ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/cv/mgflib/context.c
Revision: 1.24
Committed: Wed Feb 12 11:38:52 1997 UTC (27 years, 2 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.23: +7 -6 lines
Log Message:
allow negative weights in cmix entity

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