Needed a change in flextGL to allow merging in 3rd party gl.xml
additions because Chrome is apparently a center of the universe and thus
doesn't need to bother upstreaming its extensions, ffs.
Those are now also available under WebGL 1/2 and OpenGL ES 3.O (strangely
not OpenGL ES 2.0) under EXT_texture_compression_{rgtc,bptc}. The GL names
are extra weird-ass now that all other APIs use the BC names.
This fixes a conflicting definition of GLsizeiptr and GLintptr when
Magnum is combined with qopengl.h from Qt on Windows. Khronos has it as
`signed long int`, whereas qopengl.h as ptrdiff_t, which is just `int`.
It is superseded by core functionality. The only annoyance is that you
need to use TextureFormat::SRGB in ES2 and TextureFormat::SRGB8 in ES3,
but that's with many other formats anyway. Also apparently the unsized
format is still allowed in core desktop GL, which is a shame.
This was the actual problem. Most of ES extensions are not available in
WebGL, thus the GL headers and the code was far more bloated than it
needed to be. The GL header is now reduced and the previous 13 commits
were disabling features that aren't actually available in WebGL.
The final executable size is reduced by ~50 kB, which actually isn't
much, but still something.
Some ES extensions (ANGLE_depth_texture and ANGLE_instanced_arrays) have
now WEBGL_* prefix. I'm still using the original prefix in the
implementation because there are headers for these, but in public docs
and elsewhere they are exposed with WEBGL_*.
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.
Currently just regenerated the stock headers using flextGL, reducing
line count a bit. No dynamic extension loading or function pointers yet,
trying to make as little changes as possible.
Vladimír Vondruš