1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.18 |
static const char RCSid[] = "$Id: srcsupp.c,v 2.17 2008/12/06 01:08:53 greg Exp $"; |
3 |
greg |
1.1 |
#endif |
4 |
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/* |
5 |
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* Support routines for source objects and materials |
6 |
greg |
2.9 |
* |
7 |
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* External symbols declared in source.h |
8 |
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*/ |
9 |
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10 |
greg |
2.10 |
#include "copyright.h" |
11 |
greg |
1.1 |
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12 |
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#include "ray.h" |
13 |
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14 |
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#include "otypes.h" |
15 |
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16 |
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#include "source.h" |
17 |
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18 |
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#include "cone.h" |
19 |
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20 |
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#include "face.h" |
21 |
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22 |
greg |
2.12 |
#define SRCINC 8 /* realloc increment for array */ |
23 |
greg |
1.1 |
|
24 |
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SRCREC *source = NULL; /* our list of sources */ |
25 |
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int nsources = 0; /* the number of sources */ |
26 |
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27 |
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SRCFUNC sfun[NUMOTYPE]; /* source dispatch table */ |
28 |
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29 |
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30 |
greg |
2.9 |
void |
31 |
greg |
1.1 |
initstypes() /* initialize source dispatch table */ |
32 |
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{ |
33 |
greg |
1.9 |
extern VSMATERIAL mirror_vs, direct1_vs, direct2_vs; |
34 |
greg |
1.14 |
static SOBJECT fsobj = {fsetsrc, flatpart, fgetplaneq, fgetmaxdisk}; |
35 |
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static SOBJECT ssobj = {ssetsrc, nopart}; |
36 |
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static SOBJECT sphsobj = {sphsetsrc, nopart}; |
37 |
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static SOBJECT cylsobj = {cylsetsrc, cylpart}; |
38 |
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static SOBJECT rsobj = {rsetsrc, flatpart, rgetplaneq, rgetmaxdisk}; |
39 |
greg |
1.1 |
|
40 |
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sfun[MAT_MIRROR].mf = &mirror_vs; |
41 |
greg |
1.9 |
sfun[MAT_DIRECT1].mf = &direct1_vs; |
42 |
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sfun[MAT_DIRECT2].mf = &direct2_vs; |
43 |
greg |
1.1 |
sfun[OBJ_FACE].of = &fsobj; |
44 |
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sfun[OBJ_SOURCE].of = &ssobj; |
45 |
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sfun[OBJ_SPHERE].of = &sphsobj; |
46 |
greg |
1.14 |
sfun[OBJ_CYLINDER].of = &cylsobj; |
47 |
greg |
1.1 |
sfun[OBJ_RING].of = &rsobj; |
48 |
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} |
49 |
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50 |
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51 |
greg |
1.2 |
int |
52 |
greg |
1.1 |
newsource() /* allocate new source in our array */ |
53 |
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{ |
54 |
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if (nsources == 0) |
55 |
greg |
1.13 |
source = (SRCREC *)malloc(SRCINC*sizeof(SRCREC)); |
56 |
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else if (nsources%SRCINC == 0) |
57 |
greg |
2.11 |
source = (SRCREC *)realloc((void *)source, |
58 |
greg |
1.13 |
(unsigned)(nsources+SRCINC)*sizeof(SRCREC)); |
59 |
greg |
1.1 |
if (source == NULL) |
60 |
greg |
1.2 |
return(-1); |
61 |
greg |
1.1 |
source[nsources].sflags = 0; |
62 |
greg |
2.14 |
source[nsources].nhits = 1; |
63 |
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source[nsources].ntests = 2; /* initial hit probability = 50% */ |
