GrConvolutionEffect.cpp revision 194d775edcf5fa6e82098a97ad53018d70db1155 
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 GrDrawEffect&);
22
23    virtual void emitCode(GrGLShaderBuilder*,
24                          const GrDrawEffect&,
25                          EffectKey,
26                          const char* outputColor,
27                          const char* inputColor,
28                          const TextureSamplerArray&) SK_OVERRIDE;
29
30    virtual void setData(const GrGLUniformManager& uman, const GrDrawEffect&) SK_OVERRIDE;
31
32    static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&);
33
34private:
35    int width() const { return Gr1DKernelEffect::WidthFromRadius(fRadius); }
36    bool useCropRect() const { return fUseCropRect; }
37
38    int                 fRadius;
39    bool                fUseCropRect;
40    UniformHandle       fKernelUni;
41    UniformHandle       fImageIncrementUni;
42    UniformHandle       fCropRectUni;
43    GrGLEffectMatrix    fEffectMatrix;
44
45    typedef GrGLEffect INHERITED;
46};
47
48GrGLConvolutionEffect::GrGLConvolutionEffect(const GrBackendEffectFactory& factory,
49                                             const GrDrawEffect& drawEffect)
50    : INHERITED(factory)
51    , fKernelUni(kInvalidUniformHandle)
52    , fImageIncrementUni(kInvalidUniformHandle)
53    , fCropRectUni(kInvalidUniformHandle)
54    , fEffectMatrix(drawEffect.castEffect<GrConvolutionEffect>().coordsType()) {
55    const GrConvolutionEffect& c = drawEffect.castEffect<GrConvolutionEffect>();
56    fRadius = c.radius();
57    fUseCropRect = c.useCropRect();
58}
59
60void GrGLConvolutionEffect::emitCode(GrGLShaderBuilder* builder,
61                                     const GrDrawEffect&,
62                                     EffectKey key,
63                                     const char* outputColor,
64                                     const char* inputColor,
65                                     const TextureSamplerArray& samplers) {
66    const char* coords;
67    fEffectMatrix.emitCodeMakeFSCoords2D(builder, key, &coords);
68    fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
69                                             kVec2f_GrSLType, "ImageIncrement");
70    if (this->useCropRect()) {
71        fCropRectUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
72                                           kVec4f_GrSLType, "CropRect");
73    }
74    fKernelUni = builder->addUniformArray(GrGLShaderBuilder::kFragment_ShaderType,
75                                          kFloat_GrSLType, "Kernel", this->width());
76
77    builder->fsCodeAppendf("\t\t%s = vec4(0, 0, 0, 0);\n", outputColor);
78
79    int width = this->width();
80    const GrGLShaderVar& kernel = builder->getUniformVariable(fKernelUni);
81    const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
82
83    builder->fsCodeAppendf("\t\tvec2 coord = %s - %d.0 * %s;\n", coords, fRadius, imgInc);
84
85    // Manually unroll loop because some drivers don't; yields 20-30% speedup.
86    for (int i = 0; i < width; i++) {
87        SkString index;
88        SkString kernelIndex;
89        index.appendS32(i);
90        kernel.appendArrayAccess(index.c_str(), &kernelIndex);
91        builder->fsCodeAppendf("\t\t%s += ", outputColor);
92        builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType, samplers[0], "coord");
93        if (this->useCropRect()) {
94            const char* cropRect = builder->getUniformCStr(fCropRectUni);
95            builder->fsCodeAppendf(" * float(coord.x >= %s.x && coord.x <= %s.y && coord.y >= %s.z && coord.y <= %s.w)",
96            cropRect, cropRect, cropRect, cropRect);
97        }
98        builder->fsCodeAppendf(" * %s;\n", kernelIndex.c_str());
99        builder->fsCodeAppendf("\t\tcoord += %s;\n", imgInc);
100    }
101
102    SkString modulate;
103    GrGLSLMulVarBy4f(&modulate, 2, outputColor, inputColor);
104    builder->fsCodeAppend(modulate.c_str());
105}
106
107void GrGLConvolutionEffect::setData(const GrGLUniformManager& uman,
108                                    const GrDrawEffect& drawEffect) {
109    const GrConvolutionEffect& conv = drawEffect.castEffect<GrConvolutionEffect>();
110    GrTexture& texture = *conv.texture(0);
111    // the code we generated was for a specific kernel radius
112    GrAssert(conv.radius() == fRadius);
113    float imageIncrement[2] = { 0 };
114    float ySign = texture.origin() != kTopLeft_GrSurfaceOrigin ? 1.0f : -1.0f;
115    switch (conv.direction()) {
116        case Gr1DKernelEffect::kX_Direction:
117            imageIncrement[0] = 1.0f / texture.width();
118            break;
119        case Gr1DKernelEffect::kY_Direction:
120            imageIncrement[1] = ySign / texture.height();
121            break;
122        default:
123            GrCrash("Unknown filter direction.");
124    }
125    uman.set2fv(fImageIncrementUni, 0, 1, imageIncrement);
126    if (conv.useCropRect()) {
127        float c[4];
128        memcpy(c, conv.cropRect(), sizeof(c));
