From f4ac13d6718d6433f69eb21311110c8225a95aee Mon Sep 17 00:00:00 2001 From: Tim Foley Date: Fri, 14 Jul 2017 12:00:29 -0700 Subject: Adjust type layout when parameter block constains member using the same resource If we have something like to following in HLSL: cbuffer C { Texture2D t; ... } and we are compiling to GLSL, then both `C` and `C.t` consume the same kind of resource (a descriptor-table slot). The way reflection was working right now, querying the index of `C` would return its binding (let's say it is `4` just to be concrete) and then a query on `C::t` would give its offset, which was being computed as `0` because it is the first field in the logical `struct` type. That obviously leads to bad math and requires some subtle `+1`s in cases to get things right (e.g., when scalaring during lowering, I had to carefully add one in some cases). It is unreasonable to expect users to deal with this. This commit changes it so that the offset of field `C::t` is `1` so that hopefully more things Just Work. The special-case logic in lowering is now gone. One important catch here is that this pretty much only works in the case where the element type of a parameter block is a `struct` type (which is really all that makes sense right now). If we ever want to generalize this in the future, then it will probably be necessary to change the `TypeLayout` case for parameter blocks to store a `VarLayout` for the element, rather than just a `TypeLayout`. --- source/slang/parameter-binding.cpp | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'source/slang/parameter-binding.cpp') diff --git a/source/slang/parameter-binding.cpp b/source/slang/parameter-binding.cpp index 01727fb36..007c023e2 100644 --- a/source/slang/parameter-binding.cpp +++ b/source/slang/parameter-binding.cpp @@ -1342,8 +1342,9 @@ void generateParameterBindings( { auto globalConstantBufferLayout = createParameterBlockTypeLayout( nullptr, - globalScopeStructLayout, - globalScopeRules); + globalScopeRules, + globalScopeRules->GetObjectLayout(ShaderParameterKind::ConstantBuffer), + globalScopeStructLayout); globalScopeLayout = globalConstantBufferLayout; } -- cgit v1.2.3