HOW TO COMPUTE TEXTURE COORDINATES

THEORY:
-- need a map from a surface S (in R^3) into R^2:

f: S --> R^2

SIMPLE CASES:

1. S = polygonal patch
2. S = cylinder
3. S = banana
4. S = sphere (unbounded distortion at poles)
5. S = cube

2-STEP APPROACH

	Eric A. Bier and Kenneth R. Sloan, Jr., "Two-Part Texture
        Mappings", IEEE Computer Graphics and Applications V.6 #9, Sept.
        1986, pp 40-53.

1. Use an intermediate canonical surface S'.
2. O-map: find map from S to S'. texture (R^2).
3. S-map: find map from S' to texture (R^2).
4. "SHRINK WRAP" implementation of O-map

ENVIRONMENTAL MAP:
-- Can be done by appropriate choice of O-map in [Bier&Sloan] scheme.

OPENGL's SUPPORT FOR COMPUTED TEXTURE COORDINATES