It's faster that way because it doesn't involve a linear lookup, if the
resource is already imported it's a constant-time check and it becomes a
no-op.
Wanted to add a proper variant that reads all layers at once into an
Image3D, but that requires the Image APIs to be made less crappy first.
So it's just this for noew because now I badly need it for
Text::DistanceFieldGlyphCacheArrayGL tests.
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".
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.
Partially needed to avoid build breakages because Corrade itself
switched as well, partially because a cleanup is always good. Done
except for (STL-heavy) code that's deprecated or SceneGraph-related APIs
that are still quite full of STL as well.
Mainly important for Shader::addSource() to prevent it from creating a
needless copy, but doesn't hurt to do the same also for
uniformLocation(), bindAttributeLocation() etc. -- it'll avoid a runtime
strlen() in that case at least.
Same as in the previous commit, most cases are inputs so a StringStl.h
compatibility include will do, the only breaking change is
GL::Shader::sources() which now returns a StringIterable instead of a
std::vector<std::string> (ew).
Awesome about this whole thing is that The Shader API now allows
creating a shader from sources coming either from string view literals
or Utility::Resource completely without having to allocate any strings
internally, because all those can be just non-owning references wrapped
with String::nullTerminatedGlobalView(). The only parts which aren't
references are the #line markers, but (especially on 64bit) those can
easily fit into the 22-byte (or 10-byte on 32bit) SSO storage.
Also, various Shader constructors and assignment operators had to be
deinlined in order to avoid having to include the String header, which
would be needed for Array destruction during a move.
Co-authored-by: Hugo Amiard <hugo.amiard@wonderlandengine.com>
There's no reason for those to exist anymore -- origiinally they were
added in a hopeful attempt to make use of parallel shader compilation,
but in practice that meant compiling at most two or three shaders at
once and still stalling until that was done, so not that great at all.
The new APIs provide much better opportunities for parallelism.
Fun fact:
CORRADE_INTERNAL_ASSERT_OUTPUT(vert.compile() && frag.compile());
is actually one character shorter than
CORRADE_INTERNAL_ASSERT_OUTPUT(GL::Shader::compile({vert, frag}));
so not even typing convenience would be a reason to keep these.
What's left is *a lot* of places taking monstrous
std::vector<std::reference_wrapper> and that can't be changed to
std::vector<Containers::Reference> in a source-compatible way. Even that
would be only a temporary change, since the goal is to fully avoid
dependency on STL in those cases.
The final version of these APIs should take
Containers::ArrayView<Containers::Reference> and be implicitly
convertible froom e.g. std::vector<Containers::Reference>. That's
definitely possible, but not in time for 2019.01, so instead of forcing
users to temporary pass a `{vec.begin(), vec.size()}` everywhere instead
of just `vec`, I'm rather keeping these APIs intact.
Vladimír Vondruš