ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/cv/mgflib/context.c
Revision: 1.26
Committed: Mon Dec 15 09:41:37 1997 UTC (26 years, 10 months ago) by gregl
Content type: text/plain
Branch: MAIN
Changes since 1.25: +1 -0 lines
Log Message:
added stdlib.h for better reliability on some systems

File Contents

# Content
1 /* Copyright (c) 1997 Regents of the University of California */
2
3 #ifndef lint
4 static char SCCSid[] = "$SunId$ LBL";
5 #endif
6
7 /*
8 * Context handlers
9 */
10
11 #include <stdio.h>
12 #include <math.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include "parser.h"
16 #include "lookup.h"
17
18 /* default context values */
19 static C_COLOR c_dfcolor = C_DEFCOLOR;
20 static C_MATERIAL c_dfmaterial = C_DEFMATERIAL;
21 static C_VERTEX c_dfvertex = C_DEFVERTEX;
22
23 /* the unnamed contexts */
24 static C_COLOR c_uncolor = C_DEFCOLOR;
25 static C_MATERIAL c_unmaterial = C_DEFMATERIAL;
26 static C_VERTEX c_unvertex = C_DEFVERTEX;
27
28 /* the current contexts */
29 C_COLOR *c_ccolor = &c_uncolor;
30 char *c_ccname = NULL;
31 C_MATERIAL *c_cmaterial = &c_unmaterial;
32 char *c_cmname = NULL;
33 C_VERTEX *c_cvertex = &c_unvertex;
34 char *c_cvname = NULL;
35
36 static LUTAB clr_tab = LU_SINIT(free,free); /* color lookup table */
37 static LUTAB mat_tab = LU_SINIT(free,free); /* material lookup table */
38 static LUTAB vtx_tab = LU_SINIT(free,free); /* vertex lookup table */
39
40 /* CIE 1931 Standard Observer curves */
41 static C_COLOR cie_xf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
42 {14,42,143,435,1344,2839,3483,3362,2908,1954,956,
43 320,49,93,633,1655,2904,4334,5945,7621,9163,10263,
44 10622,10026,8544,6424,4479,2835,1649,874,468,227,
45 114,58,29,14,7,3,2,1,0}, 106836L, .467, .368, 362.230
46 };
47 static C_COLOR cie_yf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
48 {0,1,4,12,40,116,230,380,600,910,1390,2080,3230,
49 5030,7100,8620,9540,9950,9950,9520,8700,7570,6310,
50 5030,3810,2650,1750,1070,610,320,170,82,41,21,10,
51 5,2,1,1,0,0}, 106856L, .398, .542, 493.525
52 };
53 static C_COLOR cie_zf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
54 {65,201,679,2074,6456,13856,17471,17721,16692,
55 12876,8130,4652,2720,1582,782,422,203,87,39,21,17,
56 11,8,3,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
57 106770L, .147, .077, 54.363
58 };
59 /* Derived CIE 1931 Primaries (imaginary) */
60 static C_COLOR cie_xp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
61 {-174,-198,-195,-197,-202,-213,-235,-272,-333,
62 -444,-688,-1232,-2393,-4497,-6876,-6758,-5256,
63 -3100,-815,1320,3200,4782,5998,6861,7408,7754,
64 7980,8120,8199,8240,8271,8292,8309,8283,8469,
65 8336,8336,8336,8336,8336,8336},
66 127424L, 1., .0,
67 };
68 static C_COLOR cie_yp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
69 {-451,-431,-431,-430,-427,-417,-399,-366,-312,
70 -204,57,691,2142,4990,8810,9871,9122,7321,5145,
71 3023,1123,-473,-1704,-2572,-3127,-3474,-3704,
72 -3846,-3927,-3968,-3999,-4021,-4038,-4012,-4201,
73 -4066,-4066,-4066,-4066,-4066,-4066},
74 -23035L, .0, 1.,
75 };
76 static C_COLOR cie_zp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
77 {4051,4054,4052,4053,4054,4056,4059,4064,4071,
78 4074,4056,3967,3677,2933,1492,313,-440,-795,
