void emitCode(EmitArgs& args) override {
const GrColorSpaceXformEffect& csxe = args.fFp.cast<GrColorSpaceXformEffect>();
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
fColorSpaceHelper.emitCode(uniformHandler, csxe.colorXform());
SkString childColor("src_color");
this->emitChild(0, &childColor, args);
SkString xformedColor;
fragBuilder->appendColorGamutXform(&xformedColor, childColor.c_str(), &fColorSpaceHelper);
fragBuilder->codeAppendf("%s = %s * %s;", args.fOutputColor, xformedColor.c_str(),
args.fInputColor);
}
void GrGLBicubicEffect::emitCode(EmitArgs& args) {
const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>();
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kVec2f_GrSLType, kDefault_GrSLPrecision,
"ImageIncrement");
const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);
fColorSpaceHelper.emitCode(uniformHandler, bicubicEffect.colorSpaceXform());
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
/*
* Filter weights come from Don Mitchell & Arun Netravali's 'Reconstruction Filters in Computer
* Graphics', ACM SIGGRAPH Computer Graphics 22, 4 (Aug. 1988).
* ACM DL: http://dl.acm.org/citation.cfm?id=378514
* Free : http://www.cs.utexas.edu/users/fussell/courses/cs384g/lectures/mitchell/Mitchell.pdf
*
* The authors define a family of cubic filters with two free parameters (B and C):
*
* { (12 - 9B - 6C)|x|^3 + (-18 + 12B + 6C)|x|^2 + (6 - 2B) if |x| < 1
* k(x) = 1/6 { (-B - 6C)|x|^3 + (6B + 30C)|x|^2 + (-12B - 48C)|x| + (8B + 24C) if 1 <= |x| < 2
* { 0 otherwise
*
* Various well-known cubic splines can be generated, and the authors select (1/3, 1/3) as their
* favorite overall spline - this is now commonly known as the Mitchell filter, and is the
* source of the specific weights below.
*
* This is GLSL, so the matrix is column-major (transposed from standard matrix notation).
*/
fragBuilder->codeAppend("mat4 kMitchellCoefficients = mat4("
" 1.0 / 18.0, 16.0 / 18.0, 1.0 / 18.0, 0.0 / 18.0,"
"-9.0 / 18.0, 0.0 / 18.0, 9.0 / 18.0, 0.0 / 18.0,"
"15.0 / 18.0, -36.0 / 18.0, 27.0 / 18.0, -6.0 / 18.0,"
"-7.0 / 18.0, 21.0 / 18.0, -21.0 / 18.0, 7.0 / 18.0);");
fragBuilder->codeAppendf("vec2 coord = %s - %s * vec2(0.5);", 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.
fragBuilder->codeAppendf("coord /= %s;", imgInc);
fragBuilder->codeAppend("vec2 f = fract(coord);");
fragBuilder->codeAppendf("coord = (coord - f + vec2(0.5)) * %s;", imgInc);
fragBuilder->codeAppend("vec4 wx = kMitchellCoefficients * vec4(1.0, f.x, f.x * f.x, f.x * f.x * f.x);");
fragBuilder->codeAppend("vec4 wy = kMitchellCoefficients * vec4(1.0, f.y, f.y * f.y, f.y * f.y * f.y);");
fragBuilder->codeAppend("vec4 rowColors[4];");
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(fragBuilder,
args.fUniformHandler,
args.fShaderCaps,
bicubicEffect.domain(),
sampleVar.c_str(),
coord,
args.fTexSamplers[0]);
}
fragBuilder->codeAppendf(
"vec4 s%d = wx.x * rowColors[0] + wx.y * rowColors[1] + wx.z * rowColors[2] + wx.w * rowColors[3];",
y);
}
SkString bicubicColor("(wy.x * s0 + wy.y * s1 + wy.z * s2 + wy.w * s3)");
if (fColorSpaceHelper.isValid()) {
SkString xformedColor;
fragBuilder->appendColorGamutXform(&xformedColor, bicubicColor.c_str(), &fColorSpaceHelper);
bicubicColor.swap(xformedColor);
}
fragBuilder->codeAppendf("%s = %s * %s;", args.fOutputColor, bicubicColor.c_str(),
args.fInputColor);
}
void GrGLBicubicEffect::emitCode(EmitArgs& args) {
const GrBicubicEffect& bicubicEffect = args.fFp.cast<GrBicubicEffect>();
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
fCoefficientsUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kMat44f_GrSLType, kDefault_GrSLPrecision,
"Coefficients");
fImageIncrementUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kVec2f_GrSLType, kDefault_GrSLPrecision,
"ImageIncrement");
const char* imgInc = uniformHandler->getUniformCStr(fImageIncrementUni);
const char* coeff = uniformHandler->getUniformCStr(fCoefficientsUni);
GrGLSLColorSpaceXformHelper colorSpaceHelper(uniformHandler, bicubicEffect.colorSpaceXform(),
&fColorSpaceXformUni);
SkString cubicBlendName;
static const GrGLSLShaderVar gCubicBlendArgs[] = {
GrGLSLShaderVar("coefficients", kMat44f_GrSLType),
GrGLSLShaderVar("t", kFloat_GrSLType),
GrGLSLShaderVar("c0", kVec4f_GrSLType),
GrGLSLShaderVar("c1", kVec4f_GrSLType),
GrGLSLShaderVar("c2", kVec4f_GrSLType),
GrGLSLShaderVar("c3", kVec4f_GrSLType),
};
GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
SkString coords2D = fragBuilder->ensureCoords2D(args.fTransformedCoords[0]);
fragBuilder->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);
fragBuilder->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.
fragBuilder->codeAppendf("\tcoord /= %s;\n", imgInc);
fragBuilder->codeAppend("\tvec2 f = fract(coord);\n");
fragBuilder->codeAppendf("\tcoord = (coord - f + vec2(0.5)) * %s;\n", imgInc);
fragBuilder->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(fragBuilder,
args.fUniformHandler,
args.fGLSLCaps,
bicubicEffect.domain(),
sampleVar.c_str(),
coord,
args.fTexSamplers[0]);
}
fragBuilder->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);
if (colorSpaceHelper.getXformMatrix()) {
SkString xformedColor;
fragBuilder->appendColorGamutXform(&xformedColor, bicubicColor.c_str(), &colorSpaceHelper);
bicubicColor.swap(xformedColor);
}
fragBuilder->codeAppendf("\t%s = %s;\n",
args.fOutputColor, (GrGLSLExpr4(bicubicColor.c_str()) *
GrGLSLExpr4(args.fInputColor)).c_str());
}
