commit 12c5d29ba676988f9026c3067212ee332fc11d24
author Brian Osman <brianosman@google.com> Mon Jul 13 16:11:35 2020 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Tue Jul 14 15:43:56 2020 +0000
tree a704654a006b09b7ebbcdb0b9f0f8bf82c65b161
parent ceebe424b1475ebdcf55f769e58b5e1a45b272c9

In FPs, store pointers for all child slots, even nullptr

This simplifies things like ConstantOutputForConstantInput and
invokeChild. It also removes the need for child indices: generated
FPs now directly refer to their children by slot number.

Change-Id: I69bbb042d5d72d21b999256f969c467702d0774d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/302436
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>

src/gpu/GrFragmentProcessor.h

diff --git a/src/gpu/GrFragmentProcessor.h b/src/gpu/GrFragmentProcessor.h
index 812f06f..ac7570e 100644
--- a/src/gpu/GrFragmentProcessor.h
+++ b/src/gpu/GrFragmentProcessor.h
@@ -123,17 +123,22 @@
 
     void getGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const {
         this->onGetGLSLProcessorKey(caps, b);
-        for (int i = 0; i < fChildProcessors.count(); ++i) {
-            fChildProcessors[i]->getGLSLProcessorKey(caps, b);
+        for (const auto& child : fChildProcessors) {
+            if (child) {
+                child->getGLSLProcessorKey(caps, b);
+            }
         }
     }
 
     int numVaryingCoordsUsed() const { return this->usesVaryingCoordsDirectly() ? 1 : 0; }
 
     int numChildProcessors() const { return fChildProcessors.count(); }
+    int numNonNullChildProcessors() const;
 
-    GrFragmentProcessor& childProcessor(int index) { return *fChildProcessors[index]; }
-    const GrFragmentProcessor& childProcessor(int index) const { return *fChildProcessors[index]; }
+    GrFragmentProcessor* childProcessor(int index) { return fChildProcessors[index].get(); }
+    const GrFragmentProcessor* childProcessor(int index) const {
+        return fChildProcessors[index].get();
+    }
 
     SkDEBUGCODE(bool isInstantiated() const;)
 
@@ -331,7 +336,7 @@
 
     /** Useful when you can't call fp->optimizationFlags() on a base class object from a subclass.*/
     static OptimizationFlags ProcessorOptimizationFlags(const GrFragmentProcessor* fp) {
-        return fp->optimizationFlags();
+        return fp ? fp->optimizationFlags() : kAll_OptimizationFlags;
     }
 
     /**
@@ -339,10 +344,14 @@
      * constantOutputForConstantInput. It must only be called when
      * hasConstantOutputForConstantInput() is known to be true.
      */
-    static SkPMColor4f ConstantOutputForConstantInput(const GrFragmentProcessor& fp,
+    static SkPMColor4f ConstantOutputForConstantInput(const GrFragmentProcessor* fp,
                                                       const SkPMColor4f& input) {
-        SkASSERT(fp.hasConstantOutputForConstantInput());
-        return fp.constantOutputForConstantInput(input);
+        if (fp) {
+            SkASSERT(fp->hasConstantOutputForConstantInput());
+            return fp->constantOutputForConstantInput(input);
+        } else {
+            return input;
+        }
     }
 
     /**
@@ -356,15 +365,8 @@
      *
      * The SampleUsage parameter describes all of the ways that the child is sampled by the parent.
      */
-    int registerChild(std::unique_ptr<GrFragmentProcessor> child,
-                      SkSL::SampleUsage sampleUsage = SkSL::SampleUsage::PassThrough());
-
-    /**
-     * This method takes an existing fragment processor, clones it, registers it as a child of this
-     * fragment processor, and returns its child index. It also takes care of any boilerplate in the
-     * cloning process.
-     */
-    int cloneAndRegisterChildProcessor(const GrFragmentProcessor& fp);
+    void registerChild(std::unique_ptr<GrFragmentProcessor> child,
+                       SkSL::SampleUsage sampleUsage = SkSL::SampleUsage::PassThrough());
 
     /**
      * This method takes an existing fragment processor, clones all of its children, and registers