GPU-based blur cleanup.  Clean up some issues raised in code review:

- convolveRect() is too low-level; made it private and exposed convolveInX() and
convolveInY() instead
- added GrAutoTextureEntry to automatically unlock a texture entry
- the clipping and bounder checks were returning false from
drawWithGPUMaskFilter(), causing the software blur to kick in; return true
instead
- the Windows build was giving a spurious warning about reading an uninitialized
variable; rearrange the code to fix it

Review URL:  http://codereview.appspot.com/4710042/



git-svn-id: http://skia.googlecode.com/svn/trunk@1842 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrContext.h b/gpu/include/GrContext.h
index 0c873ee..d80aef2 100644
--- a/gpu/include/GrContext.h
+++ b/gpu/include/GrContext.h
@@ -491,20 +491,30 @@
                      GrPixelConfig, const void* buffer, size_t stride);
 
     /**
-     * Performs a 1D convolution over a rectangle of pixels.  Set
-     * imageIncrement to (1/w, 0) for a convolution in X, (0, 1/h) for a
-     * convolution in Y, where w, h are the texture dimensions.
-     * @param srcTexture      the texture to read from
-     * @param dstRect         the destination rectangle
-     * @param imageIncrement  the displacement between pixel samples
+     * Applies a 1D convolution kernel in the X direction to a rectangle of
+     * pixels from a given texture.
+     * @param texture         the texture to read from
+     * @param rect            the destination rectangle
      * @param kernel          the convolution kernel (kernelWidth elements)
      * @param kernelWidth     the width of the convolution kernel
      */
-    void convolveRect(GrTexture* srcTexture,
-                      const SkRect& dstRect,
-                      float imageIncrement[2],
-                      const float* kernel,
-                      int kernelWidth);
+    void convolveInX(GrTexture* texture,
+                     const SkRect& rect,
+                     const float* kernel,
+                     int kernelWidth);
+    /**
+     * Applies a 1D convolution kernel in the Y direction to a rectangle of
+     * pixels from a given texture.
+     * direction.
+     * @param texture         the texture to read from
+     * @param rect            the destination rectangle
+     * @param kernel          the convolution kernel (kernelWidth elements)
+     * @param kernelWidth     the width of the convolution kernel
+     */
+    void convolveInY(GrTexture* texture,
+                     const SkRect& rect,
+                     const float* kernel,
+                     int kernelWidth);
     ///////////////////////////////////////////////////////////////////////////
     // Helpers
 
@@ -630,6 +640,12 @@
     void cleanupOffscreenAA(GrDrawTarget* target,
                             GrPathRenderer* pr,
                             OffscreenRecord* record);
+
+    void convolve(GrTexture* texture,
+                  const SkRect& rect,
+                  float imageIncrement[2],
+                  const float* kernel,
+                  int kernelWidth);
     
     // computes vertex layout bits based on the paint. If paint expresses
     // a texture for a stage, the stage coords will be bound to postitions
@@ -663,6 +679,25 @@
     GrMatrix    fMatrix;
 };
 
+/**
+ * Unlocks a texture entry when this goes out of scope.  Entry may be NULL.
+ */
+class GrAutoUnlockTextureEntry : ::GrNoncopyable {
+public:
+    GrAutoUnlockTextureEntry(GrContext* context, GrTextureEntry* entry)
+      : fContext(context)
+      , fEntry(entry) {
+    }
+    ~GrAutoUnlockTextureEntry() {
+        if (fContext && fEntry) {
+            fContext->unlockTexture(fEntry);
+        }
+    }
+private:
+    GrContext*      fContext;
+    GrTextureEntry* fEntry;
+};
+
 #endif
 
 #include "GrContext_impl.h"
diff --git a/gpu/src/GrContext.cpp b/gpu/src/GrContext.cpp
index 092b0ba..dc4bac8 100644
--- a/gpu/src/GrContext.cpp
+++ b/gpu/src/GrContext.cpp
@@ -1699,22 +1699,38 @@
     }
 }
 
-void GrContext::convolveRect(GrTexture* srcTexture,
-                             const SkRect& rect,
-                             float imageIncrement[2],
-                             const float* kernel,
-                             int kernelWidth) {
+void GrContext::convolveInX(GrTexture* texture,
+                            const SkRect& rect,
+                            const float* kernel,
+                            int kernelWidth) {
+    float imageIncrement[2] = {1.0f / texture->width(), 0.0f};
+    convolve(texture, rect, imageIncrement, kernel, kernelWidth);
+}
+
+void GrContext::convolveInY(GrTexture* texture,
+                            const SkRect& rect,
+                            const float* kernel,
+                            int kernelWidth) {
+    float imageIncrement[2] = {0.0f, 1.0f / texture->height()};
+    convolve(texture, rect, imageIncrement, kernel, kernelWidth);
+}
+
+void GrContext::convolve(GrTexture* texture,
+                         const SkRect& rect,
+                         float imageIncrement[2],
+                         const float* kernel,
+                         int kernelWidth) {
     GrDrawTarget::AutoStateRestore asr(fGpu);
     GrMatrix sampleM;
     GrSamplerState sampler(GrSamplerState::kClamp_WrapMode, 
                            GrSamplerState::kClamp_WrapMode,
                            GrSamplerState::kConvolution_Filter);
     sampler.setConvolutionParams(kernelWidth, kernel, imageIncrement);
-    sampleM.setScale(GR_Scalar1 / srcTexture->width(),
-                     GR_Scalar1 / srcTexture->height());
+    sampleM.setScale(GR_Scalar1 / texture->width(),
+                     GR_Scalar1 / texture->height());
     sampler.setMatrix(sampleM);
     fGpu->setSamplerState(0, sampler);
     fGpu->setViewMatrix(GrMatrix::I());
-    fGpu->setTexture(0, srcTexture);
+    fGpu->setTexture(0, texture);
     fGpu->drawSimpleRect(rect, NULL, 1 << 0);
 }