void emitOutputsForBlendState(const EmitArgs& args) override {
// This emit code should be empty. However, on the nexus 6 there is a driver bug where if
// you do not give gl_FragColor a value, the gl context is lost and we end up drawing
// nothing. So this fix just sets the gl_FragColor arbitrarily to 0.
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
fragBuilder->codeAppendf("%s = vec4(0);", args.fOutputPrimary);
}
void GrGLSLXferProcessor::emitCode(const EmitArgs& args) {
if (!args.fXP.willReadDstColor()) {
this->emitOutputsForBlendState(args);
return;
}
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
GrGLSLUniformHandler* uniformHandler = args.fUniformHandler;
const char* dstColor = fragBuilder->dstColor();
if (args.fXP.getDstTexture()) {
bool topDown = kTopLeft_GrSurfaceOrigin == args.fXP.getDstTexture()->origin();
if (args.fInputCoverage) {
// We don't think any shaders actually output negative coverage, but just as a safety
// check for floating point precision errors we compare with <= here
fragBuilder->codeAppendf("if (all(lessThanEqual(%s, vec4(0)))) {"
" discard;"
"}", args.fInputCoverage);
}
const char* dstTopLeftName;
const char* dstCoordScaleName;
fDstTopLeftUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kVec2f_GrSLType,
kDefault_GrSLPrecision,
"DstTextureUpperLeft",
&dstTopLeftName);
fDstScaleUni = uniformHandler->addUniform(kFragment_GrShaderFlag,
kVec2f_GrSLType,
kDefault_GrSLPrecision,
"DstTextureCoordScale",
&dstCoordScaleName);
const char* fragPos = fragBuilder->fragmentPosition();
fragBuilder->codeAppend("// Read color from copy of the destination.\n");
fragBuilder->codeAppendf("vec2 _dstTexCoord = (%s.xy - %s) * %s;",
fragPos, dstTopLeftName, dstCoordScaleName);
if (!topDown) {
fragBuilder->codeAppend("_dstTexCoord.y = 1.0 - _dstTexCoord.y;");
}
fragBuilder->codeAppendf("vec4 %s = ", dstColor);
fragBuilder->appendTextureLookup(args.fTexSamplers[0], "_dstTexCoord", kVec2f_GrSLType);
fragBuilder->codeAppend(";");
}
this->emitBlendCodeForDstRead(fragBuilder,
uniformHandler,
args.fInputColor,
args.fInputCoverage,
dstColor,
args.fOutputPrimary,
args.fOutputSecondary,
args.fXP);
}
void emitOutputsForBlendState(const EmitArgs& args) override {
const CoverageSetOpXP& xp = args.fXP.cast<CoverageSetOpXP>();
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
if (xp.invertCoverage()) {
fragBuilder->codeAppendf("%s = 1.0 - %s;", args.fOutputPrimary, args.fInputCoverage);
} else {
fragBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, args.fInputCoverage);
}
}
void emitOutputsForBlendState(const EmitArgs& args) override {
if (args.fShaderCaps->mustWriteToFragColor()) {
// This emit code should be empty. However, on the nexus 6 there is a driver bug where
// if you do not give gl_FragColor a value, the gl context is lost and we end up drawing
// nothing. So this fix just sets the gl_FragColor arbitrarily to 0.
// https://bugs.chromium.org/p/chromium/issues/detail?id=445377
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
fragBuilder->codeAppendf("%s = half4(0);", args.fOutputPrimary);
}
}
void emitOutputsForBlendState(const EmitArgs& args) override {
const CustomXP& xp = args.fXP.cast<CustomXP>();
SkASSERT(xp.hasHWBlendEquation());
GrGLSLXPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
fsBuilder->enableAdvancedBlendEquationIfNeeded(xp.hwBlendEquation());
// Apply coverage by multiplying it into the src color before blending. Mixed samples will
// "just work" automatically. (See onGetOptimizations())
if (xp.readsCoverage()) {
fsBuilder->codeAppendf("%s = %s * %s;",
args.fOutputPrimary, args.fInputCoverage, args.fInputColor);
} else {
fsBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, args.fInputColor);
}
}
void emitOutputsForBlendState(const EmitArgs& args) override {
GrGLSLXPFragmentBuilder* fragBuilder = args.fXPFragBuilder;
SkASSERT(args.fInputCoverage);
fragBuilder->codeAppendf("%s = %s * %s;", args.fOutputPrimary, args.fInputColor,
args.fInputCoverage);
}
void emitOutputsForBlendState(const EmitArgs& args) override {
GrGLSLXPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
fsBuilder->codeAppendf("%s = %s * %s;", args.fOutputPrimary, args.fInputColor,
args.fInputCoverage);
}
