Split GrDrawState and GrOptDrawState into separate classes and remove base class.

src/gpu/GrDrawState.cpp

Index: src/gpu/GrDrawState.cpp
diff --git a/src/gpu/GrDrawState.cpp b/src/gpu/GrDrawState.cpp
index 168cf0b9c3b0c2962c65e4c8e1dd38f6ae45c9dd..872d20a1ab48cb0c9ae6b0e93fb066a4a3e9fa7c 100644
--- a/src/gpu/GrDrawState.cpp
+++ b/src/gpu/GrDrawState.cpp
@@ -16,14 +16,16 @@ GrOptDrawState* GrDrawState::createOptState(const GrDrawTargetCaps& caps) const
     if (NULL == fCachedOptState || caps.getUniqueID() != fCachedCapsID) {
         GrBlendCoeff srcCoeff;
         GrBlendCoeff dstCoeff;
-        BlendOptFlags blendFlags = this->getBlendOpts(false, &srcCoeff, &dstCoeff);
+        GrOptDrawState::BlendOptFlags blendFlags =
+            (GrOptDrawState::BlendOptFlags) this->getBlendOpts(false, &srcCoeff, &dstCoeff);
         fCachedOptState = SkNEW_ARGS(GrOptDrawState, (*this, blendFlags, srcCoeff, dstCoeff, caps));
         fCachedCapsID = caps.getUniqueID();
     } else {
 #ifdef SK_DEBUG
         GrBlendCoeff srcCoeff;
         GrBlendCoeff dstCoeff;
-        BlendOptFlags blendFlags = this->getBlendOpts(false, &srcCoeff, &dstCoeff);
+        GrOptDrawState::BlendOptFlags blendFlags =
+            (GrOptDrawState::BlendOptFlags) this->getBlendOpts(false, &srcCoeff, &dstCoeff);
         SkASSERT(GrOptDrawState(*this, blendFlags, srcCoeff, dstCoeff, caps) == *fCachedOptState);
 #endif
     }
@@ -33,6 +35,66 @@ GrOptDrawState* GrDrawState::createOptState(const GrDrawTargetCaps& caps) const
 
 //////////////////////////////////////////////////////////////////////////////s
 
+bool GrDrawState::isEqual(const GrDrawState& that) const {
+    bool usingVertexColors = this->hasColorVertexAttribute();
+    if (!usingVertexColors && this->fColor != that.fColor) {
+        return false;
+    }
+
+    if (this->getRenderTarget() != that.getRenderTarget() ||
+        this->fColorStages.count() != that.fColorStages.count() ||
+        this->fCoverageStages.count() != that.fCoverageStages.count() ||
+        !this->fViewMatrix.cheapEqualTo(that.fViewMatrix) ||
+        this->fSrcBlend != that.fSrcBlend ||
+        this->fDstBlend != that.fDstBlend ||
+        this->fBlendConstant != that.fBlendConstant ||
+        this->fFlagBits != that.fFlagBits ||
+        this->fVACount != that.fVACount ||
+        this->fVAStride != that.fVAStride ||
+        memcmp(this->fVAPtr, that.fVAPtr, this->fVACount * sizeof(GrVertexAttrib)) ||
+        this->fStencilSettings != that.fStencilSettings ||
+        this->fDrawFace != that.fDrawFace) {
+        return false;
+    }
+
+    bool usingVertexCoverage = this->hasCoverageVertexAttribute();
+    if (!usingVertexCoverage && this->fCoverage != that.fCoverage) {
+        return false;
+    }
+
+    bool explicitLocalCoords = this->hasLocalCoordAttribute();
+    if (this->hasGeometryProcessor()) {
+        if (!that.hasGeometryProcessor()) {
+            return false;
+        } else if (!GrProcessorStage::AreCompatible(*this->getGeometryProcessor(),
+                                                    *that.getGeometryProcessor(),
+                                                    explicitLocalCoords)) {
+            return false;
+        }
+    } else if (that.hasGeometryProcessor()) {
+        return false;
+    }
+
+    for (int i = 0; i < this->numColorStages(); i++) {
+        if (!GrProcessorStage::AreCompatible(this->getColorStage(i), that.getColorStage(i),
+                                             explicitLocalCoords)) {
+            return false;
+        }
+    }
+    for (int i = 0; i < this->numCoverageStages(); i++) {
+        if (!GrProcessorStage::AreCompatible(this->getCoverageStage(i), that.getCoverageStage(i),
+                                             explicitLocalCoords)) {
+            return false;
+        }
+    }
+
+    SkASSERT(0 == memcmp(this->fFixedFunctionVertexAttribIndices,
+                         that.fFixedFunctionVertexAttribIndices,
+                         sizeof(this->fFixedFunctionVertexAttribIndices)));
+
+    return true;
+}
+
 GrDrawState::CombinedState GrDrawState::CombineIfPossible(
     const GrDrawState& a, const GrDrawState& b, const GrDrawTargetCaps& caps) {
 