64 |
greg |
2.12 |
#if SHADCACHE |
65 |
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source[nsources].obscache = NULL; |
66 |
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#endif |
67 |
greg |
1.2 |
return(nsources++); |
68 |
greg |
1.1 |
} |
69 |
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70 |
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71 |
greg |
2.9 |
void |
72 |
greg |
1.14 |
setflatss(src) /* set sampling for a flat source */ |
73 |
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register SRCREC *src; |
74 |
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{ |
75 |
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double mult; |
76 |
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register int i; |
77 |
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78 |
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src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0; |
79 |
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for (i = 0; i < 3; i++) |
80 |
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if (src->snorm[i] < 0.6 && src->snorm[i] > -0.6) |
81 |
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break; |
82 |
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src->ss[SV][i] = 1.0; |
83 |
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fcross(src->ss[SU], src->ss[SV], src->snorm); |
84 |
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mult = .5 * sqrt( src->ss2 / DOT(src->ss[SU],src->ss[SU]) ); |
85 |
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for (i = 0; i < 3; i++) |
86 |
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src->ss[SU][i] *= mult; |
87 |
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fcross(src->ss[SV], src->snorm, src->ss[SU]); |
88 |
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} |
89 |
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90 |
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91 |
greg |
2.9 |
void |
92 |
greg |
1.1 |
fsetsrc(src, so) /* set a face as a source */ |
93 |
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register SRCREC *src; |
94 |
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OBJREC *so; |
95 |
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{ |
96 |
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register FACE *f; |
97 |
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register int i, j; |
98 |
greg |
1.14 |
double d; |
99 |
greg |
1.1 |
|
100 |
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src->sa.success = 2*AIMREQT-1; /* bitch on second failure */ |
101 |
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src->so = so; |
102 |
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/* get the face */ |
103 |
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f = getface(so); |
104 |
greg |
2.16 |
if (f->area == 0.0) |
105 |
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objerror(so, USER, "zero source area"); |
106 |
greg |
1.1 |
/* find the center */ |
107 |
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for (j = 0; j < 3; j++) { |
108 |
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src->sloc[j] = 0.0; |
109 |
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for (i = 0; i < f->nv; i++) |
110 |
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src->sloc[j] += VERTEX(f,i)[j]; |
111 |
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src->sloc[j] /= (double)f->nv; |
112 |
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} |
113 |
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if (!inface(src->sloc, f)) |
114 |
greg |
2.16 |
objerror(so, USER, "cannot hit source center"); |
115 |
greg |
1.1 |
src->sflags |= SFLAT; |
116 |
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VCOPY(src->snorm, f->norm); |
117 |
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src->ss2 = f->area; |
118 |
greg |
1.14 |
/* find maximum radius */ |
119 |
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src->srad = 0.; |
120 |
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for (i = 0; i < f->nv; i++) { |
121 |
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d = dist2(VERTEX(f,i), src->sloc); |
122 |
