Need some way of loading a GLSL shader directly instead of converting from HLSL, or a binding in skshaderc for GLSL samplerExternalOES

[nrewkowski]

Need some way of loading a GLSL shader directly instead of converting from HLSL, or a binding in skshaderc for GLSL samplerExternalOES

[maluoi]

Linking this discussion here, as it's quite relevant: #874

I have been meaning to look into this! My preference I think is still primarily towards adding tags for OES textures.

[maluoi]

Making a note here for myself, looks like spirv_cross has a Compiler::set_variable_type_remap_callback function which is explicitly designed for cases like samplerExternalOES.

This probably fits in skshaderc somewhere around here (this is a branch with some other improvements I'd like to get in), but unfortunately set_variable_type_remap_callback is only available in spirv_cross's C++ API. skshaderc uses the C API, so the GLSL emitting function will either need to be re-written with the C++ API (most likely), or some backdoor will need to be used to get the Compiler object (might be beyond my C++ skills).

[maluoi]

An update on this one, I've got this working in a sk_gpu branch! Shader format is using a slightly new version though, so it'll need to be integrated into latest StereoKit before it'll be useful.

No big surprises, it'll basically just use an external tag, and looks like this:

//--tex_name : external = white
Texture2D    tex_name         : register(t0);
SamplerState tex_name_sampler : register(s0);

[nrewkowski]

Great, thanks! looking forward to the merge