magnum/src/MagnumExternal/OpenGL/GLES2

OpenGL header and extension loader is generated using flextGL, get it at https://github.com/ginkgo/flextGL.

See extensions.txt for requested version and a list of non-core extensions. Call flextGLgen.py in this directory with the following arguments to generate files for generic GLES2 implementations:

.../flextGLgen.py -D . -t . extensions.txt

It will generate flextGL.h, flextGL.cpp, flextGLPlatform.cpp, flextGLWindowsDesktop.h, flextGLWindowsDesktop.cpp, flextGLPlatformWindowsDesktop.cpp and flextGLPlatformIOS.cpp files.

Desktop GLES on Windows still links to the ancient opengl32.dll which exports only OpenGL 1.1 symbols, so we have a special set of headers that queries pointers for everything above OpenGL 1.1 (instead of everything above OpenGL ES 2.0).

iOS, on the other hand, doesn't have any extension loader mechanism and all supported entrypoints are exported from the library, so we set the function pointers to those exported symbols in case the system GL header defines them.

NaCl and Emscripten don't have the ability to manually load extension pointers, thus they have only header files:

.../flextGLgen.py -D . -t NaCl/ extensions.txt
.../flextGLgen.py -D . -t Emscripten/ Emscripten/extensions.txt

This will generate stripped-down flextGLNaCl.h and flextGLEmscripten.h files.

As usual, be sure to check the diff for suspicious changes and whitespace-at-EOL (although there shouldn't be any).