I’ve seen well-textured balls, planets, and other spherical objects in couple of games, last time in UFO: aftermath. If you just splatter a texture into latitude/longditude as u and w -coordinates you’ll get lots of ugly texture distortion to poles.
I can think myself an one way to implement a spherical map with minimum distortion. By mapping in triangles instead of squares. But I don’t know any algorithms. How to produce vertices and texture coordinates for such spheres?
Also, I don’t see a way to generate a complete spherical map from a simple flat square map. Is there some intuitive way on drawing such maps without real trouble?
Though, is there other algorithms to render a sphere without or with minimal distortion?
Both raytracing and rasterising algorithms are interesting.
The hairy ball theorem states that it is impossible to define continuous texture coordinates on a sphere without any poles that distort the texture.