GL entrypoint resolution is now done manually. This has a couple
immediate benefits, such as not having to retrieve hundreds of
functions pointers that we'll never use. It's also nice to have
an exact overview of all the entrypoints used by mkxp.
This change allows mkxp to run fine with core contexts, not sure
how relevant that is going to be in the future.
What's noteworthy is that _all_ entrypoints, even the ones core
in 1.1 and guaranteed to be in every libGL, are resolved
dynamically.
This has the added benefit of not having to link directly against
libGL anymore, which also cleans up the output of `ldd` quite
a bit (SDL2 loads most system deps dynamically at runtime).
GL headers are still required at build time.
This gets rid of the "batch/flush" semantics for #set_pixel
and instead just directly uploads the pixel color to the
texture, circumventing the float conversion entirely.
Also makes a lot of code simpler in many places as calling
'flush()' is no longer required for bitmaps.
nearly all of the previous required extensions are CORE in OpenGL 2.0
the remaining ones need to have fallback checks for ARB vs EXT vs APPLE
variants..
The general rule I'm aiming for is to <> include
system wide / installed paths / generally everything
that's outside the git managed source tree (this means
mruby paths too!), and "" include everything else,
ie. local mkxp headers.
The only current exception are the mri headers, which
all have './' at their front as to not clash with
system wide ruby headers. I'm leaving them be for now
until I can come up with a better general solution.
The drawing is now completely shader based, which makes away
with all usage of the depracted matrix stack. This also allows
us to do things like simple translations and texture coordinate
translation directly instead of doing everything indirectly
through matrices.
Fixed vertex attributes ('vertexPointer()' etc) are also
replaced with user defined attribute arrays.
Jonas Kulla
Edward Rudd