@@ -218,11 +280,54 @@ void GrDrawState::setFromPaint(const GrPaint& paint, const SkMatrix& vm, GrRende
 
 ////////////////////////////////////////////////////////////////////////////////
 
+bool GrDrawState::validateVertexAttribs() const {
+    // check consistency of effects and attributes
+    GrSLType slTypes[kMaxVertexAttribCnt];
+    for (int i = 0; i < kMaxVertexAttribCnt; ++i) {
+        slTypes[i] = static_cast<GrSLType>(-1);
+    }
+
+    if (this->hasGeometryProcessor()) {
+        const GrGeometryStage& stage = *this->getGeometryProcessor();
+        const GrGeometryProcessor* gp = stage.getGeometryProcessor();
+        SkASSERT(gp);
+        // make sure that any attribute indices have the correct binding type, that the attrib
+        // type and effect's shader lang type are compatible, and that attributes shared by
+        // multiple effects use the same shader lang type.
+        const GrGeometryProcessor::VertexAttribArray& s = gp->getVertexAttribs();
+
+        int effectIndex = 0;
+        for (int index = 0; index < fVACount; index++) {
+            if (kGeometryProcessor_GrVertexAttribBinding != fVAPtr[index].fBinding) {
+                // we only care about effect bindings
+                continue;
+            }
+            SkASSERT(effectIndex < s.count());
+            GrSLType effectSLType = s[effectIndex].getType();
+            GrVertexAttribType attribType = fVAPtr[index].fType;
+            int slVecCount = GrSLTypeVectorCount(effectSLType);
+            int attribVecCount = GrVertexAttribTypeVectorCount(attribType);
+            if (slVecCount != attribVecCount ||
+                (static_cast<GrSLType>(-1) != slTypes[index] && slTypes[index] != effectSLType)) {
+                return false;
+            }
+            slTypes[index] = effectSLType;
+            effectIndex++;
+        }
+        // Make sure all attributes are consumed and we were able to find everything
+        SkASSERT(s.count() == effectIndex);
+    }
+
+    return true;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 static void validate_vertex_attribs(const GrVertexAttrib* attribs, int count, size_t stride) {
     // this works as long as we're 4 byte-aligned
 #ifdef SK_DEBUG
     uint32_t overlapCheck = 0;
-    SkASSERT(count <= GrRODrawState::kMaxVertexAttribCnt);
+    SkASSERT(count <= GrDrawState::kMaxVertexAttribCnt);
     for (int index = 0; index < count; ++index) {
         size_t attribSize = GrVertexAttribTypeSize(attribs[index].fType);
         size_t attribOffset = attribs[index].fOffset;
@@ -305,11 +410,39 @@ bool GrDrawState::couldApplyCoverage(const GrDrawTargetCaps& caps) const {
     GrBlendCoeff srcCoeff;
     GrBlendCoeff dstCoeff;
     BlendOptFlags flag = this->getBlendOpts(true, &srcCoeff, &dstCoeff);
-    return GrRODrawState::kNone_BlendOpt != flag ||
+    return GrDrawState::kNone_BlendOpt != flag ||
            (this->willEffectReadDstColor() &&
             kOne_GrBlendCoeff == srcCoeff && kZero_GrBlendCoeff == dstCoeff);
 }
 