129        if (texture.origin() != kTopLeft_GrSurfaceOrigin) {
130            float tmp = 1.0f - c[2];
131            c[2] = 1.0f - c[3];
132            c[3] = tmp;
133        }
134        uman.set4fv(fCropRectUni, 0, 1, c);
135    }
136    uman.set1fv(fKernelUni, 0, this->width(), conv.kernel());
137    fEffectMatrix.setData(uman, conv.getMatrix(), drawEffect, conv.texture(0));
138}
139
140GrGLEffect::EffectKey GrGLConvolutionEffect::GenKey(const GrDrawEffect& drawEffect,
141                                                    const GrGLCaps&) {
142    const GrConvolutionEffect& conv = drawEffect.castEffect<GrConvolutionEffect>();
143    EffectKey key = conv.radius() << 1;
144    key |= conv.useCropRect() ? 0x1 : 0x0;
145    key <<= GrGLEffectMatrix::kKeyBits;
146    EffectKey matrixKey = GrGLEffectMatrix::GenKey(conv.getMatrix(),
147                                                   drawEffect,
148                                                   conv.coordsType(),
149                                                   conv.texture(0));
150    return key | matrixKey;
151}
152
153///////////////////////////////////////////////////////////////////////////////
154
155GrConvolutionEffect::GrConvolutionEffect(GrTexture* texture,
156                                         Direction direction,
157                                         int radius,
158                                         const float* kernel,
159                                         bool useCropRect,
160                                         float cropRect[4])
161    : Gr1DKernelEffect(texture, direction, radius), fUseCropRect(useCropRect) {
162    GrAssert(radius <= kMaxKernelRadius);
163    GrAssert(NULL != kernel);
164    int width = this->width();
165    for (int i = 0; i < width; i++) {
166        fKernel[i] = kernel[i];
167    }
168    memcpy(fCropRect, cropRect, sizeof(fCropRect));
169}
170
171GrConvolutionEffect::GrConvolutionEffect(GrTexture* texture,
172                                         Direction direction,
173                                         int radius,
174                                         float gaussianSigma,
175                                         bool useCropRect,
176                                         float cropRect[4])
177    : Gr1DKernelEffect(texture, direction, radius), fUseCropRect(useCropRect) {
178    GrAssert(radius <= kMaxKernelRadius);
179    int width = this->width();
180
181    float sum = 0.0f;
182    float denom = 1.0f / (2.0f * gaussianSigma * gaussianSigma);
183    for (int i = 0; i < width; ++i) {
184        float x = static_cast<float>(i - this->radius());
185        // Note that the constant term (1/(sqrt(2*pi*sigma^2)) of the Gaussian
186        // is dropped here, since we renormalize the kernel below.
187        fKernel[i] = sk_float_exp(- x * x * denom);
188        sum += fKernel[i];
189    }
190    // Normalize the kernel
191    float scale = 1.0f / sum;
192    for (int i = 0; i < width; ++i) {
193        fKernel[i] *= scale;
194    }
195    memcpy(fCropRect, cropRect, sizeof(fCropRect));
196}
197
198GrConvolutionEffect::~GrConvolutionEffect() {
199}
200
201const GrBackendEffectFactory& GrConvolutionEffect::getFactory() const {
202    return GrTBackendEffectFactory<GrConvolutionEffect>::getInstance();
203}
204
205bool GrConvolutionEffect::onIsEqual(const GrEffect& sBase) const {
206    const GrConvolutionEffect& s = CastEffect<GrConvolutionEffect>(sBase);
207    return (this->texture(0) == s.texture(0) &&
208            this->radius() == s.radius() &&
209            this->direction() == s.direction() &&
210            0 == memcmp(fCropRect, s.fCropRect, sizeof(fCropRect)) &&
211            0 == memcmp(fKernel, s.fKernel, this->width() * sizeof(float)));
212}
213
214///////////////////////////////////////////////////////////////////////////////
215
216GR_DEFINE_EFFECT_TEST(GrConvolutionEffect);
217
218GrEffectRef* GrConvolutionEffect::TestCreate(SkMWCRandom* random,
219                                             GrContext*,
220                                             const GrDrawTargetCaps&,
221                                             GrTexture* textures[]) {
222    int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
223                                      GrEffectUnitTest::kAlphaTextureIdx;
224    Direction dir = random->nextBool() ? kX_Direction : kY_Direction;
225    int radius = random->nextRangeU(1, kMaxKernelRadius);
226    float kernel[kMaxKernelRadius];
227    float cropRect[4];
228    for (int i = 0; i < kMaxKernelRadius; ++i) {
229        kernel[i] = random->nextSScalar1();
230    }
231    for (int i = 0; i < 4; ++i) {
232        cropRect[i] = random->nextF();
233    }
234
235    bool useCropRect = random->nextBool();
236    return GrConvolutionEffect::Create(textures[texIdx],
237                                       dir,
238                                       radius,
239                                       kernel,
240                                       useCropRect,
241                                       cropRect);
242}
243