## HLSL Shaders

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

### Status

Tested on Ubuntu 18.04 + GeForce RTX 2080 Ti


Shaders written to mirror the GLSL versions at `eddd724`. There have been changes made to the GLSL shaders since then, which will need to be updated.


| Name                       | GLSL @`eddd724e7` | HLSL @`eddd724e7` | GLSL @`10a1ecaf7` | HLSL @`eddd724e7`
|----------------------------|-------------------|-------------------|-------------------|-------------------
| bloom                      | ☑           | ☑           | ☑           | ☑
| computecloth               | ☑           | ☑           | ☑           | ☑
| computecullandlod          | ☑           | ☑           | ☑           | ☑
| computeheadless            | ☑           | ☑           | ☑           | ☑
| computenbody               | ☑           | ☑           | ☑           | ☑
| computeparticles           | ☑           | ❌          | ☑           | ❌
| computeraytracing          | ☑           | ☑           | ☑           | ☑
| computeshader              | ☑           | ☑           | ☑           | ☑
| conditionalrender          | ☑           | ☑           | ☑           | ☑
| conservativeraster         | ☑           | ☑           | ☑           | ☑
| debugmarker                | ☑           | ☑           | ☑           | ☑
| deferred                   | ☑           | ☑           | ☑           | ☑
| deferredmultisampling      | ☑           | ☑           | ☑           | ☑
| deferredshadows            | ☑           | ☑           | ☑           | ☑
| descriptorsets             | ☑           | ☑           | ☑           | ☑
| displacement               | ☑           | ☑           | ☑           | ☑
| distancefieldfonts         | ☑           | ☑           | ☑           | ☑
| dynamicuniformbuffer       | ☑           | ☑           | ☑           | ☑
| gears                      | ☑           | ☑           | ☑           | ☑
| geometryshader             | ☑           | ☑           | ☑           | ☑
| gltfscene                  | -                 | -                 | ☑           | ❌
| hdr                        | ☑           | ❌          | ☑           | ❌
| imgui                      | ☑           | ☑           | ☑           | ☑
| indirectdraw               | ☑           | ☑           | ☑           | ☑
| inlineuniformblocks        | ☑           | ☑           | ☑           | ☑
| inputattachments           | ☑           | ☑           | ☑           | ☑
| instancing                 | ☑           | ☑           | ☑           | ☑
| mesh                       | ☑           | ☑           | ❌          | ☑
| multisampling              | ☑           | ☑           | ☑           | ❌
| multithreading             | ☑           | ☑           | ☑           | ☑
| multiview                  | ☑           | ☑           | ☑           | ☑
| negativeviewportheight     | ☑           | ☑           | ☑           | ☑
| nv_ray_tracing_basic       | ☑           | ☑           | ☑           | ☑
| nv_ray_tracing_reflections | ☑           | ☑           | ☑           | ☑
| nv_ray_tracing_shadows     | ☑           | ☑           | ☑           | ☑
| occlusionquery             | ☑           | ☑           | ☑           | ☑
| offscreen                  | ☑           | ☑           | ☑           | ❌
| parallaxmapping            | ☑           | ☑           | ☑           | ☑
| particlefire               | ☑           | ☑           | ☑           | ☑
| pbrbasic                   | ☑           | ☑           | ☑           | ☑
| pbribl                     | ☑           | ☑           | ☑           | ☑
| pbrtexture                 | ☑           | ☑           | ☑           | ☑
| pipelines                  | ☑           | ☑           | ☑           | ☑
| pipelinestatistics         | ☑           | ☑           | ☑           | ☑
| pushconstants              | ☑           | ☑           | ☑           | ☑
| pushdescriptors            | ☑           | ☑           | ☑           | ☑
| radialblur                 | ☑           | ☑           | ☑           | ☑
| renderheadless             | ☑           | ☑           | ☑           | ☑
| scenerendering             | ☑           | ☑           | ☑           | ☑
| screenshot                 | ☑           | ☑           | ☑           | ☑
| shadowmapping              | ☑           | ☑           | ☑           | ☑
| shadowmappingcascade       | ☑           | ☑           | ☑           | ☑
| shadowmappingomni          | ☑           | ☑           | ☑           | ☑
| skeletalanimation          | ☑           | ☑           | ☑           | ❌
| specializationconstants    | ☑           | ☑           | ☑           | ☑
| sphericalenvmapping        | ☑           | ☑           | ☑           | ☑
| ssao                       | ☑           | ☑           | ☑           | ☑
| stencilbuffer              | ☑           | ☑           | ☑           | ☑
| subpasses                  | ☑           | ☑           | ☑           | ☑
| terraintessellation        | ☑           | ☑           | ☑           | ☑
| tessellation               | ☑           | ☑           | ☑           | ☑
| textoverlay                | ☑           | ☑           | ☑           | ☑
| texture                    | ☑           | ☑           | ☑           | ☑
| texture3d                  | ☑           | ☑           | ☑           | ☑
| texturearray               | ☑           | ☑           | ☑           | ☑
| texturecubemap             | ☑           | ❌          | ☑           | ❌
| texturemipmapgen           | ☑           | ☑           | ☑           | ☑
| texturesparseresidency     | ☑           | ☑           | ☑           | ☑
| triangle                   | ☑           | ☑           | ☑           | ☑
| viewportarray              | ☑           | ☑           | ☑           | ☑
| vulkanscene                | ☑           | ☑           | ☑           | ☑

### 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.