Allow single-pass filters (which use asNewEffect()) to participate in the image filter DAG.  This was done by introducing the SkSinglePassImageFilter abstract base class, which implements canFilterImageGPU() and filterImageGPU() on behalf of the derived class.  The derived class still only needs to asNewEffect().  This allows us to recurse on the filter input in SkSinglePassImageFilter::onFilterImageGPU().  It also allows us to remove any knowledge of single-pass image filters from SkGpuDevice and from the SkImageFilter base class as well.

BUG=

Review URL: https://codereview.chromium.org/13602013

git-svn-id: http://skia.googlecode.com/svn/trunk@8563 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/core.gypi b/gyp/core.gypi
index 811f89b..3fc5263 100644
--- a/gyp/core.gypi
+++ b/gyp/core.gypi
@@ -96,6 +96,7 @@
         '<(skia_src_path)/core/SkGraphics.cpp',
         '<(skia_src_path)/core/SkInstCnt.cpp',
         '<(skia_src_path)/core/SkImageFilter.cpp',
+        '<(skia_src_path)/core/SkImageFilterUtils.cpp',
         '<(skia_src_path)/core/SkLineClipper.cpp',
         '<(skia_src_path)/core/SkMallocPixelRef.cpp',
         '<(skia_src_path)/core/SkMask.cpp',
@@ -230,6 +231,7 @@
         '<(skia_include_path)/core/SkGeometry.h',
         '<(skia_include_path)/core/SkGraphics.h',
         '<(skia_include_path)/core/SkImageFilter.h',
+        '<(skia_include_path)/core/SkImageFilterUtils.h',
         '<(skia_include_path)/core/SkInstCnt.h',
         '<(skia_include_path)/core/SkMallocPixelRef.h',
         '<(skia_include_path)/core/SkMask.h',
diff --git a/gyp/effects.gypi b/gyp/effects.gypi
index e3f4bf5..3eb0d95 100644
--- a/gyp/effects.gypi
+++ b/gyp/effects.gypi
@@ -31,7 +31,6 @@
     '<(skia_src_path)/effects/SkEmbossMask.h',
     '<(skia_src_path)/effects/SkEmbossMask_Table.h',
     '<(skia_src_path)/effects/SkEmbossMaskFilter.cpp',
-    '<(skia_src_path)/effects/SkImageFilterUtils.cpp',
     '<(skia_src_path)/effects/SkKernel33MaskFilter.cpp',
     '<(skia_src_path)/effects/SkLayerDrawLooper.cpp',
     '<(skia_src_path)/effects/SkLayerRasterizer.cpp',
@@ -89,7 +88,6 @@
     '<(skia_include_path)/effects/SkDrawExtraPathEffect.h',
     '<(skia_include_path)/effects/SkEmbossMaskFilter.h',
     '<(skia_include_path)/effects/SkGradientShader.h',
-    '<(skia_include_path)/effects/SkImageFilterUtils.h',
     '<(skia_include_path)/effects/SkKernel33MaskFilter.h',
     '<(skia_include_path)/effects/SkLayerDrawLooper.h',
     '<(skia_include_path)/effects/SkLayerRasterizer.h',
diff --git a/include/core/SkImageFilter.h b/include/core/SkImageFilter.h
index 6cc53c0..d89befa 100644
--- a/include/core/SkImageFilter.h
+++ b/include/core/SkImageFilter.h
@@ -99,16 +99,18 @@
      *  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().
-     *  The default implementation returns false.
+     *  The default implementation returns asNewEffect(NULL, NULL).
      */
     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 effects, 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().
      */
     virtual bool filterImageGPU(Proxy*, const SkBitmap& src, SkBitmap* result);
 
diff --git a/include/core/SkImageFilterUtils.h b/include/core/SkImageFilterUtils.h
new file mode 100644
index 0000000..72a25fe
--- /dev/null
+++ b/include/core/SkImageFilterUtils.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2013 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkImageFilterUtils_DEFINED
+#define SkImageFilterUtils_DEFINED
+
+#if SK_SUPPORT_GPU
+
+#include "SkImageFilter.h"
+
+class SkBitmap;
+class GrTexture;
+class SkImageFilter;
+
+class SK_API SkImageFilterUtils {
+public:
+    /**
+     * Wrap the given texture in a texture-backed SkBitmap.
+     */
+    static bool WrapTexture(GrTexture* texture, int width, int height, SkBitmap* result);
+
+    /**
+     * Recursively evaluate the given filter on the GPU.  If filter is NULL,
+     * this function returns src.  If the filter has no GPU implementation, it
+     * will be processed in software and uploaded to the GPU.
+     */
+    static bool GetInputResultGPU(SkImageFilter* filter, SkImageFilter::Proxy* proxy, const SkBitmap& src, SkBitmap* result);
+};
+
+#endif
+
+#endif
diff --git a/include/effects/SkMagnifierImageFilter.h b/include/effects/SkMagnifierImageFilter.h
index e013426..80e3af6 100644
--- a/include/effects/SkMagnifierImageFilter.h
+++ b/include/effects/SkMagnifierImageFilter.h
@@ -16,7 +16,9 @@
 public:
     SkMagnifierImageFilter(SkRect srcRect, SkScalar inset);
 
