From b487516880f56fd69ff76bf7cb3f0f1711bc356d Mon Sep 17 00:00:00 2001 From: Tim Foley Date: Wed, 29 Nov 2017 11:45:15 -0800 Subject: Add API to query stage of varying parameter (#302) Fixes #301 The problem here is that if you have input GLSL code like: ```glsl // example.vs in vec3 pos; ``` and: ```glsl // example.fs in vec3 worldPos; ``` Then both `pos` and `worldPos` are reflected as global variables (parameters of the *program*), which both get bound to "varying input" resources, but there is no way to tell through the API that `pos` is a vertex parameter while `worldPos` is a fragment one. The original request in issue #301 was to expose parameters like this not as a global variables, but rather as parameters of the entry point in their specific file. That is, treat it as if the user had written, e.g.: ```glsl // example.vs void vsMain(in vec3 pos) { ... } ``` Doing that would unify the GLSL and HLSL/Slang cases a bit, but would require the Slang reflection API to lie about the structure of code the user wrote. At a more basic level, that would have been hard to implement because the current reflection API just exposes the underlying AST, and the AST *needs* to leave `pos` at the global scope so that when we go and spit GLSL back out we retain the original structure. This PR implements a more simplistic solution, where the user is allowed to query the stage that a varying parameter "belongs" to. For right now I'm only enabling this to work for varying parameters (but it doesn't care if they are entry-point or global-scope varyings). Despite what I said on #301, this should work for both the top-level parameter's variable layout, *and* any variable layouts for fields within its type reflection. In terms of implementation, I took the simple but wasteful route: every `VarLayout` now has a `stage` field that is by default initialized to `SLANG_STAGE_NONE`. When collecting varying parameters, I take advantage of the fact that everything bottlenecks through `processEntryPointParameter()` which takes an `EntryPointParameterState` so that I can set the `VarLayout::stage` field for any varying parameter in one place. While I was making this change, I also did a bit of cleanup so that the "official" names for the varying parameter categories are `VARYING_INPUT` and `VARYING_OUTPUT`, with `VERTEX_INPUT` and `FRAGMENT_OUTPUT` being "deprecated" in principle. I didn't do the bulk rename inside the codebase yet. --- source/slang/type-layout.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'source/slang/type-layout.h') diff --git a/source/slang/type-layout.h b/source/slang/type-layout.h index 07530bdfc..66763c8a7 100644 --- a/source/slang/type-layout.h +++ b/source/slang/type-layout.h @@ -251,6 +251,12 @@ public: String semanticName; int semanticIndex; + // The stage this variable belongs to, in case it is + // stage-specific. + // TODO: This is wasteful to be storing on every single + // variable layout. + Stage stage = Stage::Unknown; + // The start register(s) for any resources struct ResourceInfo { -- cgit v1.2.3