Calculate stage stats in GrOptDrawState

src/gpu/GrOptDrawState.cpp

Index: src/gpu/GrOptDrawState.cpp
diff --git a/src/gpu/GrOptDrawState.cpp b/src/gpu/GrOptDrawState.cpp
index c1d28c9591b52a39a91ecd0332c900e974c98b14..be2a6bc7e484937e14d0a44dc8e06ed9742a93d9 100644
--- a/src/gpu/GrOptDrawState.cpp
+++ b/src/gpu/GrOptDrawState.cpp
@@ -41,6 +41,7 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
     this->copyEffectiveCoverageStages(drawState);
     this->adjustFromBlendOpts();
     this->remapEffectStagesVAIndices();
+    this->getStageStats();
 };
 
 void GrOptDrawState::initializeVAIndexMap() {
@@ -213,6 +214,34 @@ void GrOptDrawState::copyEffectiveCoverageStages(const GrDrawState& ds) {
     }
 }
 
+static void get_stage_stats(const GrEffectStage& stage, bool* readsDst,
+                            bool* readsFragPosition, bool* requiresVertexShader) {
+    if (stage.getEffect()->willReadDstColor()) {
+        *readsDst = true;
+    }
+    if (stage.getEffect()->willReadFragmentPosition()) {
+        *readsFragPosition = true;
+    }
+    if (stage.getEffect()->requiresVertexShader()) {

[bsalomon, 2014/09/05 15:27:54]

this is going away... reqVS will be equivalent to this->hasGeometryProcessor().

+        *requiresVertexShader = true;
+    }
+}
+
+void GrOptDrawState::getStageStats() {
+    fReadsDst = false;
+    fReadsFragPosition = false;
+    fRequiresVertexShader = false;
+
+    for (int s = 0; s < this->numColorStages(); ++s) {
+        const GrEffectStage& stage = this->getColorStage(s);
+        get_stage_stats(stage, &fReadsDst, &fReadsFragPosition, &fRequiresVertexShader);
+    }
+    for (int s = 0; s < this->numCoverageStages(); ++s) {
+        const GrEffectStage& stage = this->getCoverageStage(s);
+        get_stage_stats(stage, &fReadsDst, &fReadsFragPosition, &fRequiresVertexShader);
+    }
+}
+
 bool GrOptDrawState::operator== (const GrOptDrawState& that) const {
     return this->isEqual(that);
 }