Interesting, the shader reinterpret code was added in 2016 but nothing
mentions *why* it was needed, what driver actually needs that. In 2025
all drivers I tested with are happy just with a passthrough.
Which means, this reinterpret is still only ever done in a single
overload of these APIs, reading to a buffer or reading a cube map
doesn't have this code path.
I just don't see a point in those. PBOs are for when a roundtrip through
a CPU memory would be wasteful, but these utils are mainly for use in
tests. Definitely not for being called several times per frame, because
the temporary framebuffer creation just doesn't make sense. Not sure
what was I thinking in 2016 when I added those, apart from "feature
parity for no practical reason".
Compared to Corrade, the improvement in compile time is about a minute
cumulative across all cores, or about 8 seconds on an 8-core system (~2
minutes before, ~1:52 after). Not bad at all. And this is with a
deprecated build, the non-deprecated build is 1:48 -> 1:41.
Ugh. Was using this to verify that the glyph cache was correctly
populated, only to end up with a GL error that I thought was coming from
the glyph cache itself and not here. Wasted too much time on that.
There will be numerous additions to this one so it made sense to make it
a static library instead of a header-only library. That also allows
CMake users to just link to Magnum::OpenGLTester instead of going
through the pain of a huge branching in order to find a correct
windowless application just to run their tests. It could have been done
even without the static library using a INTERFACE target, but that
wouldn't work on CMake < 3.0 (which, unfortunately, quite a few people
are still stuck with).
Unfortunately it's already heavily used elsewhere so I had to go through
the pain of deprecating the old implementation. The old implementation
was header-only so it can't be just typedef'd to the new one as there
would be linker failures. So the old header is just kept as it was, with
only the macros reduced.