2D kernel initial wiring for Guassian

src/effects/SkGpuBlurUtils.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuBlurUtils.h"
 
 #include "SkRect.h"
 
 #if SK_SUPPORT_GPU
 #include "effects/GrConvolutionEffect.h"
+#include "effects/GrMatrixConvolutionEffect.h"
 #include "effects/GrTextureDomain.h"
 #include "GrContext.h"
 #endif
 
 namespace SkGpuBlurUtils {
 
 #if SK_SUPPORT_GPU
 
 #define MAX_BLUR_SIGMA 4.0f
 
@@ skipping 30 matching lines @@
                                    float bounds[2]) {
     GrPaint paint;
     paint.reset();
     SkAutoTUnref<GrEffect> conv(GrConvolutionEffect::CreateGaussian(
         texture, direction, radius, sigma, useBounds, bounds));
     paint.reset();
     paint.addColorEffect(conv);
     context->drawRectToRect(paint, dstRect, srcRect);
 }
 
+// a 2d gaussian convolution pass
+static void convolve_gaussian_pass(GrContext* context,
+                                   const SkRect& srcRect,
+                                   const SkRect& dstRect,
+                                   GrTexture* texture,
+                                   int radiusX,
+                                   int radiusY,
+                                   SkScalar sigmaX,
+                                   SkScalar sigmaY,
+                                   bool useBounds,
+                                   SkIRect bounds) {
+    SkISize size = SkISize::Make(2 * radiusX + 1,  2 * radiusY + 1);
+    SkIPoint kernelOffset = SkIPoint::Make(radiusX, radiusY);
+    GrPaint paint;
+    paint.reset();
+    SkAutoTUnref<GrEffect> conv(GrMatrixConvolutionEffect::CreateGaussian(
+        texture, bounds, size, 1.0, 0.0, kernelOffset, GrMatrixConvolutionEffect::kClamp_TileMode,
+        true, useBounds, sigmaX, sigmaY));
+    paint.reset();
+    paint.addColorEffect(conv);
+    context->drawRectToRect(paint, dstRect, srcRect);
+}
+
 static void convolve_gaussian(GrContext* context,
                               const SkRect& srcRect,
                               const SkRect& dstRect,
                               GrTexture* texture,
                               Gr1DKernelEffect::Direction direction,
                               int radius,
                               float sigma,
                               bool cropToSrcRect) {
     float bounds[2] = { 0.0f, 1.0f };
     if (!cropToSrcRect) {
@@ skipping 115 matching lines @@
                              i < scaleFactorY ? 0.5f : 1.0f);
         context->drawRectToRect(paint, dstRect, srcRect);
         srcRect = dstRect;
         srcTexture = dstTexture;
         SkTSwap(dstTexture, tempTexture);
     }
 
     SkIRect srcIRect;
     srcRect.roundOut(&srcIRect);
 
-    if (sigmaX > 0.0f) {
+    // if square, and small than do one pass instead of 2, actually small rectangular blocks
+    // are okay too but for simplicity only handle the square case for now
+    if (sigmaX > 0.0f && sigmaY > 0 &&
+        (2 * radiusX + 1) * (2 * radiusY + 1) <= MAX_KERNEL_SIZE) {
         if (scaleFactorX > 1) {
             // Clear out a radius to the right of the srcRect to prevent the
             // X convolution from reading garbage.
             clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
                                           radiusX, srcIRect.height());
             context->clear(&clearRect, 0x0, false);
         }
-        context->setRenderTarget(dstTexture->asRenderTarget());
-        SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
-        convolve_gaussian(context, srcRect, dstRect, srcTexture,
-                          Gr1DKernelEffect::kX_Direction, radiusX, sigmaX, cropToRect);
-        srcTexture = dstTexture;
-        srcRect = dstRect;
-        SkTSwap(dstTexture, tempTexture);
-    }
-
-    if (sigmaY > 0.0f) {
-        if (scaleFactorY > 1 || sigmaX > 0.0f) {
+        if (scaleFactorY > 1) {
             // Clear out a radius below the srcRect to prevent the Y
             // convolution from reading garbage.
             clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
                                           srcIRect.width(), radiusY);
             context->clear(&clearRect, 0x0, false);
         }
-
         context->setRenderTarget(dstTexture->asRenderTarget());
         SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
-        convolve_gaussian(context, srcRect, dstRect, srcTexture,
-                          Gr1DKernelEffect::kY_Direction, radiusY, sigmaY, cropToRect);
+        // TODO we have a ton of perf verification to do here, but its an open question if we should
+        // do 4 draw calls with bounds then 1 without, or 1 with bounds, or just fall back to
+        // separable when we have to crop to src rect
+        convolve_gaussian_pass(context, srcRect, dstRect, srcTexture,
+                          radiusX, radiusY, sigmaX, sigmaY, cropToRect, srcIRect);
         srcTexture = dstTexture;
         srcRect = dstRect;
         SkTSwap(dstTexture, tempTexture);
     }
+    else {
+        if (sigmaX > 0.0f) {
+            if (scaleFactorX > 1) {
+                // Clear out a radius to the right of the srcRect to prevent the
+                // X convolution from reading garbage.
+                clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
+                                              radiusX, srcIRect.height());
+                context->clear(&clearRect, 0x0, false);
+            }
+            context->setRenderTarget(dstTexture->asRenderTarget());
+            SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
+            convolve_gaussian(context, srcRect, dstRect, srcTexture,
+                              Gr1DKernelEffect::kX_Direction, radiusX, sigmaX, cropToRect);
+            srcTexture = dstTexture;
+            srcRect = dstRect;
+            SkTSwap(dstTexture, tempTexture);
+        }
+
+        if (sigmaY > 0.0f) {
+            if (scaleFactorY > 1 || sigmaX > 0.0f) {
+                // Clear out a radius below the srcRect to prevent the Y
+                // convolution from reading garbage.
+                clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
+                                              srcIRect.width(), radiusY);
+                context->clear(&clearRect, 0x0, false);
+            }
+
+            context->setRenderTarget(dstTexture->asRenderTarget());
+            SkRect dstRect = SkRect::MakeWH(srcRect.width(), srcRect.height());
+            convolve_gaussian(context, srcRect, dstRect, srcTexture,
+                              Gr1DKernelEffect::kY_Direction, radiusY, sigmaY, cropToRect);
+            srcTexture = dstTexture;
+            srcRect = dstRect;
+            SkTSwap(dstTexture, tempTexture);
+        }
+    }
 
     if (scaleFactorX > 1 || scaleFactorY > 1) {
         // Clear one pixel to the right and below, to accommodate bilinear
         // upsampling.
         clearRect = SkIRect::MakeXYWH(srcIRect.fLeft, srcIRect.fBottom,
                                       srcIRect.width() + 1, 1);
         context->clear(&clearRect, 0x0, false);
         clearRect = SkIRect::MakeXYWH(srcIRect.fRight, srcIRect.fTop,
                                       1, srcIRect.height());
         context->clear(&clearRect, 0x0, false);
@@ skipping 18 matching lines @@
     } else if (srcTexture == temp2.texture()) {
         return temp2.detach();
     } else {
         srcTexture->ref();
         return srcTexture;
     }
 }
 #endif
 
 }