[comp.graphics] Intersections in spherical coordinates

carlson@aftac.tis.llnl.gov (John Carlson) (07/12/88)

I would like to intersect a line with the surface defined in spherical
coordinates

	rho = A + B * cos (C * theta) * cos (D * phi)


	where A, B, C and D are arbitrary constants, and cos is cosine.
			(Try |C| < 1 or |D| < 1)

I am currently using a bounding sphere, Newtons's method and
bisection if Newton's fails.

Is there a good reference on intersections of lines and surfaces in
spherical coordinates?  Can I take the trigonometry out of the problem?
Does a deterministic method exist for breaking up the surface into
polygons if C and D aren't integers?

Thank you,

John Carlson
carlson@aftac.tis.llnl.gov