* It's not particularly scalable and can be brittle to driver changes, and we
can use targeted specific pixel tests to check what we really want - to see if
the output has rendered correctly.
* Overlay tests still check files directly - this is a future refactor to
remove.
* Visual assist comes with a pre-defined interpretation of TEST() for
googletest, which conflicts with ours. We can't seem to override it with a
va_stdafx.h even
* Instead of only doing a very lightweight check to see if the API is available
up-front, we now share the API initialisation among all API tests far enough
to determine availability of extensions, features, etc. Then we can precisely
determine which tests are available and which aren't before running.
* This is the only way in GL to do rendering from one mip to another. We handle
it and display the whole texture even if it's temporarily constricted, and
display the mip state in the pipeline viewer.
* If the mip state is constricted at the start of the frame capture, only mips
0..MAX will be visible at all and other mips will be assumed to not be valid.
baldurk