Based on the design document, "The runtime will not clamp or validate
the input, but implementations may clamp to the range [0,1] if necessary.",
so we test for the EXT_depth_range_unrestricted extension, and only clamp if
it's not available (thus, necessary to do so).
NaNs are converted to zero as per "NaNs must be treated as 0, but the runtime
will convert NaNs to 0 on behalf of the implementation.", and a default bounds
are set to 0.0 and 1.0.
This would allow us to use vkd3d-utils directly in Wine [with the exception of
D3D_COMPILE_STANDARD_FILE_INCLUDE, but we can simply pass the ID3DInclude object
to D3DCompile2VKD3D().]
This is a proposed API change in 946, which won't make it into this release.
The intent is to allow slightly larger constants to be specified in the updated
vkd3d_shader_parameter1 structure. In particular, this is large enough to pass
4-dimensional integer or float vectors inline, which the proposed clip plane
implementation will use, as well as other Direct3D FFP parameters.
We could also simply add vkd3d_shader_immediate_constant1 as a separate union
member in vkd3d_shader_parameter1, but this API is a bit cleaner and simpler.
