Make all blending up to GrOptDrawState be handled by the xp/xp factory.

src/gpu/GrOptDrawState.cpp

Index: src/gpu/GrOptDrawState.cpp
diff --git a/src/gpu/GrOptDrawState.cpp b/src/gpu/GrOptDrawState.cpp
index b7875968135b4703fb323e0d995d5acf33f33b07..a16f8af518e8bdab8d15b2b803e867d9727b3712 100644
--- a/src/gpu/GrOptDrawState.cpp
+++ b/src/gpu/GrOptDrawState.cpp
@@ -11,6 +11,7 @@
 #include "GrDrawTargetCaps.h"
 #include "GrGpu.h"
 #include "GrProcOptInfo.h"
+#include "GrXferProcessor.h"
 
 GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
                                const GrDrawTargetCaps& caps,
@@ -19,14 +20,35 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
                                GrGpu::DrawType drawType)
     : fFinalized(false) {
     fDrawType = drawType;
-    GrBlendCoeff optSrcCoeff;
-    GrBlendCoeff optDstCoeff;
-    GrDrawState::BlendOpt blendOpt = drawState.getBlendOpt(false, &optSrcCoeff, &optDstCoeff);
+
+    const GrProcOptInfo& colorPOI = drawState.colorProcInfo();
+    const GrProcOptInfo& coveragePOI = drawState.coverageProcInfo();
+    
+    fColor = colorPOI.inputColorToEffectiveStage();
+    fCoverage = drawState.getCoverage();
+
+    // Create XferProcessor from DS's XPFactory
+    GrXferProcessor* xferProcessor = drawState.getXPFactory()->createXferProcessor(colorPOI,
+                                                                                   coveragePOI);
+
+    GrXferProcessor::BlendOptFlags blendOptFlags;
+    if (xferProcessor) {
+        fXferProcessor.reset(xferProcessor);
+
+        blendOptFlags = xferProcessor->getBlendOpts(colorPOI,
+                                                    coveragePOI,
+                                                    drawState.isCoverageDrawing(),
+                                                    drawState.isColorWriteDisabled(),
+                                                    drawState.getStencil().doesWrite(),
+                                                    &fColor,
+                                                    &fCoverage);
+    }
 
     // When path rendering the stencil settings are not always set on the draw state
     // so we must check the draw type. In cases where we will skip drawing we simply return a
     // null GrOptDrawState.
-    if (GrDrawState::kSkipDraw_BlendOpt == blendOpt && GrGpu::kStencilPath_DrawType != drawType) {
+    if (NULL == xferProcessor || ((GrXferProcessor::kSkipDraw_BlendOptFlag & blendOptFlags) &&
+                                 GrGpu::kStencilPath_DrawType != drawType)) {
         // Set the fields that don't default init and return. The lack of a render target will
         // indicate that this can be skipped.
         fFlags = 0;
@@ -37,17 +59,14 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
         fViewMatrix.reset();
         return;
     }
+    xferProcessor->unref();
 
     fRenderTarget.reset(drawState.fRenderTarget.get());
     SkASSERT(fRenderTarget);
     fScissorState = scissorState;
     fViewMatrix = drawState.getViewMatrix();
-    fBlendConstant = drawState.getBlendConstant();
     fStencilSettings = drawState.getStencil();
     fDrawFace = drawState.getDrawFace();
-    fSrcBlend = optSrcCoeff;
-    fDstBlend = optDstCoeff;
-
     // TODO move this out of optDrawState
     if (dstCopy) {
         fDstCopy = *dstCopy;
@@ -73,10 +92,8 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
     bool hasLocalCoords = drawState.hasGeometryProcessor() &&
                           drawState.getGeometryProcessor()->hasLocalCoords();
 
-    const GrProcOptInfo& colorPOI = drawState.colorProcInfo();
     int firstColorStageIdx = colorPOI.firstEffectiveStageIndex();
     fDescInfo.fInputColorIsUsed = colorPOI.inputColorIsUsed();
-    fColor = colorPOI.inputColorToEffectiveStage();
     if (colorPOI.removeVertexAttrib()) {
         fDescInfo.fHasVertexColor = false;
     }
@@ -85,12 +102,18 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
     // drawState's coverageProcInfo (like color above) to set this initial information.
     int firstCoverageStageIdx = 0;
     fDescInfo.fInputCoverageIsUsed = true;
-    fCoverage = drawState.getCoverage();
 
