GrConvolutionEffect.cpp revision 68b58c95384dd6c2fd389a5b4bbf8fc468819454 
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#include "GrConvolutionEffect.h"
9#include "gl/GrGLEffect.h"
10#include "gl/GrGLEffectMatrix.h"
11#include "gl/GrGLSL.h"
12#include "gl/GrGLTexture.h"
13#include "GrTBackendEffectFactory.h"
14
15// For brevity
16typedef GrGLUniformManager::UniformHandle UniformHandle;
17static const UniformHandle kInvalidUniformHandle = GrGLUniformManager::kInvalidUniformHandle;
18
19class GrGLConvolutionEffect : public GrGLEffect {
20public:
21    GrGLConvolutionEffect(const GrBackendEffectFactory&, const GrEffect&);
22
23    virtual void emitCode(GrGLShaderBuilder*,
24                          const GrEffectStage&,
25                          EffectKey,
26                          const char* vertexCoords,
27                          const char* outputColor,
28                          const char* inputColor,
29                          const TextureSamplerArray&) SK_OVERRIDE;
30
31    virtual void setData(const GrGLUniformManager& uman, const GrEffectStage&) SK_OVERRIDE;
32
33    static inline EffectKey GenKey(const GrEffectStage&, const GrGLCaps&);
34
35private:
36    int width() const { return Gr1DKernelEffect::WidthFromRadius(fRadius); }
37
38    int                 fRadius;
39    UniformHandle       fKernelUni;
40    UniformHandle       fImageIncrementUni;
41    GrGLEffectMatrix    fEffectMatrix;
42
43    typedef GrGLEffect INHERITED;
44};
45
46GrGLConvolutionEffect::GrGLConvolutionEffect(const GrBackendEffectFactory& factory,
47                                             const GrEffect& effect)
48    : INHERITED(factory)
49    , fKernelUni(kInvalidUniformHandle)
50    , fImageIncrementUni(kInvalidUniformHandle) {
51    const GrConvolutionEffect& c =
52        static_cast<const GrConvolutionEffect&>(effect);
53    fRadius = c.radius();
54}
55
56void GrGLConvolutionEffect::emitCode(GrGLShaderBuilder* builder,
57                                     const GrEffectStage&,
58                                     EffectKey key,
59                                     const char* vertexCoords,
60                                     const char* outputColor,
61                                     const char* inputColor,
62                                     const TextureSamplerArray& samplers) {
63    const char* coords;
64    fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, vertexCoords, &coords);
65    fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
66                                             kVec2f_GrSLType, "ImageIncrement");
67    fKernelUni = builder->addUniformArray(GrGLShaderBuilder::kFragment_ShaderType,
68                                          kFloat_GrSLType, "Kernel", this->width());
69    SkString* code = &builder->fFSCode;
70
71    code->appendf("\t\t%s = vec4(0, 0, 0, 0);\n", outputColor);
72
73    int width = this ->width();
74    const GrGLShaderVar& kernel = builder->getUniformVariable(fKernelUni);
75    const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
76
77    code->appendf("\t\tvec2 coord = %s - %d.0 * %s;\n", coords, fRadius, imgInc);
78
79    // Manually unroll loop because some drivers don't; yields 20-30% speedup.
