Because the library still links to the old crappy opengl32.dll, we need
to load all symbols above OpenGL 1.1, not just those that are above
OpenGL ES 2.0/3.0.
Just added them to the list, nothing integrated or implemented yet. Also
added some more stuff into OpenGL mapping table, as I apparently forgot
some entries.
In OpenGL ES 2.0 there is EXT_draw_buffers, which I overlooked somehow,
so I added it to extension list and included in the implementation. It
combines NV_draw_buffers and NV_fbo_color_attachments, so the
implementation now selects one of the two based on which extension is
supported, preferring the EXT one. Updated the documentation to be
less confusing, fixed extension links. Also the single-output
mapForDraw() is not handled separately on ES anymore and just calls
DrawBuffers implementation with single parameter, resulting in less
generated code.
EXT_draw_buffers can also be called on default framebuffer and
apparently in ES there is no way to map front framebuffer for drawing,
so I removed it from the DefaultFramebuffer::DrawAttachment enum.
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.
Vladimír Vondruš