Implement morphology as a custom effect
Review URL: http://codereview.appspot.com/6250073/
git-svn-id: http://skia.googlecode.com/svn/trunk@4102 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/effects/GrConvolutionEffect.h b/src/gpu/effects/GrConvolutionEffect.h
index df164d5..fd6883b 100644
--- a/src/gpu/effects/GrConvolutionEffect.h
+++ b/src/gpu/effects/GrConvolutionEffect.h
@@ -8,40 +8,58 @@
#ifndef GrConvolutionEffect_DEFINED
#define GrConvolutionEffect_DEFINED
-#include "GrCustomStage.h"
-#include "GrSamplerState.h" // for MAX_KENEL_WIDTH, FilterDirection
+#include "Gr1DKernelEffect.h"
class GrGLConvolutionEffect;
-class GrConvolutionEffect : public GrCustomStage {
+/**
+ * A convolution effect. The kernel is specified as an array of 2 * half-width
+ * + 1 weights. Each texel is multiplied by it's weight and summed to determine
+ * the output color. The output color is modulated by the input color.
+ */
+class GrConvolutionEffect : public Gr1DKernelEffect {
public:
- GrConvolutionEffect(GrSamplerState::FilterDirection direction,
- unsigned int kernelWidth, const float* kernel);
+ GrConvolutionEffect(Direction, int halfWidth, const float* kernel = NULL);
virtual ~GrConvolutionEffect();
- unsigned int width() const { return fKernelWidth; }
+ void setKernel(const float* kernel) {
+ memcpy(fKernel, kernel, this->width());
+ }
+
+ /**
+ * Helper to set the kernel to a Gaussian. Replaces the existing kernel.
+ */
+ void setGaussianKernel(float sigma);
+
const float* kernel() const { return fKernel; }
- GrSamplerState::FilterDirection direction() const { return fDirection; }
static const char* Name() { return "Convolution"; }
typedef GrGLConvolutionEffect GLProgramStage;
virtual const GrProgramStageFactory& getFactory() const SK_OVERRIDE;
- virtual bool isEqual(const GrCustomStage *) const SK_OVERRIDE;
+ virtual bool isEqual(const GrCustomStage&) const SK_OVERRIDE;
+
+ enum {
+ // This was decided based on the min allowed value for the max texture
+ // samples per fragment program run in DX9SM2 (32). A sigma param of 4.0
+ // on a blur filter gives a kernel width of 25 while a sigma of 5.0
+ // would exceed a 32 wide kernel.
+ kMaxKernelRadius = 12,
+ // With a C++11 we could have a constexpr version of WidthFromRadius()
+ // and not have to duplicate this calculation.
+ kMaxKernelWidth = 2 * kMaxKernelRadius + 1,
+ };
protected:
- GrSamplerState::FilterDirection fDirection;
- unsigned int fKernelWidth;
- float fKernel[MAX_KERNEL_WIDTH];
-
+ float fKernel[kMaxKernelWidth];
private:
- typedef GrCustomStage INHERITED;
+ typedef Gr1DKernelEffect INHERITED;
};
#endif