+#if SK_SUPPORT_GPU
     virtual bool asNewEffect(GrEffectRef** effect, GrTexture* texture) const SK_OVERRIDE;
+#endif
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkMagnifierImageFilter)
 
diff --git a/include/effects/SkMatrixConvolutionImageFilter.h b/include/effects/SkMatrixConvolutionImageFilter.h
index cd2a16f..78a66f8 100644
--- a/include/effects/SkMatrixConvolutionImageFilter.h
+++ b/include/effects/SkMatrixConvolutionImageFilter.h
@@ -62,7 +62,7 @@
                                SkBitmap* result, SkIPoint* loc) SK_OVERRIDE;
 
 #if SK_SUPPORT_GPU
-    virtual bool asNewEffect(GrEffectRef**, GrTexture*) const SK_OVERRIDE;
+    virtual bool asNewEffect(GrEffectRef** effect, GrTexture*) const SK_OVERRIDE;
 #endif
 
 private:
diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index 56fb1ae..2d81026 100644
--- a/src/core/SkImageFilter.cpp
+++ b/src/core/SkImageFilter.cpp
@@ -10,6 +10,11 @@
 #include "SkBitmap.h"
 #include "SkFlattenableBuffers.h"
 #include "SkRect.h"
+#if SK_SUPPORT_GPU
+#include "GrContext.h"
+#include "GrTexture.h"
+#include "SkImageFilterUtils.h"
+#endif
 
 SK_DEFINE_INST_COUNT(SkImageFilter)
 
@@ -104,12 +109,45 @@
 }
 
 bool SkImageFilter::canFilterImageGPU() const {
-    return false;
+    return this->asNewEffect(NULL, NULL);
 }
 
 bool SkImageFilter::filterImageGPU(Proxy* proxy, const SkBitmap& src, SkBitmap* result) {
-    SkASSERT(false);  // Should never be called, since canFilterImageGPU() returned false.
+#if SK_SUPPORT_GPU
+    SkBitmap input;
+    SkASSERT(fInputCount == 1);
+    if (!SkImageFilterUtils::GetInputResultGPU(this->getInput(0), proxy, src, &input)) {
+        return false;
+    }
+    GrTexture* srcTexture = (GrTexture*) input.getTexture();
+    SkRect rect;
+    src.getBounds(&rect);
+    GrContext* context = srcTexture->getContext();
+
+    GrTextureDesc desc;
+    desc.fFlags = kRenderTarget_GrTextureFlagBit,
+    desc.fWidth = input.width();
+    desc.fHeight = input.height();
+    desc.fConfig = kRGBA_8888_GrPixelConfig;
+
+    GrAutoScratchTexture dst(context, desc);
+    GrContext::AutoMatrix am;
+    am.setIdentity(context);
+    GrContext::AutoRenderTarget art(context, dst.texture()->asRenderTarget());
+    GrContext::AutoClip acs(context, rect);
+    GrEffectRef* effect;
+    this->asNewEffect(&effect, srcTexture);
+    SkASSERT(effect);
+    SkAutoUnref effectRef(effect);
+    GrPaint paint;
+    paint.colorStage(0)->setEffect(effect);
+    context->drawRect(paint, rect);
+    SkAutoTUnref<GrTexture> resultTex(dst.detach());
+    SkImageFilterUtils::WrapTexture(resultTex, input.width(), input.height(), result);
+    return true;
+#else
     return false;
+#endif
 }
 
 bool SkImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
diff --git a/src/effects/SkImageFilterUtils.cpp b/src/core/SkImageFilterUtils.cpp
similarity index 95%
rename from src/effects/SkImageFilterUtils.cpp
rename to src/core/SkImageFilterUtils.cpp
index 2dfb33d..d6e109c 100644
--- a/src/effects/SkImageFilterUtils.cpp
+++ b/src/core/SkImageFilterUtils.cpp
@@ -15,7 +15,6 @@
 #include "SkGr.h"
 
