Add Coverage Drawing XP

src/gpu/effects/GrCoverageSetOpXP.cpp

Index: src/gpu/effects/GrCoverageSetOpXP.cpp
diff --git a/src/gpu/effects/GrCoverageSetOpXP.cpp b/src/gpu/effects/GrCoverageSetOpXP.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..cddbbfb49e7f1665ba54b7e3c2069006db69f545
--- /dev/null
+++ b/src/gpu/effects/GrCoverageSetOpXP.cpp
@@ -0,0 +1,235 @@
+
+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "effects/GrCoverageSetOpXP.h"
+#include "GrColor.h"
+#include "GrDrawTargetCaps.h"
+#include "GrInvariantOutput.h"
+#include "GrProcessor.h"
+#include "GrProcOptInfo.h"
+#include "gl/GrGLXferProcessor.h"
+#include "gl/builders/GrGLFragmentShaderBuilder.h"
+#include "gl/builders/GrGLProgramBuilder.h"
+
+class GrGLCoverageSetOpXP : public GrGLXferProcessor {
+public:
+    GrGLCoverageSetOpXP(const GrProcessor&) {}
+
+    ~GrGLCoverageSetOpXP() SK_OVERRIDE {}
+
+    void emitCode(const EmitArgs& args) SK_OVERRIDE {
+        const GrCoverageSetOpXP& xp = args.fXP.cast<GrCoverageSetOpXP>();
+        GrGLFPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
+
+        if (xp.invertCoverage()) {
+            fsBuilder->codeAppendf("%s = 1.0 - %s;", args.fOutputPrimary, args.fInputCoverage);
+        } else {
+            fsBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, args.fInputCoverage);
+        }
+    }
+
+    void setData(const GrGLProgramDataManager&, const GrXferProcessor&) SK_OVERRIDE {};
+
+    static void GenKey(const GrProcessor& processor, const GrGLCaps& caps,
+                       GrProcessorKeyBuilder* b) {
+        const GrCoverageSetOpXP& xp = processor.cast<GrCoverageSetOpXP>();
+        uint32_t key = xp.invertCoverage() ?  0x0 : 0x1;
+        b->add32(key);
+    };
+
+private:
+    typedef GrGLXferProcessor INHERITED;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+GrCoverageSetOpXP::GrCoverageSetOpXP(SkRegion::Op regionOp, bool invertCoverage)
+    : fRegionOp(regionOp)
+    , fInvertCoverage(invertCoverage) {
+    this->initClassID<GrCoverageSetOpXP>();
+}
+
+GrCoverageSetOpXP::~GrCoverageSetOpXP() {
+}
+
+void GrCoverageSetOpXP::getGLProcessorKey(const GrGLCaps& caps, GrProcessorKeyBuilder* b) const {
+    GrGLCoverageSetOpXP::GenKey(*this, caps, b);
+}
+
+GrGLXferProcessor* GrCoverageSetOpXP::createGLInstance() const {
+    return SkNEW_ARGS(GrGLCoverageSetOpXP, (*this));
+}
+
+GrXferProcessor::OptFlags
+GrCoverageSetOpXP::getOptimizations(const GrProcOptInfo& colorPOI,
+                                    const GrProcOptInfo& coveragePOI,
+                                    bool colorWriteDisabled,
+                                    bool doesStencilWrite,
+                                    GrColor* color,
+                                    const GrDrawTargetCaps& caps) {
+    // We never look at the color input
+    return GrXferProcessor::kIgnoreColor_OptFlag; 
+}
+
+void GrCoverageSetOpXP::getBlendInfo(GrXferProcessor::BlendInfo* blendInfo) const {
+    switch (fRegionOp) {
+        case SkRegion::kReplace_Op:
+            blendInfo->fSrcBlend = kOne_GrBlendCoeff;
+            blendInfo->fDstBlend = kZero_GrBlendCoeff;
+            break;
+        case SkRegion::kIntersect_Op:
+            blendInfo->fSrcBlend = kDC_GrBlendCoeff;
+            blendInfo->fDstBlend = kZero_GrBlendCoeff;
+            break;
+        case SkRegion::kUnion_Op:
+            blendInfo->fSrcBlend = kOne_GrBlendCoeff;
+            blendInfo->fDstBlend = kISC_GrBlendCoeff;
+            break;
+        case SkRegion::kXOR_Op:
+            blendInfo->fSrcBlend = kIDC_GrBlendCoeff;
+            blendInfo->fDstBlend = kISC_GrBlendCoeff;
+            break;
+        case SkRegion::kDifference_Op:
+            blendInfo->fSrcBlend = kZero_GrBlendCoeff;
+            blendInfo->fDstBlend = kISC_GrBlendCoeff;
+            break;
+        case SkRegion::kReverseDifference_Op:
+            blendInfo->fSrcBlend = kIDC_GrBlendCoeff;
+            blendInfo->fDstBlend = kZero_GrBlendCoeff;
+            break;
+    }
+    blendInfo->fBlendConstant = 0;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+GrCoverageSetOpXPFactory::GrCoverageSetOpXPFactory(SkRegion::Op regionOp, bool invertCoverage)
+    : fRegionOp(regionOp)
+    , fInvertCoverage(invertCoverage) {
+    this->initClassID<GrCoverageSetOpXPFactory>();
+}
+
+GrXPFactory* GrCoverageSetOpXPFactory::Create(SkRegion::Op regionOp, bool invertCoverage) {
+    switch (regionOp) {
+        case SkRegion::kReplace_Op: {
+            if (invertCoverage) {
+                static GrCoverageSetOpXPFactory gReplaceCDXPFI(regionOp, invertCoverage);
+                return SkRef(&gReplaceCDXPFI);
