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/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gl/builders/GrGLProgramBuilder.h"
#include "GrBicubicEffect.h"
#include "GrInvariantOutput.h"
#define DS(x) SkDoubleToScalar(x)
const SkScalar GrBicubicEffect::gMitchellCoefficients[16] = {
DS( 1.0 / 18.0), DS(-9.0 / 18.0), DS( 15.0 / 18.0), DS( -7.0 / 18.0),
DS(16.0 / 18.0), DS( 0.0 / 18.0), DS(-36.0 / 18.0), DS( 21.0 / 18.0),
DS( 1.0 / 18.0), DS( 9.0 / 18.0), DS( 27.0 / 18.0), DS(-21.0 / 18.0),
DS( 0.0 / 18.0), DS( 0.0 / 18.0), DS( -6.0 / 18.0), DS( 7.0 / 18.0),
};
class GrGLBicubicEffect : public GrGLFragmentProcessor {
public:
GrGLBicubicEffect(const GrBackendProcessorFactory& factory,
const GrProcessor&);
virtual void emitCode(GrGLFPBuilder*,
const GrFragmentProcessor&,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray&,
const TextureSamplerArray&) SK_OVERRIDE;
virtual void setData(const GrGLProgramDataManager&, const GrProcessor&) SK_OVERRIDE;
static inline void GenKey(const GrProcessor& effect, const GrGLCaps&,
GrProcessorKeyBuilder* b) {
const GrTextureDomain& domain = effect.cast<GrBicubicEffect>().domain();
b->add32(GrTextureDomain::GLDomain::DomainKey(domain));
}
private:
typedef GrGLProgramDataManager::UniformHandle UniformHandle;
UniformHandle fCoefficientsUni;
UniformHandle fImageIncrementUni;
GrTextureDomain::GLDomain fDomain;
typedef GrGLFragmentProcessor INHERITED;
};
GrGLBicubicEffect::GrGLBicubicEffect(const GrBackendProcessorFactory& factory, const GrProcessor&)
: INHERITED(factory) {
}
void GrGLBicubicEffect::emitCode(GrGLFPBuilder* builder,
const GrFragmentProcessor& effect,
const char* outputColor,
const char* inputColor,
const TransformedCoordsArray& coords,
const TextureSamplerArray& samplers) {
const GrTextureDomain& domain = effect.cast<GrBicubicEffect>().domain();
fCoefficientsUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kMat44f_GrSLType, "Coefficients");
fImageIncrementUni = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
kVec2f_GrSLType, "ImageIncrement");
const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
const char* coeff = builder->getUniformCStr(fCoefficientsUni);
SkString cubicBlendName;
static const GrGLShaderVar gCubicBlendArgs[] = {
GrGLShaderVar("coefficients", kMat44f_GrSLType),
GrGLShaderVar("t", kFloat_GrSLType),
GrGLShaderVar("c0", kVec4f_GrSLType),
GrGLShaderVar("c1", kVec4f_GrSLType),
GrGLShaderVar("c2", kVec4f_GrSLType),
GrGLShaderVar("c3", kVec4f_GrSLType),
};
GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
fsBuilder->emitFunction(kVec4f_GrSLType,
"cubicBlend",
SK_ARRAY_COUNT(gCubicBlendArgs),
gCubicBlendArgs,
"\tvec4 ts = vec4(1.0, t, t * t, t * t * t);\n"
"\tvec4 c = coefficients * ts;\n"
"\treturn c.x * c0 + c.y * c1 + c.z * c2 + c.w * c3;\n",
&cubicBlendName);
fsBuilder->codeAppendf("\tvec2 coord = %s - %s * vec2(0.5);\n", coords2D.c_str(), imgInc);
// We unnormalize the coord in order to determine our fractional offset (f) within the texel
// We then snap coord to a texel center and renormalize. The snap prevents cases where the
// starting coords are near a texel boundary and accumulations of imgInc would cause us to skip/
// double hit a texel.
