[SDL] rendering from a different thread.

[Peter Ketting]

> afaik you can only render in the main thread - at least, I've tried
> to no avail.
> SDL docs seem to support this.

> Ed

I've succesfuly rendered using a seperate thread and it worked
just as suspected. The way I did it was to set up a render thread
which rendered the graphics constantly, while a timer signaled the
main thread to process the game logic at a constant frame rate.

Cheers,
Peter