void GrGLSLFragmentShaderBuilder::enableSecondaryOutput() {
SkASSERT(!fHasSecondaryOutput);
fHasSecondaryOutput = true;
const GrGLSLCaps& caps = *fProgramBuilder->glslCaps();
if (const char* extension = caps.secondaryOutputExtensionString()) {
this->addFeature(1 << kBlendFuncExtended_GLSLPrivateFeature, extension);
}
// If the primary output is declared, we must declare also the secondary output
// and vice versa, since it is not allowed to use a built-in gl_FragColor and a custom
// output. The condition also co-incides with the condition in whici GLES SL 2.0
// requires the built-in gl_SecondaryFragColorEXT, where as 3.0 requires a custom output.
if (caps.mustDeclareFragmentShaderOutput()) {
fOutputs.push_back().set(kVec4f_GrSLType, GrGLSLShaderVar::kOut_TypeModifier,
DeclaredSecondaryColorOutputName());
}
}
const char* GrGLSLFragmentShaderBuilder::getSecondaryColorOutputName() const {
const GrGLSLCaps& caps = *fProgramBuilder->glslCaps();
return caps.mustDeclareFragmentShaderOutput() ? DeclaredSecondaryColorOutputName()
: "gl_SecondaryFragColorEXT";
}
