Index: src/effects/SkBlurImageFilter.cpp |
diff --git a/src/effects/SkBlurImageFilter.cpp b/src/effects/SkBlurImageFilter.cpp |
index a820152fb39c6a1f9ed4b31b6af8ee6669957e68..c5a76c1257d07c5a9919525abb5371e839ceaca2 100644 |
--- a/src/effects/SkBlurImageFilter.cpp |
+++ b/src/effects/SkBlurImageFilter.cpp |
@@ -101,6 +101,8 @@ static void boxBlurY(const SkBitmap& src, SkBitmap* dst, int kernelSize, |
} |
const SkColor* sptr = src.getAddr32(bounds.fLeft + x, bounds.fTop); |
+ const SkColor* back = sptr - topOffset * srcStride; |
+ const SkColor* front = sptr + (bottomOffset + 1) * srcStride; |
SkColor* dptr = dst->getAddr32(x, 0); |
for (int y = 0; y < height; ++y) { |
*dptr = SkPackARGB32(sumA / kernelSize, |
@@ -108,21 +110,23 @@ static void boxBlurY(const SkBitmap& src, SkBitmap* dst, int kernelSize, |
sumG / kernelSize, |
sumB / kernelSize); |
if (y >= topOffset) { |
- SkColor l = *(sptr - topOffset * srcStride); |
+ SkColor l = *back; |
sumA -= SkGetPackedA32(l); |
sumR -= SkGetPackedR32(l); |
sumG -= SkGetPackedG32(l); |
sumB -= SkGetPackedB32(l); |
} |
if (y + bottomOffset + 1 < height) { |
- SkColor r = *(sptr + (bottomOffset + 1) * srcStride); |
+ SkColor r = *front; |
sumA += SkGetPackedA32(r); |
sumR += SkGetPackedR32(r); |
sumG += SkGetPackedG32(r); |
sumB += SkGetPackedB32(r); |
} |
- sptr += srcStride; |
- dptr += dstStride; |
+ front += srcStride; |
+ SK_PREFETCH(front); // This step by srcStride seems to be hard to predict. |
Stephen White
2013/11/04 16:24:17
I'm a little leery of prefetch instructions, due t
|
+ back += srcStride; // back will probably still be cached, so no hint needed. |
+ dptr += dstStride; |
} |
} |
} |