79 -904,-918,-898,-884,-869,-863,-855,-855,-851,
80 -848,-847,-846,-846,-846,-845,-846,-843,-845,
81 -845,-845,-845,-845,-845},
82 36057L, .0, .0,
83 };
84
85 static int setspectrum();
86 static int setbbtemp();
87 static void mixcolors();
88
89
90 int
91 c_hcolor(ac, av) /* handle color entity */
92 int ac;
93 register char **av;
94 {
95 double w, wsum;
96 register int i;
97 register LUENT *lp;
98
99 switch (mg_entity(av[0])) {
100 case MG_E_COLOR: /* get/set color context */
101 if (ac > 4)
102 return(MG_EARGC);
103 if (ac == 1) { /* set unnamed color context */
104 c_uncolor = c_dfcolor;
105 c_ccolor = &c_uncolor;
106 c_ccname = NULL;
107 return(MG_OK);
108 }
109 if (!isname(av[1]))
110 return(MG_EILL);
111 lp = lu_find(&clr_tab, av[1]); /* lookup context */
112 if (lp == NULL)
113 return(MG_EMEM);
114 c_ccname = lp->key;
115 c_ccolor = (C_COLOR *)lp->data;
116 if (ac == 2) { /* reestablish previous context */
117 if (c_ccolor == NULL)
118 return(MG_EUNDEF);
119 return(MG_OK);
120 }
121 if (av[2][0] != '=' || av[2][1])
122 return(MG_ETYPE);
123 if (c_ccolor == NULL) { /* create new color context */
124 lp->key = (char *)malloc(strlen(av[1])+1);
125 if (lp->key == NULL)
126 return(MG_EMEM);
127 strcpy(lp->key, av[1]);
128 lp->data = (char *)malloc(sizeof(C_COLOR));
129 if (lp->data == NULL)
130 return(MG_EMEM);
131 c_ccname = lp->key;
132 c_ccolor = (C_COLOR *)lp->data;
133 c_ccolor->clock = 0;
134 c_ccolor->client_data = NULL;
135 }
136 i = c_ccolor->clock;
137 if (ac == 3) { /* use default template */
138 *c_ccolor = c_dfcolor;
139 c_ccolor->clock = i + 1;
140 return(MG_OK);
141 }
142 lp = lu_find(&clr_tab, av[3]); /* lookup template */
143 if (lp == NULL)
144 return(MG_EMEM);
145 if (lp->data == NULL)
146 return(MG_EUNDEF);
147 *c_ccolor = *(C_COLOR *)lp->data;
148 c_ccolor->clock = i + 1;
149 return(MG_OK);
150 case MG_E_CXY: /* assign CIE XY value */
151 if (ac != 3)
152 return(MG_EARGC);
153 if (!isflt(av[1]) | !isflt(av[2]))
154 return(MG_ETYPE);
155 c_ccolor->cx = atof(av[1]);
156 c_ccolor->cy = atof(av[2]);
157 c_ccolor->flags = C_CDXY|C_CSXY;
158 if (c_ccolor->cx < 0. | c_ccolor->cy < 0. |
159 c_ccolor->cx + c_ccolor->cy > 1.)
160 return(MG_EILL);
161 c_ccolor->clock++;
162 return(MG_OK);
163 case MG_E_CSPEC: /* assign spectral values */
164 if (ac < 5)
165 return(MG_EARGC);
166 if (!isflt(av[1]) | !isflt(av[2]))
167 return(MG_ETYPE);
168 return(setspectrum(c_ccolor, atof(av[1]), atof(av[2]),
169 ac-3, av+3));
170 case MG_E_CCT: /* assign black body spectrum */
171 if (ac != 2)
172 return(MG_EARGC);
173 if (!isflt(av[1]))
174 return(MG_ETYPE);
175 return(setbbtemp(c_ccolor, atof(av[1])));
176 case MG_E_CMIX: /* mix colors */
177 if (ac < 5 || (ac-1)%2)
178 return(MG_EARGC);
179 if (!isflt(av[1]))
180 return(MG_ETYPE);
181 wsum = atof(av[1]);
182 if ((lp = lu_find(&clr_tab, av[2])) == NULL)
183 return(MG_EMEM);
184 if (lp->data == NULL)
185 return(MG_EUNDEF);
186 *c_ccolor = *(C_COLOR *)lp->data;
187 for (i = 3; i < ac; i += 2) {
188 if (!isflt(av[i]))
189 return(MG_ETYPE);
190 w = atof(av[i]);
191 if ((lp = lu_find(&clr_tab, av[i+1])) == NULL)
192 return(MG_EMEM);
193 if (lp->data == NULL)
194 return(MG_EUNDEF);
195 mixcolors(c_ccolor, wsum, c_ccolor,
196 w, (C_COLOR *)lp->data);
197 wsum += w;
198 }
199 if (wsum <= 0.)
