[Kde-games-devel] KDE & OpenGL 3.1

[Casper van Donderen]

(For now I only send this to the games list, later it has to go
towards the KWin people too I think)

Last week at the Game Developer Conference '09 the Khronos Group
released the OGL3.1 specification. Which (finally) involves a massive
API change. I believe that 95% of the old API is now removed from the
official spec (and put into the ARB OpenGL 1.0-2.1 deprecated
extension). This is very important, since the new graphics chips all
have something like 800 processors which can all be used for
everything in OpenGL3.1 there is no fixed functionality anymore. This
allows the programmer to reserve a part of his graphics chip for a
certain application, and should thus greatly enhance the speed of
programmer-chosen parts of code.

This is also important for KDE. Most KDE people I talked with in
person believe that Intel graphics are good enough, which obviously
doesn't support OGL3.0/3.1. The problem is the new Intel Larrabee
videochip (coming next year) which has to support the newest version.

The reason for sending this mail is the following: I'm working on the
3D-engine for Kolf-NG and the development of KGLEngine looks to be
going quite fluently as well. But how are we going to tackle the
upcoming problems with API not being supported anymore?

For Kolf I'm thinking checking at the start of the application which
codepath to follow:
(some pseudo code)
if (getGLVersion() > 3.0)
{
   openGL 3+ codepath
}
else
{
   openGL 3- codepath
}

But this creates a much larger codebase, which will take longer to
compile, but I think this is needed in the current overlapping time
period. (the newest NVIDIA-driver already supports OGL3.0, in about 2
months the driver should support OGL3.1 for GeForce 8+ series cards, I
don't know about AMD/Mesa)

Any ideas (leave OGL3+ support out of KDE for now?)

Casper