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if (d > src->srad) |
123 |
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src->srad = d; |
124 |
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} |
125 |
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src->srad = sqrt(src->srad); |
126 |
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/* compute size vectors */ |
127 |
greg |
2.7 |
if (f->nv == 4) /* parallelogram case */ |
128 |
greg |
1.14 |
for (j = 0; j < 3; j++) { |
129 |
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src->ss[SU][j] = .5*(VERTEX(f,1)[j]-VERTEX(f,0)[j]); |
130 |
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src->ss[SV][j] = .5*(VERTEX(f,3)[j]-VERTEX(f,0)[j]); |
131 |
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} |
132 |
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else |
133 |
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setflatss(src); |
134 |
greg |
1.1 |
} |
135 |
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136 |
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137 |
greg |
2.9 |
void |
138 |
greg |
1.1 |
ssetsrc(src, so) /* set a source as a source */ |
139 |
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register SRCREC *src; |
140 |
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register OBJREC *so; |
141 |
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{ |
142 |
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double theta; |
143 |
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144 |
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src->sa.success = 2*AIMREQT-1; /* bitch on second failure */ |
145 |
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src->so = so; |
146 |
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if (so->oargs.nfargs != 4) |
147 |
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objerror(so, USER, "bad arguments"); |
148 |
greg |
2.17 |
src->sflags |= (SDISTANT|SCIR); |
149 |
greg |
1.1 |
VCOPY(src->sloc, so->oargs.farg); |
150 |
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if (normalize(src->sloc) == 0.0) |
151 |
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objerror(so, USER, "zero direction"); |
152 |
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theta = PI/180.0/2.0 * so->oargs.farg[3]; |
153 |
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if (theta <= FTINY) |
154 |
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objerror(so, USER, "zero size"); |
155 |
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src->ss2 = 2.0*PI * (1.0 - cos(theta)); |
156 |
greg |
1.14 |
/* the following is approximate */ |
157 |
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src->srad = sqrt(src->ss2/PI); |
158 |
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VCOPY(src->snorm, src->sloc); |
159 |
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setflatss(src); /* hey, whatever works */ |
160 |
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src->ss[SW][0] = src->ss[SW][1] = src->ss[SW][2] = 0.0; |
161 |
greg |
1.1 |
} |
162 |
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163 |
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164 |
greg |
2.9 |
void |
165 |
greg |
1.1 |
sphsetsrc(src, so) /* set a sphere as a source */ |
166 |
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register SRCREC *src; |
167 |
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register OBJREC *so; |
168 |
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{ |
169 |
greg |
1.14 |
register int i; |
170 |
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171 |
greg |
1.1 |
src->sa.success = 2*AIMREQT-1; /* bitch on second failure */ |
172 |
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src->so = so; |
173 |
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if (so->oargs.nfargs != 4) |
174 |
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objerror(so, USER, "bad # arguments"); |
175 |
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if (so->oargs.farg[3] <= FTINY) |
176 |
greg |
2.16 |
objerror(so, USER, "illegal source radius"); |
177 |
greg |
2.17 |
src->sflags |= SCIR; |
178 |
greg |
1.1 |
VCOPY(src->sloc, so->oargs.farg); |
179 |
greg |
1.14 |
src->srad = so->oargs.farg[3]; |
180 |
