[ODE] cylinder plane bug

[David Walters]

> I find one bug in cylinder vs plane collide.
> www.klinik.frehost.pl/filmiki/cylinder_plane_bug.avi
> this is hapend when center of bottom disk intersect a plane.
>
> I fixed this bug, but a think that problem is in isect_disc_plane(...)
> or in isect_plane_plane(...)

Hi, thanks for your fix. To test I hacked test_boxstack to limit the
object count to 5, set the gravity from 0.5 to 5.0 and hit 'y' for a
bit. The lack of cyl-cyl made this job a lot easier :-)

It seems that although it generally works most of the time - there's a
problem when the cylinder hits the plane on a corner at around 45
degrees. It acts like there's a 'hole' there which causes the cylinder
to fall through the plane a fair amount.

With this fix in place this falling is limited but still wrong -
without it though, I've seen them fall forever :-(

Bram, how can we fix this? :-)

ps. This was in a vs2005 Single build.

Regards,
Dave