emitChild() used to generate a mangled outputColor based on the parent's outputColor; now it just accepts an outputColor string. It's now up to the programmer to declare outputColors if needed before emitting child code.

BUG=skia:4182

Review URL: https://codereview.chromium.org/1321253003

4 files changed, 14 insertions, 28 deletions

diff --git a/src/gpu/gl/GrGLFragmentProcessor.cpp b/src/gpu/gl/GrGLFragmentProcessor.cpp
index 078491a5bf..6d91c72fcf 100644
--- a/src/gpu/gl/GrGLFragmentProcessor.cpp
+++ b/src/gpu/gl/GrGLFragmentProcessor.cpp
@@ -20,16 +20,12 @@ void GrGLFragmentProcessor::setData(const GrGLProgramDataManager& pdman,
 }
 
 void GrGLFragmentProcessor::emitChild(int childIndex, const char* inputColor,
-                                      SkString* outputColor, EmitArgs& args) {
+                                      const char* outputColor, EmitArgs& args) {
     GrGLFragmentBuilder* fb = args.fBuilder->getFragmentShaderBuilder();
     fb->onBeforeChildProcEmitCode();  // call first so mangleString is updated
 
     const GrFragmentProcessor& childProc = args.fFp.childProcessor(childIndex);
 
-    // Mangle the name of the outputColor
-    outputColor->set(args.fOutputColor);
-    outputColor->append(fb->getMangleStringThisLevel());
-
     /*
      * We now want to find the subset of coords and samplers that belong to the child and its
      * descendants and put that into childCoords and childSamplers. To do so, we'll do a forwards
@@ -78,13 +74,12 @@ void GrGLFragmentProcessor::emitChild(int childIndex, const char* inputColor,
     }
 
     // emit the code for the child in its own scope
-    fb->codeAppendf("vec4 %s;\n", outputColor->c_str());
     fb->codeAppend("{\n");
     fb->codeAppendf("// Child Index %d (mangle: %s): %s\n", childIndex,
                     fb->getMangleString().c_str(), childProc.name());
     EmitArgs childArgs(args.fBuilder,
                        childProc,
-                       outputColor->c_str(),
+                       outputColor,
                        inputColor,
                        childCoords,
                        childSamplers);
diff --git a/src/gpu/gl/GrGLFragmentProcessor.h b/src/gpu/gl/GrGLFragmentProcessor.h
index b8e2afc1bb..e11d28b26b 100644
--- a/src/gpu/gl/GrGLFragmentProcessor.h
+++ b/src/gpu/gl/GrGLFragmentProcessor.h
@@ -80,7 +80,12 @@ public:
         return fChildProcessors[index];
     }
 
-    void emitChild(int childIndex, const char* inputColor, SkString* outputColor, EmitArgs& args);
+    /** Will emit the code of a child proc in its own scope. Pass in the parent's EmitArgs and
+     * emitChild will automatically extract the coords and samplers of that child and pass them
+     * on to the child's emitCode().  Also, any uniforms or functions emitted by the child will
+     * have their names mangled to prevent redefinitions.
+     */
+    void emitChild(int childIndex, const char* inputColor, const char* outputColor, EmitArgs& args);
 
 protected:
     /** A GrGLFragmentProcessor instance can be reused with any GrFragmentProcessor that produces
diff --git a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
index 20bb3a3893..a5b3a99ebe 100644
--- a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
@@ -302,13 +302,17 @@ void GrGLFragmentShaderBuilder::addVarying(GrGLVarying* v, GrSLPrecision fsPrec)
 }
 
 void GrGLFragmentBuilder::onBeforeChildProcEmitCode() {
-    fSubstageIndices.back()++;
+    SkASSERT(fSubstageIndices.count() >= 1);
     fSubstageIndices.push_back(0);
-    fMangleString.append(this->getMangleStringThisLevel());
+    // second-to-last value in the fSubstageIndices stack is the index of the child proc
+    // at that level which is currently emitting code.
+    fMangleString.appendf("_c%d", fSubstageIndices[fSubstageIndices.count() - 2]);
 }
 
 void GrGLFragmentBuilder::onAfterChildProcEmitCode() {
+    SkASSERT(fSubstageIndices.count() >= 2);
     fSubstageIndices.pop_back();
+    fSubstageIndices.back()++;
     int removeAt = fMangleString.findLastOf('_');
     fMangleString.remove(removeAt, fMangleString.size() - removeAt);
 }
diff --git a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.h b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.h
index 912de0a645..4f17b68ae6 100644
--- a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.h
+++ b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.h
@@ -57,26 +57,8 @@ public:
     void onBeforeChildProcEmitCode();
     void onAfterChildProcEmitCode();
 
-    int getChildNumberThisLevel() const {
-        if (fSubstageIndices.count() > 1) {
-            // second-to-last value in the fSubstageIndices stack is the index of the child proc
-            // at that level which is currently emitting code.
-            return fSubstageIndices[fSubstageIndices.count() - 2];
-        }
-        return -1;
-    }
-
     const SkString& getMangleString() const { return fMangleString; }
 
-    SkString getMangleStringThisLevel() const {
-        SkString ret;
-        int childNumber = this->getChildNumberThisLevel();
-        if (childNumber >= 0) {
-            ret.printf("_c%d", childNumber);
-        }
-        return ret;
-    }
-
 private:
     /*
      * State that tracks which child proc in the proc tree is currently emitting code.  This is