It seems that there is no such thing as eglGetProcAddress() and thus we
are able to use only functions that are defined in the ES[23]/glext.h
header and no others. So, currently, the function loader internally
undefs all function name macros that were defined in our flextgl.h
header, then includes the Apple's glext.h header and assigns function
pointers of those extensions that are defined in the header. Apple also
has some minor differences in function signatures (different constness
of pointer-to-pointer variables) so I had to reinterpret_cast
everything.
Might seem to be uglier than including glext.h directly in our code,
but I made bad experience when doing so -- I want to depend on my
header bugs that are consistent across all platforms instead of
depending on whatever changes Apple makes in its headers. I also want to
have all functions defined and not only those that are supported on
iOS.
Phew. Thank you, flextGL, for making it way easier than it appeared to
be at first.
The actual WebGL 2 distinction was done as a part of previous WebGL
cleanup. It compiles, but is completely broken, as Emscripten has some
missing bits to go through at least Context class creation.
Using GLES extension functions in the code won't cause linker failures
anymore, but their addresses aren't being loaded yet. As said before,
NaCl and Emscripten is still a special case.
Currently just regenerated the stock headers using flextGL, reducing
line count a bit. No dynamic extension loading or function pointers yet,
trying to make as little changes as possible.
The function pointer loading is now moved to Application classes to make
it possible to decide about platform-specific API at usage time, not at
library compilation time.
Currently it's not possible to create the Magnum context any other way
than through Application classes, will solve that in next commits.
Everything what was in src/ is now in src/Corrade, everything from
src/Plugins is now in src/MagnumPlugins, everything from external/ is in
src/MagnumExternal. Added new CMakeLists.txt file and updated the other
ones for the moves, no other change was made. If MAGNUM_BUILD_DEPRECATED
is set, everything compiles and installs like previously except for the
plugins, which are now in MagnumPlugins and not in Magnum/Plugins.
Caused linker problems mainly on Windows, where every symbol would need
to be exported manually, on Linux this was done implicitly (or with
`-fvisibility=default`). I now maintain glLoadGen fork at
https://github.com/mosra/glloadgen.git containing changes needed for
Magnum.
The `ogl_*()` functions are used only internally, various global
variables for extension queries are not used at all and thus they don't
need to be exported. I thus enabled `-fvisibility=hidden`.
Fixes#16.
Vladimír Vondruš