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:	1.2
Committed:	Tue Mar 18 17:30:16 2003 UTC (22 years, 7 months ago) by greg
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.1:	+0 -0 lines
State:	*FILE REMOVED*
Log Message:	Decided to move ray/lib directory into non-CVS distribution
#	User	Rev	Content
1	greg	1.1	{
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));