API for dynamically loading GL extensions

[nrdvana]

Since OpenGL supports loading function pointers on demand, and this varies per platform, it seems reasonable to abstract this behavior in the Alien:: module. There is an entire separate project "GLEW" to deal with this problem, which we might or might not want to include. The main theme of GLEW is just to declare a lot of global pointer-to-function, and then lazy-load them on demand. I came up with a (greatly) simplified version of their loader for my OpenGL::Sandbox project, dealing with only the functions I needed, and named it "glducktape". I think the giant table of function pointers might be too much for the alien module (maybe best saved for a OpenGL::GLEW module), but wrapping the C loader function with a platform-neutral API would be small-ish and quite useful for the perl ecosystem.

The loader I wrote (linked above) is

void* glducktape_initProcAddress(const char *name, void **fnptr);

and implemented for Linux, Mac, and Win32. It is just a wrapper around dlsym, GetProcAddress, or glXGetProcAccress.