Add HLSL shaders from SaschaWillems repo

[dnovillo]

Description

This ports the HLSL shader code from https://github.com/SaschaWillems/Vulkan/tree/master/data/shaders/hlsl to the shaders/ directory.

These shaders are not used by any samples. They can be compiled using the script shaders/hlsl/compile.py, which requires a DXC binary (see shaders/hlsl/README.md) for details.

General Checklist:

Please ensure the following points are checked:

• [ x ] My code follows the coding style
• [ x ] I have reviewed file licenses
• [ x ] I have commented any added functions (in line with Doxygen)
• [ x ] I have commented any code that could be hard to understand
• [ x ] My changes do not add any new compiler warnings
• [ x ] My changes do not add any new validation layer errors or warnings
• [ x ] I have used existing framework/helper functions where possible
• [ x ] My changes build on Windows, Linux, macOS and Android. Otherwise I have documented any exceptions
• [ x ] My changes do not add any regressions
• [ x ] I have tested every sample to ensure everything runs correctly
• [ x ] This PR describes the scope and expected impact of the changes I am making

[CLAassistant]

All committers have signed the CLA.

[SaschaWillems]

As discussed on the last call, here is a list of my samples that have been ported to this repo:

API

• compute_nbody
• dynamic_uniform_buffers
• hdr
• instancing
• terrain_tessellation
• texture_loading (2D Textures)
• texture_mipmap_generation

Extensions

• conservative_rasterization
• push_descriptors
• raytracing_basic

The following samples have been written exclusively for this repo, so HLSL shaders would need to be written from scratch:

Extensions

• debug_utils (replacement for the old debug extensions sample)

I think it would be best to base the HLSL shaders based on the GLSL ones in this repo, as they may differ compared to those from my repo here and there.

[dnovillo]

Thanks @SaschaWillems. I'll take a look.

[dnovillo]

It's been a couple of months and this keeps getting flushed out of my plate. I'm sorry folks. I'm not likely to be able to handle this for a while. Instead of letting it bitrot, I've asked for help internally. @ehsannas has graciously offered help with this. Ehsan is the main developer for DXC's SPIR-V backend. Thanks Ehsan!

[ehsannas]

Hi folks, I'll look into this once I get versed on the Vulkan-Samples repo. Thanks!

[SaschaWillems]

Per the discussion on today's call we'll close this one for now and add HLSL shaders in a different way.