[Bug 33814] Ground Control: poor fps performance

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=33814

--- Comment #33 from Steve Schnepp  ---
I finally fixed it.

On buildings & jungle there's DrawPrimitive() calls with a bigger number of
vertices (5 or 6 and up to 8).

So the code flushed the buffer needlessly.

Once I rewrote the whole buffering code to code with any number of vertices,
the slowdowns are fully gone.