Dynamically create stencil buffer when needed.

Review URL: https://codereview.chromium.org/938383004

gyp/gpu.gypi

@@ -149,6 +149,7 @@
       '<(skia_src_path)/gpu/GrRectanizer_skyline.h',
       '<(skia_src_path)/gpu/GrRedBlackTree.h',
       '<(skia_src_path)/gpu/GrRenderTarget.cpp',
+      '<(skia_src_path)/gpu/GrRenderTargetPriv.h',
       '<(skia_src_path)/gpu/GrReducedClip.cpp',
       '<(skia_src_path)/gpu/GrReducedClip.h',
       '<(skia_src_path)/gpu/GrResourceCache.cpp',

include/gpu/GrRenderTarget.h

@@ -12,6 +12,7 @@
 #include "SkRect.h"
 
 class GrStencilBuffer;
+class GrRenderTargetPriv;
 
 /**
  * GrRenderTarget represents a 2D buffer of pixels that can be rendered to.
@@ -88,11 +89,9 @@ public:
     };
     virtual ResolveType getResolveType() const = 0;
 
-    /**
+    // Provides access to functions that aren't part of the public API.
-     * GrStencilBuffer is not part of the public API.
+    GrRenderTargetPriv renderTargetPriv();
-     */
+    const GrRenderTargetPriv renderTargetPriv() const;
-    GrStencilBuffer* getStencilBuffer() const { return fStencilBuffer; }
-    void setStencilBuffer(GrStencilBuffer* stencilBuffer);
 
 protected:
     GrRenderTarget(GrGpu* gpu, LifeCycle lifeCycle, const GrSurfaceDesc& desc)
@@ -106,6 +105,11 @@ protected:
     void onRelease() SK_OVERRIDE;
 
 private:
+    // Checked when this object is asked to attach a stencil buffer.
+    virtual bool canAttemptStencilAttachment() const = 0;
+
+    friend class GrRenderTargetPriv;
+
     GrStencilBuffer*  fStencilBuffer;
 
     SkIRect           fResolveRect;

include/gpu/GrTypes.h

@@ -390,10 +390,7 @@ enum GrSurfaceFlags {
      */
     kRenderTarget_GrSurfaceFlag     = 0x1,
     /**
-     * By default all render targets have an associated stencil buffer that
+     * DEPRECATED. This has no effect.
-     * may be required for path filling. This flag overrides stencil buffer
-     * creation.
-     * MAKE THIS PRIVATE?
      */
     kNoStencil_GrSurfaceFlag        = 0x2,
     /**

src/effects/SkAlphaThresholdFilter.cpp

@@ -273,7 +273,7 @@ bool SkAlphaThresholdFilterImpl::asFragmentProcessor(GrFragmentProcessor** fp,
         } else {
             maskDesc.fConfig = kRGBA_8888_GrPixelConfig;
         }
-        maskDesc.fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+        maskDesc.fFlags = kRenderTarget_GrSurfaceFlag;
         // Add one pixel of border to ensure that clamp mode will be all zeros
         // the outside.
         maskDesc.fWidth = texture->width();

src/effects/SkDisplacementMapEffect.cpp

@@ -417,7 +417,7 @@ bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src,
     GrContext* context = color->getContext();
 
     GrSurfaceDesc desc;
-    desc.fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fWidth = bounds.width();
     desc.fHeight = bounds.height();
     desc.fConfig = kSkia8888_GrPixelConfig;

src/effects/SkGpuBlurUtils.cpp

@@ -167,7 +167,7 @@ GrTexture* GaussianBlur(GrContext* context,
              kAlpha_8_GrPixelConfig == srcTexture->config());
 
     GrSurfaceDesc desc;
-    desc.fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fWidth = SkScalarFloorToInt(srcRect.width());
     desc.fHeight = SkScalarFloorToInt(srcRect.height());
     desc.fConfig = srcTexture->config();

src/effects/SkMorphologyImageFilter.cpp

@@ -657,7 +657,7 @@ bool apply_morphology(const SkBitmap& input,
 
     SkIRect dstRect = SkIRect::MakeWH(rect.width(), rect.height());
     GrSurfaceDesc desc;
-    desc.fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fWidth = rect.width();
     desc.fHeight = rect.height();
     desc.fConfig = kSkia8888_GrPixelConfig;

src/effects/SkXfermodeImageFilter.cpp

@@ -145,7 +145,7 @@ bool SkXfermodeImageFilter::filterImageGPU(Proxy* proxy,
     GrFragmentProcessor* xferProcessor = NULL;
 