200 return(MG_EILL);
201 c_ccolor->clock++;
202 return(MG_OK);
203 }
204 return(MG_EUNK);
205 }
206
207
208 int
209 c_hmaterial(ac, av) /* handle material entity */
210 int ac;
211 register char **av;
212 {
213 int i;
214 register LUENT *lp;
215
216 switch (mg_entity(av[0])) {
217 case MG_E_MATERIAL: /* get/set material context */
218 if (ac > 4)
219 return(MG_EARGC);
220 if (ac == 1) { /* set unnamed material context */
221 c_unmaterial = c_dfmaterial;
222 c_cmaterial = &c_unmaterial;
223 c_cmname = NULL;
224 return(MG_OK);
225 }
226 if (!isname(av[1]))
227 return(MG_EILL);
228 lp = lu_find(&mat_tab, av[1]); /* lookup context */
229 if (lp == NULL)
230 return(MG_EMEM);
231 c_cmname = lp->key;
232 c_cmaterial = (C_MATERIAL *)lp->data;
233 if (ac == 2) { /* reestablish previous context */
234 if (c_cmaterial == NULL)
235 return(MG_EUNDEF);
236 return(MG_OK);
237 }
238 if (av[2][0] != '=' || av[2][1])
239 return(MG_ETYPE);
240 if (c_cmaterial == NULL) { /* create new material */
241 lp->key = (char *)malloc(strlen(av[1])+1);
242 if (lp->key == NULL)
243 return(MG_EMEM);
244 strcpy(lp->key, av[1]);
245 lp->data = (char *)malloc(sizeof(C_MATERIAL));
246 if (lp->data == NULL)
247 return(MG_EMEM);
248 c_cmname = lp->key;
249 c_cmaterial = (C_MATERIAL *)lp->data;
250 c_cmaterial->clock = 0;
251 c_cmaterial->client_data = NULL;
252 }
253 i = c_cmaterial->clock;
254 if (ac == 3) { /* use default template */
255 *c_cmaterial = c_dfmaterial;
256 c_cmaterial->clock = i + 1;
257 return(MG_OK);
258 }
259 lp = lu_find(&mat_tab, av[3]); /* lookup template */
260 if (lp == NULL)
261 return(MG_EMEM);
262 if (lp->data == NULL)
263 return(MG_EUNDEF);
264 *c_cmaterial = *(C_MATERIAL *)lp->data;
265 c_cmaterial->clock = i + 1;
266 return(MG_OK);
267 case MG_E_IR: /* set index of refraction */
268 if (ac != 3)
269 return(MG_EARGC);
270 if (!isflt(av[1]) | !isflt(av[2]))
271 return(MG_ETYPE);
272 c_cmaterial->nr = atof(av[1]);
273 c_cmaterial->ni = atof(av[2]);
274 if (c_cmaterial->nr <= FTINY)
275 return(MG_EILL);
276 c_cmaterial->clock++;
277 return(MG_OK);
278 case MG_E_RD: /* set diffuse reflectance */
279 if (ac != 2)
280 return(MG_EARGC);
281 if (!isflt(av[1]))
282 return(MG_ETYPE);
283 c_cmaterial->rd = atof(av[1]);
284 if (c_cmaterial->rd < 0. | c_cmaterial->rd > 1.)
