Questions about spheres

[chronozphere]

Great.. You're totally right. Its based on an octahedron.

I will try to make a geosphere creation method.
Maybe i'll post some code when i'm done. If someone needs it.

I am sure there is a good way to generate the texture-coords.. i will try to figure that out.

[JSoftware]

Made this right now. Subdividing is pretty simple and texture coordinates are easily interpolated if you use normal sphere mapping.
Vertex generation is simply interpolate each vertice in a triangle to generate new edge vertices and then normalizing each to get a unit vector which sits nicely on a sphere

[grudzio]

Made this right now. Subdividing is pretty simple and texture coordinates are easily interpolated if you use normal sphere mapping.

The problem with sphere texture mapping is with the singularities on at the north and south pole. When you make sphere from rectangle the upper and lower edges are squashed to a point. So it is not obwious what texture coordinates should be chosen for both poles. Each triangle that owns such point needs different texture coordinate or there will be artefacts.

Normal sphere generation method solves this problem by creating for each vertical slice separate north and south pole (Look at the link Cragwolf gave).So those triangles near poles are not triangles but degenerated quads. It is easy then to set appopriate texture coordinates.

For geosphere, each triangle that contains south or north pole must have separate texture coordinate for that point. It is possible to do, but IMO not during the subdivision proccess.

[JSoftware]

Finally I get your point.. I'll look for a workaround