     GrSurfaceDesc desc;
-    desc.fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fWidth = src.width();
     desc.fHeight = src.height();
     desc.fConfig = kSkia8888_GrPixelConfig;

src/gpu/GrClipMaskManager.cpp

@@ -13,6 +13,7 @@
 #include "GrPaint.h"
 #include "GrPathRenderer.h"
 #include "GrRenderTarget.h"
+#include "GrRenderTargetPriv.h"
 #include "GrStencilBuffer.h"
 #include "GrSWMaskHelper.h"
 #include "SkRasterClip.h"
@@ -675,8 +676,7 @@ bool GrClipMaskManager::createStencilClipMask(GrRenderTarget* rt,
     SkASSERT(kNone_ClipMaskType == fCurrClipMaskType);
     SkASSERT(rt);
 
-    // TODO: dynamically attach a SB when needed.
+    GrStencilBuffer* stencilBuffer = rt->renderTargetPriv().attachStencilBuffer();
-    GrStencilBuffer* stencilBuffer = rt->getStencilBuffer();
     if (NULL == stencilBuffer) {
         return false;
     }
@@ -905,9 +905,9 @@ void GrClipMaskManager::setPipelineBuilderStencil(GrPipelineBuilder* pipelineBui
         settings = pipelineBuilder->getStencil();
     }
 
-    // TODO: dynamically attach a stencil buffer
     int stencilBits = 0;
-    GrStencilBuffer* stencilBuffer = pipelineBuilder->getRenderTarget()->getStencilBuffer();
+    GrRenderTarget* rt = pipelineBuilder->getRenderTarget();
+    GrStencilBuffer* stencilBuffer = rt->renderTargetPriv().attachStencilBuffer();
     if (stencilBuffer) {
         stencilBits = stencilBuffer->bits();
     }
@@ -1084,7 +1084,6 @@ void GrClipMaskManager::setClipTarget(GrClipTarget* clipTarget) {
 
 void GrClipMaskManager::adjustPathStencilParams(const GrStencilBuffer* stencilBuffer,
                                                 GrStencilSettings* settings) {
-    // TODO: dynamically attach a stencil buffer
     if (stencilBuffer) {
         int stencilBits = stencilBuffer->bits();
         this->adjustStencilParams(settings, fClipMode, stencilBits);

src/gpu/GrContext.cpp

@@ -23,6 +23,7 @@
 #include "GrOvalRenderer.h"
 #include "GrPathRenderer.h"
 #include "GrPathUtils.h"
+#include "GrRenderTargetPriv.h"
 #include "GrResourceCache.h"
 #include "GrSoftwarePathRenderer.h"
 #include "GrStencilAndCoverTextContext.h"
@@ -213,10 +214,12 @@ GrTextContext* GrContext::createTextContext(GrRenderTarget* renderTarget,
                                             const SkDeviceProperties&
                                             leakyProperties,
                                             bool enableDistanceFieldFonts) {
-    if (fGpu->caps()->pathRenderingSupport() && renderTarget->getStencilBuffer() && 
+    if (fGpu->caps()->pathRenderingSupport() && renderTarget->isMultisampled()) {
-                                                renderTarget->isMultisampled()) {
+        GrStencilBuffer* sb = renderTarget->renderTargetPriv().attachStencilBuffer();
+        if (sb) {
             return GrStencilAndCoverTextContext::Create(this, leakyProperties);
         }
+    } 
 
     return GrDistanceFieldTextContext::Create(this, leakyProperties, enableDistanceFieldFonts);
 }
@@ -278,14 +281,10 @@ GrTexture* GrContext::refScratchTexture(const GrSurfaceDesc& desc, ScratchTexMat
 
 GrTexture* GrContext::internalRefScratchTexture(const GrSurfaceDesc& inDesc, uint32_t flags) {
     SkASSERT(!GrPixelConfigIsCompressed(inDesc.fConfig));
-    // kNoStencil has no meaning if kRT isn't set.
-    SkASSERT((inDesc.fFlags & kRenderTarget_GrSurfaceFlag) ||
-             !(inDesc.fFlags & kNoStencil_GrSurfaceFlag));
 
     SkTCopyOnFirstWrite<GrSurfaceDesc> desc(inDesc);
 
     if (fGpu->caps()->reuseScratchTextures() || (desc->fFlags & kRenderTarget_GrSurfaceFlag)) {
-        GrSurfaceFlags origFlags = desc->fFlags;
         if (!(kExact_ScratchTextureFlag & flags)) {
             // bin by pow2 with a reasonable min
             static const int MIN_SIZE = 16;
@@ -294,7 +293,6 @@ GrTexture* GrContext::internalRefScratchTexture(const GrSurfaceDesc& inDesc, uin
             wdesc->fHeight = SkTMax(MIN_SIZE, GrNextPow2(desc->fHeight));
         }
 
