1 |
greg |
2.1 |
/* Copyright (c) 1996 Regents of the University of California */ |
2 |
|
|
|
3 |
|
|
#ifndef lint |
4 |
|
|
static char SCCSid[] = "$SunId$ LBL"; |
5 |
|
|
#endif |
6 |
|
|
|
7 |
|
|
/* |
8 |
|
|
* Draw small sources into image in case we missed them. |
9 |
|
|
*/ |
10 |
|
|
|
11 |
|
|
#include "ray.h" |
12 |
|
|
|
13 |
|
|
#include "view.h" |
14 |
|
|
|
15 |
|
|
#include "source.h" |
16 |
|
|
|
17 |
|
|
|
18 |
|
|
#define CLIP_ABOVE 1 |
19 |
|
|
#define CLIP_BELOW 2 |
20 |
|
|
#define CLIP_RIGHT 3 |
21 |
|
|
#define CLIP_LEFT 4 |
22 |
|
|
|
23 |
|
|
#define MAXVERT 10 |
24 |
|
|
|
25 |
|
|
|
26 |
|
|
static int |
27 |
|
|
inregion(p, cv, crit) /* check if vertex is in region */ |
28 |
|
|
FLOAT p[2]; |
29 |
|
|
double cv; |
30 |
|
|
int crit; |
31 |
|
|
{ |
32 |
|
|
switch (crit) { |
33 |
|
|
case CLIP_ABOVE: |
34 |
|
|
return(p[1] < cv); |
35 |
|
|
case CLIP_BELOW: |
36 |
|
|
return(p[1] >= cv); |
37 |
|
|
case CLIP_RIGHT: |
38 |
|
|
return(p[0] < cv); |
39 |
|
|
case CLIP_LEFT: |
40 |
|
|
return(p[0] >= cv); |
41 |
|
|
} |
42 |
|
|
return(-1); |
43 |
|
|
} |
44 |
|
|
|
45 |
|
|
|
46 |
|
|
static |
47 |
|
|
clipregion(a, b, cv, crit, r) /* find intersection with boundary */ |
48 |
|
|
register FLOAT a[2], b[2]; |
49 |
|
|
double cv; |
50 |
|
|
int crit; |
51 |
|
|
FLOAT r[2]; /* return value */ |
52 |
|
|
{ |
53 |
|
|
switch (crit) { |
54 |
|
|
case CLIP_ABOVE: |
55 |
|
|
case CLIP_BELOW: |
56 |
|
|
r[1] = cv; |
57 |
|
|
r[0] = a[0] + (cv-a[1])/(b[1]-a[1])*(b[0]-a[0]); |
58 |
|
|
return; |
59 |
|
|
case CLIP_RIGHT: |
60 |
|
|
case CLIP_LEFT: |
61 |
|
|
r[0] = cv; |
62 |
|
|
r[1] = a[1] + (cv-a[0])/(b[0]-a[0])*(b[1]-a[1]); |
63 |
|
|
return; |
64 |
|
|
} |
65 |
|
|
} |
66 |
|
|
|
67 |
|
|
|
68 |
|
|
static int |
69 |
|
|
hp_clip_poly(vl, nv, cv, crit, vlo) /* clip polygon to half-plane */ |
70 |
|
|
FLOAT vl[][2]; |
71 |
|
|
int nv; |
72 |
|
|
double cv; |
73 |
|
|
int crit; |
74 |
|
|
FLOAT vlo[][2]; /* return value */ |
75 |
|
|
{ |
76 |
|
|
FLOAT *s, *p; |
77 |
|
|
register int j, nvo; |
78 |
|
|
|
79 |
|
|
s = vl[nv-1]; |
80 |
|
|
nvo = 0; |
81 |
|
|
for (j = 0; j < nv; j++) { |
82 |
|
|
p = vl[j]; |
83 |
|
|
if (inregion(p, cv, crit)) { |
84 |
|
|
if (!inregion(s, cv, crit)) |
85 |
|
|
clipregion(s, p, cv, crit, vlo[nvo++]); |
86 |
|
|
vlo[nvo][0] = p[0]; vlo[nvo++][1] = p[1]; |
87 |
|
|
} else if (inregion(s, cv, crit)) |
88 |
|
|
clipregion(s, p, cv, crit, vlo[nvo++]); |
89 |
|
|
s = p; |
90 |
|
|
} |
91 |
|
|
return(nvo); |
92 |
