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root/radiance/ray/src/common/fvect.c
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Comparing ray/src/common/fvect.c (file contents):
Revision 2.12 by greg, Sun Sep 26 15:42:48 2010 UTC vs.
Revision 2.17 by greg, Thu Nov 22 06:07:17 2012 UTC

# Line 13 | Line 13 | static const char      RCSid[] = "$Id$";
13  
14   double
15   fdot(                           /* return the dot product of two vectors */
16 < FVECT v1,
17 < FVECT v2
16 > const FVECT v1,
17 > const FVECT v2
18   )
19   {
20          return(DOT(v1,v2));
# Line 23 | Line 23 | FVECT v2
23  
24   double
25   dist2(                          /* return square of distance between points */
26 < FVECT p1,
27 < FVECT p2
26 > const FVECT p1,
27 > const FVECT p2
28   )
29   {
30          FVECT  delta;
# Line 39 | Line 39 | FVECT p2
39  
40   double
41   dist2line(                      /* return square of distance to line */
42 < FVECT p,                /* the point */
43 < FVECT ep1,
44 < FVECT ep2               /* points on the line */
42 > const FVECT p,          /* the point */
43 > const FVECT ep1,
44 > const FVECT ep2         /* points on the line */
45   )
46   {
47          double  d, d1, d2;
# Line 56 | Line 56 | FVECT ep2              /* points on the line */
56  
57   double
58   dist2lseg(                      /* return square of distance to line segment */
59 < FVECT p,                /* the point */
60 < FVECT ep1,
61 < FVECT ep2               /* the end points */
59 > const FVECT p,          /* the point */
60 > const FVECT ep1,
61 > const FVECT ep2         /* the end points */
62   )
63   {
64          double  d, d1, d2;
# Line 83 | Line 83 | FVECT ep2              /* the end points */
83   void
84   fcross(                         /* vres = v1 X v2 */
85   FVECT vres,
86 < FVECT v1,
87 < FVECT v2
86 > const FVECT v1,
87 > const FVECT v2
88   )
89   {
90          vres[0] = v1[1]*v2[2] - v1[2]*v2[1];
# Line 96 | Line 96 | FVECT v2
96   void
97   fvsum(                          /* vres = v0 + f*v1 */
98   FVECT vres,
99 < FVECT v0,
100 < FVECT v1,
99 > const FVECT v0,
100 > const FVECT v1,
101   double f
102   )
103   {
# Line 119 | Line 119 | FVECT  v
119          if (d == 0.0)
120                  return(0.0);
121          
122 <        if (d <= 1.0+FTINY && d >= 1.0-FTINY) {
122 >        if ((d <= 1.0+FTINY) & (d >= 1.0-FTINY)) {
123                  len = 0.5 + 0.5*d;      /* first order approximation */
124                  d = 2.0 - len;
125          } else {
# Line 137 | Line 137 | FVECT  v
137   int
138   closestapproach(                        /* closest approach of two rays */
139   RREAL t[2],             /* returned distances along each ray */
140 < FVECT rorg0,            /* first origin */
141 < FVECT rdir0,            /* first direction (normalized) */
142 < FVECT rorg1,            /* second origin */
143 < FVECT rdir1             /* second direction (normalized) */
140 > const FVECT rorg0,              /* first origin */
141 > const FVECT rdir0,              /* first direction (normalized) */
142 > const FVECT rorg1,              /* second origin */
143 > const FVECT rdir1               /* second direction (normalized) */
144   )
145   {
146          double  dotprod = DOT(rdir0, rdir1);
# Line 162 | Line 162 | FVECT rdir1            /* second direction (normalized) */
162  
163   void
164   spinvector(                             /* rotate vector around normal */
165 < FVECT vres,             /* returned vector */
166 < FVECT vorig,            /* original vector */
167 < FVECT vnorm,            /* normalized vector for rotation */
168 < double theta            /* left-hand radians */
165 > FVECT vres,             /* returned vector (same magnitude as vorig) */
166 > const FVECT vorig,              /* original vector */
167 > const FVECT vnorm,              /* normalized vector for rotation */
168 > double theta            /* right-hand radians */
169   )
170   {
171          double  sint, cost, normprod;
# Line 183 | Line 183 | double theta           /* left-hand radians */
183          fcross(vperp, vnorm, vorig);
184          for (i = 0; i < 3; i++)
185                  vres[i] = vorig[i]*cost + vnorm[i]*normprod + vperp[i]*sint;
186 + }
187 +
188 + double
189 + geodesic(               /* rotate vector on great circle towards target */
190 + FVECT vres,             /* returned vector (same magnitude as vorig) */
191 + const FVECT vorig,      /* original vector */
192 + const FVECT vtarg,      /* vector we are rotating towards */
193 + double t,               /* amount along arc directed towards vtarg */
194 + int meas                /* distance measure (radians, absolute, relative) */
195 + )
196 + {
197 +        FVECT   normtarg;
198 +        double  volen, dotprod, sintr, cost;
199 +        int     i;
200 +
201 +        VCOPY(normtarg, vtarg);         /* in case vtarg==vres */
202 +        if (vres != vorig)
203 +                VCOPY(vres, vorig);
204 +        if (t == 0.0)
205 +                return(VLEN(vres));     /* no rotation requested */
206 +        if ((volen = normalize(vres)) == 0.0)
207 +                return(0.0);
208 +        if (normalize(normtarg) == 0.0)
209 +                return(0.0);            /* target vector is zero */
210 +        dotprod = DOT(vres, normtarg);
211 +                                        /* check for colinear */
212 +        if (dotprod >= 1.0-FTINY*FTINY) {
213 +                if (meas != GEOD_REL)
214 +                        return(0.0);
215 +                vres[0] *= volen; vres[1] *= volen; vres[2] *= volen;
216 +                return(volen);
217 +        }
218 +        if (dotprod <= -1.0+FTINY*FTINY)
219 +                return(0.0);
220 +        if (meas == GEOD_ABS)
221 +                t /= volen;
222 +        else if (meas == GEOD_REL)
223 +                t *= acos(dotprod);
224 +        cost = cos(t);
225 +        sintr = sin(t) / sqrt(1. - dotprod*dotprod);
226 +        for (i = 0; i < 3; i++)
227 +                vres[i] = volen*( cost*vres[i] +
228 +                                  sintr*(normtarg[i] - dotprod*vres[i]) );
229 +
230 +        return(volen);                  /* return vector length */
231   }

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