 bool SkImageFilterUtils::WrapTexture(GrTexture* texture, int width, int height, SkBitmap* result) {
-    SkASSERT(texture->config() == kSkia8888_GrPixelConfig);
     result->setConfig(SkBitmap::kARGB_8888_Config, width, height);
     result->setPixelRef(SkNEW_ARGS(SkGrPixelRef, (texture)))->unref();
     return true;
diff --git a/src/effects/SkLightingImageFilter.cpp b/src/effects/SkLightingImageFilter.cpp
index a22bc6f..bb2927b 100644
--- a/src/effects/SkLightingImageFilter.cpp
+++ b/src/effects/SkLightingImageFilter.cpp
@@ -264,7 +264,9 @@
                                  SkScalar kd, SkImageFilter* input);
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDiffuseLightingImageFilter)
 
+#if SK_SUPPORT_GPU
     virtual bool asNewEffect(GrEffectRef** effect, GrTexture*) const SK_OVERRIDE;
+#endif
     SkScalar kd() const { return fKD; }
 
 protected:
@@ -284,7 +286,10 @@
     SkSpecularLightingImageFilter(SkLight* light, SkScalar surfaceScale, SkScalar ks, SkScalar shininess, SkImageFilter* input);
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkSpecularLightingImageFilter)
 
+#if SK_SUPPORT_GPU
     virtual bool asNewEffect(GrEffectRef** effect, GrTexture*) const SK_OVERRIDE;
+#endif
+
     SkScalar ks() const { return fKS; }
     SkScalar shininess() const { return fShininess; }
 
@@ -859,19 +864,15 @@
     return true;
 }
 
-bool SkDiffuseLightingImageFilter::asNewEffect(GrEffectRef** effect,
-                                               GrTexture* texture) const {
 #if SK_SUPPORT_GPU
+bool SkDiffuseLightingImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture) const {
     if (effect) {
         SkScalar scale = SkScalarMul(surfaceScale(), SkIntToScalar(255));
         *effect = GrDiffuseLightingEffect::Create(texture, light(), scale, kd());
     }
     return true;
-#else
-    SkDEBUGFAIL("Should not call in GPU-less build");
-    return false;
-#endif
 }
+#endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -928,19 +929,15 @@
     return true;
 }
 
-bool SkSpecularLightingImageFilter::asNewEffect(GrEffectRef** effect,
-                                                GrTexture* texture) const {
 #if SK_SUPPORT_GPU
+bool SkSpecularLightingImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture) const {
     if (effect) {
         SkScalar scale = SkScalarMul(surfaceScale(), SkIntToScalar(255));
         *effect = GrSpecularLightingEffect::Create(texture, light(), scale, ks(), shininess());
     }
     return true;
-#else
-    SkDEBUGFAIL("Should not call in GPU-less build");
-    return false;
-#endif
 }
+#endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
diff --git a/src/effects/SkMagnifierImageFilter.cpp b/src/effects/SkMagnifierImageFilter.cpp
index f6675c4..a68ab7c 100644
--- a/src/effects/SkMagnifierImageFilter.cpp
+++ b/src/effects/SkMagnifierImageFilter.cpp
@@ -212,7 +212,7 @@
     uint32_t y = random->nextULessThan(kMaxHeight - height);
     SkScalar inset = SkIntToScalar(random->nextULessThan(kMaxInset));
 
-    SkAutoTUnref<SkImageFilter> filter(
+    SkAutoTUnref<SkMagnifierImageFilter> filter(
             new SkMagnifierImageFilter(
                 SkRect::MakeXYWH(SkIntToScalar(x), SkIntToScalar(y),
                                  SkIntToScalar(width), SkIntToScalar(height)),
@@ -263,22 +263,20 @@
     SkASSERT(srcRect.x() >= 0 && srcRect.y() >= 0 && inset >= 0);
 }
 
