| 1 |
/* Copyright (c) 1986 Regents of the University of California */ |
| 2 |
|
| 3 |
#ifndef lint |
| 4 |
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
#endif |
| 6 |
|
| 7 |
/* |
| 8 |
* fvect.c - routines for float vector calculations |
| 9 |
* |
| 10 |
* 8/14/85 |
| 11 |
*/ |
| 12 |
|
| 13 |
#include "fvect.h" |
| 14 |
|
| 15 |
#define FTINY 1e-7 |
| 16 |
|
| 17 |
|
| 18 |
double |
| 19 |
fdot(v1, v2) /* return the dot product of two vectors */ |
| 20 |
register FVECT v1, v2; |
| 21 |
{ |
| 22 |
return(DOT(v1,v2)); |
| 23 |
} |
| 24 |
|
| 25 |
|
| 26 |
double |
| 27 |
dist2(p1, p2) /* return square of distance between points */ |
| 28 |
register FVECT p1, p2; |
| 29 |
{ |
| 30 |
static FVECT delta; |
| 31 |
|
| 32 |
delta[0] = p2[0] - p1[0]; |
| 33 |
delta[1] = p2[1] - p1[1]; |
| 34 |
delta[2] = p2[2] - p1[2]; |
| 35 |
return(DOT(delta, delta)); |
| 36 |
} |
| 37 |
|
| 38 |
|
| 39 |
double |
| 40 |
dist2line(p, ep1, ep2) /* return square of distance to line */ |
| 41 |
FVECT p; /* the point */ |
| 42 |
FVECT ep1, ep2; /* points on the line */ |
| 43 |
{ |
| 44 |
static double d, d1, d2; |
| 45 |
|
| 46 |
d = dist2(ep1, ep2); |
| 47 |
d1 = dist2(ep1, p); |
| 48 |
d2 = dist2(ep2, p); |
| 49 |
|
| 50 |
return(d1 - (d+d1-d2)*(d+d1-d2)/d/4); |
| 51 |
} |
| 52 |
|
| 53 |
|
| 54 |
double |
| 55 |
dist2lseg(p, ep1, ep2) /* return square of distance to line segment */ |
| 56 |
FVECT p; /* the point */ |
| 57 |
FVECT ep1, ep2; /* the end points */ |
| 58 |
{ |
| 59 |
static double d, d1, d2; |
| 60 |
|
| 61 |
d = dist2(ep1, ep2); |
| 62 |
d1 = dist2(ep1, p); |
| 63 |
d2 = dist2(ep2, p); |
| 64 |
|
| 65 |
if (d2 > d1) { /* check if past endpoints */ |
| 66 |
if (d2 - d1 > d) |
| 67 |
return(d1); |
| 68 |
} else { |
| 69 |
if (d1 - d2 > d) |
| 70 |
return(d2); |
| 71 |
} |
| 72 |
|
| 73 |
return(d1 - (d+d1-d2)*(d+d1-d2)/d/4); /* distance to line */ |
| 74 |
} |
| 75 |
|
| 76 |
|
| 77 |
fcross(vres, v1, v2) /* vres = v1 X v2 */ |
| 78 |
register FVECT vres, v1, v2; |
| 79 |
{ |
| 80 |
vres[0] = v1[1]*v2[2] - v1[2]*v2[1]; |
| 81 |
vres[1] = v1[2]*v2[0] - v1[0]*v2[2]; |
| 82 |
vres[2] = v1[0]*v2[1] - v1[1]*v2[0]; |
| 83 |
} |
| 84 |
|
| 85 |
|
| 86 |
double |
| 87 |
normalize(v) /* normalize a vector, return old magnitude */ |
| 88 |
register FVECT v; |
| 89 |
{ |
| 90 |
static double len; |
| 91 |
|
| 92 |
len = DOT(v, v); |
| 93 |
|
| 94 |
if (len <= 0.0) |
| 95 |
return(0.0); |
| 96 |
|
| 97 |
/****** problematic |
| 98 |
if (len >= (1.0-FTINY)*(1.0-FTINY) && |
| 99 |
len <= (1.0+FTINY)*(1.0+FTINY)) |
| 100 |
return(1.0); |
| 101 |
******/ |
| 102 |
|
| 103 |
len = sqrt(len); |
| 104 |
v[0] /= len; |
| 105 |
v[1] /= len; |
| 106 |
v[2] /= len; |
| 107 |
return(len); |
| 108 |
} |
