Fix GPU blur cacheing bug. Sometimes, the texture cache serves us textures of

different sizes for srcTexture and dstTexture (this is fair; they're supposed
to be approximate).  Code was assuming otherwise while downsampling; fix is to
reapply the scale on each downsample.   (Yes, I could cache these reciprocals
if and when they prove to be a hot spot).

Also, use setIDiv(w,h) everywhere for conciseness.

Review URL:  http://codereview.appspot.com/4798041/



git-svn-id: http://skia.googlecode.com/svn/trunk@1907 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 5 insertions, 6 deletions

diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index cc669fe311..c4e0ebecd1 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -936,8 +936,7 @@ static bool drawWithGPUMaskFilter(GrContext* context, const SkPath& path,
     SkTSwap(srcTexture, dstTexture);
 
     GrMatrix sampleM;
-    sampleM.setScale(GR_Scalar1 / srcTexture->width(),
-                     GR_Scalar1 / srcTexture->height());
+    sampleM.setIDiv(srcTexture->width(), srcTexture->height());
     GrPaint paint;
     paint.reset();
     paint.getTextureSampler(0)->setFilter(GrSamplerState::kBilinear_Filter);
@@ -955,6 +954,8 @@ static bool drawWithGPUMaskFilter(GrContext* context, const SkPath& path,
     }
     GrAutoUnlockTextureEntry origLock(context, origEntry);
     for (int i = 1; i < scaleFactor; i *= 2) {
+        sampleM.setIDiv(srcTexture->width(), srcTexture->height());
+        paint.getTextureSampler(0)->setMatrix(sampleM);
         context->setRenderTarget(dstTexture->asRenderTarget());
         SkRect dstRect(srcRect);
         scaleRect(&dstRect, 0.5f);
@@ -984,8 +985,7 @@ static bool drawWithGPUMaskFilter(GrContext* context, const SkPath& path,
     if (scaleFactor > 1) {
         // FIXME:  This should be mitchell, not bilinear.
         paint.getTextureSampler(0)->setFilter(GrSamplerState::kBilinear_Filter);
-        sampleM.setScale(GR_Scalar1 / srcTexture->width(),
-                         GR_Scalar1 / srcTexture->height());
+        sampleM.setIDiv(srcTexture->width(), srcTexture->height());
         paint.getTextureSampler(0)->setMatrix(sampleM);
         context->setRenderTarget(dstTexture->asRenderTarget());
         // Clear out 2 pixel border for bicubic filtering.
@@ -1002,8 +1002,7 @@ static bool drawWithGPUMaskFilter(GrContext* context, const SkPath& path,
     if (blurType != SkMaskFilter::kNormal_BlurType) {
         GrTexture* origTexture = origEntry->texture();
         paint.getTextureSampler(0)->setFilter(GrSamplerState::kNearest_Filter);
-        sampleM.setScale(GR_Scalar1 / origTexture->width(),
-                         GR_Scalar1 / origTexture->height());
+        sampleM.setIDiv(origTexture->width(), origTexture->height());
         paint.getTextureSampler(0)->setMatrix(sampleM);
         // Blend origTexture over srcTexture.
         context->setRenderTarget(srcTexture->asRenderTarget());