-        do {
         GrScratchKey key;
         GrTexturePriv::ComputeScratchKey(*desc, &key);
         uint32_t scratchFlags = 0;
@@ -314,24 +312,6 @@ GrTexture* GrContext::internalRefScratchTexture(const GrSurfaceDesc& inDesc, uin
             }
             return surface->asTexture();
         }
-
-            if (kExact_ScratchTextureFlag & flags) {
-                break;
-            }
-            // We had a cache miss and we are in approx mode, relax the fit of the flags.
-
-            // We no longer try to reuse textures that were previously used as render targets in
-            // situations where no RT is needed; doing otherwise can confuse the video driver and
-            // cause significant performance problems in some cases.
-            if (desc->fFlags & kNoStencil_GrSurfaceFlag) {
-                desc.writable()->fFlags = desc->fFlags & ~kNoStencil_GrSurfaceFlag;
-            } else {
-                break;
-            }
-
-        } while (true);
-
-        desc.writable()->fFlags = origFlags;
     }
 
     if (!(kNoCreate_ScratchTextureFlag & flags)) {

src/gpu/GrDrawTarget.cpp

@@ -14,6 +14,7 @@
 #include "GrPath.h"
 #include "GrPipeline.h"
 #include "GrRenderTarget.h"
+#include "GrRenderTargetPriv.h"
 #include "GrSurfacePriv.h"
 #include "GrTemplates.h"
 #include "GrTexture.h"
@@ -607,9 +608,9 @@ void GrDrawTarget::stencilPath(GrPipelineBuilder* pipelineBuilder,
 
     // set stencil settings for path
     GrStencilSettings stencilSettings;
-    this->getPathStencilSettingsForFilltype(fill,
+    GrRenderTarget* rt = pipelineBuilder->getRenderTarget();
-                                            pipelineBuilder->getRenderTarget()->getStencilBuffer(),
+    GrStencilBuffer* sb = rt->renderTargetPriv().attachStencilBuffer();
-                                            &stencilSettings);
+    this->getPathStencilSettingsForFilltype(fill, sb, &stencilSettings);
 
     this->onStencilPath(*pipelineBuilder, pathProc, path, scissorState, stencilSettings);
 }
@@ -636,9 +637,9 @@ void GrDrawTarget::drawPath(GrPipelineBuilder* pipelineBuilder,
 
     // set stencil settings for path
     GrStencilSettings stencilSettings;
-    this->getPathStencilSettingsForFilltype(fill,
+    GrRenderTarget* rt = pipelineBuilder->getRenderTarget();
-                                            pipelineBuilder->getRenderTarget()->getStencilBuffer(),
+    GrStencilBuffer* sb = rt->renderTargetPriv().attachStencilBuffer();
-                                            &stencilSettings);
+    this->getPathStencilSettingsForFilltype(fill, sb, &stencilSettings);
 
     GrDrawTarget::PipelineInfo pipelineInfo(pipelineBuilder, &scissorState, pathProc, &devBounds,
                                             this);
@@ -676,9 +677,9 @@ void GrDrawTarget::drawPaths(GrPipelineBuilder* pipelineBuilder,
 
     // set stencil settings for path
     GrStencilSettings stencilSettings;
-    this->getPathStencilSettingsForFilltype(fill,
+    GrRenderTarget* rt = pipelineBuilder->getRenderTarget();
-                                            pipelineBuilder->getRenderTarget()->getStencilBuffer(),
+    GrStencilBuffer* sb = rt->renderTargetPriv().attachStencilBuffer();
-                                            &stencilSettings);
+    this->getPathStencilSettingsForFilltype(fill, sb, &stencilSettings);
 
     // Don't compute a bounding box for dst copy texture, we'll opt
     // instead for it to just copy the entire dst. Realistically this is a moot

src/gpu/GrDrawTarget.h

@@ -726,7 +726,7 @@ private:
     void initCopySurfaceDstDesc(const GrSurface* src, GrSurfaceDesc* dstDesc) {
         if (!this->onInitCopySurfaceDstDesc(src, dstDesc)) {
             dstDesc->fOrigin = kDefault_GrSurfaceOrigin;
-            dstDesc->fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+            dstDesc->fFlags = kRenderTarget_GrSurfaceFlag;
             dstDesc->fConfig = src->config();
         }
     }

src/gpu/GrGpu.cpp

@@ -15,6 +15,7 @@
 #include "GrGpuResourcePriv.h"
 #include "GrIndexBuffer.h"
 #include "GrResourceCache.h"
+#include "GrRenderTargetPriv.h"
 #include "GrStencilBuffer.h"
 #include "GrVertexBuffer.h"
 