|
|
} |
93 |
|
|
|
94 |
|
|
|
95 |
|
|
static int |
96 |
|
|
box_clip_poly(vl, nv, xl, xr, yb, ya, vlo) /* clip polygon to box */ |
97 |
|
|
FLOAT vl[MAXVERT][2]; |
98 |
|
|
int nv; |
99 |
|
|
double xl, xr, yb, ya; |
100 |
|
|
FLOAT vlo[MAXVERT][2]; /* return value */ |
101 |
|
|
{ |
102 |
|
|
FLOAT vlt[MAXVERT][2]; |
103 |
|
|
int nvt, nvo; |
104 |
|
|
|
105 |
|
|
nvt = hp_clip_poly(vl, nv, yb, CLIP_BELOW, vlt); |
106 |
|
|
nvo = hp_clip_poly(vlt, nvt, ya, CLIP_ABOVE, vlo); |
107 |
|
|
nvt = hp_clip_poly(vlo, nvo, xl, CLIP_LEFT, vlt); |
108 |
|
|
nvo = hp_clip_poly(vlt, nvt, xr, CLIP_RIGHT, vlo); |
109 |
|
|
|
110 |
|
|
return(nvo); |
111 |
|
|
} |
112 |
|
|
|
113 |
|
|
|
114 |
|
|
static double |
115 |
|
|
minw2(vl, nv, ar2) /* compute square of minimum width */ |
116 |
|
|
FLOAT vl[][2]; |
117 |
|
|
int nv; |
118 |
|
|
double ar2; |
119 |
|
|
{ |
120 |
|
|
double d2, w2, w2min, w2max; |
121 |
|
|
register FLOAT *p0, *p1, *p2; |
122 |
|
|
int i, j; |
123 |
|
|
/* find minimum for all widths */ |
124 |
|
|
w2min = FHUGE; |
125 |
|
|
p0 = vl[nv-1]; |
126 |
|
|
for (i = 0; i < nv; i++) { /* for each edge */ |
127 |
|
|
p1 = vl[i]; |
128 |
|
|
d2 = (p1[0]-p0[0])*(p1[0]-p0[0]) + |
129 |
|
|
(p1[1]-p0[1])*(p1[1]-p0[1])*ar2; |
130 |
|
|
w2max = 0.; /* find maximum for this side */ |
131 |
|
|
for (j = 1; j < nv-1; j++) { |
132 |
|
|
p2 = vl[(i+j)%nv]; |
133 |
|
|
w2 = (p1[0]-p0[0])*(p2[1]-p0[1]) - |
134 |
|
|
(p1[1]-p0[1])*(p2[0]-p0[0]); |
135 |
|
|
w2 = w2*w2*ar2/d2; /* triangle height squared */ |
136 |
|
|
if (w2 > w2max) |
137 |
|
|
w2max = w2; |
138 |
|
|
} |
139 |
|
|
if (w2max < w2min) /* global min. based on local max.'s */ |
140 |
|
|
w2min = w2max; |
141 |
|
|
p0 = p1; |
142 |
|
|
} |
143 |
|
|
return(w2min); |
144 |
|
|
} |
145 |
|
|
|
146 |
|
|
|
147 |
|
|
static |
148 |
|
|
convex_center(vl, nv, cv) /* compute center of convex polygon */ |
149 |
|
|
register FLOAT vl[][2]; |
150 |
|
|
int nv; |
151 |
|
|
FLOAT cv[2]; /* return value */ |
152 |
|
|
{ |
153 |
|
|
register int i; |
154 |
|
|
/* simple average (suboptimal) */ |
155 |
|
|
cv[0] = cv[1] = 0.; |
156 |
|
|
for (i = 0; i < nv; i++) { |
157 |
|
|
cv[0] += vl[i][0]; |
158 |
|
|
cv[1] += vl[i][1]; |
159 |
|
|
} |
160 |
|
|
cv[0] /= (double)nv; |
161 |
|
|
cv[1] /= (double)nv; |
162 |
|
|
} |
163 |
|
|
|
164 |
|
|
|
165 |
|
|
static double |
166 |
|
|
poly_area(vl, nv) /* compute area of polygon */ |
167 |
|
|
register FLOAT vl[][2]; |
168 |
|
|
int nv; |
169 |
|
|
{ |
170 |
|
|
double a; |