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src->ss2 = PI * src->srad * src->srad; |
181 |
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for (i = 0; i < 3; i++) |
182 |
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src->ss[SU][i] = src->ss[SV][i] = src->ss[SW][i] = 0.0; |
183 |
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for (i = 0; i < 3; i++) |
184 |
greg |
2.17 |
src->ss[i][i] = 0.7236 * so->oargs.farg[3]; |
185 |
greg |
1.1 |
} |
186 |
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187 |
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188 |
greg |
2.9 |
void |
189 |
greg |
1.1 |
rsetsrc(src, so) /* set a ring (disk) as a source */ |
190 |
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register SRCREC *src; |
191 |
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OBJREC *so; |
192 |
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{ |
193 |
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register CONE *co; |
194 |
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195 |
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src->sa.success = 2*AIMREQT-1; /* bitch on second failure */ |
196 |
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src->so = so; |
197 |
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/* get the ring */ |
198 |
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co = getcone(so, 0); |
199 |
greg |
2.16 |
if (CO_R1(co) <= FTINY) |
200 |
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objerror(so, USER, "illegal source radius"); |
201 |
greg |
1.1 |
VCOPY(src->sloc, CO_P0(co)); |
202 |
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if (CO_R0(co) > 0.0) |
203 |
greg |
2.16 |
objerror(so, USER, "cannot hit source center"); |
204 |
greg |
2.17 |
src->sflags |= (SFLAT|SCIR); |
205 |
greg |
1.1 |
VCOPY(src->snorm, co->ad); |
206 |
greg |
1.14 |
src->srad = CO_R1(co); |
207 |
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src->ss2 = PI * src->srad * src->srad; |
208 |
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setflatss(src); |
209 |
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} |
210 |
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211 |
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212 |
greg |
2.9 |
void |
213 |
greg |
1.14 |
cylsetsrc(src, so) /* set a cylinder as a source */ |
214 |
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register SRCREC *src; |
215 |
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OBJREC *so; |
216 |
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{ |
217 |
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register CONE *co; |
218 |
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register int i; |
219 |
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220 |
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src->sa.success = 4*AIMREQT-1; /* bitch on fourth failure */ |
221 |
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src->so = so; |
222 |
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/* get the cylinder */ |
223 |
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co = getcone(so, 0); |
224 |
greg |
2.16 |
if (CO_R0(co) <= FTINY) |
225 |
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objerror(so, USER, "illegal source radius"); |
226 |
greg |
1.14 |
if (CO_R0(co) > .2*co->al) /* heuristic constraint */ |
227 |
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objerror(so, WARNING, "source aspect too small"); |
228 |
greg |
1.15 |
src->sflags |= SCYL; |
229 |
greg |
1.14 |
for (i = 0; i < 3; i++) |
230 |
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src->sloc[i] = .5 * (CO_P1(co)[i] + CO_P0(co)[i]); |
231 |
greg |
1.15 |
src->srad = .5*co->al; |
232 |
greg |
1.14 |
src->ss2 = 2.*CO_R0(co)*co->al; |
233 |
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/* set sampling vectors */ |
234 |
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for (i = 0; i < 3; i++) |
235 |
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src->ss[SU][i] = .5 * co->al * co->ad[i]; |
236 |
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src->ss[SV][0] = src->ss[SV][1] = src->ss[SV][2] = 0.0; |
237 |
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for (i = 0; i < 3; i++) |
238 |
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if (co->ad[i] < 0.6 && co->ad[i] > -0.6) |