@@ -61,16 +62,6 @@ GrTexture* GrGpu::createTexture(const GrSurfaceDesc& desc, bool budgeted,
     } else {
         this->handleDirtyContext();
         tex = this->onCreateTexture(desc, budgeted, srcData, rowBytes);
-        if (tex &&
-            (kRenderTarget_GrSurfaceFlag & desc.fFlags) &&
-            !(kNoStencil_GrSurfaceFlag & desc.fFlags)) {
-            SkASSERT(tex->asRenderTarget());
-            // TODO: defer this and attach dynamically
-            if (!this->attachStencilBufferToRenderTarget(tex->asRenderTarget())) {
-                tex->unref();
-                return NULL;
-            }
-        }
     }
     if (!this->caps()->reuseScratchTextures() && !isRT) {
         tex->resourcePriv().removeScratchKey();
@@ -85,7 +76,7 @@ GrTexture* GrGpu::createTexture(const GrSurfaceDesc& desc, bool budgeted,
 }
 
 bool GrGpu::attachStencilBufferToRenderTarget(GrRenderTarget* rt) {
-    SkASSERT(NULL == rt->getStencilBuffer());
+    SkASSERT(NULL == rt->renderTargetPriv().getStencilBuffer());
     GrUniqueKey sbKey;
 
     int width = rt->width();
@@ -99,12 +90,11 @@ bool GrGpu::attachStencilBufferToRenderTarget(GrRenderTarget* rt) {
     SkAutoTUnref<GrStencilBuffer> sb(static_cast<GrStencilBuffer*>(
         this->getContext()->getResourceCache()->findAndRefUniqueResource(sbKey)));
     if (sb) {
-        rt->setStencilBuffer(sb);
+        if (this->attachStencilBufferToRenderTarget(sb, rt)) {
-        bool attached = this->attachStencilBufferToRenderTarget(sb, rt);
+            rt->renderTargetPriv().didAttachStencilBuffer(sb);
-        if (!attached) {
+            return true;
-            rt->setStencilBuffer(NULL);
         }
-        return attached;
+        return false;
     }
     if (this->createStencilBufferForRenderTarget(rt, width, height)) {
         // Right now we're clearing the stencil buffer here after it is
@@ -116,7 +106,8 @@ bool GrGpu::attachStencilBufferToRenderTarget(GrRenderTarget* rt) {
         // FBO. But iOS doesn't allow a stencil-only FBO. It reports unsupported
         // FBO status.
         this->clearStencil(rt);
-        rt->getStencilBuffer()->resourcePriv().setUniqueKey(sbKey);
+        GrStencilBuffer* sb = rt->renderTargetPriv().getStencilBuffer();
+        sb->resourcePriv().setUniqueKey(sbKey);
         return true;
     } else {
         return false;

src/gpu/GrGpu.h

@@ -405,6 +405,9 @@ public:
     void saveActiveTraceMarkers();
     void restoreActiveTraceMarkers();
 
+    // Given a rt, find or create a stencil buffer and attach it
+    bool attachStencilBufferToRenderTarget(GrRenderTarget* target);
+
 protected:
     // Functions used to map clip-respecting stencil tests into normal
     // stencil funcs supported by GPUs.
@@ -489,9 +492,6 @@ private:
     // clears target's entire stencil buffer to 0
     virtual void clearStencil(GrRenderTarget* target) = 0;
 
-    // Given a rt, find or create a stencil buffer and attach it
-    bool attachStencilBufferToRenderTarget(GrRenderTarget* target);
-
     virtual void didAddGpuTraceMarker() = 0;
     virtual void didRemoveGpuTraceMarker() = 0;
 

src/gpu/GrRenderTarget.cpp

@@ -11,6 +11,7 @@
 
 #include "GrContext.h"
 #include "GrGpu.h"
+#include "GrRenderTargetPriv.h"
 #include "GrStencilBuffer.h"
 
 void GrRenderTarget::discard() {
@@ -46,18 +47,30 @@ void GrRenderTarget::overrideResolveRect(const SkIRect rect) {
     }
 }
 
-void GrRenderTarget::setStencilBuffer(GrStencilBuffer* stencilBuffer) {
-    SkRefCnt_SafeAssign(fStencilBuffer, stencilBuffer);
-}
-
 void GrRenderTarget::onRelease() {
-    this->setStencilBuffer(NULL);
+    this->renderTargetPriv().didAttachStencilBuffer(NULL);
 
     INHERITED::onRelease();
 }
 
 void GrRenderTarget::onAbandon() {
-    this->setStencilBuffer(NULL);
+    this->renderTargetPriv().didAttachStencilBuffer(NULL);
 
     INHERITED::onAbandon();
 }
+
+///////////////////////////////////////////////////////////////////////////////
+
+void GrRenderTargetPriv::didAttachStencilBuffer(GrStencilBuffer* stencilBuffer) {
+    SkRefCnt_SafeAssign(fRenderTarget->fStencilBuffer, stencilBuffer);
+}
+
+GrStencilBuffer* GrRenderTargetPriv::attachStencilBuffer() const {
+    if (fRenderTarget->fStencilBuffer) {
+        return fRenderTarget->fStencilBuffer;
+    }
+    if (!fRenderTarget->wasDestroyed() && fRenderTarget->canAttemptStencilAttachment()) {
+        fRenderTarget->getGpu()->attachStencilBufferToRenderTarget(fRenderTarget);
+    }
+    return fRenderTarget->fStencilBuffer;
+}

