Create MSAA render target for blur mask texture

src/gpu/SkGpuDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuDevice.h"
 
 #include "effects/GrBicubicEffect.h"
 #include "effects/GrDashingEffect.h"
 #include "effects/GrTextureDomain.h"
 #include "effects/GrSimpleTextureEffect.h"
 
 #include "GrContext.h"
 #include "GrBitmapTextContext.h"
 #include "GrDistanceFieldTextContext.h"
 #include "GrLayerCache.h"
 #include "GrLayerHoister.h"
 #include "GrPictureUtils.h"
 #include "GrRecordReplaceDraw.h"
 #include "GrStrokeInfo.h"
 #include "GrTracing.h"
+#include "GrGpu.h"
 
 #include "SkGrTexturePixelRef.h"
 
 #include "SkDeviceImageFilterProxy.h"
 #include "SkDrawProcs.h"
 #include "SkGlyphCache.h"
 #include "SkImageFilter.h"
 #include "SkMaskFilter.h"
 #include "SkPathEffect.h"
 #include "SkPicture.h"
@@ skipping 606 matching lines @@
 bool create_mask_GPU(GrContext* context,
                      const SkRect& maskRect,
                      const SkPath& devPath,
                      const GrStrokeInfo& strokeInfo,
                      bool doAA,
                      GrAutoScratchTexture* mask) {
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit;
     desc.fWidth = SkScalarCeilToInt(maskRect.width());
     desc.fHeight = SkScalarCeilToInt(maskRect.height());
+    // try multisampled target if possible

[bsalomon, 2014/10/02 16:59:16]

Why don't we just pass the sample count of the SkGpuDevice's GrRenderTarget here
and use it?

That's what we do for saveLayer (the GrRT created for the layer copies the
sample count of the base SkGpuDevice's GrRT).

+    int maxSampleCnt = context->getGpu()->caps()->maxSampleCount();
+    desc.fSampleCnt = maxSampleCnt >= 4 ? 4 : maxSampleCnt;
     // We actually only need A8, but it often isn't supported as a
     // render target so default to RGBA_8888
     desc.fConfig = kRGBA_8888_GrPixelConfig;
-    if (context->isConfigRenderable(kAlpha_8_GrPixelConfig, false)) {
+
+    bool msaa = desc.fSampleCnt > 0;
+    if (context->isConfigRenderable(kAlpha_8_GrPixelConfig, msaa)) {
         desc.fConfig = kAlpha_8_GrPixelConfig;
     }
 
     mask->set(context, desc);
     if (NULL == mask->texture()) {
         return false;
     }
 
     GrTexture* maskTexture = mask->texture();
     SkRect clipRect = SkRect::MakeWH(maskRect.width(), maskRect.height());
@@ skipping 1217 matching lines @@
     GrLayerHoister::UnlockLayers(fContext->getLayerCache(), picture);
 
     return true;
 }
 
 SkImageFilter::Cache* SkGpuDevice::getImageFilterCache() {
     // We always return a transient cache, so it is freed after each
     // filter traversal.
     return SkImageFilter::Cache::Create(kDefaultImageFilterCacheSize);
 }