Enable vertexless shading when path rendering is supported

src/gpu/gl/GrGLShaderBuilder.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gl/GrGLShaderBuilder.h"
 #include "gl/GrGLProgram.h"
 #include "gl/GrGLUniformHandle.h"
@@ skipping 84 matching lines @@
                                      GrGLUniformManager& uniformManager,
                                      const GrGLProgramDesc& desc,
                                      bool hasVertexShaderEffects)
     : fUniforms(kVarsPerBlock)
     , fCtxInfo(ctxInfo)
     , fUniformManager(uniformManager)
     , fFSFeaturesAddedMask(0)
     , fFSInputs(kVarsPerBlock)
     , fFSOutputs(kMaxFSOutputs)
     , fSetupFragPosition(false)
-    , fTopLeftFragPosRead(kTopLeftFragPosRead_FragPosKey == desc.getHeader().fFragPosKey) {
+    , fTopLeftFragPosRead(kTopLeftFragPosRead_FragPosKey == desc.getHeader().fFragPosKey)
+    , fNumTexGenUnits(0) {
 
     const GrGLProgramDesc::KeyHeader& header = desc.getHeader();
 
-    // TODO: go vertexless when possible.
-    fVertexBuilder.reset(SkNEW_ARGS(VertexBuilder, (this, desc)));
+    // We only go without a vertex shader if every effect supports vertexless mode, the context
+    // has fixed function/path rendering support, and position is the only vertex attribute.
+    if (hasVertexShaderEffects ||
+        !ctxInfo.caps()->fixedFunctionSupport() ||
+        !ctxInfo.caps()->pathStencilingSupport() ||
+        -1 != header.fLocalCoordAttributeIndex ||
+        -1 != header.fColorAttributeIndex ||
+        -1 != header.fCoverageAttributeIndex) {
+        fVertexBuilder.reset(SkNEW_ARGS(VertexBuilder, (this, desc)));
+    }
 
     // Emit code to read the dst copy textue if necessary.
     if (kNoDstRead_DstReadKey != header.fDstReadKey &&
         GrGLCaps::kNone_FBFetchType == ctxInfo.caps()->fbFetchType()) {
         bool topDown = SkToBool(kTopLeftOrigin_DstReadKeyBit & header.fDstReadKey);
         const char* dstCopyTopLeftName;
         const char* dstCopyCoordScaleName;
         uint32_t configMask;
         if (SkToBool(kUseAlphaConfig_DstReadKeyBit & header.fDstReadKey)) {
             configMask = kA_GrColorComponentFlag;
@@ skipping 306 matching lines @@
         args[i].appendDecl(fCtxInfo, &fFSFunctions);
         if (i < argCnt - 1) {
             fFSFunctions.append(", ");
         }
     }
     fFSFunctions.append(") {\n");
     fFSFunctions.append(body);
     fFSFunctions.append("}\n\n");
 }
 
+void GrGLShaderBuilder::addTexGenUnit(GrSLType type,
+                                      SkString* fsInName,
+                                      int* unitIdx,
+                                      int* numComponents)
+{

[bsalomon, 2013/09/10 13:51:06]

style nit: { up on prev line

+    const int index = fNumTexGenUnits++;
+    if (fsInName) {
+        fsInName->printf("%s(gl_TexCoord[%u])", GrGLSLTypeString(type), index);
+    }
+    if (unitIdx) {
+        *unitIdx = index;
+    }
+    if (numComponents) {
+        *numComponents = GrSLTypeToVecLength(type);
+    }
+}
+
 namespace {
 
 inline void append_default_precision_qualifier(GrGLShaderVar::Precision p,
                                                GrGLBinding binding,
                                                SkString* str) {
     // Desktop GLSL has added precision qualifiers but they don't do anything.
     if (kES_GrGLBinding == binding) {
         switch (p) {
             case GrGLShaderVar::kHigh_Precision:
                 str->append("precision highp float;\n");
@@ skipping 256 matching lines @@
     for (const AttributePair* attrib = this->getEffectAttributes().begin();
          attrib != attribEnd;
          ++attrib) {
         if (attrib->fIndex == attributeIndex) {
             return &attrib->fName;
         }
     }
 
     return NULL;
 }