roadway tracing

[joevenzon]

If you don't use roads.trk, then you just get the basic ray-triangle intersection to find the roadway. This doesn't work very well on roads that aren't flat, because you're driving on triangles instead of a smooth surface. If you use roads.trk, you're actually driving on a sweet ass bezier patch that is totally continuous and smooth... which is pretty necessary on roads that aren't completely flat if you're going fast. However, my ray/bezier collision code seems to have some lingering bugs, and they cause the bumps you described. It may soon be time to audit the code and try to find what's causing the bug (I did this before and fixed ONE bug that was causing the bumps, but this second bug remains).

The extra entries are for each control point of the bezier patch. Each patch has a 4 x 4 control point grid that is automagically generated from the points you selected as well as the previous and next patch.

I'll refer you to the Racer developer guy for further info:
http://www.racer.nl/tech/splines.htm
(his solution is a bit funky, I think -- but I shouldn't talk, as my code is still kind of buggy)

Oh yeah, the driveable thing was deprecated because the code now lets you drive on anything that you can collide with and collide with anything you can drive on. Originally this wasn't so.