239 |
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break; |
240 |
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src->ss[SV][i] = 1.0; |
241 |
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fcross(src->ss[SW], src->ss[SV], co->ad); |
242 |
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normalize(src->ss[SW]); |
243 |
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for (i = 0; i < 3; i++) |
244 |
greg |
1.15 |
src->ss[SW][i] *= .8559 * CO_R0(co); |
245 |
greg |
1.14 |
fcross(src->ss[SV], src->ss[SW], co->ad); |
246 |
greg |
1.1 |
} |
247 |
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248 |
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249 |
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SPOT * |
250 |
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makespot(m) /* make a spotlight */ |
251 |
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register OBJREC *m; |
252 |
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{ |
253 |
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register SPOT *ns; |
254 |
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255 |
greg |
2.5 |
if ((ns = (SPOT *)m->os) != NULL) |
256 |
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return(ns); |
257 |
greg |
1.1 |
if ((ns = (SPOT *)malloc(sizeof(SPOT))) == NULL) |
258 |
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return(NULL); |
259 |
greg |
2.16 |
if (m->oargs.farg[3] <= FTINY) |
260 |
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objerror(m, USER, "zero angle"); |
261 |
greg |
1.1 |
ns->siz = 2.0*PI * (1.0 - cos(PI/180.0/2.0 * m->oargs.farg[3])); |
262 |
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VCOPY(ns->aim, m->oargs.farg+4); |
263 |
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if ((ns->flen = normalize(ns->aim)) == 0.0) |
264 |
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objerror(m, USER, "zero focus vector"); |
265 |
greg |
2.5 |
m->os = (char *)ns; |
266 |
greg |
1.1 |
return(ns); |
267 |
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} |
268 |
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269 |
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|
270 |
greg |
2.9 |
int |
271 |
greg |
2.8 |
spotout(r, s) /* check if we're outside spot region */ |
272 |
greg |
2.5 |
register RAY *r; |
273 |
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register SPOT *s; |
274 |
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{ |
275 |
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double d; |
276 |
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FVECT vd; |
277 |
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278 |
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if (s == NULL) |
279 |
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return(0); |
280 |
greg |
2.8 |
if (s->flen < -FTINY) { /* distant source */ |
281 |
greg |
2.5 |
vd[0] = s->aim[0] - r->rorg[0]; |
282 |
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vd[1] = s->aim[1] - r->rorg[1]; |
283 |
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vd[2] = s->aim[2] - r->rorg[2]; |
284 |
|
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d = DOT(r->rdir,vd); |
285 |
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/* wrong side? |
286 |
|
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if (d <= FTINY) |
287 |
|
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return(1); */ |
288 |
|
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d = DOT(vd,vd) - d*d; |
289 |
|
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if (PI*d > s->siz) |
290 |
|
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return(1); /* out */ |
291 |
|
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return(0); /* OK */ |
292 |
|
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} |
293 |
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/* local source */ |
294 |
|
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if (s->siz < 2.0*PI * (1.0 + DOT(s->aim,r->rdir))) |
295 |
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return(1); /* out */ |
296 |
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return(0); /* OK */ |
297 |
|
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} |