285 return(MG_EILL);
286 c_cmaterial->rd_c = *c_ccolor;
287 c_cmaterial->clock++;
288 return(MG_OK);
289 case MG_E_ED: /* set diffuse emittance */
290 if (ac != 2)
291 return(MG_EARGC);
292 if (!isflt(av[1]))
293 return(MG_ETYPE);
294 c_cmaterial->ed = atof(av[1]);
295 if (c_cmaterial->ed < 0.)
296 return(MG_EILL);
297 c_cmaterial->ed_c = *c_ccolor;
298 c_cmaterial->clock++;
299 return(MG_OK);
300 case MG_E_TD: /* set diffuse transmittance */
301 if (ac != 2)
302 return(MG_EARGC);
303 if (!isflt(av[1]))
304 return(MG_ETYPE);
305 c_cmaterial->td = atof(av[1]);
306 if (c_cmaterial->td < 0. | c_cmaterial->td > 1.)
307 return(MG_EILL);
308 c_cmaterial->td_c = *c_ccolor;
309 c_cmaterial->clock++;
310 return(MG_OK);
311 case MG_E_RS: /* set specular reflectance */
312 if (ac != 3)
313 return(MG_EARGC);
314 if (!isflt(av[1]) | !isflt(av[2]))
315 return(MG_ETYPE);
316 c_cmaterial->rs = atof(av[1]);
317 c_cmaterial->rs_a = atof(av[2]);
318 if (c_cmaterial->rs < 0. | c_cmaterial->rs > 1. |
319 c_cmaterial->rs_a < 0.)
320 return(MG_EILL);
321 c_cmaterial->rs_c = *c_ccolor;
322 c_cmaterial->clock++;
323 return(MG_OK);
324 case MG_E_TS: /* set specular transmittance */
325 if (ac != 3)
326 return(MG_EARGC);
327 if (!isflt(av[1]) | !isflt(av[2]))
328 return(MG_ETYPE);
329 c_cmaterial->ts = atof(av[1]);
330 c_cmaterial->ts_a = atof(av[2]);
331 if (c_cmaterial->ts < 0. | c_cmaterial->ts > 1. |
332 c_cmaterial->ts_a < 0.)
333 return(MG_EILL);
334 c_cmaterial->ts_c = *c_ccolor;
335 c_cmaterial->clock++;
336 return(MG_OK);
337 case MG_E_SIDES: /* set number of sides */
338 if (ac != 2)
339 return(MG_EARGC);
340 if (!isint(av[1]))
341 return(MG_ETYPE);
342 i = atoi(av[1]);
343 if (i == 1)
344 c_cmaterial->sided = 1;
345 else if (i == 2)
346 c_cmaterial->sided = 0;
347 else
348 return(MG_EILL);
349 c_cmaterial->clock++;
350 return(MG_OK);
351 }
352 return(MG_EUNK);
353 }
354
355
356 int
357 c_hvertex(ac, av) /* handle a vertex entity */
358 int ac;
359 register char **av;
360 {
361 int i;
362 register LUENT *lp;
363
364 switch (mg_entity(av[0])) {
365 case MG_E_VERTEX: /* get/set vertex context */
366 if (ac > 4)
367 return(MG_EARGC);
368 if (ac == 1) { /* set unnamed vertex context */
369 c_unvertex = c_dfvertex;
370 c_cvertex = &c_unvertex;
371 c_cvname = NULL;
372 return(MG_OK);
373 }
374 if (!isname(av[1]))
375 return(MG_EILL);
376 lp = lu_find(&vtx_tab, av[1]); /* lookup context */
377 if (lp == NULL)
378 return(MG_EMEM);
379 c_cvname = lp->key;
380 c_cvertex = (C_VERTEX *)lp->data;
381 if (ac == 2) { /* reestablish previous context */
382 if (c_cvertex == NULL)
383 return(MG_EUNDEF);
384 return(MG_OK);
385 }
386 if (av[2][0] != '=' || av[2][1])
387 return(MG_ETYPE);
388 if (c_cvertex == NULL) { /* create new vertex context */