-    this->adjustProgramForBlendOpt(drawState, blendOpt, &firstColorStageIdx,
-                                   &firstCoverageStageIdx);
 
-    this->getStageStats(drawState, firstColorStageIdx, firstCoverageStageIdx, hasLocalCoords);
+    GrXferProcessor::BlendInfo blendInfo;
+    fXferProcessor->getBlendInfo(&blendInfo);
+    fSrcBlend = blendInfo.fSrcBlend;
+    fDstBlend = blendInfo.fDstBlend;
+    fBlendConstant = blendInfo.fBlendConstant;
+
+    this->adjustProgramFromBlendOpts(drawState, blendOptFlags, colorPOI, coveragePOI,
+                                     &firstColorStageIdx, &firstCoverageStageIdx);
+
+    fDescInfo.fRequiresLocalCoordAttrib = hasLocalCoords;
 
     // Copy GeometryProcesssor from DS or ODS
     SkASSERT(GrGpu::IsPathRenderingDrawType(drawType) ||
@@ -98,17 +121,13 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
              drawState.hasGeometryProcessor());
     fGeometryProcessor.reset(drawState.getGeometryProcessor());
 
-    // Create XferProcessor from DS's XPFactory
-    const GrXferProcessor* xpProcessor = drawState.getXPFactory()->createXferProcessor();
-    fXferProcessor.reset(xpProcessor);
-    xpProcessor->unref();
-
     // Copy Stages from DS to ODS
     for (int i = firstColorStageIdx; i < drawState.numColorStages(); ++i) {
         SkNEW_APPEND_TO_TARRAY(&fFragmentStages,
                                GrPendingFragmentStage,
                                (drawState.fColorStages[i], hasLocalCoords));
     }
+
     fNumColorStages = fFragmentStages.count();
     for (int i = firstCoverageStageIdx; i < drawState.numCoverageStages(); ++i) {
         SkNEW_APPEND_TO_TARRAY(&fFragmentStages,
@@ -116,11 +135,11 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
                                (drawState.fCoverageStages[i], hasLocalCoords));
     }
 
-    this->setOutputStateInfo(drawState, blendOpt, caps);
-};
+    this->setOutputStateInfo(drawState, blendOptFlags, caps);
+}
 
 void GrOptDrawState::setOutputStateInfo(const GrDrawState& ds,
-                                        GrDrawState::BlendOpt blendOpt,
+                                        GrXferProcessor::BlendOptFlags blendOpts,
                                         const GrDrawTargetCaps& caps) {
     // Set this default and then possibly change our mind if there is coverage.
     fDescInfo.fPrimaryOutputType = GrProgramDesc::kModulate_PrimaryOutputType;
@@ -128,8 +147,7 @@ void GrOptDrawState::setOutputStateInfo(const GrDrawState& ds,
 
     // Determine whether we should use dual source blending or shader code to keep coverage
     // separate from color.
-    bool keepCoverageSeparate = !(GrDrawState::kCoverageAsAlpha_BlendOpt == blendOpt ||
-                                  GrDrawState::kEmitCoverage_BlendOpt == blendOpt);
+    bool keepCoverageSeparate = !(blendOpts & GrXferProcessor::kSetCoverageDrawing_BlendOptFlag);
     if (keepCoverageSeparate && !ds.hasSolidCoverage()) {
         if (caps.dualSourceBlendingSupport()) {
             if (kZero_GrBlendCoeff == fDstBlend) {
@@ -153,64 +171,35 @@ void GrOptDrawState::setOutputStateInfo(const GrDrawState& ds,
     }
 }
 
