bmap_to_uv(bmap)
Converts the given bmap into a UV offsets map, needed for environment
bump mapping. An UV offsets map contains, at each pixel position,
the luminance difference values of the blue channel of the original
bmap in u and v direction.
Parameters:
bmap - bitmap to be converted to uv offsets
Returns:
0 if the conversion failed
, otherwise the bmap pointer
Speed:
Slow
Edition:
C
P
Remarks:
While DOT3 bump mapping modulates the texture brighness
according to a light vector, environment bump mapping modulates the
texture UV offset, creating bumps on a mirror like surface.
See also:
bmap_to_normals, bmap_to_mipmap