1 |
gregl |
3.1 |
/* Copyright (c) 1997 Silicon Graphics, Inc. */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ SGI"; |
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#endif |
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/* |
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gregl |
3.2 |
* Holodeck beam support for display process |
9 |
gregl |
3.1 |
*/ |
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#include "rholo.h" |
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#include "rhdisp.h" |
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#include "view.h" |
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gregl |
3.4 |
struct cellist { |
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GCOORD *cl; |
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int n; |
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}; |
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gregl |
3.1 |
|
20 |
gregl |
3.4 |
|
21 |
gregl |
3.1 |
int |
22 |
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npixels(vp, hr, vr, hp, bi) /* compute appropriate number to evaluate */ |
23 |
gregl |
3.5 |
register VIEW *vp; |
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gregl |
3.1 |
int hr, vr; |
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HOLO *hp; |
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int bi; |
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{ |
28 |
gregl |
3.5 |
VIEW vrev; |
29 |
gregl |
3.1 |
GCOORD gc[2]; |
30 |
gregl |
3.5 |
FVECT cp[4], ip[4]; |
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double af, ab; |
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gregl |
3.1 |
register int i; |
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/* compute cell corners in image */ |
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if (!hdbcoord(gc, hp, bi)) |
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error(CONSISTENCY, "bad beam index in npixels"); |
36 |
gregl |
3.5 |
hdcell(cp, hp, gc+1); /* find cell on front image */ |
37 |
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for (i = 0; i < 4; i++) { |
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viewloc(ip[i], vp, cp[i]); |
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if (ip[i][2] < 0.) { |
40 |
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af = 0; |
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goto getback; |
42 |
gregl |
3.4 |
} |
43 |
gregl |
3.5 |
ip[i][0] *= (double)hr; /* scale by resolution */ |
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ip[i][1] *= (double)vr; |
45 |
gregl |
3.4 |
} |
46 |
gregl |
3.5 |
/* compute front area */ |
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af = (ip[1][0]-ip[0][0])*(ip[2][1]-ip[0][1]) - |
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(ip[2][0]-ip[0][0])*(ip[1][1]-ip[0][1]); |
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af += (ip[2][0]-ip[3][0])*(ip[1][1]-ip[3][1]) - |
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(ip[1][0]-ip[3][0])*(ip[2][1]-ip[3][1]); |
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if (af >= 0) af *= 0.5; |
52 |
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else af *= -0.5; |
53 |
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getback: |
54 |
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copystruct(&vrev, vp); /* compute reverse view */ |
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for (i = 0; i < 3; i++) { |
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vrev.vdir[i] = -vp->vdir[i]; |
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vrev.vup[i] = -vp->vup[i]; |
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vrev.hvec[i] = -vp->hvec[i]; |
59 |
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vrev.vvec[i] = -vp->vvec[i]; |
60 |
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} |
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hdcell(cp, hp, gc); /* find cell on back image */ |
62 |
gregl |
3.1 |
for (i = 0; i < 4; i++) { |
63 |
gregl |
3.5 |
viewloc(ip[i], &vrev, cp[i]); |
64 |
gregl |
3.1 |
if (ip[i][2] < 0.) |
65 |
gregl |
3.5 |
return((int)(af + 0.5)); |
66 |
gregl |
3.1 |
ip[i][0] *= (double)hr; /* scale by resolution */ |
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ip[i][1] *= (double)vr; |
68 |
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} |
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gregl |
3.5 |
/* compute back area */ |
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ab = (ip[1][0]-ip[0][0])*(ip[2][1]-ip[0][1]) - |
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gregl |
3.1 |
(ip[2][0]-ip[0][0])*(ip[1][1]-ip[0][1]); |
72 |
gregl |
3.5 |
ab += (ip[2][0]-ip[3][0])*(ip[1][1]-ip[3][1]) - |
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gregl |
3.1 |
(ip[1][0]-ip[3][0])*(ip[2][1]-ip[3][1]); |
74 |
