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root/radiance/ray/src/cv/mgflib/context.c
Revision: 1.23
Committed: Mon Aug 28 16:44:12 1995 UTC (28 years, 8 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.22: +2 -2 lines
Log Message:
allow negative values for spectral components

File Contents

# Content
1 /* Copyright (c) 1994 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 (wsum < 0.)
181 return(MG_EILL);
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 (w < 0.)
192 return(MG_EILL);
193 if ((lp = lu_find(&clr_tab, av[i+1])) == NULL)
194 return(MG_EMEM);
195 if (lp->data == NULL)
196 return(MG_EUNDEF);
197 mixcolors(c_ccolor, wsum, c_ccolor,
198 w, (C_COLOR *)lp->data);
199 wsum += w;
200 }
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 }
252 i = c_cmaterial->clock;
253 if (ac == 3) { /* use default template */
254 *c_cmaterial = c_dfmaterial;
255 c_cmaterial->clock = i + 1;
256 return(MG_OK);
257 }
258 lp = lu_find(&mat_tab, av[3]); /* lookup template */
259 if (lp == NULL)
260 return(MG_EMEM);
261 if (lp->data == NULL)
262 return(MG_EUNDEF);
263 *c_cmaterial = *(C_MATERIAL *)lp->data;
264 c_cmaterial->clock = i + 1;
265 return(MG_OK);
266 case MG_E_IR: /* set index of refraction */
267 if (ac != 3)
268 return(MG_EARGC);
269 if (!isflt(av[1]) | !isflt(av[2]))
270 return(MG_ETYPE);
271 c_cmaterial->nr = atof(av[1]);
272 c_cmaterial->ni = atof(av[2]);
273 if (c_cmaterial->nr <= FTINY)
274 return(MG_EILL);
275 c_cmaterial->clock++;
276 return(MG_OK);
277 case MG_E_RD: /* set diffuse reflectance */
278 if (ac != 2)
279 return(MG_EARGC);
280 if (!isflt(av[1]))
281 return(MG_ETYPE);
282 c_cmaterial->rd = atof(av[1]);
283 if (c_cmaterial->rd < 0. | c_cmaterial->rd > 1.)
284 return(MG_EILL);
285 c_cmaterial->rd_c = *c_ccolor;
286 c_cmaterial->clock++;
287 return(MG_OK);
288 case MG_E_ED: /* set diffuse emittance */
289 if (ac != 2)
290 return(MG_EARGC);
291 if (!isflt(av[1]))
292 return(MG_ETYPE);
293 c_cmaterial->ed = atof(av[1]);
294 if (c_cmaterial->ed < 0.)
295 return(MG_EILL);
296 c_cmaterial->ed_c = *c_ccolor;
297 c_cmaterial->clock++;
298 return(MG_OK);
299 case MG_E_TD: /* set diffuse transmittance */
300 if (ac != 2)
301 return(MG_EARGC);
302 if (!isflt(av[1]))
303 return(MG_ETYPE);
304 c_cmaterial->td = atof(av[1]);
305 if (c_cmaterial->td < 0. | c_cmaterial->td > 1.)
306 return(MG_EILL);
307 c_cmaterial->td_c = *c_ccolor;
308 c_cmaterial->clock++;
309 return(MG_OK);
310 case MG_E_RS: /* set specular reflectance */
311 if (ac != 3)
312 return(MG_EARGC);
313 if (!isflt(av[1]) | !isflt(av[2]))
314 return(MG_ETYPE);
315 c_cmaterial->rs = atof(av[1]);
316 c_cmaterial->rs_a = atof(av[2]);
317 if (c_cmaterial->rs < 0. | c_cmaterial->rs > 1. |
318 c_cmaterial->rs_a < 0.)
319 return(MG_EILL);
320 c_cmaterial->rs_c = *c_ccolor;
321 c_cmaterial->clock++;
322 return(MG_OK);
323 case MG_E_TS: /* set specular transmittance */
324 if (ac != 3)
325 return(MG_EARGC);
326 if (!isflt(av[1]) | !isflt(av[2]))
327 return(MG_ETYPE);
328 c_cmaterial->ts = atof(av[1]);
329 c_cmaterial->ts_a = atof(av[2]);
330 if (c_cmaterial->ts < 0. | c_cmaterial->ts > 1. |
331 c_cmaterial->ts_a < 0.)