171 |
|
|
FLOAT v0[2], v1[2]; |
172 |
|
|
register int i; |
173 |
|
|
|
174 |
|
|
a = 0.; |
175 |
|
|
v0[0] = vl[1][0] - vl[0][0]; |
176 |
|
|
v0[1] = vl[1][1] - vl[0][1]; |
177 |
|
|
for (i = 2; i < nv; i++) { |
178 |
|
|
v1[0] = vl[i][0] - vl[0][0]; |
179 |
|
|
v1[1] = vl[i][1] - vl[0][1]; |
180 |
|
|
a += v0[0]*v1[1] - v0[1]*v1[0]; |
181 |
|
|
v0[0] = v1[0]; v0[1] = v1[1]; |
182 |
|
|
} |
183 |
|
|
return(a * (a >= 0. ? .5 : -.5)); |
184 |
|
|
} |
185 |
|
|
|
186 |
|
|
|
187 |
|
|
static int |
188 |
|
|
convex_hull(vl, nv, vlo) /* compute polygon's convex hull */ |
189 |
|
|
FLOAT vl[][2]; |
190 |
|
|
int nv; |
191 |
|
|
FLOAT vlo[][2]; /* return value */ |
192 |
|
|
{ |
193 |
|
|
int nvo, nvt; |
194 |
|
|
FLOAT vlt[MAXVERT][2]; |
195 |
|
|
double voa, vta; |
196 |
|
|
register int i, j; |
197 |
|
|
/* start with original polygon */ |
198 |
|
|
for (i = nvo = nv; i--; ) { |
199 |
|
|
vlo[i][0] = vl[i][0]; vlo[i][1] = vl[i][1]; |
200 |
|
|
} |
201 |
|
|
voa = poly_area(vlo, nvo); /* compute its area */ |
202 |
|
|
for (i = 0; i < nvo; i++) { /* for each output vertex */ |
203 |
|
|
for (j = 0; j < i; j++) { |
204 |
|
|
vlt[j][0] = vlo[j][0]; vlt[j][1] = vlo[j][1]; |
205 |
|
|
} |
206 |
|
|
nvt = nvo - 1; /* make poly w/o vertex */ |
207 |
|
|
for (j = i; j < nvt; j++) { |
208 |
|
|
vlt[j][0] = vlo[j+1][0]; vlt[j][1] = vlo[j+1][1]; |
209 |
|
|
} |
210 |
|
|
vta = poly_area(vlt, nvt); |
211 |
|
|
if (vta >= voa) { /* is simpler poly bigger? */ |
212 |
|
|
voa = vta; /* then use it */ |
213 |
|
|
for (j = nvo = nvt; j--; ) { |
214 |
|
|
vlo[j][0] = vlt[j][0]; vlo[j][1] = vlt[j][1]; |
215 |
|
|
} |
216 |
|
|
i--; /* next adjust */ |
217 |
|
|
} |
218 |
|
|
} |
219 |
|
|
return(nvo); |
220 |
|
|
} |
221 |
|
|
|
222 |
|
|
|
223 |
|
|
int |
224 |
|
|
sourcepoly(vw, sn, sp) /* compute image polygon for source */ |
225 |
|
|
VIEW *vw; |
226 |
|
|
int sn; |
227 |
|
|
FLOAT sp[MAXVERT][2]; |
228 |
|
|
{ |
229 |
|
|
static char cubeord[8][6] = {{1,3,2,6,4,5},{0,4,5,7,3,2}, |
230 |
|
|
{0,1,3,7,6,4},{0,1,5,7,6,2}, |
231 |
|
|
{0,2,6,7,5,1},{0,4,6,7,3,1}, |
232 |
|
|
{0,2,3,7,5,4},{1,5,4,6,2,3}}; |
233 |
|
|
register SRCREC *s = source + sn; |
234 |
|
|
FVECT ap, ip; |
235 |
|
|
FLOAT pt[6][2]; |
236 |
|
|
int dir; |
237 |
|
|
register int i, j; |
238 |
|
|
|
239 |
|
|
if (s->sflags & (SDISTANT|SFLAT)) { |
240 |
|
|
if (s->sflags & SDISTANT && vw->type == VT_PAR) |
241 |
|
|
return(0); /* all or nothing case */ |
242 |
|
|
if (s->sflags & SFLAT) { |
243 |
|
|
