[fpc-pascal] How to use OpenGL 2.0 features

[Michalis Kamburelis]

Lord Satan wrote:
> On Sun, 10 May 2009 18:46:26 +0400 dmitry boyarintsev
> <skalogryz.lists at gmail.com> wrote:
> 
>>> So it looks like I have to init all OpenGL versions from 1.2 to
>>> 2.0 to make sure that all OpenGL 2.0 core functions are
>>> initialized. Is this true?
>> Judging from glext, it's true.
> This makes no sense to me. I can submit a patch so that all lower
> version functions are loaded when the higher version is loaded (hope
> it is understood what I mean). I already modified the glext file and
> just want to know if there is any interest or if the current
> behaviour has any advantages I fail to see.
> 

You mean you want to change Load_GL_version_2_0 to also call
Load_GL_version_1_5 under the hood, and then Load_GL_version_1_5 to call
Load_GL_version_1_4 under the hood and so on? I guess that's Ok, go for it.

Be aware that this will *not* work for OpenGL 3.x versions, where 3.0
deprecates and 3.1 removes some functions. Since 3.1, OpenGL versions
are *not* guaranteed to be backwards compatible. Programmer will have to
call Load_GL_version_3_1 and Load_GL_version_2_0 (or check
ARB_compatibility) separately, since these are orthogonal.

I guess this is the advantage of current approach: it doesn't assume
that OpenGL versions are backwards compatible, and indeed they don't
have to be since 3.1.

But for GL 2.x and lower, sure, this will work fine.

Michalis