michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef GrConvolutionEffect_DEFINED
michael@0: #define GrConvolutionEffect_DEFINED
michael@0: 
michael@0: #include "Gr1DKernelEffect.h"
michael@0: 
michael@0: class GrGLConvolutionEffect;
michael@0: 
michael@0: /**
michael@0:  * A convolution effect. The kernel is specified as an array of 2 * half-width
michael@0:  * + 1 weights. Each texel is multiplied by it's weight and summed to determine
michael@0:  * the output color. The output color is modulated by the input color.
michael@0:  */
michael@0: class GrConvolutionEffect : public Gr1DKernelEffect {
michael@0: 
michael@0: public:
michael@0: 
michael@0:     /// Convolve with an arbitrary user-specified kernel
michael@0:     static GrEffectRef* Create(GrTexture* tex,
michael@0:                                Direction dir,
michael@0:                                int halfWidth,
michael@0:                                const float* kernel,
michael@0:                                bool useBounds,
michael@0:                                float bounds[2]) {
michael@0:         AutoEffectUnref effect(SkNEW_ARGS(GrConvolutionEffect, (tex,
michael@0:                                                                 dir,
michael@0:                                                                 halfWidth,
michael@0:                                                                 kernel,
michael@0:                                                                 useBounds,
michael@0:                                                                 bounds)));
michael@0:         return CreateEffectRef(effect);
michael@0:     }
michael@0: 
michael@0:     /// Convolve with a Gaussian kernel
michael@0:     static GrEffectRef* CreateGaussian(GrTexture* tex,
michael@0:                                        Direction dir,
michael@0:                                        int halfWidth,
michael@0:                                        float gaussianSigma,
michael@0:                                        bool useBounds,
michael@0:                                        float bounds[2]) {
michael@0:         AutoEffectUnref effect(SkNEW_ARGS(GrConvolutionEffect, (tex,
michael@0:                                                                 dir,
michael@0:                                                                 halfWidth,
michael@0:                                                                 gaussianSigma,
michael@0:                                                                 useBounds,
michael@0:                                                                 bounds)));
michael@0:         return CreateEffectRef(effect);
michael@0:     }
michael@0: 
michael@0:     virtual ~GrConvolutionEffect();
michael@0: 
michael@0:     const float* kernel() const { return fKernel; }
michael@0: 
michael@0:     const float* bounds() const { return fBounds; }
michael@0:     bool useBounds() const { return fUseBounds; }
michael@0: 
michael@0:     static const char* Name() { return "Convolution"; }
michael@0: 
michael@0:     typedef GrGLConvolutionEffect GLEffect;
michael@0: 
michael@0:     virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE;
michael@0: 
michael@0:     virtual void getConstantColorComponents(GrColor*, uint32_t* validFlags) const {
michael@0:         // If the texture was opaque we could know that the output color if we knew the sum of the
michael@0:         // kernel values.
michael@0:         *validFlags = 0;
michael@0:     }
michael@0: 
michael@0:     enum {
michael@0:         // This was decided based on the min allowed value for the max texture
michael@0:         // samples per fragment program run in DX9SM2 (32). A sigma param of 4.0
michael@0:         // on a blur filter gives a kernel width of 25 while a sigma of 5.0
michael@0:         // would exceed a 32 wide kernel.
michael@0:         kMaxKernelRadius = 12,
michael@0:         // With a C++11 we could have a constexpr version of WidthFromRadius()
michael@0:         // and not have to duplicate this calculation.
michael@0:         kMaxKernelWidth = 2 * kMaxKernelRadius + 1,
michael@0:     };
michael@0: 
michael@0: protected:
michael@0: 
michael@0:     float fKernel[kMaxKernelWidth];
michael@0:     bool fUseBounds;
michael@0:     float fBounds[2];
michael@0: 
michael@0: private:
michael@0:     GrConvolutionEffect(GrTexture*, Direction,
michael@0:                         int halfWidth,
michael@0:                         const float* kernel,
michael@0:                         bool useBounds,
michael@0:                         float bounds[2]);
michael@0: 
michael@0:     /// Convolve with a Gaussian kernel
michael@0:     GrConvolutionEffect(GrTexture*, Direction,
michael@0:                         int halfWidth,
michael@0:                         float gaussianSigma,
michael@0:                         bool useBounds,
michael@0:                         float bounds[2]);
michael@0: 
michael@0:     virtual bool onIsEqual(const GrEffect&) const SK_OVERRIDE;
michael@0: 
michael@0:     GR_DECLARE_EFFECT_TEST;
michael@0: 
michael@0:     typedef Gr1DKernelEffect INHERITED;
michael@0: };
michael@0: 
michael@0: #endif