1 /* 2 * Copyright 2012 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef GrGaussianConvolutionFragmentProcessor_DEFINED 9 #define GrGaussianConvolutionFragmentProcessor_DEFINED 10 11 #include "Gr1DKernelEffect.h" 12 #include "GrTextureDomain.h" 13 14 /** 15 * A 1D Gaussian convolution effect. The kernel is computed as an array of 2 * half-width weights. 16 * Each texel is multiplied by it's weight and summed to determine the filtered color. The output 17 * color is set to a modulation of the filtered and input colors. 18 */ 19 class GrGaussianConvolutionFragmentProcessor : public Gr1DKernelEffect { 20 public: 21 /// Convolve with a Gaussian kernel 22 static sk_sp<GrFragmentProcessor> Make(sk_sp<GrTextureProxy> proxy, 23 Direction dir, 24 int halfWidth, 25 float gaussianSigma, 26 GrTextureDomain::Mode mode, 27 int* bounds) { 28 return sk_sp<GrFragmentProcessor>(new GrGaussianConvolutionFragmentProcessor( 29 std::move(proxy), dir, halfWidth, gaussianSigma, mode, bounds)); 30 } 31 32 ~GrGaussianConvolutionFragmentProcessor() override; 33 34 const float* kernel() const { return fKernel; } 35 36 const int* bounds() const { return fBounds; } 37 bool useBounds() const { return fMode != GrTextureDomain::kIgnore_Mode; } 38 39 GrTextureDomain::Mode mode() const { return fMode; } 40 41 const char* name() const override { return "GaussianConvolution"; } 42 43 // This was decided based on the min allowed value for the max texture 44 // samples per fragment program run in DX9SM2 (32). A sigma param of 4.0 45 // on a blur filter gives a kernel width of 25 while a sigma of 5.0 46 // would exceed a 32 wide kernel. 47 static const int kMaxKernelRadius = 12; 48 // With a C++11 we could have a constexpr version of WidthFromRadius() 49 // and not have to duplicate this calculation. 50 static const int kMaxKernelWidth = 2 * kMaxKernelRadius + 1; 51 52 private: 53 /// Convolve with a Gaussian kernel 54 GrGaussianConvolutionFragmentProcessor(sk_sp<GrTextureProxy>, Direction, 55 int halfWidth, float gaussianSigma, 56 GrTextureDomain::Mode mode, int bounds[2]); 57 58 GrGLSLFragmentProcessor* onCreateGLSLInstance() const override; 59 60 void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override; 61 62 bool onIsEqual(const GrFragmentProcessor&) const override; 63 64 GR_DECLARE_FRAGMENT_PROCESSOR_TEST 65 66 // TODO: Inline the kernel constants into the generated shader code. This may involve pulling 67 // some of the logic from SkGpuBlurUtils into this class related to radius/sigma calculations. 68 float fKernel[kMaxKernelWidth]; 69 int fBounds[2]; 70 GrTextureDomain::Mode fMode; 71 72 typedef Gr1DKernelEffect INHERITED; 73 }; 74 75 #endif 76
