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greg |
1.1 |
/* Copyright (c) 1986 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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/* |
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* fvect.c - routines for float vector calculations |
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* |
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* 8/14/85 |
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*/ |
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#include "fvect.h" |
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#define FTINY 1e-7 |
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double |
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fdot(v1, v2) /* return the dot product of two vectors */ |
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register FVECT v1, v2; |
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{ |
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return(DOT(v1,v2)); |
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} |
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double |
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dist2(p1, p2) /* return square of distance between points */ |
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register FVECT p1, p2; |
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{ |
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static FVECT delta; |
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delta[0] = p2[0] - p1[0]; |
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delta[1] = p2[1] - p1[1]; |
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delta[2] = p2[2] - p1[2]; |
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return(DOT(delta, delta)); |
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} |
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double |
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dist2line(p, ep1, ep2) /* return square of distance to line */ |
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FVECT p; /* the point */ |
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FVECT ep1, ep2; /* points on the line */ |
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{ |
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static double d, d1, d2; |
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d = dist2(ep1, ep2); |
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d1 = dist2(ep1, p); |
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d2 = dist2(ep2, p); |
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return(d1 - (d+d1-d2)*(d+d1-d2)/d/4); |
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} |
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double |
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dist2lseg(p, ep1, ep2) /* return square of distance to line segment */ |
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FVECT p; /* the point */ |
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FVECT ep1, ep2; /* the end points */ |
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{ |
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static double d, d1, d2; |
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d = dist2(ep1, ep2); |
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d1 = dist2(ep1, p); |
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d2 = dist2(ep2, p); |
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if (d2 > d1) { /* check if past endpoints */ |
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if (d2 - d1 > d) |
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return(d1); |
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} else { |
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if (d1 - d2 > d) |
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return(d2); |
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} |
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return(d1 - (d+d1-d2)*(d+d1-d2)/d/4); /* distance to line */ |
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} |
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fcross(vres, v1, v2) /* vres = v1 X v2 */ |
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register FVECT vres, v1, v2; |
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{ |
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vres[0] = v1[1]*v2[2] - v1[2]*v2[1]; |
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vres[1] = v1[2]*v2[0] - v1[0]*v2[2]; |
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vres[2] = v1[0]*v2[1] - v1[1]*v2[0]; |
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} |
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double |
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normalize(v) /* normalize a vector, return old magnitude */ |
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register FVECT v; |
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{ |
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static double len; |
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len = DOT(v, v); |
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greg |
1.3 |
if (len <= 0.0) |
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greg |
1.1 |
return(0.0); |
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greg |
1.2 |
/****** problematic |
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greg |
1.1 |
if (len >= (1.0-FTINY)*(1.0-FTINY) && |
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len <= (1.0+FTINY)*(1.0+FTINY)) |
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return(1.0); |
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greg |
1.2 |
******/ |
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greg |
1.1 |
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len = sqrt(len); |
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v[0] /= len; |
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v[1] /= len; |
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v[2] /= len; |
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return(len); |
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} |
