[Celestia-developers] Checkin: Ring shadows

[<cl...@ns...>]

With this checkin, shadows from rings will now appear on planet
s surfaces.  This requires vertex programs and and the clamp to border
extension to work.  There are workarounds for both requirements . . .  I
actually implemented an approximate version of the ring shadow code which
just uses standard OpenGL texture coordinate generation, but I wasn't too
happy with it, so it's disabled.  For Celestia 1.2.6, I'm going to rewrite
all the vertex programs using the OpenGL 1.4 vertex program extension so
that they'll be usable on Radeon cards.  But for now, it's only GeForce
users who get to have all the fun.

--Chris