We were running out of descriptor sets, as they weren't being freed at all.
Now there's a 1-1 table of texture-descset, and no way to run out of them.
Better solution would be to move this descset management to vk_render, and allocate them dynamically from a smaller pool.
Traditional renderer operates in sRGB-γ space (as everyone was in 199x).
Making vulkan textures explicitly SRGB for RT renderer breaks color for
trad rendere. Make sure trad renderer still has raw SRGB-unaware texture
sampling.
Adds an UNORM image view for all relevant SRGB textures, and uses them
exclusively for trad renderer. RT still gets proper SRGB views.
Also rename XVK_ to R_Vk for images
On Windows we're seeing a max size = 0x0 swapchains. Those cannot be created or used. Make sure that we're not, and we're not trying to draw anything when there's no swapchain available.
Unfortunately we still have to call some rendering functions (without actually rendering anything) to make sure that various invariants hold.
fixes#463
Ivan Avdeev