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..cbce70ae6937ed487410aa8ae3eaf7ea553bcb7b
--- /dev/null
+++ b/src/gpu/effects/GrCoverageSetOpXP.cpp
@@ -0,0 +1,242 @@
+
+/*
+ * 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&) {}
+
+    virtual ~GrGLCoverageSetOpXP() {}
+
+    virtual 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);
+        }
+    }
+
+    virtual void setData(const GrGLProgramDataManager&, const GrXferProcessor&) SK_OVERRIDE {};
+

[bsalomon, 2014/12/16 17:35:56]

don't need virtuals on these overrides. Also can declare the ~ override instead
of virtual.

[egdaniel, 2014/12/17 21:12:37]

Done.

+    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;
+        default:

[bsalomon, 2014/12/16 17:35:56]

If you've exhausted all the possible values for k*_Op then just omit this. We
get a warning that all the cases aren't covered which is more useful than a
runtime failure.

[egdaniel, 2014/12/17 21:12:37]

Done.

+            SkASSERT(false);
+            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 {
+    if (!covPOI.isFourChannelOutput()) {
+        return GrCoverageSetOpXP::Create(fRegionOp, fInvertCoverage);
+    } else {
+        return NULL;
+    }
+}
+
+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,

[bsalomon, 2014/12/16 17:35:56]

This is kind of confusing now that we have a coverage only XP. Also, seems like
the opaque part of the name refers to how this is used upstack and not about
what it is computing. Is opaqueness different than !willBlendWithDst()?

getKnownOutputValues()?

Also, how does this interact with secondary output? Should we have two
GrColor*/uint32_t*s? Should it just return false if there is a secondary output?

[egdaniel, 2014/12/17 21:12:37]

As per our conversation, I will clean up these functions in a follow up cl.

+                                                      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);
+}
+