DX12 initial backend implementation

[adriengivry]

Given that the Vulkan implementation is now in a decent state, we should start looking into adding DX12 support. The API will certainly need to be updated to suit both APIs.

[RobTOsb]

Hey Adrian!

I'm willing to give the DirectX 12 implementation a crack if you'd let me, there's just a few questions I have:

1. Is the render pass api set in stone? DirectX12 uses the equivalent of the dynamic rendering extension in Vulkan, I was thinking of extending the command buffer api to include BeginRendering(RenderingInfo &info); and the end to try and bring the api's closer together. Another thing to add to this is that renderpasses in Vulkan have been deprecated for dynamic rendering in Vulkan 1.4 (according to this) so maybe this would worth doing now while the project has not gotten too big.

2. How would you like the fence/semaphore issue to be resolved? From my understanding the fence in dx12 encompasses both the semaphore and fence functionality in Vulkan, would you prefer me to try to implement as it is right now? (separate fence and semaphore structs).

Thanks!

[adriengivry]

Hey @RobTOsb, thanks for your interest in OpenRHI!

I've created a discussion thread here so we can discuss implementation details.