I have a problem with vanishing spheres… I am displaying a large sphere (using gluSphere - radius is 13000, for what it’s worth) and moving the sphere away from the viewpoint. My z clipping plane is large (250000000.0). However, the sphere vanishes long before I’d expect it to. I’ve tried moving the z clipping plane further away, but the same thing happens.
Is this a case of the polygons becoming too small to draw? Or am I doing something silly? Would I, perhaps, be better off using a NURBS for this?
Hmmm. I’d be happy if they were just one pixel, but the sphere is still significantly large. The effect I get is that the sphere kind of fades out - as if they were being clipped.
I tried using fewer slices for the sphere, but they still disappear at the same point.
Is there perhaps some kind of maximum for the z clipping plane? I can’t find any documentation which tells me anything about this…
yep, I use linux too, and I have the same problem. don’t care how far/big I set the fustrum, polygons get clipped really early, so I guess it must be a driver problem?
I use a riva128, so if you use the same nvidia driver, the problem must be right there…
[This message has been edited by Sjonny (edited 03-08-2000).]
The problem could be the precision of the Z buffer. As I read in another thread, the zbuffer must span across the z-range (from nearz to farz), so when zbuffer has few bits the z-fight conditions increase dramatically, due to the stepping of Z values to represent a large range. The only solution to this, is to find a good compromise between Zbuffer precision and Z range.