gregl |
3.5 |
if (ab >= 0) ab *= 0.5; |
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else ab *= -0.5; |
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/* round off smaller area */ |
77 |
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if (af <= ab) |
78 |
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return((int)(af + 0.5)); |
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return((int)(ab + 0.5)); |
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gregl |
3.1 |
} |
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82 |
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83 |
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/* |
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* The ray directions that define the pyramid in visit_cells() needn't |
85 |
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* be normalized, but they must be given in clockwise order as seen |
86 |
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* from the pyramid's apex (origin). |
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gregl |
3.8 |
* If no cell centers fall within the domain, the closest cell is visited. |
88 |
gregl |
3.1 |
*/ |
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int |
90 |
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visit_cells(orig, pyrd, hp, vf, dp) /* visit cells within a pyramid */ |
91 |
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FVECT orig, pyrd[4]; /* pyramid ray directions in clockwise order */ |
92 |
gregl |
3.8 |
register HOLO *hp; |
93 |
gregl |
3.1 |
int (*vf)(); |
94 |
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char *dp; |
95 |
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{ |
96 |
gregl |
3.8 |
int ncalls = 0, n = 0; |
97 |
gregl |
3.1 |
int inflags = 0; |
98 |
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FVECT gp, pn[4], lo, ld; |
99 |
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double po[4], lbeg, lend, d, t; |
100 |
gregl |
3.8 |
GCOORD gc, gc2[2]; |
101 |
gregl |
3.1 |
register int i; |
102 |
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/* figure out whose side we're on */ |
103 |
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hdgrid(gp, hp, orig); |
104 |
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for (i = 0; i < 3; i++) { |
105 |
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inflags |= (gp[i] > FTINY) << (i<<1); |
106 |
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inflags |= (gp[i] < hp->grid[i]-FTINY) << (i<<1 | 1); |
107 |
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} |
108 |
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/* compute pyramid planes */ |
109 |
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for (i = 0; i < 4; i++) { |
110 |
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fcross(pn[i], pyrd[i], pyrd[(i+1)&03]); |
111 |
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po[i] = DOT(pn[i], orig); |
112 |
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} |
113 |
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/* traverse each wall */ |
114 |
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for (gc.w = 0; gc.w < 6; gc.w++) { |
115 |
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if (!(inflags & 1<<gc.w)) /* origin on wrong side */ |
116 |
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continue; |
117 |
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/* scanline algorithm */ |
118 |
gregl |
3.9 |
for (gc.i[1] = hp->grid[hdwg1[gc.w]]; gc.i[1]--; ) { |
119 |
gregl |
3.1 |
/* compute scanline */ |
120 |
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gp[gc.w>>1] = gc.w&1 ? hp->grid[gc.w>>1] : 0; |
121 |
gregl |
3.9 |
gp[hdwg0[gc.w]] = 0; |
122 |
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gp[hdwg1[gc.w]] = gc.i[1] + 0.5; |
123 |
gregl |
3.1 |
hdworld(lo, hp, gp); |
124 |
gregl |
3.9 |
gp[hdwg0[gc.w]] = 1; |
125 |
gregl |
3.1 |
hdworld(ld, hp, gp); |
126 |
gregl |
3.2 |
ld[0] -= lo[0]; ld[1] -= lo[1]; ld[2] -= lo[2]; |
127 |
gregl |
3.1 |
/* find scanline limits */ |
128 |
gregl |
3.9 |
lbeg = 0; lend = hp->grid[hdwg0[gc.w]]; |
129 |
gregl |
3.1 |
for (i = 0; i < 4; i++) { |
130 |
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t = DOT(pn[i], lo) - po[i]; |
131 |
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d = -DOT(pn[i], ld); |
132 |
gregl |
3.2 |
if (d > FTINY) { /* <- plane */ |
133 |
gregl |
3.1 |
if ((t /= d) < lend) |
134 |
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lend = t; |
135 |
gregl |
3.2 |
} else if (d < -FTINY) { /* plane -> */ |
136 |
gregl |
3.1 |
if ((t /= d) > lbeg) |
137 |
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lbeg = t; |
138 |
gregl |
3.3 |
} else if (t < 0) { /* outside */ |
139 |
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lend = -1; |
140 |