+bool GrDrawState::hasSolidCoverage() const {
+    // If we're drawing coverage directly then coverage is effectively treated as color.
+    if (this->isCoverageDrawing()) {
+        return true;
+    }
+
+    GrColor coverage;
+    uint32_t validComponentFlags;
+    // Initialize to an unknown starting coverage if per-vertex coverage is specified.
+    if (this->hasCoverageVertexAttribute()) {
+        validComponentFlags = 0;
+    } else {
+        coverage = fCoverage;
+        validComponentFlags = kRGBA_GrColorComponentFlags;
+    }
+
+    // Run through the coverage stages and see if the coverage will be all ones at the end.
+    if (this->hasGeometryProcessor()) {
+        const GrGeometryProcessor* gp = fGeometryProcessor->getGeometryProcessor();
+        gp->getConstantColorComponents(&coverage, &validComponentFlags);
+    }
+    for (int s = 0; s < this->numCoverageStages(); ++s) {
+        const GrProcessor* processor = this->getCoverageStage(s).getProcessor();
+        processor->getConstantColorComponents(&coverage, &validComponentFlags);
+    }
+    return (kRGBA_GrColorComponentFlags == validComponentFlags) && (0xffffffff == coverage);
+}
+
 //////////////////////////////////////////////////////////////////////////////
 
 GrDrawState::AutoVertexAttribRestore::AutoVertexAttribRestore(GrDrawState* drawState) {
@@ -323,6 +456,22 @@ GrDrawState::AutoVertexAttribRestore::AutoVertexAttribRestore(GrDrawState* drawS
 
 //////////////////////////////////////////////////////////////////////////////s
 
+bool GrDrawState::willEffectReadDstColor() const {
+    if (!this->isColorWriteDisabled()) {
+        for (int s = 0; s < this->numColorStages(); ++s) {
+            if (this->getColorStage(s).getFragmentProcessor()->willReadDstColor()) {
+                return true;
+            }
+        }
+    }
+    for (int s = 0; s < this->numCoverageStages(); ++s) {
+        if (this->getCoverageStage(s).getFragmentProcessor()->willReadDstColor()) {
+            return true;
+        }
+    }
+    return false;
+}
+
 void GrDrawState::AutoRestoreEffects::set(GrDrawState* ds) {
     if (fDrawState) {
         // See the big comment on the class definition about GPs.
@@ -360,6 +509,28 @@ void GrDrawState::AutoRestoreEffects::set(GrDrawState* ds) {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+// Some blend modes allow folding a fractional coverage value into the color's alpha channel, while
+// others will blend incorrectly.
+bool GrDrawState::canTweakAlphaForCoverage() const {
+    /*
+     The fractional coverage is f.
+     The src and dst coeffs are Cs and Cd.
+     The dst and src colors are S and D.
+     We want the blend to compute: f*Cs*S + (f*Cd + (1-f))D. By tweaking the source color's alpha
+     we're replacing S with S'=fS. It's obvious that that first term will always be ok. The second
+     term can be rearranged as [1-(1-Cd)f]D. By substituting in the various possibilities for Cd we
+     find that only 1, ISA, and ISC produce the correct destination when applied to S' and D.
+     Also, if we're directly rendering coverage (isCoverageDrawing) then coverage is treated as
+     color by definition.
+     */
+    return kOne_GrBlendCoeff == fDstBlend ||
+           kISA_GrBlendCoeff == fDstBlend ||
+           kISC_GrBlendCoeff == fDstBlend ||
+           this->isCoverageDrawing();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 void GrDrawState::AutoViewMatrixRestore::restore() {
     if (fDrawState) {
         SkDEBUGCODE(--fDrawState->fBlockEffectRemovalCnt;)
@@ -462,6 +633,22 @@ void GrDrawState::AutoViewMatrixRestore::doEffectCoordChanges(const SkMatrix& co
 
