) {
+            return kPreservesOpaqueInput_OptimizationFlag |
+                   kCompatibleWithCoverageAsAlpha_OptimizationFlag;
+        } else {
+            return kCompatibleWithCoverageAsAlpha_OptimizationFlag;
+        }
+    }
+}
+
+@cppEnd {
+    #endif
+}
+
+void main() {
+    vec4 color = texture(image, sk_TransformedCoords2D[0], colorXform);
+    vec4 mask_color = texture(mask, sk_TransformedCoords2D[1]);
+    if (mask_color.a < 0.5) {
+        if (color.a > outerThreshold) {
+            float scale = outerThreshold / color.a;
+            color.rgb *= scale;
+            color.a = outerThreshold;
+        }
+    } else if (color.a < innerThreshold) {
+        float scale = innerThreshold / max(0.001, color.a);
+        color.rgb *= scale;
+        color.a = innerThreshold;
+    }
+    sk_OutColor = color;
+}
+
+@test(testData) {
+    sk_sp<GrTextureProxy> bmpProxy = testData->textureProxy(GrProcessorUnitTest::kSkiaPMTextureIdx);
+    sk_sp<GrTextureProxy> maskProxy = testData->textureProxy(GrProcessorUnitTest::kAlphaTextureIdx);
+    // Make the inner and outer thresholds be in (0, 1) exclusive and be sorted correctly.
+    float innerThresh = testData->fRandom->nextUScalar1() * .99f + 0.005f;
+    float outerThresh = testData->fRandom->nextUScalar1() * .99f + 0.005f;
+    const int kMaxWidth = 1000;
+    const int kMaxHeight = 1000;
+    uint32_t width = testData->fRandom->nextULessThan(kMaxWidth);
+    uint32_t height = testData->fRandom->nextULessThan(kMaxHeight);
+    uint32_t x = testData->fRandom->nextULessThan(kMaxWidth - width);
+    uint32_t y = testData->fRandom->nextULessThan(kMaxHeight - height);
+    SkIRect bounds = SkIRect::MakeXYWH(x, y, width, height);
+    sk_sp<GrColorSpaceXform> colorSpaceXform = GrTest::TestColorXform(testData->fRandom);
+    return GrAlphaThresholdFragmentProcessor::Make(
+                                std::move(bmpProxy),
+                                colorSpaceXform,
+                                std::move(maskProxy),
+                                innerThresh, outerThresh,
+                                bounds);
+}
+\ No newline at end of file