This commit unhacks some parts of the 3D rendering.
Most notably:
- possibility to use negative texture units
(no longer weird manual index allocation for user samplers)
- refactoring of light code, now sorts in a different way,
should yield better performance
- fixes a crash while saving (because of "Illegal instruction" execution)
when using a decent compiler (clang, it's clang. Thanks GCC for not telling me about UB).
This commit adds a new rendering backend, GLES2, and adds a
project setting to enable it.
Currently this backend can only be used on the X11 platform,
but integrating into other platforms is planned.
Marcin Zawiejski
Thomas Herzog
Rémi Verschelde
Juan Linietsky
Poommetee Ketson