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SPV: Handle GLSL bool loads from a uniform buffer as a conversion from int -> bool.

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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'.
This commit is contained in:
John Kessenich
2016-02-08 21:38:15 -07:00
parent 10110596a3
commit 103bef9d74
4 changed files with 96 additions and 51 deletions
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21
SPIRV/GlslangToSpv.cpp
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@@ -1570,7 +1570,12 @@ spv::Id TGlslangToSpvTraverser::convertGlslangToSpvType(const glslang::TType& ty
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 @@ spv::Id TGlslangToSpvTraverser::convertGlslangToSpvType(const glslang::TType& ty
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