We previously thought this wasn't possible because constant buffer offsets and
partial updates were unavailable, but we were reading the wrong table - this is
only the case for D3D11...
https://learn.microsoft.com/en-us/windows/win32/direct3d11/overviews-direct3d-11-devices-downlevel-intro
... while 12 doesn't list this feature at all:
https://learn.microsoft.com/en-us/windows/win32/direct3d12/hardware-feature-levels
We double checked and Jesse Natalie confirmed that this feature is required for
D3D12 even for 11_0 drivers. (Thanks Jesse!)
Additionally, D3D12 requires that UAVs are accessible from all shader stages,
meaning Tier 2 is enough to support the number of UAVs we need. Tier 1 could be
a property to lower the requirements, but that can be done later.
For a depth buffer in D3D12 that is also going to be used in a texture sampler, the creation (on an Intel HD 5500 igpu) fails. e.g. SDL_GPUTextureCreateInfo type = TEXTURE_2D, format = D32_FLOAT, usage = DEPTH_STENCIL_TARGET | SAMPLER
The error messages are:
D32_FLOAT
D3D12 ERROR: ID3D12Device::CreateShaderResourceView: The Format (0x29, R32_FLOAT) is invalid when creating a View; the
Resource was already created with a fully qualified Format, which is not castable (0x28, D32_FLOAT).
D24_UNORM
D3D12 ERROR: ID3D12Device::CreateShaderResourceView: For the resource format D24_UNORM_S8_UINT, when making a D3D view, the format name for the view can't be R24_UNORM_X8_TYPELESS.
I found this is because the texture format needs to be created as _TYPELESS, then the views (depth stencil view, shader resource view) should then be created as their respective types - e.g. texture = R32_TYPELESS, dsv = D32_FLOAT, srv = R32_FLOAT
Tested and working on:
NVidia RTX 3050 (D3D12 feature set 12_2)
Intel HD 5500 (D3D12 feature set 11_1)
We may want to extend this with additional properties in the future.
Also removed SDL_PROP_GPU_DEVICE_DEBUG_VULKAN_CONFORMANCE_STRING. If we need feature level queries we can add them in the future.
Since there is no option to change it this seems like a much better default value. The stretching behaviour is really off-putting.
The new behavior shows a small black border when resizing the windows. This makes it more in line with the other backends and it's what you would expect to happen as a user.
