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[Fix, Test] (MG_Impl, MG_State, MG_IntegrationTest): glUniform*d stores what the demoted shader reads

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swung0x48
2026-08-12 06:20:11 -04:00
parent 532836c058
commit 62a2dae5ba
4 changed files with 418 additions and 62 deletions
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MobileGL/MG_State/GLState/ProgramState/ProgramObject.h
+13 -6
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@@ -326,15 +326,22 @@ namespace MobileGL::MG_State::GLState {
: kInvalidUniformOffset;
}
Uint GetUniformSizesInBytes(Uint location) const { return MG_Util::GetGLTypeSize(GetUniformType(location)); }
// Bytes a uniform actually occupies in the global UBO, which is not its GL type size:
// std140 pads each column of a float matrix out to a vec4, so a mat3 spans 48 bytes
// even though only 36 of them carry components. Anything reading or writing a whole
// uniform's storage - a bounds check, a copy between two programs' shadows - wants
// this rather than GetUniformSizesInBytes.
// Bytes a uniform actually occupies in the global UBO, which is not its GL type size,
// for two reasons. std140 pads each column of a matrix out to a vec4, so a mat3 spans
// 48 bytes even though only 36 of them carry components. And every 64-bit float in a
// shader is narrowed to 32 bits before the module reaches a backend
// (ShaderTranspiler::DemoteFloat64Pass) - the global UBO is laid out by reflecting that
// demoted module - so a `double` uniform occupies exactly what its float-typed twin
// would, half its GL type size, and a `dmat4` is padded like any other matrix. Anything
// reading or writing a whole uniform's storage - a bounds check, a copy between two
// programs' shadows - wants this rather than GetUniformSizesInBytes.
static SizeT UniformStorageSpanInBytes(const glslang::TType* type, SizeT tightSize) {
if (type != nullptr && type->isMatrix() && type->getBasicType() != glslang::EbtDouble) {
if (type != nullptr && type->isMatrix()) {
return static_cast<SizeT>(type->getMatrixCols()) * 4 * sizeof(Float);
}
if (type != nullptr && type->getBasicType() == glslang::EbtDouble) {
return tightSize / 2;
}
return tightSize;
}
SizeT GetUniformStorageSpanInBytes(Uint location) const {