void GrGLBlend::AppendPorterDuffBlend(GrGLFragmentBuilder* fsBuilder, const char* srcColor,
const char* dstColor, const char* outColor,
SkXfermode::Mode mode) {
SkXfermode::Coeff srcCoeff, dstCoeff;
SkXfermode::ModeAsCoeff(mode, &srcCoeff, &dstCoeff);
fsBuilder->codeAppendf("%s = ", outColor);
// append src blend
bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor,
false);
// append dst blend
if(!append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor, didAppend)) {
fsBuilder->codeAppend("vec4(0, 0, 0, 0)");
}
fsBuilder->codeAppend(";");
}
void emitBlendCodeForDstRead(GrGLXPBuilder* pb, const char* srcColor, const char* dstColor,
const char* outColor, const GrXferProcessor& proc) override {
const ShaderPDXferProcessor& xp = proc.cast<ShaderPDXferProcessor>();
GrGLXPFragmentBuilder* fsBuilder = pb->getFragmentShaderBuilder();
SkXfermode::Coeff srcCoeff, dstCoeff;
SkXfermode::ModeAsCoeff(xp.getXfermode(), &srcCoeff, &dstCoeff);
fsBuilder->codeAppendf("%s =", outColor);
// append src blend
bool didAppend = append_porterduff_term(fsBuilder, srcCoeff, srcColor, srcColor, dstColor,
false);
// append dst blend
SkAssertResult(append_porterduff_term(fsBuilder, dstCoeff, dstColor, srcColor, dstColor,
didAppend));
fsBuilder->codeAppend(";");
}
void onEmitCode(const EmitArgs& args) override {
const ShaderPDXferProcessor& xp = args.fXP.cast<ShaderPDXferProcessor>();
GrGLXPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
SkXfermode::Coeff srcCoeff, dstCoeff;
SkXfermode::ModeAsCoeff(xp.getXfermode(), &srcCoeff, &dstCoeff);
const char* dstColor = fsBuilder->dstColor();
fsBuilder->codeAppend("vec4 colorBlend =");
// append src blend
bool didAppend = append_porterduff_term(fsBuilder, srcCoeff,
args.fInputColor, args.fInputColor,
dstColor, false);
// append dst blend
SkAssertResult(append_porterduff_term(fsBuilder, dstCoeff,
dstColor, args.fInputColor,
dstColor, didAppend));
fsBuilder->codeAppend(";");
fsBuilder->codeAppendf("%s = %s * colorBlend + (vec4(1.0) - %s) * %s;",
args.fOutputPrimary, args.fInputCoverage, args.fInputCoverage,
dstColor);
}
void onEmitCode(const EmitArgs& args) override {
const PorterDuffXferProcessor& xp = args.fXP.cast<PorterDuffXferProcessor>();
GrGLXPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
if (PorterDuffXferProcessor::kCustom_PrimaryOutputType != xp.primaryOutputType()) {
SkASSERT(!xp.willReadDstColor());
switch(xp.secondaryOutputType()) {
case PorterDuffXferProcessor::kNone_SecondaryOutputType:
break;
case PorterDuffXferProcessor::kCoverage_SecondaryOutputType:
fsBuilder->codeAppendf("%s = %s;", args.fOutputSecondary,
args.fInputCoverage);
break;
case PorterDuffXferProcessor::kCoverageISA_SecondaryOutputType:
fsBuilder->codeAppendf("%s = (1.0 - %s.a) * %s;",
args.fOutputSecondary, args.fInputColor,
args.fInputCoverage);
break;
case PorterDuffXferProcessor::kCoverageISC_SecondaryOutputType:
fsBuilder->codeAppendf("%s = (vec4(1.0) - %s) * %s;",
args.fOutputSecondary, args.fInputColor,
args.fInputCoverage);
break;
default:
SkFAIL("Unexpected Secondary Output");
}
switch (xp.primaryOutputType()) {
case PorterDuffXferProcessor::kNone_PrimaryOutputType:
fsBuilder->codeAppendf("%s = vec4(0);", args.fOutputPrimary);
break;
case PorterDuffXferProcessor::kColor_PrimaryOutputType:
fsBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, args.fInputColor);
break;
case PorterDuffXferProcessor::kCoverage_PrimaryOutputType:
fsBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, args.fInputCoverage);
break;
case PorterDuffXferProcessor::kModulate_PrimaryOutputType:
fsBuilder->codeAppendf("%s = %s * %s;", args.fOutputPrimary, args.fInputColor,
args.fInputCoverage);
break;
default:
SkFAIL("Unexpected Primary Output");
}
} else {
SkASSERT(xp.willReadDstColor());
const char* dstColor = fsBuilder->dstColor();
fsBuilder->codeAppend("vec4 colorBlend =");
// append src blend
bool didAppend = append_porterduff_term(fsBuilder, xp.getSrcBlend(),
args.fInputColor, args.fInputColor,
dstColor, false);
// append dst blend
SkAssertResult(append_porterduff_term(fsBuilder, xp.getDstBlend(),
dstColor, args.fInputColor,
dstColor, didAppend));
fsBuilder->codeAppend(";");
fsBuilder->codeAppendf("%s = %s * colorBlend + (vec4(1.0) - %s) * %s;",
args.fOutputPrimary, args.fInputCoverage, args.fInputCoverage,
dstColor);
}
}
