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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "GrConvolutionEffect.h"
#include "gl/GrGLProgramStage.h"
#include "gl/GrGLSL.h"
#include "gl/GrGLTexture.h"
#include "GrProgramStageFactory.h"
// For brevity
typedef GrGLUniformManager::UniformHandle UniformHandle;
static const UniformHandle kInvalidUniformHandle = GrGLUniformManager::kInvalidUniformHandle;
class GrGLConvolutionEffect : public GrGLLegacyProgramStage {
public:
GrGLConvolutionEffect(const GrProgramStageFactory&, const GrEffect&);
virtual void setupVariables(GrGLShaderBuilder* builder) SK_OVERRIDE;
virtual void emitVS(GrGLShaderBuilder* builder,
const char* vertexCoords) SK_OVERRIDE {};
virtual void emitFS(GrGLShaderBuilder* builder,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray&) SK_OVERRIDE;
virtual void setData(const GrGLUniformManager& uman, const GrEffect&) SK_OVERRIDE;
static inline StageKey GenKey(const GrEffect&, const GrGLCaps&);
private:
int width() const { return Gr1DKernelEffect::WidthFromRadius(fRadius); }
int fRadius;
UniformHandle fKernelUni;
UniformHandle fImageIncrementUni;
typedef GrGLLegacyProgramStage INHERITED;
};
GrGLConvolutionEffect::GrGLConvolutionEffect(const GrProgramStageFactory& factory,
const GrEffect& effect)
: INHERITED(factory)
, fKernelUni(kInvalidUniformHandle)
, fImageIncrementUni(kInvalidUniformHandle) {
const GrConvolutionEffect& c =
static_cast<const GrConvolutionEffect&>(effect);
fRadius = c.radius();
}
void GrGLConvolutionEffect::setupVariables(GrGLShaderBuilder* builder) {
fImageIncrementUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
kVec2f_GrSLType, "ImageIncrement");
fKernelUni = builder->addUniformArray(GrGLShaderBuilder::kFragment_ShaderType,
kFloat_GrSLType, "Kernel", this->width());
}
void GrGLConvolutionEffect::emitFS(GrGLShaderBuilder* builder,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray& samplers) {
SkString* code = &builder->fFSCode;
code->appendf("\t\t%s = vec4(0, 0, 0, 0);\n", outputColor);
int width = this ->width();
const GrGLShaderVar& kernel = builder->getUniformVariable(fKernelUni);
const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
code->appendf("\t\tvec2 coord = %s - %d.0 * %s;\n",
builder->defaultTexCoordsName(), fRadius, imgInc);
// Manually unroll loop because some drivers don't; yields 20-30% speedup.
for (int i = 0; i < width; i++) {
SkString index;
SkString kernelIndex;
index.appendS32(i);
kernel.appendArrayAccess(index.c_str(), &kernelIndex);
code->appendf("\t\t%s += ", outputColor);
builder->appendTextureLookup(&builder->fFSCode, samplers[0], "coord");
code->appendf(" * %s;\n", kernelIndex.c_str());
code->appendf("\t\tcoord += %s;\n", imgInc);
}
GrGLSLMulVarBy4f(&builder->fFSCode, 2, outputColor, inputColor);
}
void GrGLConvolutionEffect::setData(const GrGLUniformManager& uman, const GrEffect& data) {
const GrConvolutionEffect& conv =
static_cast<const GrConvolutionEffect&>(data);
GrTexture& texture = *data.texture(0);
// the code we generated was for a specific kernel radius
GrAssert(conv.radius() == fRadius);
float imageIncrement[2] = { 0 };
switch (conv.direction()) {
case Gr1DKernelEffect::kX_Direction:
imageIncrement[0] = 1.0f / texture.width();
break;
case Gr1DKernelEffect::kY_Direction:
imageIncrement[1] = 1.0f / texture.height();
break;
default:
GrCrash("Unknown filter direction.");
}
uman.set2fv(fImageIncrementUni, 0, 1, imageIncrement);
uman.set1fv(fKernelUni, 0, this->width(), conv.kernel());
}
GrGLProgramStage::StageKey GrGLConvolutionEffect::GenKey(const GrEffect& s,
const GrGLCaps& caps) {
return static_cast<const GrConvolutionEffect&>(s).radius();
}
///////////////////////////////////////////////////////////////////////////////
GrConvolutionEffect::GrConvolutionEffect(GrTexture* texture,
Direction direction,
int radius,
const float* kernel)
: Gr1DKernelEffect(texture, direction, radius) {
GrAssert(radius <= kMaxKernelRadius);
int width = this->width();
if (NULL != kernel) {
for (int i = 0; i < width; i++) {
fKernel[i] = kernel[i];
}
}
}
GrConvolutionEffect::GrConvolutionEffect(GrTexture* texture,
Direction direction,
int radius,
float gaussianSigma)
: Gr1DKernelEffect(texture, direction, radius) {
GrAssert(radius <= kMaxKernelRadius);
int width = this->width();
float sum = 0.0f;
float denom = 1.0f / (2.0f * gaussianSigma * gaussianSigma);
for (int i = 0; i < width; ++i) {
float x = static_cast<float>(i - this->radius());
// Note that the constant term (1/(sqrt(2*pi*sigma^2)) of the Gaussian
// is dropped here, since we renormalize the kernel below.
fKernel[i] = sk_float_exp(- x * x * denom);
sum += fKernel[i];
}
// Normalize the kernel
float scale = 1.0f / sum;
for (int i = 0; i < width; ++i) {
fKernel[i] *= scale;
}
}
GrConvolutionEffect::~GrConvolutionEffect() {
}
const GrProgramStageFactory& GrConvolutionEffect::getFactory() const {
return GrTProgramStageFactory<GrConvolutionEffect>::getInstance();
}
bool GrConvolutionEffect::isEqual(const GrEffect& sBase) const {
const GrConvolutionEffect& s =
static_cast<const GrConvolutionEffect&>(sBase);
return (INHERITED::isEqual(sBase) &&
this->radius() == s.radius() &&
this->direction() == s.direction() &&
0 == memcmp(fKernel, s.fKernel, this->width() * sizeof(float)));
}
///////////////////////////////////////////////////////////////////////////////
GR_DEFINE_EFFECT_TEST(GrConvolutionEffect);
GrEffect* GrConvolutionEffect::TestCreate(SkRandom* random,
GrContext* context,
GrTexture* textures[]) {
int texIdx = random->nextBool() ? GrEffectUnitTest::kSkiaPMTextureIdx :
GrEffectUnitTest::kAlphaTextureIdx;
Direction dir = random->nextBool() ? kX_Direction : kY_Direction;
int radius = random->nextRangeU(1, kMaxKernelRadius);
float kernel[kMaxKernelRadius];
for (int i = 0; i < kMaxKernelRadius; ++i) {
kernel[i] = random->nextSScalar1();
}
return SkNEW_ARGS(GrConvolutionEffect, (textures[texIdx], dir, radius, kernel));
}
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