389 lp->key = (char *)malloc(strlen(av[1])+1);
390 if (lp->key == NULL)
391 return(MG_EMEM);
392 strcpy(lp->key, av[1]);
393 lp->data = (char *)malloc(sizeof(C_VERTEX));
394 if (lp->data == NULL)
395 return(MG_EMEM);
396 c_cvname = lp->key;
397 c_cvertex = (C_VERTEX *)lp->data;
398 c_cvertex->clock = 0;
399 c_cvertex->client_data = NULL;
400 }
401 i = c_cvertex->clock;
402 if (ac == 3) { /* use default template */
403 *c_cvertex = c_dfvertex;
404 c_cvertex->clock = i + 1;
405 return(MG_OK);
406 }
407 lp = lu_find(&vtx_tab, av[3]); /* lookup template */
408 if (lp == NULL)
409 return(MG_EMEM);
410 if (lp->data == NULL)
411 return(MG_EUNDEF);
412 *c_cvertex = *(C_VERTEX *)lp->data;
413 c_cvertex->clock = i + 1;
414 return(MG_OK);
415 case MG_E_POINT: /* set point */
416 if (ac != 4)
417 return(MG_EARGC);
418 if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
419 return(MG_ETYPE);
420 c_cvertex->p[0] = atof(av[1]);
421 c_cvertex->p[1] = atof(av[2]);
422 c_cvertex->p[2] = atof(av[3]);
423 c_cvertex->clock++;
424 return(MG_OK);
425 case MG_E_NORMAL: /* set normal */
426 if (ac != 4)
427 return(MG_EARGC);
428 if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
429 return(MG_ETYPE);
430 c_cvertex->n[0] = atof(av[1]);
431 c_cvertex->n[1] = atof(av[2]);
432 c_cvertex->n[2] = atof(av[3]);
433 (void)normalize(c_cvertex->n);
434 c_cvertex->clock++;
435 return(MG_OK);
436 }
437 return(MG_EUNK);
438 }
439
440
441 void
442 c_clearall() /* empty context tables */
443 {
444 c_uncolor = c_dfcolor;
445 c_ccolor = &c_uncolor;
446 c_ccname = NULL;
447 lu_done(&clr_tab);
448 c_unmaterial = c_dfmaterial;
449 c_cmaterial = &c_unmaterial;
450 c_cmname = NULL;
451 lu_done(&mat_tab);
452 c_unvertex = c_dfvertex;
453 c_cvertex = &c_unvertex;
454 c_cvname = NULL;
455 lu_done(&vtx_tab);
456 }
457
458
459 C_MATERIAL *
460 c_getmaterial(name) /* get a named material */
461 char *name;
462 {
463 register LUENT *lp;
464
465 if ((lp = lu_find(&mat_tab, name)) == NULL)
466 return(NULL);
467 return((C_MATERIAL *)lp->data);
468 }
469
470
471 C_VERTEX *
472 c_getvert(name) /* get a named vertex */
473 char *name;
474 {
475 register LUENT *lp;
476
477 if ((lp = lu_find(&vtx_tab, name)) == NULL)
478 return(NULL);
479 return((C_VERTEX *)lp->data);
480 }
481
482
483 C_COLOR *
484 c_getcolor(name) /* get a named color */
485 char *name;
486 {
487 register LUENT *lp;
488
489 if ((lp = lu_find(&clr_tab, name)) == NULL)
490 return(NULL);
491 return((C_COLOR *)lp->data);
492 }
493
494
495 int
496 c_isgrey(clr) /* check if color is grey */
497 register C_COLOR *clr;
498 {
499 if (!(clr->flags & (C_CSXY|C_CSSPEC)))
500 return(1); /* no settings == grey */
501 c_ccvt(clr, C_CSXY);
502 return(clr->cx >= .323 && clr->cx <= .343 &&
503 clr->cy >= .323 && clr->cy <= .343);