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break; |
141 |
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} |
142 |
gregl |
3.1 |
} |
143 |
gregl |
3.3 |
if (lbeg >= lend) |
144 |
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continue; |
145 |
gregl |
3.1 |
i = lend + .5; /* visit cells on this scan */ |
146 |
gregl |
3.8 |
for (gc.i[0] = lbeg + .5; gc.i[0] < i; gc.i[0]++) { |
147 |
gregl |
3.1 |
n += (*vf)(&gc, dp); |
148 |
gregl |
3.8 |
ncalls++; |
149 |
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} |
150 |
gregl |
3.1 |
} |
151 |
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} |
152 |
gregl |
3.8 |
if (ncalls) /* got one at least */ |
153 |
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return(n); |
154 |
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/* else find closest cell */ |
155 |
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VSUM(ld, pyrd[0], pyrd[1], 1.); |
156 |
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VSUM(ld, ld, pyrd[2], 1.); |
157 |
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VSUM(ld, ld, pyrd[3], 1.); |
158 |
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#if 0 |
159 |
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if (normalize(ld) == 0.0) /* technically not necessary */ |
160 |
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return(0); |
161 |
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#endif |
162 |
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d = hdinter(gc2, NULL, &t, hp, orig, ld); |
163 |
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if (d >= FHUGE || t <= 0.) |
164 |
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return(0); |
165 |
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return((*vf)(gc2+1, dp)); /* visit it */ |
166 |
gregl |
3.1 |
} |
167 |
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168 |
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169 |
gregl |
3.4 |
sect_behind(hp, vp) /* check if section is "behind" viewpoint */ |
170 |
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register HOLO *hp; |
171 |
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register VIEW *vp; |
172 |
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{ |
173 |
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FVECT hcent; |
174 |
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/* compute holodeck section center */ |
175 |
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VSUM(hcent, hp->orig, hp->xv[0], 0.5); |
176 |
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VSUM(hcent, hcent, hp->xv[1], 0.5); |
177 |
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VSUM(hcent, hcent, hp->xv[2], 0.5); |
178 |
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/* behind if center is behind */ |
179 |
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return(DOT(vp->vdir,hcent) < DOT(vp->vdir,vp->vp)); |
180 |
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} |
181 |
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182 |
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183 |
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viewpyramid(org, dir, hp, vp) /* compute view pyramid */ |
184 |
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FVECT org, dir[4]; |
185 |
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HOLO *hp; |
186 |
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VIEW *vp; |
187 |
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{ |
188 |
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register int i; |
189 |
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/* check view type */ |
190 |
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if (vp->type == VT_PAR) |
191 |
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return(0); |
192 |
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/* in front or behind? */ |
193 |
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if (!sect_behind(hp, vp)) { |
194 |
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if (viewray(org, dir[0], vp, 0., 0.) < -FTINY) |
195 |
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return(0); |
196 |
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if (viewray(org, dir[1], vp, 0., 1.) < -FTINY) |
197 |
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return(0); |
198 |
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if (viewray(org, dir[2], vp, 1., 1.) < -FTINY) |
199 |
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return(0); |
200 |
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if (viewray(org, dir[3], vp, 1., 0.) < -FTINY) |
201 |
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return(0); |
202 |
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return(1); |
203 |
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} /* reverse pyramid */ |
204 |