src/gpu/GrRenderTargetPriv.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrRenderTargetPriv_DEFINED
+#define GrRenderTargetPriv_DEFINED
+
+#include "GrRenderTarget.h"
+
+/** Class that adds methods to GrRenderTarget that are only intended for use internal to Skia.
+    This class is purely a privileged window into GrRenderTarget. It should never have additional
+    data members or virtual methods. */
+class GrRenderTargetPriv {
+public:
+    /**
+     * GrStencilBuffer is not part of the public API.
+     */
+    GrStencilBuffer* getStencilBuffer() const { return fRenderTarget->fStencilBuffer; }
+
+    /**
+     * If this render target already has a stencil buffer, return it. Otherwise attempt to attach
+     * one.
+     */
+    GrStencilBuffer* attachStencilBuffer() const;
+
+    void didAttachStencilBuffer(GrStencilBuffer*);
+
+private:
+    explicit GrRenderTargetPriv(GrRenderTarget* renderTarget) : fRenderTarget(renderTarget) {}
+    GrRenderTargetPriv(const GrRenderTargetPriv&) {} // unimpl
+    GrRenderTargetPriv& operator=(const GrRenderTargetPriv&); // unimpl
+
+    // No taking addresses of this type.
+    const GrRenderTargetPriv* operator&() const;
+    GrRenderTargetPriv* operator&();
+
+    GrRenderTarget* fRenderTarget;
+        
+    friend class GrRenderTarget; // to construct/copy this type.
+};
+
+inline GrRenderTargetPriv GrRenderTarget::renderTargetPriv() { return GrRenderTargetPriv(this); }
+
+inline const GrRenderTargetPriv GrRenderTarget::renderTargetPriv () const {
+    return GrRenderTargetPriv(const_cast<GrRenderTarget*>(this));
+}
+
+#endif

src/gpu/GrStencilAndCoverPathRenderer.cpp

@@ -12,6 +12,8 @@
 #include "GrDrawTargetCaps.h"
 #include "GrGpu.h"
 #include "GrPath.h"
+#include "GrRenderTarget.h"
+#include "GrRenderTargetPriv.h"
 #include "SkStrokeRec.h"
 
 /*
@@ -58,7 +60,6 @@ bool GrStencilAndCoverPathRenderer::canDrawPath(const GrDrawTarget* target,
                                                 bool antiAlias) const {
     return !stroke.isHairlineStyle() &&
            !antiAlias && // doesn't do per-path AA, relies on the target having MSAA
-           pipelineBuilder->getRenderTarget()->getStencilBuffer() &&
            pipelineBuilder->getStencil().isDisabled();
 }
 

src/gpu/GrSurfacePriv.h

@@ -34,9 +34,9 @@ public:
     bool hasPendingIO() const { return fSurface->hasPendingIO(); }
 
 private:
-    GrSurfacePriv(GrSurface* surface) : fSurface(surface) { }
+    explicit GrSurfacePriv(GrSurface* surface) : fSurface(surface) {}
-    GrSurfacePriv(const GrSurfacePriv& that) : fSurface(that.fSurface) { }
+    GrSurfacePriv(const GrSurfacePriv&); // unimpl
-    GrSurfacePriv& operator=(const GrSurface&); // unimpl
+    GrSurfacePriv& operator=(const GrSurfacePriv&); // unimpl
 
     // No taking addresses of this type.
     const GrSurfacePriv* operator&() const;

src/gpu/GrTexture.cpp

@@ -10,6 +10,8 @@
 #include "GrDrawTargetCaps.h"
 #include "GrGpu.h"
 #include "GrResourceKey.h"
+#include "GrRenderTarget.h"
+#include "GrRenderTargetPriv.h"
 #include "GrTexture.h"
 #include "GrTexturePriv.h"
 
@@ -49,17 +51,9 @@ void GrTexture::validateDesc() const {
     if (this->asRenderTarget()) {
         // This texture has a render target
         SkASSERT(0 != (fDesc.fFlags & kRenderTarget_GrSurfaceFlag));
-
-        if (this->asRenderTarget()->getStencilBuffer()) {
-            SkASSERT(0 != (fDesc.fFlags & kNoStencil_GrSurfaceFlag));
-        } else {
-            SkASSERT(0 == (fDesc.fFlags & kNoStencil_GrSurfaceFlag));
-        }
-
         SkASSERT(fDesc.fSampleCnt == this->asRenderTarget()->numSamples());
     } else {
         SkASSERT(0 == (fDesc.fFlags & kRenderTarget_GrSurfaceFlag));
-        SkASSERT(0 == (fDesc.fFlags & kNoStencil_GrSurfaceFlag));
         SkASSERT(0 == fDesc.fSampleCnt);
     }
 }

src/gpu/SkGr.cpp

@@ -198,9 +198,7 @@ GrTexture* stretch_texture_to_next_pot(GrTexture* inputTexture, Stretch stretch,
 