298 |
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299 |
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|
300 |
greg |
1.1 |
double |
301 |
|
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fgetmaxdisk(ocent, op) /* get center and squared radius of face */ |
302 |
|
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FVECT ocent; |
303 |
|
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OBJREC *op; |
304 |
|
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{ |
305 |
|
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double maxrad2; |
306 |
greg |
1.5 |
double d; |
307 |
greg |
1.1 |
register int i, j; |
308 |
|
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register FACE *f; |
309 |
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|
310 |
|
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f = getface(op); |
311 |
greg |
1.5 |
if (f->area == 0.) |
312 |
|
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return(0.); |
313 |
greg |
1.1 |
for (i = 0; i < 3; i++) { |
314 |
|
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ocent[i] = 0.; |
315 |
|
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for (j = 0; j < f->nv; j++) |
316 |
|
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ocent[i] += VERTEX(f,j)[i]; |
317 |
|
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ocent[i] /= (double)f->nv; |
318 |
|
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} |
319 |
greg |
1.5 |
d = DOT(ocent,f->norm); |
320 |
|
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for (i = 0; i < 3; i++) |
321 |
|
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ocent[i] += (f->offset - d)*f->norm[i]; |
322 |
greg |
1.1 |
maxrad2 = 0.; |
323 |
|
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for (j = 0; j < f->nv; j++) { |
324 |
greg |
1.5 |
d = dist2(VERTEX(f,j), ocent); |
325 |
|
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if (d > maxrad2) |
326 |
|
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maxrad2 = d; |
327 |
greg |
1.1 |
} |
328 |
|
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return(maxrad2); |
329 |
|
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} |
330 |
|
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|
331 |
|
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|
332 |
|
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double |
333 |
|
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rgetmaxdisk(ocent, op) /* get center and squared radius of ring */ |
334 |
|
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FVECT ocent; |
335 |
|
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OBJREC *op; |
336 |
|
|
{ |
337 |
|
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register CONE *co; |
338 |
|
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|
339 |
|
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co = getcone(op, 0); |
340 |
|
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VCOPY(ocent, CO_P0(co)); |
341 |
|
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return(CO_R1(co)*CO_R1(co)); |
342 |
|
|
} |
343 |
|
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|
344 |
|
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|
345 |
|
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double |
346 |
|
|
fgetplaneq(nvec, op) /* get plane equation for face */ |
347 |
|
|
FVECT nvec; |
348 |
|
|
OBJREC *op; |
349 |
|
|
{ |
350 |
|
|
register FACE *fo; |
351 |
|
|
|
352 |
|
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fo = getface(op); |
353 |
|
|
VCOPY(nvec, fo->norm); |
354 |
|
|
return(fo->offset); |
355 |
|
|
} |
356 |
|
|
|
357 |
|
|
|
358 |
|
|
double |
359 |
|
|
rgetplaneq(nvec, op) /* get plane equation for ring */ |
360 |
|
|
FVECT nvec; |
361 |
|
|
OBJREC *op; |
362 |
|
|
{ |
363 |
|
|
register CONE *co; |
364 |
|
|
|
365 |
|
|
co = getcone(op, 0); |
366 |
|
|
VCOPY(nvec, co->ad); |
367 |
|
|
return(DOT(nvec, CO_P0(co))); |
368 |
greg |
1.4 |
} |
369 |
|
|
|
370 |
|
|
|
371 |
greg |
2.9 |
int |
372 |
greg |
1.4 |
commonspot(sp1, sp2, org) /* set sp1 to intersection of sp1 and sp2 */ |
373 |
|
|
register SPOT *sp1, *sp2; |
374 |
|
|
FVECT org; |
375 |
|
|
{ |
376 |
|
|
FVECT cent; |
377 |
|
|
double rad2, cos1, cos2; |
378 |
|
|
|
379 |
|
|
