Revise attribute binding interface

tests/GLProgramsTest.cpp

Index: tests/GLProgramsTest.cpp
===================================================================
--- tests/GLProgramsTest.cpp	(revision 8462)
+++ tests/GLProgramsTest.cpp	(working copy)
@@ -24,18 +24,30 @@
 void GrGLProgramDesc::setRandom(SkMWCRandom* random,
                                 const GrGpuGL* gpu,
                                 const GrTexture* dstTexture,
-                                const GrEffectStage stages[GrDrawState::kNumStages]) {
-    fAttribBindings = 0;
+                                const GrEffectStage stages[GrDrawState::kNumStages],
+                                int currAttribIndex) {
     fEmitsPointSize = random->nextBool();
-    fColorInput = random->nextULessThan(kColorInputCnt);
-    fCoverageInput = random->nextULessThan(kColorInputCnt);
 
+    fPositionAttributeIndex = 0;
+
+    // if the effects have used up all off the available attributes, 
+    // don't try to use color or coverage attributes as input
+    do {
+        fColorInput = random->nextULessThan(kColorInputCnt);
+    } while (GrDrawState::kMaxVertexAttribCnt <= currAttribIndex && 
+             kAttribute_ColorInput == fColorInput);
+    fColorAttributeIndex = (fColorInput == kAttribute_ColorInput) ? currAttribIndex++ : -1;
+
+    do {
+        fCoverageInput = random->nextULessThan(kColorInputCnt);
+    } while (GrDrawState::kMaxVertexAttribCnt <= currAttribIndex  &&
+             kAttribute_ColorInput == fCoverageInput);
+    fCoverageAttributeIndex = (fCoverageInput == kAttribute_ColorInput) ? currAttribIndex++ : -1;
+
     fColorFilterXfermode = random->nextULessThan(SkXfermode::kCoeffModesCnt);
 
     fFirstCoverageStage = random->nextULessThan(GrDrawState::kNumStages);
 
-    fAttribBindings |= random->nextBool() ? GrDrawState::kCoverage_AttribBindingsBit : 0;
-
 #if GR_GL_EXPERIMENTAL_GS
     fExperimentalGS = gpu->caps()->geometryShaderSupport() && random->nextBool();
 #endif
@@ -48,18 +60,14 @@
         fDualSrcOutput = kNone_DualSrcOutput;
     }
 
-    // use separate tex coords?
-    if (random->nextBool()) {
-        fAttribBindings |= GrDrawState::kLocalCoords_AttribBindingsBit;
-    }
+    bool useLocalCoords = random->nextBool() && currAttribIndex < GrDrawState::kMaxVertexAttribCnt;
+    fLocalCoordAttributeIndex = useLocalCoords ? currAttribIndex++ : -1;
 
     bool dstRead = false;
     for (int s = 0; s < GrDrawState::kNumStages; ++s) {
         if (NULL != stages[s].getEffect()) {
             const GrBackendEffectFactory& factory = (*stages[s].getEffect())->getFactory();
-            bool explicitLocalCoords = (fAttribBindings &
-                                        GrDrawState::kLocalCoords_AttribBindingsBit);
-            GrDrawEffect drawEffect(stages[s], explicitLocalCoords);
+            GrDrawEffect drawEffect(stages[s], useLocalCoords);
             fEffectKeys[s] = factory.glEffectKey(drawEffect, gpu->glCaps());
             if ((*stages[s].getEffect())->willReadDst()) {
                 dstRead = true;
@@ -70,22 +78,6 @@
     if (dstRead) {
         this->fDstRead = GrGLShaderBuilder::KeyForDstRead(dstTexture, gpu->glCaps());
     }
-
-    int attributeIndex = 0;
-    fPositionAttributeIndex = attributeIndex;
-    ++attributeIndex;
-    if (fColorInput || (fAttribBindings & GrDrawState::kColor_AttribBindingsBit)) {
-        fColorAttributeIndex = attributeIndex;
-        ++attributeIndex;
-    }
-    if (fCoverageInput || (fAttribBindings & GrDrawState::kCoverage_AttribBindingsBit)) {
-        fCoverageAttributeIndex = attributeIndex;
-        ++attributeIndex;
-    }
-    if (fAttribBindings & GrDrawState::kLocalCoords_AttribBindingsBit) {
-        fLocalCoordsAttributeIndex = attributeIndex;
-        ++attributeIndex;
-    }
 }
 
 bool GrGpuGL::programUnitTest(int maxStages) {
@@ -118,7 +110,7 @@
         GrGLProgramDesc pdesc;
         GrEffectStage stages[GrDrawState::kNumStages];
 
-        int currAttribIndex = GrDrawState::kAttribIndexCount;
+        int currAttribIndex = 1;  // we need to always leave room for position
         int attribIndices[2];
         GrTexture* dummyTextures[] = {dummyTexture1.get(), dummyTexture2.get()};
         for (int s = 0; s < maxStages; ++s) {
@@ -131,10 +123,9 @@
                                                                                 dummyTextures));
                 int numAttribs = (*effect)->numVertexAttribs();
 
-                // If adding this effect would cause to exceed the max attrib count then generate a
-                // new random effect. The explanation for why this check is correct is a bit
-                // convoluted and this code will be removed soon.
-                if (currAttribIndex + numAttribs > GrDrawState::kCoverageOverrideAttribIndexValue) {
+                // If adding this effect would exceed the max attrib count then generate a
+                // new random effect. 
+                if (currAttribIndex + numAttribs > GrDrawState::kMaxVertexAttribCnt) {
                     --s;
                     continue;
                 }
@@ -145,8 +136,8 @@
             }
         }
         const GrTexture* dstTexture = random.nextBool() ? dummyTextures[0] : dummyTextures[1];
-        pdesc.setRandom(&random, this, dstTexture, stages);
-
+        pdesc.setRandom(&random, this, dstTexture, stages, currAttribIndex);
+ 
         const GrEffectStage* stagePtrs[GrDrawState::kNumStages];
         for (int s = 0; s < GrDrawState::kNumStages; ++s) {
             stagePtrs[s] = &stages[s];