[EXPERIMENTAL] D3D12 Backend

[TheSpydog]

I've started working on an experimental D3D12 backend for FNA3D. This is intended primarily for GDKX, although as of the time of this writing I haven't added any initialization code for Xbox. (And when I do, it will have to be under NDA. Still figuring out how that will work in terms of compilation.)

Since D3D12 is similar to Vulkan in terms of complexity (if not verbosity), my goal is to keep this as close to the general structure of the Vulkan renderer as possible. This allows us to not reinvent the wheel for things like memory management, etc.

Note that this will most likely end up getting thrown away whenever SDL_gpu materializes.

API Checklist

• [ ] DestroyDevice (partial)
• [ ] SwapBuffers (partial)
• [x] Clear
• [ ] DrawIndexedPrimitives
• [ ] DrawInstancedPrimitives
• [ ] DrawPrimitives
• [x] SetViewport
• [ ] SetScissorRect (partial)
• [x] GetBlendFactor
• [x] SetBlendFactor
• [x] GetMultiSampleMask
• [ ] SetMultiSampleMask (partial, not dynamic state in D3D12)
• [x] GetReferenceStencil
• [x] SetReferenceStencil
• [ ] SetBlendState
• [ ] SetDepthStencilState
• [ ] ApplyRasterizerState
• [ ] VerifySampler
• [x] VerifyVertexSampler
• [ ] ApplyVertexBufferBindings
• [x] SetRenderTargets
• [ ] ResolveTarget
• [x] ResetBackbuffer
• [ ] ReadBackbuffer
• [x] GetBackbufferSize
• [x] GetBackbufferSurfaceFormat
• [x] GetBackbufferDepthFormat
• [x] GetBackbufferMultiSampleCount
• [ ] CreateTexture2D
• [ ] CreateTexture3D
• [ ] CreateTextureCube
• [x] AddDisposeTexture
• [ ] SetTextureData2D
• [ ] SetTextureData3D
• [ ] SetTextureDataCube
• [ ] SetTextureDataYUV
• [ ] GetTextureData2D
• [ ] GetTextureData3D
• [ ] GetTextureDataCube
• [ ] GenColorRenderbuffer
• [ ] GenDepthStencilRenderbuffer
• [ ] AddRenderbuffer
• [ ] GenVertexBuffer
• [ ] AddDisposeVertexBuffer
• [ ] SetVertexBufferData
• [ ] GetVertexBufferData
• [ ] GenIndexBuffer
• [ ] AddDisposeIndexBuffer
• [ ] SetIndexBufferData
• [ ] GetIndexBufferData
• [ ] CreateEffect
• [ ] CloneEffect
• [ ] AddDisposeEffect
• [ ] SetEffectTechnique
• [ ] ApplyEffect
• [ ] BeginPassRestore
• [ ] EndPassRestore
• [ ] CreateQuery
• [ ] AddDisposeQuery
• [ ] QueryBegin
• [ ] QueryEnd
• [ ] QueryComplete
• [ ] QueryPixelCount
• [x] SupportsDXT1
• [x] SupportsS3TC
• [x] SupportsBC7
• [x] SupportsHardwareInstancing
• [x] SupportsNoOverwrite
• [x] SupportsSRGBRenderTargets
• [x] GetMaxTextureSlots
• [x] GetMaxMultiSampleCount
• [ ] SetStringMarker
• [ ] GetSysRenderer
• [ ] CreateSysTexture
• [x] PrepareWindowAttributes
• [x] GetDrawableSize
• [x] CreateDevice

[flibitijibibo]

For Xbox, let's separate it like we do for D3D11, but the Xbox path can be

#include "FNA3D_Driver_D3D12_GDKX.inl"

We'll host that file in its own private repo in the FNA org.

[TheSpydog]

Closing this in favor of an alternative solution. More details coming soon (hopefully)...