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root/radiance/ray/src/rt/normal.c
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Comparing ray/src/rt/normal.c (file contents):
Revision 2.22 by greg, Fri Oct 16 10:20:29 1992 UTC vs.
Revision 2.24 by greg, Mon Mar 8 12:37:27 1993 UTC

# Line 23 | Line 23 | static char SCCSid[] = "$SunId$ LBL";
23   extern double  specthresh;              /* specular sampling threshold */
24   extern double  specjitter;              /* specular sampling jitter */
25  
26 + static  gaussamp();
27 +
28   /*
29   *      This routine implements the isotropic Gaussian
30   *  model described by Ward in Siggraph `92 article.
# Line 102 | Line 104 | double  omega;                 /* light source size */
104                                                  /* + source if flat */
105                  if (np->specfl & SP_FLAT)
106                          dtmp += omega/(4.0*PI);
107 <                                                /* delta */
107 >                                                /* half vector */
108                  vtmp[0] = ldir[0] - np->rp->rdir[0];
109                  vtmp[1] = ldir[1] - np->rp->rdir[1];
110                  vtmp[2] = ldir[2] - np->rp->rdir[2];
111                  d2 = DOT(vtmp, np->pnorm);
112 <                d2 = 2.0 - 2.0*d2/sqrt(DOT(vtmp,vtmp));
112 >                d2 *= d2;
113 >                d2 = (DOT(vtmp,vtmp) - d2) / d2;
114                                                  /* gaussian */
115                  dtmp = exp(-d2/dtmp)/(4.*PI*dtmp);
116                                                  /* worth using? */

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