Not having to wait for an image->buffer copy to finish on the
GPU allows for more efficient synchronization. Significantly
improves performance in The Witcher 3.
- When a D3D11 texture was created with a mip level count of zero,
DXVK would compute the correct number of mip levels, but not write
them back to the description field.
- Framebuffers would always use the size of the top level, not the
mip levels that were actually attached to the framebuffer.
- Several image copy operations did not handle mip levels other
than the top mip level correctly.
Image mapping now returns the map pointer of a separate
buffer, rather than the the image itself. This fixes
issues with applications that ignore the RowPitch
and/or DepthPitch fields of the MappedSubresource struct.
This is required because in D3D11, typeless formats can be used
to create both depth and stencil images, and color formats can
be used to view depth images. In Vulkan, images and views that
are used as depth-stencil attachments will have to be created
with a depth-stencil format, so we have to take the image's
bind flags into account when picking a format.
