Generating vertices for a sphere

Question

In the DirectX mobile lighting sample, a cylinder is generated in the following manner:

for( DWORD i=0; i<50; i++ )
            {
                FLOAT theta          


        

Answer 1

The usual way to triangulate a unit sphere is to build a tetrahedron or a icosahedron and

• If precision is enough, stop
• Else, for each existing face:
• Add a vertex at the midpoint of each edge and normalize it so that it is on the unit sphere
• Replace the face with four new faces. One of the faces has the three new midpoints as corners (draw it on paper, and the other three faces will become obvious)
• Loop.

To avoid duplicating vertexes at the edge midpoints, you need to track the existing vertices for reuse.