procedural-3d-engine/shaders/hlsl/README.md

## HLSL Shaders

This directory contains a fork of the shaders found in [data/shaders/glsl](https://github.com/SaschaWillems/Vulkan/tree/master/data/shaders/glsl), re-written in HLSL.
These can be compiled with [DXC](https://github.com/microsoft/DirectXShaderCompiler) using the `compile.py` script.

### Known issues

- specialization constants can't be used to specify array size.
- `gl_PointCoord` not supported. HLSL has no equivalent. We changed the shaders to calulate the PointCoord manually in the shader. (`computenbody`, `computeparticles`, `particlefire` examples).
- HLSL doesn't have inverse operation (`deferred`, `hdr`, `instancing`, `skeletalanimation` & `texturecubemap` examples).
- `modf` causes compilation to fail without errors or warnings. (`modf` not used by any examples, easily confused with fmod)
- In `specializationconstants` example, shader compilation fails with error:
    ```
    --- Error msg: fatal error: failed to optimize SPIR-V: Id 10 is defined more than once
    ```
  When multiple constant ids are defined and have different types. We work around this problem by making all constant ids the same type, then use `asfloat`, `asint` or `asuint` to get the original value in the shader.
- `gl_RayTmaxNV` not supported. (`nv_ray_tracing_*` examples)
- HLSL interface for sparse residency textures is different from GLSL interface. After translating from HLSL to GLSL the shaders behave slightly different. Most important parts do behave identically though.
Add shaders re-implemented in HLSL These were written against the shaders at revision eddd724e7. There have been changes made since then, which will need to be mirrored. See `data/hlsl/README.md` for the current status of each sample. 2020-05-21 10:20:19 +00:00			`## HLSL Shaders`

Move shaders into glsl and hlsl directories Move `data/shaders` to `data/shaders/glsl` Move `data/hlsl` to `data/shaders/hlsl` Fix up shader paths in the cpp files to point to the new glsl location. `data/shaders/hlsl/compile.py` still overwrites the glsl .spv files (for now). Issue: #723 2020-05-29 16:08:53 +01:00			`This directory contains a fork of the shaders found in [data/shaders/glsl](https://github.com/SaschaWillems/Vulkan/tree/master/data/shaders/glsl), re-written in HLSL.`
Add shaders re-implemented in HLSL These were written against the shaders at revision eddd724e7. There have been changes made since then, which will need to be mirrored. See `data/hlsl/README.md` for the current status of each sample. 2020-05-21 10:20:19 +00:00			These can be compiled with [DXC](https://github.com/microsoft/DirectXShaderCompiler) using the `compile.py` script.

			`### Known issues`

			`- specialization constants can't be used to specify array size.`
			- `gl_PointCoord` not supported. HLSL has no equivalent. We changed the shaders to calulate the PointCoord manually in the shader. (`computenbody`, `computeparticles`, `particlefire` examples).
			- HLSL doesn't have inverse operation (`deferred`, `hdr`, `instancing`, `skeletalanimation` & `texturecubemap` examples).
			- `modf` causes compilation to fail without errors or warnings. (`modf` not used by any examples, easily confused with fmod)
			- In `specializationconstants` example, shader compilation fails with error:
			```
			`--- Error msg: fatal error: failed to optimize SPIR-V: Id 10 is defined more than once`
			```
			When multiple constant ids are defined and have different types. We work around this problem by making all constant ids the same type, then use `asfloat`, `asint` or `asuint` to get the original value in the shader.
			- `gl_RayTmaxNV` not supported. (`nv_ray_tracing_*` examples)
			`- HLSL interface for sparse residency textures is different from GLSL interface. After translating from HLSL to GLSL the shaders behave slightly different. Most important parts do behave identically though.`