posted December 22, 1999 02:49 AM
Check out this web site:
They seem to have a working spherical LOD renderer that looks pretty cool.
It should be possible to use Binary Triangle Trees for a spherical world, since if you start with a Tetrahedron which is connected to itself by proper neighbor pointers, it should work to split triangles in it just as you would in a flat mesh. Then you'd just need a mapping from 3-space vertex coordinates to your 2D height field, and you should be set. When you split a tri, you would need to position its new middle of hypotenuse point in 3D according to your mapping of height map to sphere, which would be a bit more work than in 2D where you can just directly make every vertex's Y coord the raw value from the height map under it.
-- Seumas McNally, Lead Programmer, Longbow Digital Arts