Add a workaround for platforms with broken geo shader invocations
BUG=skia:
Change-Id: I9105b65b522d9ffac5a90ca7126bfd4ae88f8069
Reviewed-on: https://skia-review.googlesource.com/8422
Reviewed-by: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/include/gpu/GrShaderCaps.h b/include/gpu/GrShaderCaps.h
index 918138c..36ab3c3 100644
--- a/include/gpu/GrShaderCaps.h
+++ b/include/gpu/GrShaderCaps.h
@@ -176,6 +176,9 @@
bool requiresLocalOutputColorForFBFetch() const { return fRequiresLocalOutputColorForFBFetch; }
+ // On MacBook, geometry shaders break if they have more than one invocation.
+ bool mustImplementGSInvocationsWithLoop() const { return fMustImplementGSInvocationsWithLoop; }
+
// Returns the string of an extension that must be enabled in the shader to support
// derivatives. If nullptr is returned then no extension needs to be enabled. Before calling
// this function, the caller should check that shaderDerivativeSupport exists.
@@ -304,6 +307,7 @@
bool fMustForceNegatedAtanParamToFloat : 1;
bool fAtan2ImplementedAsAtanYOverX : 1;
bool fRequiresLocalOutputColorForFBFetch : 1;
+ bool fMustImplementGSInvocationsWithLoop : 1;
PrecisionInfo fFloatPrecisions[kGrShaderTypeCount][kGrSLPrecisionCount];
int fPixelLocalStorageSize;
diff --git a/src/gpu/GrShaderCaps.cpp b/src/gpu/GrShaderCaps.cpp
index 621ac3d..69af070 100644
--- a/src/gpu/GrShaderCaps.cpp
+++ b/src/gpu/GrShaderCaps.cpp
@@ -58,6 +58,7 @@
fMustForceNegatedAtanParamToFloat = false;
fAtan2ImplementedAsAtanYOverX = false;
fRequiresLocalOutputColorForFBFetch = false;
+ fMustImplementGSInvocationsWithLoop = false;
fFlatInterpolationSupport = false;
fNoPerspectiveInterpolationSupport = false;
fMultisampleInterpolationSupport = false;
@@ -144,6 +145,8 @@
"YES" : "NO"));
r.appendf("Must use local out color for FBFetch: %s\n", (fRequiresLocalOutputColorForFBFetch ?
"YES" : "NO"));
+ r.appendf("Must implement geo shader invocations with loop : %s\n",
+ (fMustImplementGSInvocationsWithLoop ? "YES" : "NO"));
r.appendf("Flat interpolation support: %s\n", (fFlatInterpolationSupport ? "YES" : "NO"));
r.appendf("No perspective interpolation support: %s\n", (fNoPerspectiveInterpolationSupport ?
"YES" : "NO"));
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index aea875f..4c25221 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -870,6 +870,13 @@
if (shaderCaps->fFBFetchSupport && kQualcomm_GrGLVendor == ctxInfo.vendor()) {
shaderCaps->fRequiresLocalOutputColorForFBFetch = true;
}
+
+#ifdef SK_BUILD_FOR_MAC
+ // On at least some MacBooks, geometry shaders fall apart if we use more than one invocation. To
+ // work around this, we always use a single invocation and wrap the shader in a loop. The long-
+ // term plan for this WAR is for it to eventually be baked into SkSL.
+ shaderCaps->fMustImplementGSInvocationsWithLoop = true;
+#endif
}
bool GrGLCaps::hasPathRenderingSupport(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
diff --git a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.cpp b/src/gpu/glsl/GrGLSLGeometryShaderBuilder.cpp
index a8e746c..01f223f 100644
--- a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.cpp
+++ b/src/gpu/glsl/GrGLSLGeometryShaderBuilder.cpp
@@ -35,22 +35,39 @@
GrGLSLGeometryBuilder::GrGLSLGeometryBuilder(GrGLSLProgramBuilder* program)
: INHERITED(program)
- , fIsConfigured(false) {
+ , fNumInvocations(0) {
}
void GrGLSLGeometryBuilder::configure(InputType inputType, OutputType outputType, int maxVertices,
int numInvocations) {
- SkASSERT(!fIsConfigured);
+ SkASSERT(!this->isConfigured());
+ fNumInvocations = numInvocations;
+ if (this->getProgramBuilder()->shaderCaps()->mustImplementGSInvocationsWithLoop()) {
+ maxVertices *= numInvocations;
+ numInvocations = 1;
+ }
this->addLayoutQualifier(input_type_name(inputType), kIn_InterfaceQualifier);
this->addLayoutQualifier(SkStringPrintf("invocations = %i", numInvocations).c_str(),
kIn_InterfaceQualifier);
this->addLayoutQualifier(output_type_name(outputType), kOut_InterfaceQualifier);
this->addLayoutQualifier(SkStringPrintf("max_vertices = %i", maxVertices).c_str(),
kOut_InterfaceQualifier);
- fIsConfigured = true;
}
void GrGLSLGeometryBuilder::onFinalize() {
- SkASSERT(fIsConfigured);
+ SkASSERT(this->isConfigured());
fProgramBuilder->varyingHandler()->getGeomDecls(&this->inputs(), &this->outputs());
+ GrShaderVar sk_InvocationID("sk_InvocationID", kInt_GrSLType);
+ this->declareGlobal(sk_InvocationID);
+ SkASSERT(sk_InvocationID.getName() == SkString("sk_InvocationID"));
+ if (this->getProgramBuilder()->shaderCaps()->mustImplementGSInvocationsWithLoop()) {
+ SkString invokeFn;
+ this->emitFunction(kVoid_GrSLType, "invoke", 0, nullptr, this->code().c_str(), &invokeFn);
+ this->code().printf("for (sk_InvocationID = 0; sk_InvocationID < %i; ++sk_InvocationID) {"
+ "%s();"
+ "EndPrimitive();"
+ "}", fNumInvocations, invokeFn.c_str());
+ } else {
+ this->codePrependf("sk_InvocationID = gl_InvocationID;");
+ }
}
diff --git a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.h b/src/gpu/glsl/GrGLSLGeometryShaderBuilder.h
index feedcf2..04be530 100644
--- a/src/gpu/glsl/GrGLSLGeometryShaderBuilder.h
+++ b/src/gpu/glsl/GrGLSLGeometryShaderBuilder.h
@@ -31,11 +31,12 @@
};
void configure(InputType, OutputType, int maxVertices, int numInvocations = 1);
+ bool isConfigured() const { return fNumInvocations; }
private:
void onFinalize() override;
- bool fIsConfigured;
+ int fNumInvocations;
friend class GrGLProgramBuilder;