     // Either it's a cache miss or the original wasn't cached to begin with.
     GrSurfaceDesc rtDesc = inputTexture->desc();
-    rtDesc.fFlags =  rtDesc.fFlags |
+    rtDesc.fFlags =  rtDesc.fFlags | kRenderTarget_GrSurfaceFlag;
-                     kRenderTarget_GrSurfaceFlag |
-                     kNoStencil_GrSurfaceFlag;
     rtDesc.fWidth  = GrNextPow2(rtDesc.fWidth);
     rtDesc.fHeight = GrNextPow2(rtDesc.fHeight);
     rtDesc.fConfig = GrMakePixelConfigUncompressed(rtDesc.fConfig);
@@ -377,9 +375,7 @@ static GrTexture* load_yuv_texture(GrContext* ctx, const GrUniqueKey& optionalKe
     }
 
     GrSurfaceDesc rtDesc = desc;
-    rtDesc.fFlags = rtDesc.fFlags |
+    rtDesc.fFlags = rtDesc.fFlags | kRenderTarget_GrSurfaceFlag;
-                    kRenderTarget_GrSurfaceFlag |
-                    kNoStencil_GrSurfaceFlag;
 
     GrTexture* result = create_texture_for_bmp(ctx, optionalKey, rtDesc, pixelRef, NULL, 0);
     if (!result) {

src/gpu/SkGrPixelRef.cpp

@@ -77,7 +77,7 @@ static SkGrPixelRef* copy_to_new_texture_pixelref(GrTexture* texture, SkColorTyp
         desc.fHeight = subset->height();
         srcRect = *subset;
     }
-    desc.fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
     desc.fConfig = SkImageInfo2GrPixelConfig(dstCT, kPremul_SkAlphaType, dstPT);
 
     GrTexture* dst = context->createTexture(desc, false, NULL, 0);

src/gpu/effects/GrConfigConversionEffect.cpp

@@ -181,8 +181,7 @@ void GrConfigConversionEffect::TestForPreservingPMConversions(GrContext* context
     }
 
     GrSurfaceDesc desc;
-    desc.fFlags = kRenderTarget_GrSurfaceFlag |
+    desc.fFlags = kRenderTarget_GrSurfaceFlag;
-                  kNoStencil_GrSurfaceFlag;
     desc.fWidth = 256;
     desc.fHeight = 256;
     desc.fConfig = kRGBA_8888_GrPixelConfig;

src/gpu/gl/GrGLGpu.cpp

@@ -11,6 +11,7 @@
 #include "GrGLTextureRenderTarget.h"
 #include "GrGpuResourcePriv.h"
 #include "GrPipeline.h"
+#include "GrRenderTargetPriv.h"
 #include "GrSurfacePriv.h"
 #include "GrTemplates.h"
 #include "GrTexturePriv.h"
@@ -454,7 +455,7 @@ GrRenderTarget* GrGLGpu::onWrapBackendRenderTarget(const GrBackendRenderTargetDe
                                             desc.fHeight,
                                             desc.fSampleCnt,
                                             format));
-        tgt->setStencilBuffer(sb);
+        tgt->renderTargetPriv().didAttachStencilBuffer(sb);
         sb->unref();
     }
     return tgt;
@@ -1175,7 +1176,7 @@ bool GrGLGpu::createStencilBufferForRenderTarget(GrRenderTarget* rt, int width,
                                                   (this, sbDesc, width, height, samples, format)));
             if (this->attachStencilBufferToRenderTarget(sb, rt)) {
                 fLastSuccessfulStencilFmtIdx = sIdx;
-                rt->setStencilBuffer(sb);
+                rt->renderTargetPriv().didAttachStencilBuffer(sb);
                 return true;
             }
             // Remove the scratch key from this resource so we don't grab it from the cache ever
@@ -1195,7 +1196,7 @@ bool GrGLGpu::attachStencilBufferToRenderTarget(GrStencilBuffer* sb, GrRenderTar
     GrGLuint fbo = glrt->renderFBOID();
 
     if (NULL == sb) {
-        if (rt->getStencilBuffer()) {
+        if (rt->renderTargetPriv().getStencilBuffer()) {
             GL_CALL(FramebufferRenderbuffer(GR_GL_FRAMEBUFFER,
                                             GR_GL_STENCIL_ATTACHMENT,
                                             GR_GL_RENDERBUFFER, 0));
@@ -1570,10 +1571,11 @@ void GrGLGpu::clearStencil(GrRenderTarget* target) {
 void GrGLGpu::onClearStencilClip(GrRenderTarget* target, const SkIRect& rect, bool insideClip) {
     SkASSERT(target);
 
