Stop aggregating texture/buffer access objects in GrFragmentProcessor parents.

src/gpu/glsl/GrGLSLFragmentProcessor.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLSLFragmentProcessor.h"
 #include "GrFragmentProcessor.h"
 #include "GrProcessor.h"
@@ skipping 24 matching lines @@
 }
 
 void GrGLSLFragmentProcessor::internalEmitChild(int childIndex, const char* inputColor,
                                                 const char* outputColor, EmitArgs& args) {
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
 
     fragBuilder->onBeforeChildProcEmitCode();  // call first so mangleString is updated
 
     const GrFragmentProcessor& childProc = args.fFp.childProcessor(childIndex);
 
-    /*
-     * 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 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]
-     *                                  /    \
-     *                                /        \
-     *                            (B)           (D)
-     *                        [b1,b2,c1]   [d1,e1,e2,e3,f1,f2]
-     *                          /             /    \
-     *                        /             /        \
-     *                      (C)          (E)          (F)
-     *                     [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' 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 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 firstTextureAt = args.fFp.numTexturesExclChildren();
-    int firstBufferAt = args.fFp.numBuffersExclChildren();
-    for (int i = 0; i < childIndex; ++i) {
-        firstTextureAt += args.fFp.childProcessor(i).numTextures();
-        firstBufferAt += args.fFp.childProcessor(i).numBuffers();
-    }
-    const SamplerHandle* childTexSamplers = nullptr;
-    const SamplerHandle* childBufferSamplers =  nullptr;
-    if (childProc.numTextures() > 0) {
-        childTexSamplers = &args.fTexSamplers[firstTextureAt];
-    }
-    if (childProc.numBuffers() > 0) {
-        childBufferSamplers = &args.fBufferSamplers[firstBufferAt];
-    }
-
     // emit the code for the child in its own scope
     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);
+    TransformedCoordVars coordVars = args.fTransformedCoords.childInputs(childIndex);
+    TextureSamplers textureSamplers = args.fTexSamplers.childInputs(childIndex);
+    BufferSamplers bufferSamplers = args.fBufferSamplers.childInputs(childIndex);
     EmitArgs childArgs(fragBuilder,
                        args.fUniformHandler,
                        args.fGLSLCaps,
                        childProc,
                        outputColor,
                        inputColor,
                        coordVars,
-                       childTexSamplers,
-                       childBufferSamplers,
+                       textureSamplers,
+                       bufferSamplers,
                        args.fGpImplementsDistanceVector);
     this->childProcessor(childIndex)->emitCode(childArgs);
     fragBuilder->codeAppend("}\n");
 
     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();
+GrGLSLFragmentProcessor* GrGLSLFragmentProcessor::Iter::next() {
+    if (fFPStack.empty()) {
+        return nullptr;
     }
+    GrGLSLFragmentProcessor* back = fFPStack.back();
+    fFPStack.pop_back();
+    for (int i = back->numChildProcessors() - 1; i >= 0; --i) {
+        fFPStack.push_back(back->childProcessor(i));
+    }
+    return back;
 }