Approximately three or four times now, the issue of pointers being
in an inconsistent state been an issue in the video backend renderers
with regards to tripping up other developers.
Global (ugh) resources are put into a unique_ptr and will always have a
well-defined state of being - null or not null
This was relying on behaviour that GLExtensions was adding fake extensions to the supported list with ES.
This no longer happens so it needed to be changed.
This was due to specifying negative source coordinates for the texture copy, which must lie within the bounds of the source and destination textures.
The behavior now is to clamp the copy region to [0 <= size <= backbuffer size], resulting in a copy region that can be smaller than the backbuffer, but never larger.
Since ResolveSubresource cannot be used with depth textures (and throws an error with the debug layer enabled), use a shader which selects the minimum depth value from all samples.
Changes the sampler by XFBEncoder to use a linear filter, rather than point, to match GL behavior.
The spec says that vendors can set the max texture size to be 65KB and we want 1MB.
Check the maximum supported and drop to the max if it is less than 1MB
They were only called at once, so no need to seperate them.
This also removes the only dereference of the NativeVertexFormat in VideoCommon, so backends may just return nullptr.
It was only implemented in OpenGL, though the option was visible in both
backends, leading to memory leaks if you enabled it in DirectX.
And it wasn't particularly useful as a debug feature as it only showed
where in the EFB the copies were taken from, not what format it was, or
what the copy was used for, or what content was in the EFB at that point
in time.
Also, it stretched the copy regions relative to the window, so the
on-screen regions don't even line up with the window unless the game used
the full EFB (some pal games) and you game image stretched to the full
window.