+    GrStencilBuffer* sb = target->renderTargetPriv().getStencilBuffer();
     // this should only be called internally when we know we have a
     // stencil buffer.
-    SkASSERT(target->getStencilBuffer());
+    SkASSERT(sb);
-    GrGLint stencilBitCount =  target->getStencilBuffer()->bits();
+    GrGLint stencilBitCount =  sb->bits();
 #if 0
     SkASSERT(stencilBitCount > 0);
     GrGLint clipStencilMask  = (1 << (stencilBitCount - 1));
@@ -2560,7 +2562,7 @@ bool GrGLGpu::initCopySurfaceDstDesc(const GrSurface* src, GrSurfaceDesc* desc)
         // then we set up for that, otherwise fail.
         if (this->caps()->isConfigRenderable(kBGRA_8888_GrPixelConfig, false)) {
             desc->fOrigin = kDefault_GrSurfaceOrigin;
-            desc->fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+            desc->fFlags = kRenderTarget_GrSurfaceFlag;
             desc->fConfig = kBGRA_8888_GrPixelConfig;
             return true;
         }
@@ -2576,7 +2578,7 @@ bool GrGLGpu::initCopySurfaceDstDesc(const GrSurface* src, GrSurfaceDesc* desc)
         // fail.
         if (this->caps()->isConfigRenderable(src->config(), false)) {
             desc->fOrigin = kDefault_GrSurfaceOrigin;
-            desc->fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+            desc->fFlags = kRenderTarget_GrSurfaceFlag;
             desc->fConfig = src->config();
             return true;
         }

src/gpu/gl/GrGLRenderTarget.h

@@ -54,6 +54,9 @@ public:
         }
     }
 
+    /** When we don't own the FBO ID we don't attempt to modify its attachments. */
+    bool canAttemptStencilAttachment() const SK_OVERRIDE { return !fIsWrapped; }
+
 protected:
     // The public constructor registers this object with the cache. However, only the most derived
     // class should register with the cache. This constructor does not do the registration and

tests/ReadPixelsTest.cpp

@@ -313,7 +313,7 @@ DEF_GPUTEST(ReadPixels, reporter, factory) {
                     continue;
                 }
                 GrSurfaceDesc desc;
-                desc.fFlags = kRenderTarget_GrSurfaceFlag | kNoStencil_GrSurfaceFlag;
+                desc.fFlags = kRenderTarget_GrSurfaceFlag;
                 desc.fWidth = DEV_W;
                 desc.fHeight = DEV_H;
                 desc.fConfig = kSkia8888_GrPixelConfig;

tests/ResourceCacheTest.cpp

@@ -12,6 +12,8 @@
 #include "GrGpu.h"
 #include "GrGpuResourceCacheAccess.h"
 #include "GrGpuResourcePriv.h"
+#include "GrRenderTarget.h"
+#include "GrRenderTargetPriv.h"
 #include "GrResourceCache.h"
 #include "SkCanvas.h"
 #include "SkGr.h"
@@ -73,18 +75,29 @@ static void test_stencil_buffers(skiatest::Reporter* reporter, GrContext* contex
 
     // Test that two budgeted RTs with the same desc share a stencil buffer.
     SkAutoTUnref<GrTexture> smallRT0(context->createTexture(smallDesc, true));
+    if (smallRT0 && smallRT0->asRenderTarget()) {
+        smallRT0->asRenderTarget()->renderTargetPriv().attachStencilBuffer();
+    }
+
     SkAutoTUnref<GrTexture> smallRT1(context->createTexture(smallDesc, true));
+    if (smallRT1 && smallRT1->asRenderTarget()) {
+        smallRT1->asRenderTarget()->renderTargetPriv().attachStencilBuffer();
+    }
+
     REPORTER_ASSERT(reporter, smallRT0 && smallRT1 &&
                               smallRT0->asRenderTarget() && smallRT1->asRenderTarget() &&
-                              smallRT0->asRenderTarget()->getStencilBuffer() ==
+                              smallRT0->asRenderTarget()->renderTargetPriv().getStencilBuffer() ==
-                              smallRT1->asRenderTarget()->getStencilBuffer());
+                              smallRT1->asRenderTarget()->renderTargetPriv().getStencilBuffer());
 
     // An unbudgeted RT with the same desc should also share.
     SkAutoTUnref<GrTexture> smallRT2(context->createTexture(smallDesc, false));
+    if (smallRT2 && smallRT2->asRenderTarget()) {
+        smallRT2->asRenderTarget()->renderTargetPriv().attachStencilBuffer();
+    }
     REPORTER_ASSERT(reporter, smallRT0 && smallRT2 &&
                               smallRT0->asRenderTarget() && smallRT2->asRenderTarget() &&
-                              smallRT0->asRenderTarget()->getStencilBuffer() ==
+                              smallRT0->asRenderTarget()->renderTargetPriv().getStencilBuffer() ==
-                              smallRT2->asRenderTarget()->getStencilBuffer());
+                              smallRT2->asRenderTarget()->renderTargetPriv().getStencilBuffer());
 