504 }
505
506
507 void
508 c_ccvt(clr, fl) /* convert color representations */
509 register C_COLOR *clr;
510 int fl;
511 {
512 double x, y, z;
513 register int i;
514
515 fl &= ~clr->flags; /* ignore what's done */
516 if (!fl) /* everything's done! */
517 return;
518 if (!(clr->flags & (C_CSXY|C_CSSPEC))) /* nothing set! */
519 *clr = c_dfcolor;
520 if (fl & C_CSXY) { /* cspec -> cxy */
521 x = y = z = 0.;
522 for (i = 0; i < C_CNSS; i++) {
523 x += cie_xf.ssamp[i] * clr->ssamp[i];
524 y += cie_yf.ssamp[i] * clr->ssamp[i];
525 z += cie_zf.ssamp[i] * clr->ssamp[i];
526 }
527 x /= (double)cie_xf.ssum;
528 y /= (double)cie_yf.ssum;
529 z /= (double)cie_zf.ssum;
530 z += x + y;
531 clr->cx = x / z;
532 clr->cy = y / z;
533 clr->flags |= C_CSXY;
534 } else if (fl & C_CSSPEC) { /* cxy -> cspec */
535 x = clr->cx;
536 y = clr->cy;
537 z = 1. - x - y;
538 clr->ssum = 0;
539 for (i = 0; i < C_CNSS; i++) {
540 clr->ssamp[i] = x*cie_xp.ssamp[i] + y*cie_yp.ssamp[i]
541 + z*cie_zp.ssamp[i] + .5;
542 if (clr->ssamp[i] < 0) /* out of gamut! */
543 clr->ssamp[i] = 0;
544 else
545 clr->ssum += clr->ssamp[i];
546 }
547 clr->flags |= C_CSSPEC;
548 }
549 if (fl & C_CSEFF) { /* compute efficacy */
550 if (clr->flags & C_CSSPEC) { /* from spectrum */
551 y = 0.;
552 for (i = 0; i < C_CNSS; i++)
553 y += cie_yf.ssamp[i] * clr->ssamp[i];
554 clr->eff = C_CLPWM * y / clr->ssum;
555 } else /* clr->flags & C_CSXY */ { /* from (x,y) */
556 clr->eff = clr->cx*cie_xf.eff + clr->cy*cie_yf.eff +
557 (1. - clr->cx - clr->cy)*cie_zf.eff;
558 }
559 clr->flags |= C_CSEFF;
560 }
561 }
562
563
564 static int
565 setspectrum(clr, wlmin, wlmax, ac, av) /* convert a spectrum */
566 register C_COLOR *clr;
567 double wlmin, wlmax;
568 int ac;
569 char **av;
570 {
571 double scale;
572 float va[C_CNSS];
573 register int i, pos;
574 int n, imax;
575 int wl;
576 double wl0, wlstep;
577 double boxpos, boxstep;
578 /* check bounds */
579 if (wlmax <= C_CMINWL | wlmax <= wlmin | wlmin >= C_CMAXWL)
580 return(MG_EILL);
581 wlstep = (wlmax - wlmin)/(ac-1);
582 while (wlmin < C_CMINWL) {
583 wlmin += wlstep;
584 ac--; av++;
585 }
586 while (wlmax > C_CMAXWL) {
587 wlmax -= wlstep;
588 ac--;
589 }
590 imax = ac; /* box filter if necessary */
591 boxpos = 0;
592 boxstep = 1;
593 if (wlstep < C_CWLI) {
594 imax = (wlmax - wlmin)/C_CWLI + (1-FTINY);
595 boxpos = (wlmin - C_CMINWL)/C_CWLI;
596 boxstep = wlstep/C_CWLI;
597 wlstep = C_CWLI;
598 }
599 scale = 0.; /* get values and maximum */
600 pos = 0;
601 for (i = 0; i < imax; i++) {
602 va[i] = 0.; n = 0;
603 while (boxpos < i+.5 && pos < ac) {
604 if (!isflt(av[pos]))
605 return(MG_ETYPE);
606 va[i] += atof(av[pos++]);
607 n++;
608 boxpos += boxstep;
609 }
610 if (n > 1)
611 va[i] /= (double)n;
612 if (va[i] > scale)
