View Full Version : Sphere Map on drugs??

10-30-2000, 11:13 AM
I got this weird thing..
I use a sphere map on a sphere, and somehow it seems that instead of having singularities at the edge of the sphere map i have a singularity in the center???

ie. the edges of the sphere map are in the center of the sphere instead of around the edges of the sphere..

I have no idea how this is possible..
If i'd have to guess it's because of the normals are inversed..
But i can't check that without hacking around in the engine in such a way that a lot of people @ lostboys will get fairly pissed at me hehe

So, has anyone seen this effect before?
if so, do you know how this is caused and how i can prevent this?


10-30-2000, 09:36 PM
Spheremaps have a point singularity, at the back of the sphere. Generally, spheremaps are considered to be a view-dependent form of environment mapping, and this (along with the complicated texcoord formula) contributes to their unpopularity. This means that every frame, or at least every few frames, you want to update your spheremap image so that the singularity will be either invisible or at the very edge of the object.

- Matt

10-31-2000, 10:46 AM
Well that isn't the problem.. I know since it looked fine with our directx module..

But i discovered that the cubemap extension had a normal_map, which actually worked like the sphere map should oddly enough..
oh well