1 |
gwlarson |
2.4 |
/* Copyright (c) 1998 Silicon Graphics, Inc. */ |
2 |
greg |
1.1 |
|
3 |
|
|
#ifndef lint |
4 |
gwlarson |
2.4 |
static char SCCSid[] = "$SunId$ SGI"; |
5 |
greg |
1.1 |
#endif |
6 |
|
|
|
7 |
|
|
/* |
8 |
|
|
* fvect.c - routines for float vector calculations |
9 |
|
|
* |
10 |
|
|
* 8/14/85 |
11 |
|
|
*/ |
12 |
|
|
|
13 |
greg |
2.2 |
#include <math.h> |
14 |
greg |
1.1 |
#include "fvect.h" |
15 |
|
|
|
16 |
|
|
|
17 |
|
|
double |
18 |
|
|
fdot(v1, v2) /* return the dot product of two vectors */ |
19 |
|
|
register FVECT v1, v2; |
20 |
|
|
{ |
21 |
|
|
return(DOT(v1,v2)); |
22 |
|
|
} |
23 |
|
|
|
24 |
|
|
|
25 |
|
|
double |
26 |
|
|
dist2(p1, p2) /* return square of distance between points */ |
27 |
|
|
register FVECT p1, p2; |
28 |
|
|
{ |
29 |
gwlarson |
2.4 |
FVECT delta; |
30 |
greg |
1.1 |
|
31 |
|
|
delta[0] = p2[0] - p1[0]; |
32 |
|
|
delta[1] = p2[1] - p1[1]; |
33 |
|
|
delta[2] = p2[2] - p1[2]; |
34 |
gwlarson |
2.5 |
|
35 |
greg |
1.1 |
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 |
gwlarson |
2.4 |
register double d, d1, d2; |
45 |
greg |
1.1 |
|
46 |
|
|
d = dist2(ep1, ep2); |
47 |
|
|
d1 = dist2(ep1, p); |
48 |
gwlarson |
2.5 |
d2 = d + d1 - dist2(ep2, p); |
49 |
greg |
1.1 |
|
50 |
gwlarson |
2.5 |
return(d1 - 0.25*d2*d2/d); |
51 |
greg |
1.1 |
} |
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 |
gwlarson |
2.4 |
register double d, d1, d2; |
60 |
greg |
1.1 |
|
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 |
gwlarson |
2.5 |
d2 = d + d1 - d2; |
73 |
greg |
1.1 |
|
74 |
gwlarson |
2.5 |
return(d1 - 0.25*d2*d2/d); /* distance to line */ |
75 |
greg |
1.1 |
} |
76 |
|
|
|
77 |
|
|
|
78 |
|
|
fcross(vres, v1, v2) /* vres = v1 X v2 */ |
79 |
|
|
register FVECT vres, v1, v2; |
80 |
|
|
{ |
81 |
|
|
vres[0] = v1[1]*v2[2] - v1[2]*v2[1]; |
82 |
|
|
vres[1] = v1[2]*v2[0] - v1[0]*v2[2]; |
83 |
|
|
vres[2] = v1[0]*v2[1] - v1[1]*v2[0]; |
84 |
|
|
} |
85 |
|
|
|
86 |
|
|
|
87 |
greg |
1.4 |
fvsum(vres, v0, v1, f) /* vres = v0 + f*v1 */ |
88 |
gwlarson |
2.5 |
register FVECT vres, v0, v1; |
89 |
|
|
register double f; |
90 |
greg |
1.4 |
{ |
91 |
|
|
vres[0] = v0[0] + f*v1[0]; |
92 |
|
|
vres[1] = v0[1] + f*v1[1]; |
93 |
|
|
vres[2] = v0[2] + f*v1[2]; |
94 |
|
|
} |
95 |
|
|
|
96 |
|
|
|
97 |
greg |
1.1 |
double |
98 |
|
|
normalize(v) /* normalize a vector, return old magnitude */ |
99 |
|
|
register FVECT v; |
100 |
|
|
{ |
101 |
gwlarson |
2.5 |
register double len, d; |
102 |
greg |
1.1 |
|
103 |
gwlarson |
2.5 |
d = DOT(v, v); |
104 |
greg |
1.1 |
|
105 |
gwlarson |
2.5 |
if (d <= 0.0) |
106 |
greg |
1.1 |
return(0.0); |
107 |
|
|
|
108 |
gwlarson |
2.5 |
if (d <= 1.0+FTINY && d >= 1.0-FTINY) |
109 |
|
|
len = 0.5 + 0.5*d; /* first order approximation */ |
110 |
greg |
2.3 |
else |
111 |
gwlarson |
2.5 |
len = sqrt(d); |
112 |
greg |
1.1 |
|
113 |
gwlarson |
2.5 |
v[0] *= d = 1.0/len; |
114 |
|
|
v[1] *= d; |
115 |
|
|
v[2] *= d; |
116 |
greg |
2.3 |
|
117 |
greg |
1.1 |
return(len); |
118 |
|
|
} |
119 |
greg |
1.5 |
|
120 |
|
|
|
121 |
|
|
spinvector(vres, vorig, vnorm, theta) /* rotate vector around normal */ |
122 |
|
|
FVECT vres, vorig, vnorm; |
123 |
|
|
double theta; |
124 |
|
|
{ |
125 |
greg |
1.6 |
double sint, cost, normprod; |
126 |
greg |
1.5 |
FVECT vperp; |
127 |
|
|
register int i; |
128 |
|
|
|
129 |
|
|
if (theta == 0.0) { |
130 |
greg |
1.6 |
if (vres != vorig) |
131 |
|
|
VCOPY(vres, vorig); |
132 |
greg |
1.5 |
return; |
133 |
|
|
} |
134 |
greg |
1.6 |
cost = cos(theta); |
135 |
greg |
1.5 |
sint = sin(theta); |
136 |
greg |
1.6 |
normprod = DOT(vorig, vnorm)*(1.-cost); |
137 |
greg |
1.5 |
fcross(vperp, vnorm, vorig); |
138 |
|
|
for (i = 0; i < 3; i++) |
139 |
greg |
1.6 |
vres[i] = vorig[i]*cost + vnorm[i]*normprod + vperp[i]*sint; |
140 |
greg |
1.5 |
} |