613 scale = va[i];
614 else if (va[i] < -scale)
615 scale = -va[i];
616 }
617 if (scale <= FTINY)
618 return(MG_EILL);
619 scale = C_CMAXV / scale;
620 clr->ssum = 0; /* convert to our spacing */
621 wl0 = wlmin;
622 pos = 0;
623 for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI)
624 if (wl < wlmin | wl > wlmax)
625 clr->ssamp[i] = 0;
626 else {
627 while (wl0 + wlstep < wl+FTINY) {
628 wl0 += wlstep;
629 pos++;
630 }
631 if (wl+FTINY >= wl0 & wl-FTINY <= wl0)
632 clr->ssamp[i] = scale*va[pos] + .5;
633 else /* interpolate if necessary */
634 clr->ssamp[i] = .5 + scale / wlstep *
635 ( va[pos]*(wl0+wlstep - wl) +
636 va[pos+1]*(wl - wl0) );
637 clr->ssum += clr->ssamp[i];
638 }
639 clr->flags = C_CDSPEC|C_CSSPEC;
640 clr->clock++;
641 return(MG_OK);
642 }
643
644
645 static void
646 mixcolors(cres, w1, c1, w2, c2) /* mix two colors according to weights given */
647 register C_COLOR *cres, *c1, *c2;
648 double w1, w2;
649 {
650 double scale;
651 float cmix[C_CNSS];
652 register int i;
653
654 if ((c1->flags|c2->flags) & C_CDSPEC) { /* spectral mixing */
655 c_ccvt(c1, C_CSSPEC|C_CSEFF);
656 c_ccvt(c2, C_CSSPEC|C_CSEFF);
657 w1 /= c1->eff*c1->ssum;
658 w2 /= c2->eff*c2->ssum;
659 scale = 0.;
660 for (i = 0; i < C_CNSS; i++) {
661 cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i];
662 if (cmix[i] > scale)
663 scale = cmix[i];
664 }
665 scale = C_CMAXV / scale;
666 cres->ssum = 0;
667 for (i = 0; i < C_CNSS; i++)
668 cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5;
669 cres->flags = C_CDSPEC|C_CSSPEC;
670 } else { /* CIE xy mixing */
671 c_ccvt(c1, C_CSXY);
672 c_ccvt(c2, C_CSXY);
673 scale = w1/c1->cy + w2/c2->cy;
674 if (scale == 0.)
675 return;
676 scale = 1. / scale;
677 cres->cx = (c1->cx*w1/c1->cy + c2->cx*w2/c2->cy) * scale;
678 cres->cy = (w1 + w2) * scale;
679 cres->flags = C_CDXY|C_CSXY;
680 }
681 }
682
683
684 #define C1 3.741832e-16 /* W-m^2 */
685 #define C2 1.4388e-2 /* m-K */
686
687 #define bbsp(l,t) (C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.)))
688 #define bblm(t) (C2/5./(t))
689
690 static int
691 setbbtemp(clr, tk) /* set black body spectrum */
692 register C_COLOR *clr;
693 double tk;
694 {
695 double sf, wl;
696 register int i;
697
698 if (tk < 1000)
699 return(MG_EILL);
700 wl = bblm(tk); /* scalefactor based on peak */
701 if (wl < C_CMINWL*1e-9)
702 wl = C_CMINWL*1e-9;
703 else if (wl > C_CMAXWL*1e-9)
704 wl = C_CMAXWL*1e-9;
705 sf = C_CMAXV/bbsp(wl,tk);
706 clr->ssum = 0;
707 for (i = 0; i < C_CNSS; i++) {
708 wl = (C_CMINWL + i*C_CWLI)*1e-9;
709 clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5;
710 }
711 clr->flags = C_CDSPEC|C_CSSPEC;
712 clr->clock++;
713 return(MG_OK);
714 }
715
716 #undef C1
717 #undef C2
718 #undef bbsp
719 #undef bblm