80    for (int i = 0; i < width; i++) {
81        SkString index;
82        SkString kernelIndex;
83        index.appendS32(i);
84        kernel.appendArrayAccess(index.c_str(), &kernelIndex);
85        code->appendf("\t\t%s += ", outputColor);
86        builder->appendTextureLookup(&builder->fFSCode, samplers[0], "coord");
87        code->appendf(" * %s;\n", kernelIndex.c_str());
88        code->appendf("\t\tcoord += %s;\n", imgInc);
89    }
90    GrGLSLMulVarBy4f(&builder->fFSCode, 2, outputColor, inputColor);
91}
92
93void GrGLConvolutionEffect::setData(const GrGLUniformManager& uman, const GrEffectStage& stage) {
94    const GrConvolutionEffect& conv = static_cast<const GrConvolutionEffect&>(*stage.getEffect());
95    GrTexture& texture = *conv.texture(0);
96    // the code we generated was for a specific kernel radius
97    GrAssert(conv.radius() == fRadius);
98    float imageIncrement[2] = { 0 };
99    switch (conv.direction()) {
100        case Gr1DKernelEffect::kX_Direction:
101            imageIncrement[0] = 1.0f / texture.width();
102            break;
103        case Gr1DKernelEffect::kY_Direction:
104            imageIncrement[1] = 1.0f / texture.height();
105            break;
106        default:
107            GrCrash("Unknown filter direction.");
108    }
109    uman.set2fv(fImageIncrementUni, 0, 1, imageIncrement);
110    uman.set1fv(fKernelUni, 0, this->width(), conv.kernel());
111    fEffectMatrix.setData(uman, conv.getMatrix(), stage.getCoordChangeMatrix(), conv.texture(0));
112}
113
114GrGLEffect::EffectKey GrGLConvolutionEffect::GenKey(const GrEffectStage& s, const GrGLCaps&) {
115    const GrConvolutionEffect& conv = static_cast<const GrConvolutionEffect&>(*s.getEffect());
116    EffectKey key = static_cast<const GrConvolutionEffect&>(*s.getEffect()).radius();
117    key <<= GrGLEffectMatrix::kKeyBits;
118    EffectKey matrixKey = GrGLEffectMatrix::GenKey(conv.getMatrix(),
119                                                   s.getCoordChangeMatrix(),
120                                                   conv.texture(0));
121    return key | matrixKey;
122}
123
124///////////////////////////////////////////////////////////////////////////////
125
126GrConvolutionEffect::GrConvolutionEffect(GrTexture* texture,
127                                         Direction direction,
128                                         int radius,
129                                         const float* kernel)
130    : Gr1DKernelEffect(texture, direction, radius) {
131    GrAssert(radius <= kMaxKernelRadius);
132    GrAssert(NULL != kernel);
133    int width = this->width();
134    for (int i = 0; i < width; i++) {
135        fKernel[i] = kernel[i];
136    }
137}
138
139GrConvolutionEffect::GrConvolutionEffect(GrTexture* texture,
140                                         Direction direction,
141                                         int radius,
142                                         float gaussianSigma)
143    : Gr1DKernelEffect(texture, direction, radius) {
144    GrAssert(radius <= kMaxKernelRadius);
145    int width = this->width();
146
147    float sum = 0.0f;
148    float denom = 1.0f / (2.0f * gaussianSigma * gaussianSigma);
149    for (int i = 0; i < width; ++i) {
150        float x = static_cast<float>(i - this->radius());
151        // Note that the constant term (1/(sqrt(2*pi*sigma^2)) of the Gaussian
152        // is dropped here, since we renormalize the kernel below.
153        fKernel[i] = sk_float_exp(- x * x * denom);
154        sum += fKernel[i];
155    }
156    // Normalize the kernel
157    float scale = 1.0f / sum;
158    for (int i = 0; i < width; ++i) {
159        fKernel[i] *= scale;
160    }
161}
162
163GrConvolutionEffect::~GrConvolutionEffect() {
164}
165
166const GrBackendEffectFactory& GrConvolutionEffect::getFactory() const {
167    return GrTBackendEffectFactory<GrConvolutionEffect>::getInstance();
168}
169
170bool GrConvolutionEffect::onIsEqual(const GrEffect& sBase) const {
171     const GrConvolutionEffect& s = static_cast<const GrConvolutionEffect&>(sBase);
172    return (this->texture(0) == s.texture(0) &&
173            this->radius() == s.radius() &&
174            this->direction() == s.direction() &&
175            0 == memcmp(fKernel, s.fKernel, this->width() * sizeof(float)));
176}
177
178///////////////////////////////////////////////////////////////////////////////
179
180GR_DEFINE_EFFECT_TEST(GrConvolutionEffect);
181
182GrEffectRef* GrConvolutionEffect::TestCreate(SkRandom* random,
183                                             GrContext* context,
184                                             GrTexture* textures[]) {
185    int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
186                                      GrEffectUnitTest::kAlphaTextureIdx;
187    Direction dir = random->nextBool() ? kX_Direction : kY_Direction;
188    int radius = random->nextRangeU(1, kMaxKernelRadius);
189    float kernel[kMaxKernelRadius];
190    for (int i = 0; i < kMaxKernelRadius; ++i) {
191        kernel[i] = random->nextSScalar1();
192    }
193
194    return GrConvolutionEffect::Create(textures[texIdx], dir, radius,kernel);
195}
196
197