cos1 = 1. - sp1->siz/(2.*PI); |
380 |
|
|
cos2 = 1. - sp2->siz/(2.*PI); |
381 |
|
|
if (sp2->siz >= 2.*PI-FTINY) /* BIG, just check overlap */ |
382 |
|
|
return(DOT(sp1->aim,sp2->aim) >= cos1*cos2 - |
383 |
|
|
sqrt((1.-cos1*cos1)*(1.-cos2*cos2))); |
384 |
|
|
/* compute and check disks */ |
385 |
|
|
rad2 = intercircle(cent, sp1->aim, sp2->aim, |
386 |
|
|
1./(cos1*cos1) - 1., 1./(cos2*cos2) - 1.); |
387 |
|
|
if (rad2 <= FTINY || normalize(cent) == 0.) |
388 |
|
|
return(0); |
389 |
|
|
VCOPY(sp1->aim, cent); |
390 |
|
|
sp1->siz = 2.*PI*(1. - 1./sqrt(1.+rad2)); |
391 |
|
|
return(1); |
392 |
|
|
} |
393 |
|
|
|
394 |
|
|
|
395 |
greg |
2.9 |
int |
396 |
greg |
1.4 |
commonbeam(sp1, sp2, dir) /* set sp1 to intersection of sp1 and sp2 */ |
397 |
|
|
register SPOT *sp1, *sp2; |
398 |
|
|
FVECT dir; |
399 |
|
|
{ |
400 |
|
|
FVECT cent, c1, c2; |
401 |
|
|
double rad2, d; |
402 |
|
|
/* move centers to common plane */ |
403 |
|
|
d = DOT(sp1->aim, dir); |
404 |
greg |
2.18 |
VSUM(c1, sp1->aim, dir, -d); |
405 |
greg |
1.4 |
d = DOT(sp2->aim, dir); |
406 |
greg |
2.18 |
VSUM(c2, sp2->aim, dir, -d); |
407 |
greg |
1.4 |
/* compute overlap */ |
408 |
|
|
rad2 = intercircle(cent, c1, c2, sp1->siz/PI, sp2->siz/PI); |
409 |
|
|
if (rad2 <= FTINY) |
410 |
|
|
return(0); |
411 |
|
|
VCOPY(sp1->aim, cent); |
412 |
|
|
sp1->siz = PI*rad2; |
413 |
|
|
return(1); |
414 |
|
|
} |
415 |
|
|
|
416 |
|
|
|
417 |
greg |
2.9 |
int |
418 |
greg |
1.4 |
checkspot(sp, nrm) /* check spotlight for behind source */ |
419 |
|
|
register SPOT *sp; /* spotlight */ |
420 |
|
|
FVECT nrm; /* source surface normal */ |
421 |
|
|
{ |
422 |
|
|
double d, d1; |
423 |
|
|
|
424 |
|
|
d = DOT(sp->aim, nrm); |
425 |
|
|
if (d > FTINY) /* center in front? */ |
426 |
greg |
1.8 |
return(1); |
427 |
greg |
1.4 |
/* else check horizon */ |
428 |
|
|
d1 = 1. - sp->siz/(2.*PI); |
429 |
greg |
1.8 |
return(1.-FTINY-d*d < d1*d1); |
430 |
greg |
1.4 |
} |
431 |
|
|
|
432 |
|
|
|
433 |
|
|
double |
434 |
greg |
1.6 |
spotdisk(oc, op, sp, pos) /* intersect spot with object op */ |
435 |
|
|
FVECT oc; |
436 |
|
|
OBJREC *op; |
437 |
|
|
register SPOT *sp; |
438 |
|
|
FVECT pos; |
439 |
|
|
{ |
440 |
|
|
FVECT onorm; |
441 |
|
|
double offs, d, dist; |
442 |
|
|
|
443 |
|
|
offs = getplaneq(onorm, op); |
444 |
|
|
d = -DOT(onorm, sp->aim); |
445 |
|
|
if (d >= -FTINY && d <= FTINY) |
446 |
|
|
return(0.); |
447 |
|
|
dist = (DOT(pos, onorm) - offs)/d; |
448 |
|
|
if (dist < 0.) |
449 |
|
|
return(0.); |
450 |
greg |
2.18 |
VSUM(oc, pos, sp->aim, dist); |
451 |
greg |
1.6 |
return(sp->siz*dist*dist/PI/(d*d)); |
452 |
|
|
} |
453 |
|
|
|
454 |
|
|
|
455 |
|
|
double |
456 |
|
|
beamdisk(oc, op, sp, dir) /* intersect beam with object op */ |
457 |
|
|
FVECT oc; |
458 |
|
|
OBJREC *op; |
459 |
|
|
register SPOT *sp; |
460 |
|
|
FVECT dir; |
461 |
|
|
{ |
462 |
|
|
FVECT onorm; |
463 |
|
|
double offs, d, dist; |
464 |
|
|
|
465 |
|
|
offs = getplaneq(onorm, op); |
466 |
|
|
d = -DOT(onorm, dir); |
467 |
|
|
if (d >= -FTINY && d <= FTINY) |
468 |
|
|
return(0.); |
469 |
|
|
dist = (DOT(sp->aim, onorm) - offs)/d; |
470 |
greg |
2.18 |
VSUM(oc, sp->aim, dir, dist); |
471 |
greg |
1.6 |
return(sp->siz/PI/(d*d)); |
472 |
|
|
} |
473 |
|
|
|
474 |
|
|
|
475 |
|
|
double |
476 |
greg |
1.4 |
intercircle(cc, c1, c2, r1s, r2s) /* intersect two circles */ |
477 |
|
|
FVECT cc; /* midpoint (return value) */ |
478 |
|
|
FVECT c1, c2; /* circle centers */ |
479 |
|
|
double r1s, r2s; /* radii squared */ |
480 |
|
|
{ |
481 |
|
|
double a2, d2, l; |
482 |
|
|
FVECT disp; |
483 |
|
|
|
484 |
greg |
2.18 |
VSUB(disp, c2, c1); |
485 |
greg |
1.4 |
d2 = DOT(disp,disp); |
486 |
|
|
/* circle within overlap? */ |
487 |
|
|
if (r1s < r2s) { |
488 |
|
|
if (r2s >= r1s + d2) { |
489 |
|
|
VCOPY(cc, c1); |
490 |
|
|
return(r1s); |
491 |
|
|
} |
492 |
|
|
} else { |
493 |
|
|
if (r1s >= r2s + d2) { |
494 |
|
|
VCOPY(cc, c2); |
495 |
|
|
return(r2s); |
496 |
|
|
} |
497 |
|
|
} |
498 |
|
|
a2 = .25*(2.*(r1s+r2s) - d2 - (r2s-r1s)*(r2s-r1s)/d2); |
499 |
|
|
/* no overlap? */ |
500 |
|
|
if (a2 <= 0.) |
501 |
|
|
return(0.); |
502 |
|
|
/* overlap, compute center */ |
503 |
|
|
l = sqrt((r1s - a2)/d2); |
504 |
greg |
2.18 |
VSUM(cc, c1, disp, l); |
505 |
greg |
1.4 |
return(a2); |
506 |
greg |
1.1 |
} |