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if (viewray(org, dir[3], vp, 0., 0.) < -FTINY) |
205 |
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return(0); |
206 |
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if (viewray(org, dir[2], vp, 0., 1.) < -FTINY) |
207 |
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return(0); |
208 |
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if (viewray(org, dir[1], vp, 1., 1.) < -FTINY) |
209 |
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return(0); |
210 |
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if (viewray(org, dir[0], vp, 1., 0.) < -FTINY) |
211 |
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return(0); |
212 |
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for (i = 0; i < 3; i++) { |
213 |
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dir[0][i] = -dir[0][i]; |
214 |
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dir[1][i] = -dir[1][i]; |
215 |
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dir[2][i] = -dir[2][i]; |
216 |
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dir[3][i] = -dir[3][i]; |
217 |
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} |
218 |
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return(-1); |
219 |
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} |
220 |
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221 |
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222 |
gregl |
3.1 |
int |
223 |
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addcell(gcp, cl) /* add a cell to a list */ |
224 |
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GCOORD *gcp; |
225 |
gregl |
3.4 |
register struct cellist *cl; |
226 |
gregl |
3.1 |
{ |
227 |
gregl |
3.4 |
copystruct(cl->cl+cl->n, gcp); |
228 |
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cl->n++; |
229 |
gregl |
3.1 |
return(1); |
230 |
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} |
231 |
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232 |
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233 |
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int |
234 |
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cellcmp(gcp1, gcp2) /* visit_cells() cell ordering */ |
235 |
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register GCOORD *gcp1, *gcp2; |
236 |
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{ |
237 |
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register int c; |
238 |
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239 |
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if ((c = gcp1->w - gcp2->w)) |
240 |
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return(c); |
241 |
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if ((c = gcp2->i[1] - gcp1->i[1])) /* wg1 is reverse-ordered */ |
242 |
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return(c); |
243 |
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return(gcp1->i[0] - gcp2->i[0]); |
244 |
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} |
245 |
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246 |
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247 |
gregl |
3.4 |
GCOORD * |
248 |
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getviewcells(np, hp, vp) /* get ordered cell list for section view */ |
249 |
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int *np; /* returned number of cells (negative if reversed) */ |
250 |
gregl |
3.1 |
register HOLO *hp; |
251 |
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VIEW *vp; |
252 |
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{ |
253 |
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FVECT org, dir[4]; |
254 |
gregl |
3.4 |
int orient; |
255 |
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struct cellist cl; |
256 |
gregl |
3.1 |
/* compute view pyramid */ |
257 |
gregl |
3.4 |
*np = 0; |
258 |
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orient = viewpyramid(org, dir, hp, vp); |
259 |
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if (!orient) |
260 |
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return(NULL); |
261 |
gregl |
3.1 |
/* allocate enough list space */ |
262 |
gregl |
3.4 |
cl.n = 2*( hp->grid[0]*hp->grid[1] + |
263 |
|
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hp->grid[0]*hp->grid[2] + |
264 |
|
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hp->grid[1]*hp->grid[2] ); |
265 |
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cl.cl = (GCOORD *)malloc(cl.n*sizeof(GCOORD)); |
266 |
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if (cl.cl == NULL) |
267 |
gregl |
3.1 |
goto memerr; |
268 |
gregl |
3.4 |
cl.n = 0; /* add cells within pyramid */ |
269 |
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visit_cells(org, dir, hp, addcell, &cl); |
270 |