-void GrOptDrawState::adjustProgramForBlendOpt(const GrDrawState& ds,
-                                              GrDrawState::BlendOpt blendOpt,
-                                              int* firstColorStageIdx,
-                                              int* firstCoverageStageIdx) {
-    switch (blendOpt) {
-        case GrDrawState::kNone_BlendOpt:
-        case GrDrawState::kSkipDraw_BlendOpt:
-        case GrDrawState::kCoverageAsAlpha_BlendOpt:
-            break;
-        case GrDrawState::kEmitCoverage_BlendOpt:
-            fColor = 0xffffffff;
-            fDescInfo.fInputColorIsUsed = true;
-            *firstColorStageIdx = ds.numColorStages();
-            fDescInfo.fHasVertexColor = false;
-            break;
-        case GrDrawState::kEmitTransBlack_BlendOpt:
-            fColor = 0;
-            fCoverage = 0xff;
-            fDescInfo.fInputColorIsUsed = true;
-            fDescInfo.fInputCoverageIsUsed = true;
-            *firstColorStageIdx = ds.numColorStages();
-            *firstCoverageStageIdx = ds.numCoverageStages();
-            fDescInfo.fHasVertexColor = false;
-            fDescInfo.fHasVertexCoverage = false;
-            break;
-    }
-}
-
-static void get_stage_stats(const GrFragmentStage& stage, bool* readsDst, bool* readsFragPosition) {
-    if (stage.getProcessor()->willReadDstColor()) {
-        *readsDst = true;
-    }
-    if (stage.getProcessor()->willReadFragmentPosition()) {
-        *readsFragPosition = true;
-    }
-}
-
-void GrOptDrawState::getStageStats(const GrDrawState& ds, int firstColorStageIdx,
-                                   int firstCoverageStageIdx, bool hasLocalCoords) {
-    // We will need a local coord attrib if there is one currently set on the optState and we are
-    // actually generating some effect code
-    fDescInfo.fRequiresLocalCoordAttrib = hasLocalCoords &&
-        ds.numTotalStages() - firstColorStageIdx - firstCoverageStageIdx > 0;
-
+void GrOptDrawState::adjustProgramFromBlendOpts(const GrDrawState& ds,
+                                                GrXferProcessor::BlendOptFlags flags,
+                                                const GrProcOptInfo& colorPOI,
+                                                const GrProcOptInfo& coveragePOI,
+                                                int* firstColorStageIdx,
+                                                int* firstCoverageStageIdx) {
     fDescInfo.fReadsDst = false;
     fDescInfo.fReadsFragPosition = false;
 
-    for (int s = firstColorStageIdx; s < ds.numColorStages(); ++s) {
-        const GrFragmentStage& stage = ds.getColorStage(s);
-        get_stage_stats(stage, &fDescInfo.fReadsDst, &fDescInfo.fReadsFragPosition);
-    }
-    for (int s = firstCoverageStageIdx; s < ds.numCoverageStages(); ++s) {
-        const GrFragmentStage& stage = ds.getCoverageStage(s);
-        get_stage_stats(stage, &fDescInfo.fReadsDst, &fDescInfo.fReadsFragPosition);
+    if (flags & GrXferProcessor::kClearColorStages_BlendOptFlag) {
+        fDescInfo.fInputColorIsUsed = true;
+        *firstColorStageIdx = ds.numColorStages();
+        fDescInfo.fHasVertexColor = false;
+    } else {
+        fDescInfo.fReadsDst = colorPOI.readsDst();
+        fDescInfo.fReadsFragPosition = colorPOI.readsFragPosition();
     }
-    if (ds.hasGeometryProcessor()) {
-        const GrGeometryProcessor& gp = *ds.getGeometryProcessor();
-        fDescInfo.fReadsFragPosition = fDescInfo.fReadsFragPosition || gp.willReadFragmentPosition();
+
+    if (flags & GrXferProcessor::kClearCoverageStages_BlendOptFlag) {
+        fDescInfo.fInputCoverageIsUsed = true;
+        *firstCoverageStageIdx = ds.numCoverageStages();
+        fDescInfo.fHasVertexCoverage = false;
+    } else {
+        if (coveragePOI.readsDst()) {
+            fDescInfo.fReadsDst = true;
+        }
+        if (coveragePOI.readsFragPosition()) {
+            fDescInfo.fReadsFragPosition = true;
+        }
     }
 }