SPV: Handle GLSL bool loads from a uniform buffer as a conversion from int -> bool.
SPIR-V bool is abstract; it has no bit pattern for storage with transparent memory.
OpenGL's convention is a bool in a uniform buffer is 32-bit int with non-0 being 'true'.
diff --git a/SPIRV/GlslangToSpv.cpp b/SPIRV/GlslangToSpv.cpp
index 94e37e8..2a3ce8e 100755
--- a/SPIRV/GlslangToSpv.cpp
+++ b/SPIRV/GlslangToSpv.cpp
@@ -1570,7 +1570,12 @@
spvType = builder.makeFloatType(64);
break;
case glslang::EbtBool:
- spvType = builder.makeBoolType();
+ // "transparent" bool doesn't exist in SPIR-V. The GLSL convention is
+ // a 32-bit int where non-0 means true.
+ if (explicitLayout != glslang::ElpNone)
+ spvType = builder.makeUintType(32);
+ else
+ spvType = builder.makeBoolType();
break;
case glslang::EbtInt:
spvType = builder.makeIntType(32);
@@ -1764,9 +1769,21 @@
return spvType;
}
+// Wrap the builder's accessChainLoad to:
+// - localize handling of RelaxedPrecision
+// - use the SPIR-V inferred type instead of another conversion of the glslang type
+// (avoids unnecessary work and possible type punning for structures)
+// - do conversion of concrete to abstract type
spv::Id TGlslangToSpvTraverser::accessChainLoad(const glslang::TType& type)
{
- return builder.accessChainLoad(TranslatePrecisionDecoration(type), convertGlslangToSpvType(type));
+ spv::Id nominalTypeId = builder.accessChainGetInferredType();
+ spv::Id loadedId = builder.accessChainLoad(TranslatePrecisionDecoration(type), nominalTypeId);
+
+ // Need to convert to abstract types when necessary
+ if (builder.isScalarType(nominalTypeId) && type.getBasicType() == glslang::EbtBool && nominalTypeId != builder.makeBoolType())
+ loadedId = builder.createBinOp(spv::OpINotEqual, builder.makeBoolType(), loadedId, builder.makeUintConstant(0));
+
+ return loadedId;
}
// Decide whether or not this type should be