src/gen/illum.cal

{ SCCSid "$SunId$ LBL" }

{
        Coordinate computations for mkillum output.

        There are no arguments for the spherical case:

        il_alt          - Altitude (1 to -1) for spherical coordinates
        il_azi          - Azimuth (0 to 2*PI) for sphere

        For the hemispherical case, A1-A9 are the unit vectors for the
        hemisphere's coordinate system:

        il_alth         - Altitude (1 to 0) for hemispherical coordinates
        il_azih         - Azimuth (0 to 2*PI) for hemisphere
}

il_alt = Dz;
il_azi = norm_rad(atan2(Dy, Dx));

il_alth = sq(-Dx*A7-Dy*A8-Dz*A9);
il_azih = norm_rad(atan2(-Dx*A4-Dy*A5-Dz*A6, -Dx*A1-Dy*A2-Dz*A3));

norm_rad(r) = if( r, r, r+2*PI );
Revision:	1.1
Committed:	Thu Aug 22 08:49:41 1991 UTC (34 years, 2 months ago) by greg
Branch:	MAIN
Log Message:	Initial revision
#	User	Rev	Content
1	greg	1.1	{ SCCSid "$SunId$ LBL" }
2
3			{
4			Coordinate computations for mkillum output.
5
6			There are no arguments for the spherical case:
7
8			il_alt - Altitude (1 to -1) for spherical coordinates
9			il_azi - Azimuth (0 to 2*PI) for sphere
10
11			For the hemispherical case, A1-A9 are the unit vectors for the
12			hemisphere's coordinate system:
13
14			il_alth - Altitude (1 to 0) for hemispherical coordinates
15			il_azih - Azimuth (0 to 2*PI) for hemisphere
16			}
17
18			il_alt = Dz;
19			il_azi = norm_rad(atan2(Dy, Dx));
20
21			il_alth = sq(-DxA7-DyA8-Dz*A9);
22			il_azih = norm_rad(atan2(-DxA4-DyA5-DzA6, -DxA1-DyA2-DzA3));
23
24			norm_rad(r) = if( r, r, r+2*PI );