     // An RT with a much larger size should not share.
     GrSurfaceDesc bigDesc;
@@ -94,44 +107,60 @@ static void test_stencil_buffers(skiatest::Reporter* reporter, GrContext* contex
     bigDesc.fHeight = 200;
     bigDesc.fSampleCnt = 0;
     SkAutoTUnref<GrTexture> bigRT(context->createTexture(bigDesc, false));
+    if (bigRT && bigRT->asRenderTarget()) {
+        bigRT->asRenderTarget()->renderTargetPriv().attachStencilBuffer();
+    }
     REPORTER_ASSERT(reporter, smallRT0 && bigRT &&
                               smallRT0->asRenderTarget() && bigRT->asRenderTarget() &&
-                              smallRT0->asRenderTarget()->getStencilBuffer() !=
+                              smallRT0->asRenderTarget()->renderTargetPriv().getStencilBuffer() !=
-                              bigRT->asRenderTarget()->getStencilBuffer());
+                              bigRT->asRenderTarget()->renderTargetPriv().getStencilBuffer());
 
     if (context->getMaxSampleCount() >= 4) {
         // An RT with a different sample count should not share. 
         GrSurfaceDesc smallMSAADesc = smallDesc;
         smallMSAADesc.fSampleCnt = 4;
         SkAutoTUnref<GrTexture> smallMSAART0(context->createTexture(smallMSAADesc, false));
+        if (smallMSAART0 && smallMSAART0->asRenderTarget()) {
+            smallMSAART0->asRenderTarget()->renderTargetPriv().attachStencilBuffer();
+        }
 #ifdef SK_BUILD_FOR_ANDROID
         if (!smallMSAART0) {
             // The nexus player seems to fail to create MSAA textures.
             return;
         }
 #endif
-        REPORTER_ASSERT(reporter, smallRT0 && smallMSAART0 &&
+        REPORTER_ASSERT(reporter,
+                        smallRT0 && smallMSAART0 &&
                         smallRT0->asRenderTarget() && smallMSAART0->asRenderTarget() &&
-                                  smallRT0->asRenderTarget()->getStencilBuffer() !=
+                        smallRT0->asRenderTarget()->renderTargetPriv().getStencilBuffer() !=
-                                  smallMSAART0->asRenderTarget()->getStencilBuffer());
+                        smallMSAART0->asRenderTarget()->renderTargetPriv().getStencilBuffer());
         // A second MSAA RT should share with the first MSAA RT.
         SkAutoTUnref<GrTexture> smallMSAART1(context->createTexture(smallMSAADesc, false));
-        REPORTER_ASSERT(reporter, smallMSAART0 && smallMSAART1 &&
+        if (smallMSAART1 && smallMSAART1->asRenderTarget()) {
+            smallMSAART1->asRenderTarget()->renderTargetPriv().attachStencilBuffer();
+        }
+        REPORTER_ASSERT(reporter,
+                        smallMSAART0 && smallMSAART1 &&
                         smallMSAART0->asRenderTarget() &&
                         smallMSAART1->asRenderTarget() &&
-                                  smallMSAART0->asRenderTarget()->getStencilBuffer() ==
+                        smallMSAART0->asRenderTarget()->renderTargetPriv().getStencilBuffer() ==
-                                  smallMSAART1->asRenderTarget()->getStencilBuffer());
+                        smallMSAART1->asRenderTarget()->renderTargetPriv().getStencilBuffer());
         // But not one with a larger sample count should not. (Also check that the request for 4
         // samples didn't get rounded up to >= 8 or else they could share.).
         if (context->getMaxSampleCount() >= 8 && smallMSAART0 && smallMSAART0->asRenderTarget() &&
             smallMSAART0->asRenderTarget()->numSamples() < 8) {
             smallMSAADesc.fSampleCnt = 8;
             smallMSAART1.reset(context->createTexture(smallMSAADesc, false));
-            REPORTER_ASSERT(reporter, smallMSAART0 && smallMSAART1 &&
+            SkAutoTUnref<GrTexture> smallMSAART1(context->createTexture(smallMSAADesc, false));
+            if (smallMSAART1 && smallMSAART1->asRenderTarget()) {
+                smallMSAART1->asRenderTarget()->renderTargetPriv().attachStencilBuffer();
+            }
+            REPORTER_ASSERT(reporter,
+                            smallMSAART0 && smallMSAART1 &&
                             smallMSAART0->asRenderTarget() &&
                             smallMSAART1->asRenderTarget() &&
-                                      smallMSAART0->asRenderTarget()->getStencilBuffer() !=
+                            smallMSAART0->asRenderTarget()->renderTargetPriv().getStencilBuffer() !=
-                                      smallMSAART1->asRenderTarget()->getStencilBuffer());
+                            smallMSAART1->asRenderTarget()->renderTargetPriv().getStencilBuffer());
         }
     }
 }