332 return(MG_EILL);
333 c_cmaterial->ts_c = *c_ccolor;
334 c_cmaterial->clock++;
335 return(MG_OK);
336 case MG_E_SIDES: /* set number of sides */
337 if (ac != 2)
338 return(MG_EARGC);
339 if (!isint(av[1]))
340 return(MG_ETYPE);
341 i = atoi(av[1]);
342 if (i == 1)
343 c_cmaterial->sided = 1;
344 else if (i == 2)
345 c_cmaterial->sided = 0;
346 else
347 return(MG_EILL);
348 c_cmaterial->clock++;
349 return(MG_OK);
350 }
351 return(MG_EUNK);
352 }
353
354
355 int
356 c_hvertex(ac, av) /* handle a vertex entity */
357 int ac;
358 register char **av;
359 {
360 int i;
361 register LUENT *lp;
362
363 switch (mg_entity(av[0])) {
364 case MG_E_VERTEX: /* get/set vertex context */
365 if (ac > 4)
366 return(MG_EARGC);
367 if (ac == 1) { /* set unnamed vertex context */
368 c_unvertex = c_dfvertex;
369 c_cvertex = &c_unvertex;
370 c_cvname = NULL;
371 return(MG_OK);
372 }
373 if (!isname(av[1]))
374 return(MG_EILL);
375 lp = lu_find(&vtx_tab, av[1]); /* lookup context */
376 if (lp == NULL)
377 return(MG_EMEM);
378 c_cvname = lp->key;
379 c_cvertex = (C_VERTEX *)lp->data;
380 if (ac == 2) { /* reestablish previous context */
381 if (c_cvertex == NULL)
382 return(MG_EUNDEF);
383 return(MG_OK);
384 }
385 if (av[2][0] != '=' || av[2][1])
386 return(MG_ETYPE);
387 if (c_cvertex == NULL) { /* create new vertex context */
388 lp->key = (char *)malloc(strlen(av[1])+1);
389 if (lp->key == NULL)
390 return(MG_EMEM);
391 strcpy(lp->key, av[1]);
392 lp->data = (char *)malloc(sizeof(C_VERTEX));
393 if (lp->data == NULL)
394 return(MG_EMEM);
395 c_cvname = lp->key;
396 c_cvertex = (C_VERTEX *)lp->data;
397 }
398 i = c_cvertex->clock;
399 if (ac == 3) { /* use default template */
400 *c_cvertex = c_dfvertex;
401 c_cvertex->clock = i + 1;
402 return(MG_OK);
403 }
404 lp = lu_find(&vtx_tab, av[3]); /* lookup template */
405 if (lp == NULL)
406 return(MG_EMEM);
407 if (lp->data == NULL)
408 return(MG_EUNDEF);
409 *c_cvertex = *(C_VERTEX *)lp->data;
410 c_cvertex->clock = i + 1;
411 return(MG_OK);
412 case MG_E_POINT: /* set point */
413 if (ac != 4)
414 return(MG_EARGC);
415 if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
416 return(MG_ETYPE);
417 c_cvertex->p[0] = atof(av[1]);
418 c_cvertex->p[1] = atof(av[2]);
419 c_cvertex->p[2] = atof(av[3]);
420 c_cvertex->clock++;
421 return(MG_OK);
422 case MG_E_NORMAL: /* set normal */
423 if (ac != 4)
424 return(MG_EARGC);
425 if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
426 return(MG_ETYPE);
427 c_cvertex->n[0] = atof(av[1]);
428 c_cvertex->n[1] = atof(av[2]);
429 c_cvertex->n[2] = atof(av[3]);
430 (void)normalize(c_cvertex->n);
431 c_cvertex->clock++;
432 return(MG_OK);
433 }
434 return(MG_EUNK);
435 }
436
437
438 void
439 c_clearall() /* empty context tables */
440 {
441 c_uncolor = c_dfcolor;
442 c_ccolor = &c_uncolor;
443 c_ccname = NULL;
444 lu_done(&clr_tab);
445 c_unmaterial = c_dfmaterial;
446 c_cmaterial = &c_unmaterial;
447 c_cmname = NULL;
448 lu_done(&mat_tab);
449 c_unvertex = c_dfvertex;
450 c_cvertex = &c_unvertex;
451 c_cvname = NULL;
452 lu_done(&vtx_tab);
453 }
454
455
456 C_MATERIAL *
457 c_getmaterial(name) /* get a named material */
458 char *name;
459 {
