Checks if all the points are on the same plane
if there are less than three points etc ... The function also sets internal info
returns YES if the polygon is valid or NO (if not valid).
If the answer is NO it is usually because the polygon is
not convex or because the points are not on the same
plane or the bitmap cords are not good or the light intensity cords are not good.
When doing STATE_engine_add_polygon() this check is done
automatically so it is impossible to add a bad polygon
|