[fpc-pascal] fpGUI powered by OpenGL

[Darius Blaszyk]

> The above explains why it is useful for an application developer to
> use an openGL backend.
> 
> It does not explain the following: Since fpGUI already has two
> backends (afaik, X and winap), why can't openGL a third one? Did you
> change the way fpGUI interfaces with its backend? Is this change so
> incompatible with the current backends, that they cannot be modified?

The changes I think are pretty incompatible. This is because the GLut
library also provides messaging, whereas in fpGUI the messages are
implemented outside of the backend. Therefore hacks are needed to keep
the drawing messages coming correctly. With a pascal context library
everything could be merged seamless I suppose.

Darius