460 register LUENT *lp;
461
462 if ((lp = lu_find(&mat_tab, name)) == NULL)
463 return(NULL);
464 return((C_MATERIAL *)lp->data);
465 }
466
467
468 C_VERTEX *
469 c_getvert(name) /* get a named vertex */
470 char *name;
471 {
472 register LUENT *lp;
473
474 if ((lp = lu_find(&vtx_tab, name)) == NULL)
475 return(NULL);
476 return((C_VERTEX *)lp->data);
477 }
478
479
480 C_COLOR *
481 c_getcolor(name) /* get a named color */
482 char *name;
483 {
484 register LUENT *lp;
485
486 if ((lp = lu_find(&clr_tab, name)) == NULL)
487 return(NULL);
488 return((C_COLOR *)lp->data);
489 }
490
491
492 int
493 c_isgrey(clr) /* check if color is grey */
494 register C_COLOR *clr;
495 {
496 if (!(clr->flags & (C_CSXY|C_CSSPEC)))
497 return(1); /* no settings == grey */
498 c_ccvt(clr, C_CSXY);
499 return(clr->cx >= .323 && clr->cx <= .343 &&
500 clr->cy >= .323 && clr->cy <= .343);
501 }
502
503
504 void
505 c_ccvt(clr, fl) /* convert color representations */
506 register C_COLOR *clr;
507 int fl;
508 {
509 double x, y, z;
510 register int i;
511
512 fl &= ~clr->flags; /* ignore what's done */
513 if (!fl) /* everything's done! */
514 return;
515 if (!(clr->flags & (C_CSXY|C_CSSPEC))) /* nothing set! */
516 *clr = c_dfcolor;
517 if (fl & C_CSXY) { /* cspec -> cxy */
518 x = y = z = 0.;
519 for (i = 0; i < C_CNSS; i++) {
520 x += cie_xf.ssamp[i] * clr->ssamp[i];
521 y += cie_yf.ssamp[i] * clr->ssamp[i];
522 z += cie_zf.ssamp[i] * clr->ssamp[i];
523 }
524 x /= (double)cie_xf.ssum;
525 y /= (double)cie_yf.ssum;
526 z /= (double)cie_zf.ssum;
527 z += x + y;
528 clr->cx = x / z;
529 clr->cy = y / z;
530 clr->flags |= C_CSXY;
531 } else if (fl & C_CSSPEC) { /* cxy -> cspec */
532 x = clr->cx;
533 y = clr->cy;
534 z = 1. - x - y;
535 clr->ssum = 0;
536 for (i = 0; i < C_CNSS; i++) {
537 clr->ssamp[i] = x*cie_xp.ssamp[i] + y*cie_yp.ssamp[i]
538 + z*cie_zp.ssamp[i] + .5;
539 if (clr->ssamp[i] < 0) /* out of gamut! */
540 clr->ssamp[i] = 0;
541 else
542 clr->ssum += clr->ssamp[i];
543 }
544 clr->flags |= C_CSSPEC;
545 }
546 if (fl & C_CSEFF) { /* compute efficacy */
547 if (clr->flags & C_CSSPEC) { /* from spectrum */
548 y = 0.;
549 for (i = 0; i < C_CNSS; i++)
550 y += cie_yf.ssamp[i] * clr->ssamp[i];
551 clr->eff = C_CLPWM * y / clr->ssum;
552 } else /* clr->flags & C_CSXY */ { /* from (x,y) */
553 clr->eff = clr->cx*cie_xf.eff + clr->cy*cie_yf.eff +
554 (1. - clr->cx - clr->cy)*cie_zf.eff;
555 }
556 clr->flags |= C_CSEFF;
557 }
558 }
559
560
561 static int
562 setspectrum(clr, wlmin, wlmax, ac, av) /* convert a spectrum */
563 register C_COLOR *clr;
564 double wlmin, wlmax;
565 int ac;
566 char **av;
567 {
568 double scale;
569 float va[C_CNSS];
570 register int i, pos;
571 int n, imax;
572 int wl;
573 double wl0, wlstep;
574 double boxpos, boxstep;
575 /* check bounds */
576 if (wlmax <= C_CMINWL | wlmax <= wlmin | wlmin >= C_CMAXWL)
577 return(MG_EILL);
578 wlstep = (wlmax - wlmin)/(ac-1);
579 while (wlmin < C_CMINWL) {
580 wlmin += wlstep;
581 ac--; av++;
582 }
583 while (wlmax > C_CMAXWL) {
584 wlmax -= wlstep;
585 ac--;
586 }
587 imax = ac; /* box filter if necessary */
588 boxpos = 0;
589 boxstep = 1;
590 if (wlstep < C_CWLI) {
