const char* GrGLShaderBuilder::fragmentPosition() {
if (fCodeStage.inStageCode()) {
const GrEffect* effect = fCodeStage.effectStage()->getEffect();
if (!effect->willReadFragmentPosition()) {
SkDEBUGFAIL("GrGLEffect asked for frag position but its generating GrEffect "
"did not request access.");
return "";
}
}
// We only declare "gl_FragCoord" when we're in the case where we want to use layout qualifiers
// to reverse y. Otherwise it isn't necessary and whether the "in" qualifier appears in the
// declaration varies in earlier GLSL specs. So it is simpler to omit it.
if (fTopLeftFragPosRead) {
fSetupFragPosition = true;
return "gl_FragCoord";
} else if (fGpu->glCaps().fragCoordConventionsSupport()) {
if (!fSetupFragPosition) {
if (fGpu->glslGeneration() < k150_GrGLSLGeneration) {
this->addFSFeature(1 << kFragCoordConventions_GLSLPrivateFeature,
"GL_ARB_fragment_coord_conventions");
}
fFSInputs.push_back().set(kVec4f_GrSLType,
GrGLShaderVar::kIn_TypeModifier,
"gl_FragCoord",
GrGLShaderVar::kDefault_Precision,
GrGLShaderVar::kUpperLeft_Origin);
fSetupFragPosition = true;
}
return "gl_FragCoord";
} else {
static const char* kCoordName = "fragCoordYDown";
if (!fSetupFragPosition) {
// temporarily change the stage index because we're inserting non-stage code.
CodeStage::AutoStageRestore csar(&fCodeStage, NULL);
SkASSERT(!fUniformHandles.fRTHeightUni.isValid());
const char* rtHeightName;
fUniformHandles.fRTHeightUni =
this->addUniform(kFragment_Visibility, kFloat_GrSLType, "RTHeight", &rtHeightName);
// Using glFragCoord.zw for the last two components tickles an Adreno driver bug that
// causes programs to fail to link. Making this function return a vec2() didn't fix the
// problem but using 1.0 for the last two components does.
this->fFSCode.prependf("\tvec4 %s = vec4(gl_FragCoord.x, %s - gl_FragCoord.y, 1.0, "
"1.0);\n", kCoordName, rtHeightName);
fSetupFragPosition = true;
}
SkASSERT(fUniformHandles.fRTHeightUni.isValid());
return kCoordName;
}
}
const char* GrGLShaderBuilder::fragmentPosition() {
if (fCodeStage.inStageCode()) {
const GrEffectRef& effect = *fCodeStage.effectStage()->getEffect();
if (!effect->willReadFragmentPosition()) {
GrDebugCrash("GrGLEffect asked for frag position but its generating GrEffect "
"did not request access.");
return "";
}
}
if (fTopLeftFragPosRead) {
if (!fSetupFragPosition) {
fFSInputs.push_back().set(kVec4f_GrSLType,
GrGLShaderVar::kIn_TypeModifier,
"gl_FragCoord",
GrGLShaderVar::kDefault_Precision);
fSetupFragPosition = true;
}
return "gl_FragCoord";
} else if (fGpu->glCaps().fragCoordConventionsSupport()) {
if (!fSetupFragPosition) {
SkAssertResult(this->enablePrivateFeature(kFragCoordConventions_GLSLPrivateFeature));
fFSInputs.push_back().set(kVec4f_GrSLType,
GrGLShaderVar::kIn_TypeModifier,
"gl_FragCoord",
GrGLShaderVar::kDefault_Precision,
GrGLShaderVar::kUpperLeft_Origin);
fSetupFragPosition = true;
}
return "gl_FragCoord";
} else {
static const char* kCoordName = "fragCoordYDown";
if (!fSetupFragPosition) {
// temporarily change the stage index because we're inserting non-stage code.
CodeStage::AutoStageRestore csar(&fCodeStage, NULL);
SkASSERT(!fRTHeightUniform.isValid());
const char* rtHeightName;
fRTHeightUniform = this->addUniform(kFragment_Visibility,
kFloat_GrSLType,
"RTHeight",
&rtHeightName);
this->fFSCode.prependf("\tvec4 %s = vec4(gl_FragCoord.x, %s - gl_FragCoord.y, gl_FragCoord.zw);\n",
kCoordName, rtHeightName);
fSetupFragPosition = true;
}
SkASSERT(fRTHeightUniform.isValid());
return kCoordName;
}
}
void GrGLShaderBuilder::createAndEmitEffects(GrGLProgramEffectsBuilder* programEffectsBuilder,
const GrEffectStage* effectStages[],
int effectCnt,
const GrGLProgramDesc::EffectKeyProvider& keyProvider,
GrGLSLExpr4* fsInOutColor) {
bool effectEmitted = false;
GrGLSLExpr4 inColor = *fsInOutColor;
GrGLSLExpr4 outColor;
for (int e = 0; e < effectCnt; ++e) {
SkASSERT(NULL != effectStages[e] && NULL != effectStages[e]->getEffect());
const GrEffectStage& stage = *effectStages[e];
CodeStage::AutoStageRestore csar(&fCodeStage, &stage);
if (inColor.isZeros()) {
SkString inColorName;
// Effects have no way to communicate zeros, they treat an empty string as ones.
this->nameVariable(&inColorName, '\0', "input");
this->fsCodeAppendf("\tvec4 %s = %s;\n", inColorName.c_str(), inColor.c_str());
inColor = inColorName;
}
// create var to hold stage result
SkString outColorName;
this->nameVariable(&outColorName, '\0', "output");
this->fsCodeAppendf("\tvec4 %s;\n", outColorName.c_str());
outColor = outColorName;
programEffectsBuilder->emitEffect(stage,
keyProvider.get(e),
outColor.c_str(),
inColor.isOnes() ? NULL : inColor.c_str(),
fCodeStage.stageIndex());
inColor = outColor;
effectEmitted = true;
}
if (effectEmitted) {
*fsInOutColor = outColor;
}
}
