| 1 |
< |
/* Copyright (c) 1991 Regents of the University of California */ |
| 1 |
> |
/* Copyright (c) 1992 Regents of the University of California */ |
| 2 |
|
|
| 3 |
|
#ifndef lint |
| 4 |
|
static char SCCSid[] = "$SunId$ LBL"; |
| 43 |
|
* quadratic equation in t is then solved for the |
| 44 |
|
* smallest positive root, which is our point of |
| 45 |
|
* intersection. |
| 46 |
< |
* Because the ray direction is normalized, a is always 1. |
| 46 |
> |
* Since the ray is normalized, a should always be |
| 47 |
> |
* one. We compute it here to prevent instability in the |
| 48 |
> |
* intersection calculation. |
| 49 |
|
*/ |
| 50 |
< |
|
| 51 |
< |
a = 1.0; /* compute quadratic coefficients */ |
| 50 |
< |
b = c = 0.0; |
| 50 |
> |
/* compute quadratic coefficients */ |
| 51 |
> |
a = b = c = 0.0; |
| 52 |
|
for (i = 0; i < 3; i++) { |
| 53 |
+ |
a += r->rdir[i]*r->rdir[i]; |
| 54 |
|
t = r->rorg[i] - ap[i]; |
| 55 |
|
b += 2.0*r->rdir[i]*t; |
| 56 |
|
c += t*t; |