for (i = 0; i < 3; i++) |
244 |
|
|
ap[i] = s->sloc[i] - vw->vp[i]; |
245 |
|
|
if (DOT(ap, s->snorm) >= 0.) |
246 |
|
|
return(0); /* source faces away */ |
247 |
|
|
} |
248 |
|
|
for (j = 0; j < 4; j++) { /* four corners */ |
249 |
|
|
for (i = 0; i < 3; i++) { |
250 |
|
|
ap[i] = s->sloc[i]; |
251 |
|
|
if (j==1|j==2) ap[i] += s->ss[SU][i]; |
252 |
|
|
else ap[i] -= s->ss[SU][i]; |
253 |
|
|
if (j==2|j==3) ap[i] += s->ss[SV][i]; |
254 |
|
|
else ap[i] -= s->ss[SV][i]; |
255 |
|
|
if (s->sflags & SDISTANT) { |
256 |
|
|
ap[i] *= 1. + vw->vfore; |
257 |
|
|
ap[i] += vw->vp[i]; |
258 |
|
|
} |
259 |
|
|
} |
260 |
|
|
viewloc(ip, vw, ap); /* find image point */ |
261 |
|
|
if (ip[2] <= 0.) |
262 |
|
|
return(0); /* in front of view */ |
263 |
|
|
sp[j][0] = ip[0]; sp[j][1] = ip[1]; |
264 |
|
|
} |
265 |
|
|
return(4); |
266 |
|
|
} |
267 |
|
|
/* identify furthest corner */ |
268 |
|
|
for (i = 0; i < 3; i++) |
269 |
|
|
ap[i] = s->sloc[i] - vw->vp[i]; |
270 |
|
|
dir = (DOT(ap,s->ss[SU])>0.) | |
271 |
|
|
(DOT(ap,s->ss[SV])>0.)<<1 | |
272 |
|
|
(DOT(ap,s->ss[SW])>0.)<<2 ; |
273 |
|
|
/* order vertices based on this */ |
274 |
|
|
for (j = 0; j < 6; j++) { |
275 |
|
|
for (i = 0; i < 3; i++) { |
276 |
|
|
ap[i] = s->sloc[i]; |
277 |
|
|
if (cubeord[dir][j] & 1) ap[i] += s->ss[SU][i]; |
278 |
|
|
else ap[i] -= s->ss[SU][i]; |
279 |
|
|
if (cubeord[dir][j] & 2) ap[i] += s->ss[SV][i]; |
280 |
|
|
else ap[i] -= s->ss[SV][i]; |
281 |
|
|
if (cubeord[dir][j] & 4) ap[i] += s->ss[SW][i]; |
282 |
|
|
else ap[i] -= s->ss[SW][i]; |
283 |
|
|
} |
284 |
|
|
viewloc(ip, vw, ap); /* find image point */ |
285 |
|
|
if (ip[2] <= 0.) |
286 |
|
|
return(0); /* in front of view */ |
287 |
|
|
pt[j][0] = ip[0]; pt[j][1] = ip[1]; |
288 |
|
|
} |
289 |
|
|
return(convex_hull(pt, 6, sp)); /* make sure it's convex */ |
290 |
|
|
} |
291 |
|
|
|
292 |
|
|
|
293 |
|
|
/* add sources smaller than rad to computed subimage */ |
294 |
|
|
drawsources(vw, xr, yr, pic, zbf, x0, xsiz, y0, ysiz, rad) |
295 |
|
|
VIEW *vw; /* full image view */ |
296 |
|
|
int xr, yr; /* full image dimensions */ |
297 |
|
|
COLOR *pic[]; /* subimage pixel value array */ |
298 |
|
|
float *zbf[]; /* subimage distance array (opt.) */ |
299 |
|
|
int x0, xsiz, y0, ysiz; /* origin and size of subimage */ |
300 |
|
|
int rad; /* source sample size */ |
301 |
|
|
{ |
302 |
|
|
int sn; |
303 |
|
|
FLOAT spoly[MAXVERT][2], ppoly[MAXVERT][2]; |
304 |
|
|
int nsv, npv; |
305 |
|
|
int xmin, xmax, ymin, ymax, x, y, i; |