 ////////////////////////////////////////////////////////////////////////////////
 
+void GrDrawState::convertToPendingExec() {
+    fRenderTarget.markPendingIO();
+    fRenderTarget.removeRef();
+    for (int i = 0; i < fColorStages.count(); ++i) {
+        fColorStages[i].convertToPendingExec();
+    }
+    if (fGeometryProcessor) {
+        fGeometryProcessor->convertToPendingExec();
+    }
+    for (int i = 0; i < fCoverageStages.count(); ++i) {
+        fCoverageStages[i].convertToPendingExec();
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 void GrDrawState::invalidateOptState() const {
     SkSafeSetNull(fCachedOptState);
 }
@@ -473,3 +660,150 @@ GrDrawState::~GrDrawState() {
     SkASSERT(0 == fBlockEffectRemovalCnt);
 }
 
+////////////////////////////////////////////////////////////////////////////////
+
+GrDrawState::BlendOptFlags GrDrawState::getBlendOpts(bool forceCoverage,
+                                                         GrBlendCoeff* srcCoeff,
+                                                         GrBlendCoeff* dstCoeff) const {
+    GrBlendCoeff bogusSrcCoeff, bogusDstCoeff;
+    if (NULL == srcCoeff) {
+        srcCoeff = &bogusSrcCoeff;
+    }
+    if (NULL == dstCoeff) {
+        dstCoeff = &bogusDstCoeff;
+    }
+
+    *srcCoeff = this->getSrcBlendCoeff();
+    *dstCoeff = this->getDstBlendCoeff();
+
+    if (this->isColorWriteDisabled()) {
+        *srcCoeff = kZero_GrBlendCoeff;
+        *dstCoeff = kOne_GrBlendCoeff;
+    }
+
+    bool srcAIsOne = this->srcAlphaWillBeOne();
+    bool dstCoeffIsOne = kOne_GrBlendCoeff == *dstCoeff ||
+                         (kSA_GrBlendCoeff == *dstCoeff && srcAIsOne);
+    bool dstCoeffIsZero = kZero_GrBlendCoeff == *dstCoeff ||
+                         (kISA_GrBlendCoeff == *dstCoeff && srcAIsOne);
+
+    // When coeffs are (0,1) there is no reason to draw at all, unless
+    // stenciling is enabled. Having color writes disabled is effectively
+    // (0,1).
+    if ((kZero_GrBlendCoeff == *srcCoeff && dstCoeffIsOne)) {
+        if (this->getStencil().doesWrite()) {
+            return kEmitCoverage_BlendOptFlag;
+        } else {
+            *dstCoeff = kOne_GrBlendCoeff;
+            return kSkipDraw_BlendOptFlag;
+        }
+    }
+
+    bool hasCoverage = forceCoverage || !this->hasSolidCoverage();
+
+    // if we don't have coverage we can check whether the dst
+    // has to read at all. If not, we'll disable blending.
+    if (!hasCoverage) {
+        if (dstCoeffIsZero) {
+            if (kOne_GrBlendCoeff == *srcCoeff) {
+                // if there is no coverage and coeffs are (1,0) then we
+                // won't need to read the dst at all, it gets replaced by src
+                *dstCoeff = kZero_GrBlendCoeff;
+                return kNone_BlendOpt;
+            } else if (kZero_GrBlendCoeff == *srcCoeff) {
+                // if the op is "clear" then we don't need to emit a color
+                // or blend, just write transparent black into the dst.
+                *srcCoeff = kOne_GrBlendCoeff;
+                *dstCoeff = kZero_GrBlendCoeff;
+                return kEmitTransBlack_BlendOptFlag;
+            }
+        }
+    } else if (this->isCoverageDrawing()) {
+        // we have coverage but we aren't distinguishing it from alpha by request.
+        return kCoverageAsAlpha_BlendOptFlag;
+    } else {
+        // check whether coverage can be safely rolled into alpha
+        // of if we can skip color computation and just emit coverage