+            } else {
+                static GrCoverageSetOpXPFactory gReplaceCDXPF(regionOp, invertCoverage);
+                return SkRef(&gReplaceCDXPF);
+            }
+            break;
+        }
+        case SkRegion::kIntersect_Op: {
+            if (invertCoverage) {
+                static GrCoverageSetOpXPFactory gIntersectCDXPFI(regionOp, invertCoverage);
+                return SkRef(&gIntersectCDXPFI);
+            } else {
+                static GrCoverageSetOpXPFactory gIntersectCDXPF(regionOp, invertCoverage);
+                return SkRef(&gIntersectCDXPF);
+            }
+            break;
+        }
+        case SkRegion::kUnion_Op: {
+            if (invertCoverage) {
+                static GrCoverageSetOpXPFactory gUnionCDXPFI(regionOp, invertCoverage);
+                return SkRef(&gUnionCDXPFI);
+            } else {
+                static GrCoverageSetOpXPFactory gUnionCDXPF(regionOp, invertCoverage);
+                return SkRef(&gUnionCDXPF);
+            }
+            break;
+        }
+        case SkRegion::kXOR_Op: {
+            if (invertCoverage) {
+                static GrCoverageSetOpXPFactory gXORCDXPFI(regionOp, invertCoverage);
+                return SkRef(&gXORCDXPFI);
+            } else {
+                static GrCoverageSetOpXPFactory gXORCDXPF(regionOp, invertCoverage);
+                return SkRef(&gXORCDXPF);
+            }
+            break;
+        }
+        case SkRegion::kDifference_Op: {
+            if (invertCoverage) {
+                static GrCoverageSetOpXPFactory gDifferenceCDXPFI(regionOp, invertCoverage);
+                return SkRef(&gDifferenceCDXPFI);
+            } else {
+                static GrCoverageSetOpXPFactory gDifferenceCDXPF(regionOp, invertCoverage);
+                return SkRef(&gDifferenceCDXPF);
+            }
+            break;
+        }
+        case SkRegion::kReverseDifference_Op: {
+            if (invertCoverage) {
+                static GrCoverageSetOpXPFactory gRevDiffCDXPFI(regionOp, invertCoverage);
+                return SkRef(&gRevDiffCDXPFI);
+            } else {
+                static GrCoverageSetOpXPFactory gRevDiffCDXPF(regionOp, invertCoverage);
+                return SkRef(&gRevDiffCDXPF);
+            }
+            break;
+        }
+        default:
+            return NULL;
+    }
+}
+
+GrXferProcessor* GrCoverageSetOpXPFactory::createXferProcessor(const GrProcOptInfo& /* colorPOI*/,
+                                                               const GrProcOptInfo& covPOI) const {
+    return GrCoverageSetOpXP::Create(fRegionOp, fInvertCoverage);
+}
+
+bool GrCoverageSetOpXPFactory::willBlendWithDst(const GrProcOptInfo& colorPOI,
+                                                const GrProcOptInfo& coveragePOI,
+                                                bool colorWriteDisabled) const {
+    // TODO: once all SkXferEffects are XP's then we will never reads dst here since only XP's
+    // will readDst and this XP doesn't read dst.
+    if (coveragePOI.readsDst()) {
+        return true;
+    }
+
+    // Besides Replace all other SkRegion ops will either have a src coeff that references dst or a
+    // non zero dst coeff
+    return SkRegion::kReplace_Op != fRegionOp;
+}
+
+bool GrCoverageSetOpXPFactory::getOpaqueAndKnownColor(const GrProcOptInfo& colorPOI,
+                                                      const GrProcOptInfo& coveragePOI,
+                                                      GrColor* solidColor,
+                                                      uint32_t* solidColorKnownComponents) const {
+    if (!coveragePOI.isSolidWhite()) {
+        return false;
+    }
+
+    SkASSERT((NULL == solidColor) == (NULL == solidColorKnownComponents));
+
+    bool opaque = SkRegion::kReplace_Op == fRegionOp;
+    if (solidColor) {
+        if (opaque) {
+            *solidColor = GrColor_WHITE;
+            *solidColorKnownComponents = kRGBA_GrColorComponentFlags;
+        } else {
+            solidColorKnownComponents = 0;
+        }
+    }
+    return opaque;
+}
+
+GR_DEFINE_XP_FACTORY_TEST(GrCoverageSetOpXPFactory);
+
+GrXPFactory* GrCoverageSetOpXPFactory::TestCreate(SkRandom* random,
+                                                  GrContext*,
+                                                  const GrDrawTargetCaps&,
+                                                  GrTexture*[]) {
+    SkRegion::Op regionOp = SkRegion::Op(random->nextULessThan(SkRegion::kLastOp + 1));
+    bool invertCoverage = random->nextBool();
+    return GrCoverageSetOpXPFactory::Create(regionOp, invertCoverage);
+}
+