-bool SkMagnifierImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture) const {
 #if SK_SUPPORT_GPU
+bool SkMagnifierImageFilter::asNewEffect(GrEffectRef** effect, GrTexture* texture) const {
     if (effect) {
-      *effect = GrMagnifierEffect::Create(texture,
-                                          fSrcRect.x() / texture->width(),
-                                          fSrcRect.y() / texture->height(),
-                                          texture->width() / fSrcRect.width(),
-                                          texture->height() / fSrcRect.height(),
-                                          fInset / texture->width(),
-                                          fInset / texture->height());
+        *effect = GrMagnifierEffect::Create(texture,
+                                            fSrcRect.x() / texture->width(),
+                                            fSrcRect.y() / texture->height(),
+                                            texture->width() / fSrcRect.width(),
+                                            texture->height() / fSrcRect.height(),
+                                            fInset / texture->width(),
+                                            fInset / texture->height());
     }
     return true;
-#else
-    return false;
-#endif
 }
+#endif
 
 void SkMagnifierImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
diff --git a/src/effects/SkMatrixConvolutionImageFilter.cpp b/src/effects/SkMatrixConvolutionImageFilter.cpp
index e3711d2..6368096 100644
--- a/src/effects/SkMatrixConvolutionImageFilter.cpp
+++ b/src/effects/SkMatrixConvolutionImageFilter.cpp
@@ -562,18 +562,19 @@
 
 bool SkMatrixConvolutionImageFilter::asNewEffect(GrEffectRef** effect,
                                                  GrTexture* texture) const {
-    bool ok = fKernelSize.width() * fKernelSize.height() <= MAX_KERNEL_SIZE;
-    if (ok && effect) {
-        *effect = GrMatrixConvolutionEffect::Create(texture,
-                                                    fKernelSize,
-                                                    fKernel,
-                                                    fGain,
-                                                    fBias,
-                                                     fTarget,
-                                                     fTileMode,
-                                                     fConvolveAlpha);
+    if (!effect) {
+        return fKernelSize.width() * fKernelSize.height() <= MAX_KERNEL_SIZE;
     }
-    return ok;
+    SkASSERT(fKernelSize.width() * fKernelSize.height() <= MAX_KERNEL_SIZE);
+    *effect = GrMatrixConvolutionEffect::Create(texture,
+                                                fKernelSize,
+                                                fKernel,
+                                                fGain,
+                                                fBias,
+                                                fTarget,
+                                                fTileMode,
+                                                fConvolveAlpha);
+    return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 45176cf..c1364af 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -1404,26 +1404,6 @@
     fContext->drawRectToRect(*grPaint, dstRect, paintRect, &m);
 }
 
-namespace {
-
-void apply_effect(GrContext* context,
-                  GrTexture* srcTexture,
-                  GrTexture* dstTexture,
-                  const GrRect& rect,
-                  GrEffectRef* effect) {
-    SkASSERT(srcTexture && srcTexture->getContext() == context);
-    GrContext::AutoMatrix am;
-    am.setIdentity(context);
-    GrContext::AutoRenderTarget art(context, dstTexture->asRenderTarget());
-    GrContext::AutoClip acs(context, rect);
-
-    GrPaint paint;
-    paint.colorStage(0)->setEffect(effect);
-    context->drawRect(paint, rect);
-}
-
-};
-
 static SkBitmap wrap_texture(GrTexture* texture) {
     SkBitmap result;
     bool dummy;
@@ -1439,26 +1419,11 @@
     GrAssert(filter);
     SkDeviceImageFilterProxy proxy(device);
 
-    GrTextureDesc desc;
-    desc.fFlags = kRenderTarget_GrTextureFlagBit,
-    desc.fWidth = w;
-    desc.fHeight = h;
-    desc.fConfig = kRGBA_8888_GrPixelConfig;
-    GrEffectRef* effect;
-
     if (filter->canFilterImageGPU()) {
         // Save the render target and set it to NULL, so we don't accidentally draw to it in the
         // filter.  Also set the clip wide open and the matrix to identity.
         GrContext::AutoWideOpenIdentityDraw awo(context, NULL);
         return filter->filterImageGPU(&proxy, wrap_texture(texture), result);
-    } else if (filter->asNewEffect(&effect, texture)) {
-        GrAutoScratchTexture dst(context, desc);
-        SkRect r = SkRect::MakeWH(SkIntToScalar(w), SkIntToScalar(h));
-        apply_effect(context, texture, dst.texture(), r, effect);
-        SkAutoTUnref<GrTexture> resultTex(dst.detach());
-        effect->unref();
-        *result = wrap_texture(resultTex.get());
-        return true;
     } else {
         return false;
     }
@@ -1594,11 +1559,7 @@
 }
 
 bool SkGpuDevice::canHandleImageFilter(SkImageFilter* filter) {
-    if (!filter->asNewEffect(NULL, NULL) &&
-        !filter->canFilterImageGPU()) {
-        return false;
-    }
-    return true;
+    return filter->canFilterImageGPU();
 }
 
 bool SkGpuDevice::filterImage(SkImageFilter* filter, const SkBitmap& src,