306 |
|
|
FLOAT cxy[2]; |
307 |
|
|
double pa; |
308 |
|
|
RAY sr; |
309 |
|
|
/* loop through all sources */ |
310 |
|
|
for (sn = 0; sn < nsources; sn++) { |
311 |
|
|
/* compute image polygon for source */ |
312 |
|
|
if (!(nsv = sourcepoly(vw, sn, spoly))) |
313 |
|
|
continue; |
314 |
greg |
2.2 |
/* big enough for standard sampling? */ |
315 |
|
|
if (minw2(spoly, nsv, vw->vn2/vw->hn2) > (double)rad*rad/xr/xr) |
316 |
|
|
continue; |
317 |
greg |
2.1 |
/* clip source poly to subimage */ |
318 |
|
|
nsv = box_clip_poly(spoly, nsv, |
319 |
|
|
(double)x0/xr, (double)(x0+xsiz)/xr, |
320 |
|
|
(double)y0/yr, (double)(y0+ysiz)/yr, spoly); |
321 |
|
|
if (!nsv) |
322 |
|
|
continue; |
323 |
|
|
/* find common subimage (BBox) */ |
324 |
|
|
xmin = x0 + xsiz; xmax = x0; |
325 |
|
|
ymin = y0 + ysiz; ymax = y0; |
326 |
|
|
for (i = 0; i < nsv; i++) { |
327 |
|
|
if ((double)xmin/xr > spoly[i][0]) |
328 |
|
|
xmin = spoly[i][0]*xr + FTINY; |
329 |
|
|
if ((double)xmax/xr < spoly[i][0]) |
330 |
|
|
xmax = spoly[i][0]*xr - FTINY; |
331 |
|
|
if ((double)ymin/yr > spoly[i][1]) |
332 |
|
|
ymin = spoly[i][1]*yr + FTINY; |
333 |
|
|
if ((double)ymax/yr < spoly[i][1]) |
334 |
|
|
ymax = spoly[i][1]*yr - FTINY; |
335 |
|
|
} |
336 |
|
|
/* evaluate each pixel in BBox */ |
337 |
|
|
for (y = ymin; y <= ymax; y++) |
338 |
|
|
for (x = xmin; x <= xmax; x++) { |
339 |
|
|
/* subarea for pixel */ |
340 |
|
|
npv = box_clip_poly(spoly, nsv, |
341 |
|
|
(double)x/xr, (x+1.)/xr, |
342 |
|
|
(double)y/yr, (y+1.)/yr, ppoly); |
343 |
|
|
if (!npv) |
344 |
|
|
continue; /* no overlap */ |
345 |
|
|
convex_center(ppoly, npv, cxy); |
346 |
|
|
if ((sr.rmax = viewray(sr.rorg, sr.rdir, vw, |
347 |
|
|
cxy[0], cxy[1])) < -FTINY) |
348 |
|
|
continue; /* not in view */ |
349 |
|
|
if (source[sn].sflags & SSPOT && |
350 |
greg |
2.2 |
spotout(&sr, source[sn].sl.s)) |
351 |
greg |
2.1 |
continue; /* outside spot */ |
352 |
|
|
rayorigin(&sr, NULL, SHADOW, 1.0); |
353 |
|
|
sr.rsrc = sn; |
354 |
|
|
rayvalue(&sr); /* compute value */ |
355 |
|
|
if (bright(sr.rcol) <= FTINY) |
356 |
|
|
continue; /* missed/blocked */ |
357 |
|
|
/* modify pixel */ |
358 |
|
|
if (zbf[y-y0] != NULL && |
359 |
|
|
sr.rt < zbf[y-y0][x-x0]) |
360 |
|
|
zbf[y-y0][x-x0] = sr.rt; |
361 |
|
|
pa = poly_area(ppoly, npv); |
362 |
|
|
scalecolor(sr.rcol, pa*xr*yr); |
363 |
|
|
scalecolor(pic[y-y0][x-x0], (1.-pa*xr*yr)); |
364 |
|
|
addcolor(pic[y-y0][x-x0], sr.rcol); |
365 |
|
|
} |
366 |
|
|
} |
367 |
|
|
} |