+        if (this->canTweakAlphaForCoverage()) {
+            return kCoverageAsAlpha_BlendOptFlag;
+        }
+        if (dstCoeffIsZero) {
+            if (kZero_GrBlendCoeff == *srcCoeff) {
+                // the source color is not included in the blend
+                // the dst coeff is effectively zero so blend works out to:
+                // (c)(0)D + (1-c)D = (1-c)D.
+                *dstCoeff = kISA_GrBlendCoeff;
+                return  kEmitCoverage_BlendOptFlag;
+            } else if (srcAIsOne) {
+                // the dst coeff is effectively zero so blend works out to:
+                // cS + (c)(0)D + (1-c)D = cS + (1-c)D.
+                // If Sa is 1 then we can replace Sa with c
+                // and set dst coeff to 1-Sa.
+                *dstCoeff = kISA_GrBlendCoeff;
+                return  kCoverageAsAlpha_BlendOptFlag;
+            }
+        } else if (dstCoeffIsOne) {
+            // the dst coeff is effectively one so blend works out to:
+            // cS + (c)(1)D + (1-c)D = cS + D.
+            *dstCoeff = kOne_GrBlendCoeff;
+            return  kCoverageAsAlpha_BlendOptFlag;
+        }
+    }
+
+    return kNone_BlendOpt;
+}
+
+
+bool GrDrawState::srcAlphaWillBeOne() const {
+    uint32_t validComponentFlags;
+    GrColor color;
+    // Check if per-vertex or constant color may have partial alpha
+    if (this->hasColorVertexAttribute()) {
+        if (fHints & kVertexColorsAreOpaque_Hint) {
+            validComponentFlags = kA_GrColorComponentFlag;
+            color = 0xFF << GrColor_SHIFT_A;
+        } else {
+            validComponentFlags = 0;
+            color = 0; // not strictly necessary but we get false alarms from tools about uninit.
+        }
+    } else {
+        validComponentFlags = kRGBA_GrColorComponentFlags;
+        color = this->getColor();
+    }
+
+    // Run through the color stages
+    for (int s = 0; s < this->numColorStages(); ++s) {
+        const GrProcessor* processor = this->getColorStage(s).getProcessor();
+        processor->getConstantColorComponents(&color, &validComponentFlags);
+    }
+
+    // Check whether coverage is treated as color. If so we run through the coverage computation.
+    if (this->isCoverageDrawing()) {
+        // The shader generated for coverage drawing runs the full coverage computation and then
+        // makes the shader output be the multiplication of color and coverage. We mirror that here.
+        GrColor coverage;
+        uint32_t coverageComponentFlags;
+        if (this->hasCoverageVertexAttribute()) {
+            coverageComponentFlags = 0;
+            coverage = 0; // suppresses any warnings.
+        } else {
+            coverageComponentFlags = kRGBA_GrColorComponentFlags;
+            coverage = this->getCoverageColor();
+        }
+
+        // Run through the coverage stages
+        for (int s = 0; s < this->numCoverageStages(); ++s) {
+            const GrProcessor* processor = this->getCoverageStage(s).getProcessor();
+            processor->getConstantColorComponents(&coverage, &coverageComponentFlags);
+        }
+
+        // Since the shader will multiply coverage and color, the only way the final A==1 is if
+        // coverage and color both have A==1.
+        return (kA_GrColorComponentFlag & validComponentFlags & coverageComponentFlags) &&
+                0xFF == GrColorUnpackA(color) && 0xFF == GrColorUnpackA(coverage);
+
+    }
+
+    return (kA_GrColorComponentFlag & validComponentFlags) && 0xFF == GrColorUnpackA(color);
+}
+