src/gen/surf.cal

{ SCCSid "$SunId$ LBL" }

{
        surf.cal - calculation of interpolated surface normal

        A1              - dominant axis (we use the other two)
        A2  A3  A4      \
        A5  A6  A7       \ normal perturbation vector matrix
        A8  A9  A10      / multiplied by [u*v u v 1] for perturbation
        A11 A12 A13     /
}

surf_dx = surf_u*surf_v*arg(2) + surf_u*arg(5) + surf_v*arg(8) + arg(11);
surf_dy = surf_u*surf_v*arg(3) + surf_u*arg(6) + surf_v*arg(9) + arg(12);
surf_dz = surf_u*surf_v*arg(4) + surf_u*arg(7) + surf_v*arg(10) + arg(13);

surf_u = select(arg(1)+1, Py, Pz, Px);
surf_v = select(arg(1)+1, Pz, Px, Py);
Revision:	1.1
Committed:	Thu Aug 22 08:49:45 1991 UTC (32 years, 8 months ago) by greg
Branch:	MAIN
Log Message:	Initial revision
#	User	Rev	Content
1	greg	1.1	{ SCCSid "$SunId$ LBL" }
2
3			{
4			surf.cal - calculation of interpolated surface normal
5
6			A1 - dominant axis (we use the other two)
7			A2 A3 A4 \
8			A5 A6 A7 \ normal perturbation vector matrix
9			A8 A9 A10 / multiplied by [u*v u v 1] for perturbation
10			A11 A12 A13 /
11			}
12
13			surf_dx = surf_usurf_varg(2) + surf_uarg(5) + surf_varg(8) + arg(11);
14			surf_dy = surf_usurf_varg(3) + surf_uarg(6) + surf_varg(9) + arg(12);
15			surf_dz = surf_usurf_varg(4) + surf_uarg(7) + surf_varg(10) + arg(13);
16
17			surf_u = select(arg(1)+1, Py, Pz, Px);
18			surf_v = select(arg(1)+1, Pz, Px, Py);