ray/lib/ball.cal

{
        ball.cal - 2d coordinate mapping onto sphere.

        unit sphere centered at origin

        A1 = picture height/width
        A2 = unit scale for pattern
}

ball_u = Atan2(Py,Px)*Sqrt(1-Pz*Pz)/A2;
ball_v = Acos(Pz)/A2;

ball_tile_u = mod(ball_u,max(1,1/A1));
ball_tile_v = mod(ball_v,max(1,A1));

ball_match_u = tri(ball_u,max(1,1/A1));
ball_match_v = tri(ball_v,max(1,A1));
Revision:	1.1
Committed:	Wed Mar 12 17:45:47 2003 UTC (22 years, 2 months ago) by greg
Branch:	MAIN
Log Message:	Added the rest of the missing files to ray/lib/
#	Content
1	{
2	ball.cal - 2d coordinate mapping onto sphere.
3
4	unit sphere centered at origin
5
6	A1 = picture height/width
7	A2 = unit scale for pattern
8	}
9
10	ball_u = Atan2(Py,Px)Sqrt(1-PzPz)/A2;
11	ball_v = Acos(Pz)/A2;
12
13	ball_tile_u = mod(ball_u,max(1,1/A1));
14	ball_tile_v = mod(ball_v,max(1,A1));
15
16	ball_match_u = tri(ball_u,max(1,1/A1));
17	ball_match_v = tri(ball_v,max(1,A1));