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if (!cl.n) { |
271 |
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free((char *)cl.cl); |
272 |
gregl |
3.1 |
return(NULL); |
273 |
|
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} |
274 |
gregl |
3.4 |
*np = cl.n * orient; |
275 |
gregl |
3.1 |
#if 0 |
276 |
gregl |
3.2 |
/* We're just going to free this memory in a moment, and list is |
277 |
|
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* sorted automatically by visit_cells(), so we don't need this. |
278 |
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*/ |
279 |
gregl |
3.4 |
/* optimize memory use */ |
280 |
|
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cl.cl = (GCOORD *)realloc((char *)cl.cl, cl.n*sizeof(GCOORD)); |
281 |
|
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if (cl.cl == NULL) |
282 |
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goto memerr; |
283 |
gregl |
3.1 |
/* sort the list */ |
284 |
gregl |
3.4 |
qsort((char *)cl.cl, cl.n, sizeof(GCOORD), cellcmp); |
285 |
gregl |
3.1 |
#endif |
286 |
gregl |
3.4 |
return(cl.cl); |
287 |
gregl |
3.1 |
memerr: |
288 |
|
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error(SYSTEM, "out of memory in getviewcells"); |
289 |
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} |
290 |
gregl |
3.6 |
|
291 |
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|
292 |
|
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gridlines(f) /* run through holodeck section grid lines */ |
293 |
|
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int (*f)(); |
294 |
|
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{ |
295 |
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register int hd, w, i; |
296 |
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int g0, g1; |
297 |
gregl |
3.7 |
FVECT wp[2], mov; |
298 |
gregl |
3.6 |
double d; |
299 |
|
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/* do each wall on each section */ |
300 |
|
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for (hd = 0; hdlist[hd] != NULL; hd++) |
301 |
|
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for (w = 0; w < 6; w++) { |
302 |
gregl |
3.9 |
g0 = hdwg0[w]; |
303 |
|
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g1 = hdwg1[w]; |
304 |
gregl |
3.7 |
d = 1.0/hdlist[hd]->grid[g0]; |
305 |
|
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mov[0] = d * hdlist[hd]->xv[g0][0]; |
306 |
|
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mov[1] = d * hdlist[hd]->xv[g0][1]; |
307 |
|
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mov[2] = d * hdlist[hd]->xv[g0][2]; |
308 |
|
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if (w & 1) { |
309 |
gregl |
3.6 |
VSUM(wp[0], hdlist[hd]->orig, |
310 |
|
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hdlist[hd]->xv[w>>1], 1.); |
311 |
gregl |
3.7 |
VSUM(wp[0], wp[0], mov, 1.); |
312 |
|
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} else |
313 |
|
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VCOPY(wp[0], hdlist[hd]->orig); |
314 |
|
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VSUM(wp[1], wp[0], hdlist[hd]->xv[g1], 1.); |
315 |
|
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for (i = hdlist[hd]->grid[g0]; ; ) { /* g0 lines */ |
316 |
gregl |
3.6 |
(*f)(wp); |
317 |
gregl |
3.7 |
if (!--i) break; |
318 |
|
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wp[0][0] += mov[0]; wp[0][1] += mov[1]; |
319 |
|
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wp[0][2] += mov[2]; wp[1][0] += mov[0]; |
320 |
|
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wp[1][1] += mov[1]; wp[1][2] += mov[2]; |
321 |
gregl |
3.6 |
} |
322 |
gregl |
3.7 |
d = 1.0/hdlist[hd]->grid[g1]; |
323 |
|
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mov[0] = d * hdlist[hd]->xv[g1][0]; |
324 |
|
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mov[1] = d * hdlist[hd]->xv[g1][1]; |
325 |
|
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mov[2] = d * hdlist[hd]->xv[g1][2]; |
326 |
|
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if (w & 1) |
327 |
gregl |
3.6 |
VSUM(wp[0], hdlist[hd]->orig, |
328 |
|
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hdlist[hd]->xv[w>>1], 1.); |
329 |
gregl |
3.7 |
else |
330 |
|
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VSUM(wp[0], hdlist[hd]->orig, mov, 1.); |
331 |
|
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VSUM(wp[1], wp[0], hdlist[hd]->xv[g0], 1.); |
332 |
|
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for (i = hdlist[hd]->grid[g1]; ; ) { /* g1 lines */ |
333 |
gregl |
3.6 |
(*f)(wp); |
334 |
gregl |
3.7 |
if (!--i) break; |
335 |
|
|
wp[0][0] += mov[0]; wp[0][1] += mov[1]; |
336 |
|
|
wp[0][2] += mov[2]; wp[1][0] += mov[0]; |
337 |
|
|
wp[1][1] += mov[1]; wp[1][2] += mov[2]; |
338 |
gregl |
3.6 |
} |
339 |
|
|
} |
340 |
|
|
} |