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root/radiance/ray/src/rt/sphere.c
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Comparing ray/src/rt/sphere.c (file contents):
Revision 1.2 by greg, Wed Apr 19 22:24:30 1989 UTC vs.
Revision 2.2 by greg, Sat Oct 24 08:15:32 1992 UTC

# Line 1 | Line 1
1 < /* Copyright (c) 1986 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";
# Line 23 | Line 23 | register RAY  *r;
23          double  root[2];        /* quadratic roots */
24          int  nroots;
25          double  t;
26 <        register double  *ap;
26 >        register FLOAT  *ap;
27          register int  i;
28  
29 <        if (so->oargs.nfargs != 4 || so->oargs.farg[3] <= FTINY)
30 <                objerror(so, USER, "bad arguments");
31 <
29 >        if (so->oargs.nfargs != 4)
30 >                objerror(so, USER, "bad # arguments");
31          ap = so->oargs.farg;
32 +        if (ap[3] < -FTINY) {
33 +                objerror(so, WARNING, "negative radius");
34 +                so->otype = so->otype == OBJ_SPHERE ?
35 +                                OBJ_BUBBLE : OBJ_SPHERE;
36 +                ap[3] = -ap[3];
37 +        } else if (ap[3] <= FTINY)
38 +                objerror(so, USER, "zero radius");
39  
40          /*
41           *      We compute the intersection by substituting into
# Line 37 | Line 43 | register RAY  *r;
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 */
44 <        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;
# Line 71 | Line 79 | register RAY  *r;
79                  r->ron[i] = (r->rop[i] - ap[i]) / a;
80          }
81          r->rod = -DOT(r->rdir, r->ron);
82 <        r->rofs = 1.0; setident4(r->rofx);
75 <        r->robs = 1.0; setident4(r->robx);
82 >        r->rox = NULL;
83  
84          return(1);                      /* hit */
85   }

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