fsBuilder->codeAppendf("\tcoord /= %s;\n", imgInc);
fsBuilder->codeAppend("\tvec2 f = fract(coord);\n");
fsBuilder->codeAppendf("\tcoord = (coord - f + vec2(0.5)) * %s;\n", imgInc);
fsBuilder->codeAppend("\tvec4 rowColors[4];\n");
for (int y = 0; y < 4; ++y) {
for (int x = 0; x < 4; ++x) {
SkString coord;
coord.printf("coord + %s * vec2(%d, %d)", imgInc, x - 1, y - 1);
SkString sampleVar;
sampleVar.printf("rowColors[%d]", x);
fDomain.sampleTexture(fsBuilder, domain, sampleVar.c_str(), coord, samplers[0]);
}
fsBuilder->codeAppendf("\tvec4 s%d = %s(%s, f.x, rowColors[0], rowColors[1], rowColors[2], rowColors[3]);\n", y, cubicBlendName.c_str(), coeff);
}
SkString bicubicColor;
bicubicColor.printf("%s(%s, f.y, s0, s1, s2, s3)", cubicBlendName.c_str(), coeff);
fsBuilder->codeAppendf("\t%s = %s;\n", outputColor, (GrGLSLExpr4(bicubicColor.c_str()) * GrGLSLExpr4(inputColor)).c_str());
}
void GrGLBicubicEffect::setData(const GrGLProgramDataManager& pdman,
const GrProcessor& processor) {
const GrBicubicEffect& bicubicEffect = processor.cast<GrBicubicEffect>();
const GrTexture& texture = *processor.texture(0);
float imageIncrement[2];
imageIncrement[0] = 1.0f / texture.width();
imageIncrement[1] = 1.0f / texture.height();
pdman.set2fv(fImageIncrementUni, 1, imageIncrement);
pdman.setMatrix4f(fCoefficientsUni, bicubicEffect.coefficients());
fDomain.setData(pdman, bicubicEffect.domain(), texture.origin());
}
static inline void convert_row_major_scalar_coeffs_to_column_major_floats(float dst[16],
const SkScalar src[16]) {
for (int y = 0; y < 4; y++) {
for (int x = 0; x < 4; x++) {
dst[x * 4 + y] = SkScalarToFloat(src[y * 4 + x]);
}
}
}
GrBicubicEffect::GrBicubicEffect(GrTexture* texture,
const SkScalar coefficients[16],
const SkMatrix &matrix,
const SkShader::TileMode tileModes[2])
: INHERITED(texture, matrix, GrTextureParams(tileModes, GrTextureParams::kNone_FilterMode))
, fDomain(GrTextureDomain::IgnoredDomain()) {
convert_row_major_scalar_coeffs_to_column_major_floats(fCoefficients, coefficients);
}
GrBicubicEffect::GrBicubicEffect(GrTexture* texture,
const SkScalar coefficients[16],
const SkMatrix &matrix,
const SkRect& domain)
: INHERITED(texture, matrix, GrTextureParams(SkShader::kClamp_TileMode,
GrTextureParams::kNone_FilterMode))
, fDomain(domain, GrTextureDomain::kClamp_Mode) {
convert_row_major_scalar_coeffs_to_column_major_floats(fCoefficients, coefficients);
}
GrBicubicEffect::~GrBicubicEffect() {
}
const GrBackendFragmentProcessorFactory& GrBicubicEffect::getFactory() const {
return GrTBackendFragmentProcessorFactory<GrBicubicEffect>::getInstance();
}
bool GrBicubicEffect::onIsEqual(const GrFragmentProcessor& sBase) const {
const GrBicubicEffect& s = sBase.cast<GrBicubicEffect>();
return !memcmp(fCoefficients, s.coefficients(), 16) &&
fDomain == s.fDomain;
}
void GrBicubicEffect::onComputeInvariantOutput(GrInvariantOutput* inout) const {
// FIXME: Perhaps we can do better.
inout->mulByUnknownAlpha();
}
GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrBicubicEffect);
GrFragmentProcessor* GrBicubicEffect::TestCreate(SkRandom* random,
GrContext* context,
const GrDrawTargetCaps&,
GrTexture* textures[]) {
int texIdx = random->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx :
GrProcessorUnitTest::kAlphaTextureIdx;
SkScalar coefficients[16];
for (int i = 0; i < 16; i++) {
coefficients[i] = random->nextSScalar1();
}
return GrBicubicEffect::Create(textures[texIdx], coefficients);
}
//////////////////////////////////////////////////////////////////////////////
bool GrBicubicEffect::ShouldUseBicubic(const SkMatrix& matrix,
GrTextureParams::FilterMode* filterMode) {
if (matrix.isIdentity()) {
*filterMode = GrTextureParams::kNone_FilterMode;
return false;
}
SkScalar scales[2];
if (!matrix.getMinMaxScales(scales) || scales[0] < SK_Scalar1) {
// Bicubic doesn't handle arbitrary minimization well, as src texels can be skipped
// entirely,
*filterMode = GrTextureParams::kMipMap_FilterMode;
return false;
}
// At this point if scales[1] == SK_Scalar1 then the matrix doesn't do any scaling.
if (scales[1] == SK_Scalar1) {
if (matrix.rectStaysRect() && SkScalarIsInt(matrix.getTranslateX()) &&
SkScalarIsInt(matrix.getTranslateY())) {
*filterMode = GrTextureParams::kNone_FilterMode;
} else {
// Use bilerp to handle rotation or fractional translation.
*filterMode = GrTextureParams::kBilerp_FilterMode;
}
return false;
}
// When we use the bicubic filtering effect each sample is read from the texture using
// nearest neighbor sampling.
*filterMode = GrTextureParams::kNone_FilterMode;
return true;
}
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