591 imax = (wlmax - wlmin)/C_CWLI + (1-FTINY);
592 boxpos = (wlmin - C_CMINWL)/C_CWLI;
593 boxstep = wlstep/C_CWLI;
594 wlstep = C_CWLI;
595 }
596 scale = 0.; /* get values and maximum */
597 pos = 0;
598 for (i = 0; i < imax; i++) {
599 va[i] = 0.; n = 0;
600 while (boxpos < i+.5 && pos < ac) {
601 if (!isflt(av[pos]))
602 return(MG_ETYPE);
603 va[i] += atof(av[pos++]);
604 n++;
605 boxpos += boxstep;
606 }
607 if (n > 1)
608 va[i] /= (double)n;
609 if (va[i] > scale)
610 scale = va[i];
611 else if (va[i] < -scale)
612 scale = -va[i];
613 }
614 if (scale <= FTINY)
615 return(MG_EILL);
616 scale = C_CMAXV / scale;
617 clr->ssum = 0; /* convert to our spacing */
618 wl0 = wlmin;
619 pos = 0;
620 for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI)
621 if (wl < wlmin | wl > wlmax)
622 clr->ssamp[i] = 0;
623 else {
624 while (wl0 + wlstep < wl+FTINY) {
625 wl0 += wlstep;
626 pos++;
627 }
628 if (wl+FTINY >= wl0 & wl-FTINY <= wl0)
629 clr->ssamp[i] = scale*va[pos] + .5;
630 else /* interpolate if necessary */
631 clr->ssamp[i] = .5 + scale / wlstep *
632 ( va[pos]*(wl0+wlstep - wl) +
633 va[pos+1]*(wl - wl0) );
634 clr->ssum += clr->ssamp[i];
635 }
636 clr->flags = C_CDSPEC|C_CSSPEC;
637 clr->clock++;
638 return(MG_OK);
639 }
640
641
642 static void
643 mixcolors(cres, w1, c1, w2, c2) /* mix two colors according to weights given */
644 register C_COLOR *cres, *c1, *c2;
645 double w1, w2;
646 {
647 double scale;
648 float cmix[C_CNSS];
649 register int i;
650
651 if ((c1->flags|c2->flags) & C_CDSPEC) { /* spectral mixing */
652 c_ccvt(c1, C_CSSPEC|C_CSEFF);
653 c_ccvt(c2, C_CSSPEC|C_CSEFF);
654 w1 /= c1->eff*c1->ssum;
655 w2 /= c2->eff*c2->ssum;
656 scale = 0.;
657 for (i = 0; i < C_CNSS; i++) {
658 cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i];
659 if (cmix[i] > scale)
660 scale = cmix[i];
661 }
662 scale = C_CMAXV / scale;
663 cres->ssum = 0;
664 for (i = 0; i < C_CNSS; i++)
665 cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5;
666 cres->flags = C_CDSPEC|C_CSSPEC;
667 } else { /* CIE xy mixing */
668 c_ccvt(c1, C_CSXY);
669 c_ccvt(c2, C_CSXY);
670 scale = 1. / (w1/c1->cy + w2/c2->cy);
671 cres->cx = (c1->cx*w1/c1->cy + c2->cx*w2/c2->cy) * scale;
672 cres->cy = (w1 + w2) * scale;
673 cres->flags = C_CDXY|C_CSXY;
674 }
675 }
676
677
678 #define C1 3.741832e-16 /* W-m^2 */
679 #define C2 1.4388e-2 /* m-K */
680
681 #define bbsp(l,t) (C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.)))
682 #define bblm(t) (C2/5./(t))
683
684 static int
685 setbbtemp(clr, tk) /* set black body spectrum */
686 register C_COLOR *clr;
687 double tk;
688 {
689 double sf, wl;
690 register int i;
691
692 if (tk < 1000)
693 return(MG_EILL);
694 wl = bblm(tk); /* scalefactor based on peak */
695 if (wl < C_CMINWL*1e-9)
696 wl = C_CMINWL*1e-9;
697 else if (wl > C_CMAXWL*1e-9)
698 wl = C_CMAXWL*1e-9;
699 sf = C_CMAXV/bbsp(wl,tk);
700 clr->ssum = 0;
701 for (i = 0; i < C_CNSS; i++) {
702 wl = (C_CMINWL + i*C_CWLI)*1e-9;
703 clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5;
704 }
705 clr->flags = C_CDSPEC|C_CSSPEC;
706 clr->clock++;
707 return(MG_OK);
708 }
709
710 #undef C1
711 #undef C2
712 #undef bbsp
713 #undef bblm