Stop flattening GrCoordTransforms in parent GrFragmentProcessors.

src/gpu/glsl/GrGLSLFragmentProcessor.cpp

Index: src/gpu/glsl/GrGLSLFragmentProcessor.cpp
diff --git a/src/gpu/glsl/GrGLSLFragmentProcessor.cpp b/src/gpu/glsl/GrGLSLFragmentProcessor.cpp
index 9a58db77bd6cd1430f58bd8f7097b00fbbe36e6a..82a07ca39d819a88292f9ae1710f6a779b0dd1df 100644
--- a/src/gpu/glsl/GrGLSLFragmentProcessor.cpp
+++ b/src/gpu/glsl/GrGLSLFragmentProcessor.cpp
@@ -43,16 +43,16 @@ void GrGLSLFragmentProcessor::internalEmitChild(int childIndex, const char* inpu
     const GrFragmentProcessor& childProc = args.fFp.childProcessor(childIndex);
 
     /*
-     * 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
-     * linear search.
+     * TODO: Move textures and buffers to the iterator model used by coords.
+     * We now want to find the subset of samplers that belong to the child and its descendants and
+     * put that into childSamplers. To do so, we'll do a forwards linear search.
      *
      * Explanation:
-     * Each GrFragmentProcessor has a copy of all the transforms and textures of itself and
-     * all procs in its subtree. For example, suppose we have frag proc A, who has two children B
-     * and D. B has a child C, and D has two children E and F. Each frag proc's transforms array
-     * contains its own transforms, followed by the transforms of all its descendants (i.e. preorder
-     * traversal). Suppose procs A, B, C, D, E, F have 1, 2, 1, 1, 3, 2 transforms respectively.
+     * Each GrFragmentProcessor has a copy of all the textures of itself and all procs in its
+     * subtree. For example, suppose we have frag proc A, who has two children B and D. B has a
+     * child C, and D has two children E and F. Each frag proc's textures array contains its own
+     * textures, followed by the textures of all its descendants (i.e. preorder traversal). Suppose
+     * procs A, B, C, D, E, F have 1, 2, 1, 1, 3, 2 textures respectively.
      *
      *                                   (A)
      *                        [a1,b1,b2,c1,d1,e1,e2,e3,f1,f2]
@@ -66,28 +66,22 @@ void GrGLSLFragmentProcessor::internalEmitChild(int childIndex, const char* inpu
      *                     [c1]      [e1,e2,e3]      [f1,f2]
      *
      * So if we're inside proc A's emitCode, and A is about to call emitCode on proc D, we want the
-     * EmitArgs that's passed onto D to only contain its and its descendants' coords. The
-     * EmitArgs given to A would contain the transforms [a1,b1,b2,c1,d1,e1,e2,e3,f1,f2], and we want
+     * EmitArgs that's passed onto D to only contain its and its descendants' textures. The
+     * EmitArgs given to A would contain the textures [a1,b1,b2,c1,d1,e1,e2,e3,f1,f2], and we want
      * to extract the subset [d1,e1,e2,e3,f1,f2] to pass on to D. We can do this with a linear
-     * search since we know that A has 1 transform (using A.numTransformsExclChildren()), and B's
-     * subtree has 3 transforms (using B.numTransforms()), so we know the start of D's transforms is
-     * 4 after the start of A's transforms.
-     * Textures work the same way as transforms.
+     * search since we know that A has 1 texture (using A.numTexturesExclChildren()), and B's
+     * subtree has 3 textures (using B.numTextures()), so we know the start of D's textures is
+     * 4 after the start of A's textures.
+     * Textures work the same way as textures.
      */
-    int firstCoordAt = args.fFp.numTransformsExclChildren();
     int firstTextureAt = args.fFp.numTexturesExclChildren();
     int firstBufferAt = args.fFp.numBuffersExclChildren();
     for (int i = 0; i < childIndex; ++i) {
-        firstCoordAt += args.fFp.childProcessor(i).numTransforms();
         firstTextureAt += args.fFp.childProcessor(i).numTextures();
         firstBufferAt += args.fFp.childProcessor(i).numBuffers();
     }
-    SkTArray<GrShaderVar> childCoords;
     const SamplerHandle* childTexSamplers = nullptr;
     const SamplerHandle* childBufferSamplers =  nullptr;
-    if (childProc.numTransforms() > 0) {
-        childCoords.push_back_n(childProc.numTransforms(), &args.fTransformedCoords[firstCoordAt]);
-    }
     if (childProc.numTextures() > 0) {
         childTexSamplers = &args.fTexSamplers[firstTextureAt];
     }
@@ -99,13 +93,14 @@ void GrGLSLFragmentProcessor::internalEmitChild(int childIndex, const char* inpu
     fragBuilder->codeAppend("{\n");
     fragBuilder->codeAppendf("// Child Index %d (mangle: %s): %s\n", childIndex,
                              fragBuilder->getMangleString().c_str(), childProc.name());
+    TransformedCoordVars coordVars = args.fTransformedCoords.childTransforms(childIndex);
     EmitArgs childArgs(fragBuilder,
                        args.fUniformHandler,
                        args.fGLSLCaps,
                        childProc,
                        outputColor,
                        inputColor,
-                       childCoords,
+                       coordVars,
                        childTexSamplers,
                        childBufferSamplers,
                        args.fGpImplementsDistanceVector);
@@ -114,3 +109,19 @@ void GrGLSLFragmentProcessor::internalEmitChild(int childIndex, const char* inpu
 
     fragBuilder->onAfterChildProcEmitCode();
 }
+
+//////////////////////////////////////////////////////////////////////////////
+
+using TransformedCoordVars = GrGLSLFragmentProcessor::TransformedCoordVars;
+TransformedCoordVars TransformedCoordVars::childTransforms(int childIdx) const {
+    const GrFragmentProcessor* child = &fFP->childProcessor(childIdx);
+    GrFragmentProcessor::Iter iter(fFP);
+    int numToSkip = 0;
+    while (true) {
+        const GrFragmentProcessor* fp = iter.next();
+        if (fp == child) {
+            return TransformedCoordVars(child, fTransformedVars + numToSkip);
+        }
+        numToSkip += fp->numCoordTransforms();
+    }
+}