Allow single-pass filters (which use asNewEffect()) to participate in the image filter DAG. This w…

include/core/SkImageFilter.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImageFilter_DEFINED
 #define SkImageFilter_DEFINED
 
@@ skipping 75 matching lines @@
      *  GrEffect, used to process this filter on the GPU, or false if
      *  not.
      *
      *  If effect is non-NULL, a new GrEffect instance is stored
      *  in it.  The caller assumes ownership of the stage, and it is up to the
      *  caller to unref it.
      *
      *  The effect can assume its vertexCoords space maps 1-to-1 with texels
      *  in the texture.
      */
-    virtual bool asNewEffect(GrEffectRef** effect, GrTexture*) const;
+    virtual GrEffectRef* asNewEffect(GrTexture*) const;
 
     /**
      *  Returns true if the filter can be processed on the GPU.  This is most
      *  often used for multi-pass effects, where intermediate results must be
      *  rendered to textures.  For single-pass effects, use asNewEffect().

[bsalomon, 2013/04/08 17:52:17]

It seems like this comment should be updated to say that the caller must
override this if they override asNewEffect().

      *  The default implementation returns false.
      */
     virtual bool canFilterImageGPU() const;
 
     /**
-     *  Process this image filter on the GPU.  src is the source image for
-     *  processing, as a texture-backed bitmap.  result is the destination
-     *  bitmap, which should contain a texture-backed pixelref on success.
-     *  The default implementation returns returns false and ignores the
-     *  result parameter.
+     *  Process this image filter on the GPU.  This is most often used for 
+     *  multi-pass efefects, where intermediate results must be rendered to
+     *  textures.  For single-pass effects, use asNewEffect().  src is the
+     *  source image for processing, as a texture-backed bitmap.  result is
+     *  the destination bitmap, which should contain a texture-backed pixelref
+     *  on success.  The default implementation does single-pass processing
+     *  using asNewEffect().  If asNewEffect() returns NULL, the default 
+     *  implementation returns false.
      */
     virtual bool filterImageGPU(Proxy*, const SkBitmap& src, SkBitmap* result);
 
     /**
      *  Returns whether this image filter is a color filter and puts the color filter into the
      *  "filterPtr" parameter if it can. Does nothing otherwise.
      *  If this returns false, then the filterPtr is unchanged.
      *  If this returns true, then if filterPtr is not null, it must be set to a ref'd colorfitler
      *  (i.e. it may not be set to NULL).
      */
@@ skipping 40 matching lines @@
     SkBitmap getInputResult(int index, Proxy*, const SkBitmap& src, const SkMatrix&,
                             SkIPoint*);
 
 private:
     typedef SkFlattenable INHERITED;
     int fInputCount;
     SkImageFilter** fInputs;
 };
 
 #endif