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
}

norm_rad(r) : if( r, r, r+2*PI );

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));
Revision:	2.7
Committed:	Thu Jul 9 13:06:20 1998 UTC (25 years, 9 months ago) by gwlarson
Branch:	MAIN
Changes since 2.6:	+2 -2 lines
Log Message:	fixed variable ordering
#	User	Rev	Content
1	greg	1.1	{ SCCSid "$SunId$ LBL" }
2
3			{
4			Coordinate computations for mkillum output.
5
6	greg	2.5	There are no arguments for the spherical case:
7	greg	1.1
8			il_alt - Altitude (1 to -1) for spherical coordinates
9			il_azi - Azimuth (0 to 2*PI) for sphere
10
11	greg	2.5	For the hemispherical case, A1-A9 are the unit vectors for the
12	greg	1.1	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	gwlarson	2.7	norm_rad(r) : if( r, r, r+2*PI );
19
20	greg	1.1	il_alt = Dz;
21	greg	2.6	il_azi = norm_rad(Atan2(Dy, Dx));
22	greg	1.1
23	greg	2.5	il_alth = sq(-DxA7-DyA8-Dz*A9);
24	greg	2.6	il_azih = norm_rad(Atan2(-DxA4-DyA5-DzA6, -DxA1-DyA2-DzA3));