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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"
class GrGLConvolutionEffect : public GrGLProgramStage {
public:
GrGLConvolutionEffect(const GrProgramStageFactory& factory,
const GrCustomStage& stage);
virtual void setupVariables(GrGLShaderBuilder* state,
int stage) SK_OVERRIDE;
virtual void emitVS(GrGLShaderBuilder* state,
const char* vertexCoords) SK_OVERRIDE;
virtual void emitFS(GrGLShaderBuilder* state,
const char* outputColor,
const char* inputColor,
const char* samplerName) SK_OVERRIDE;
virtual void initUniforms(const GrGLInterface*, int programID) SK_OVERRIDE;
virtual void setData(const GrGLInterface*,
const GrCustomStage&,
const GrRenderTarget*,
int stageNum) SK_OVERRIDE;
static inline StageKey GenKey(const GrCustomStage&);
private:
int width() const { return Gr1DKernelEffect::WidthFromRadius(fRadius); }
int fRadius;
const GrGLShaderVar* fKernelVar;
GrGLint fKernelLocation;
const GrGLShaderVar* fImageIncrementVar;
GrGLint fImageIncrementLocation;
typedef GrGLProgramStage INHERITED;
};
GrGLConvolutionEffect::GrGLConvolutionEffect(const GrProgramStageFactory& factory,
const GrCustomStage& stage)
: GrGLProgramStage(factory)
, fKernelVar(NULL)
, fKernelLocation(0)
, fImageIncrementVar(NULL)
, fImageIncrementLocation(0) {
const GrConvolutionEffect& c =
static_cast<const GrConvolutionEffect&>(stage);
fRadius = c.radius();
}
void GrGLConvolutionEffect::setupVariables(GrGLShaderBuilder* state,
int stage) {
fImageIncrementVar = &state->addUniform(GrGLShaderBuilder::kFragment_ShaderType |
GrGLShaderBuilder::kVertex_ShaderType,
kVec2f_GrSLType, "uImageIncrement", stage);
fKernelVar = &state->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
kFloat_GrSLType, "uKernel", stage, this->width());
fImageIncrementLocation = kUseUniform;
fKernelLocation = kUseUniform;
}
void GrGLConvolutionEffect::emitVS(GrGLShaderBuilder* state,
const char* vertexCoords) {
SkString* code = &state->fVSCode;
code->appendf("\t\t%s -= vec2(%d, %d) * %s;\n",
vertexCoords, fRadius, fRadius,
fImageIncrementVar->getName().c_str());
}
void GrGLConvolutionEffect::emitFS(GrGLShaderBuilder* state,
const char* outputColor,
const char* inputColor,
const char* samplerName) {
SkString* code = &state->fFSCode;
code->appendf("\t\t%s = vec4(0, 0, 0, 0);\n", outputColor);
code->appendf("\t\tvec2 coord = %s;\n", state->fSampleCoords.c_str());
int width = this ->width();
// 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);
fKernelVar->appendArrayAccess(index.c_str(), &kernelIndex);
code->appendf("\t\t%s += ", outputColor);
state->emitTextureLookup(samplerName, "coord");
code->appendf(" * %s;\n", kernelIndex.c_str());
code->appendf("\t\tcoord += %s;\n",
fImageIncrementVar->getName().c_str());
}
if (state->fModulate.size()) {
code->appendf("\t\t%s = %s%s;\n", outputColor, outputColor,
state->fModulate.c_str());
}
}
void GrGLConvolutionEffect::initUniforms(const GrGLInterface* gl,
int programID) {
GR_GL_CALL_RET(gl, fImageIncrementLocation,
GetUniformLocation(programID,
fImageIncrementVar->getName().c_str()));
GR_GL_CALL_RET(gl, fKernelLocation,
GetUniformLocation(programID, fKernelVar->getName().c_str()));
}
void GrGLConvolutionEffect::setData(const GrGLInterface* gl,
const GrCustomStage& data,
const GrRenderTarget*,
int stageNum) {
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.");
}
GR_GL_CALL(gl, Uniform2fv(fImageIncrementLocation, 1, imageIncrement));
GR_GL_CALL(gl, Uniform1fv(fKernelLocation, this->width(), conv.kernel()));
}
GrGLProgramStage::StageKey GrGLConvolutionEffect::GenKey(
const GrCustomStage& s) {
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() {
}
const GrProgramStageFactory& GrConvolutionEffect::getFactory() const {
return GrTProgramStageFactory<GrConvolutionEffect>::getInstance();
}
bool GrConvolutionEffect::isEqual(const GrCustomStage& 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)));
}
void GrConvolutionEffect::setGaussianKernel(float sigma) {
int width = this->width();
float sum = 0.0f;
float denom = 1.0f / (2.0f * sigma * sigma);
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;
}
}
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