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root/radiance/ray/src/cv/mgflib/context.c
Revision: 1.21
Committed: Thu Apr 13 12:11:26 1995 UTC (29 years ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 1.20: +11 -0 lines
Log Message:
added material index of refraction

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 lp = lu_find(&clr_tab, av[1]); /* lookup context */
109 if (lp == NULL)
110 return(MG_EMEM);
111 c_ccname = lp->key;
112 c_ccolor = (C_COLOR *)lp->data;
113 if (ac == 2) { /* reestablish previous context */
114 if (c_ccolor == NULL)
115 return(MG_EUNDEF);
116 return(MG_OK);
117 }
118 if (av[2][0] != '=' || av[2][1])
119 return(MG_ETYPE);
120 if (c_ccolor == NULL) { /* create new color context */
121 lp->key = (char *)malloc(strlen(av[1])+1);
122 if (lp->key == NULL)
123 return(MG_EMEM);
124 strcpy(lp->key, av[1]);
125 lp->data = (char *)malloc(sizeof(C_COLOR));
126 if (lp->data == NULL)
127 return(MG_EMEM);
128 c_ccname = lp->key;
129 c_ccolor = (C_COLOR *)lp->data;
130 c_ccolor->clock = 0;
131 }
132 i = c_ccolor->clock;
133 if (ac == 3) { /* use default template */
134 *c_ccolor = c_dfcolor;
135 c_ccolor->clock = i + 1;
136 return(MG_OK);
137 }
138 lp = lu_find(&clr_tab, av[3]); /* lookup template */
139 if (lp == NULL)
140 return(MG_EMEM);
141 if (lp->data == NULL)
142 return(MG_EUNDEF);
143 *c_ccolor = *(C_COLOR *)lp->data;
144 c_ccolor->clock = i + 1;
145 return(MG_OK);
146 case MG_E_CXY: /* assign CIE XY value */
147 if (ac != 3)
148 return(MG_EARGC);
149 if (!isflt(av[1]) | !isflt(av[2]))
150 return(MG_ETYPE);
151 c_ccolor->cx = atof(av[1]);
152 c_ccolor->cy = atof(av[2]);
153 c_ccolor->flags = C_CDXY|C_CSXY;
154 if (c_ccolor->cx < 0. | c_ccolor->cy < 0. |
155 c_ccolor->cx + c_ccolor->cy > 1.)
156 return(MG_EILL);
157 c_ccolor->clock++;
158 return(MG_OK);
159 case MG_E_CSPEC: /* assign spectral values */
160 if (ac < 5)
161 return(MG_EARGC);
162 if (!isflt(av[1]) | !isflt(av[2]))
163 return(MG_ETYPE);
164 return(setspectrum(c_ccolor, atof(av[1]), atof(av[2]),
165 ac-3, av+3));
166 case MG_E_CCT: /* assign black body spectrum */
167 if (ac != 2)
168 return(MG_EARGC);
169 if (!isflt(av[1]))
170 return(MG_ETYPE);
171 return(setbbtemp(c_ccolor, atof(av[1])));
172 case MG_E_CMIX: /* mix colors */
173 if (ac < 5 || (ac-1)%2)
174 return(MG_EARGC);
175 if (!isflt(av[1]))
176 return(MG_ETYPE);
177 wsum = atof(av[1]);
178 if (wsum < 0.)
179 return(MG_EILL);
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 (w < 0.)
190 return(MG_EILL);
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 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 lp = lu_find(&mat_tab, av[1]); /* lookup context */
225 if (lp == NULL)
226 return(MG_EMEM);
227 c_cmname = lp->key;
228 c_cmaterial = (C_MATERIAL *)lp->data;
229 if (ac == 2) { /* reestablish previous context */
230 if (c_cmaterial == NULL)
231 return(MG_EUNDEF);
232 return(MG_OK);
233 }
234 if (av[2][0] != '=' || av[2][1])
235 return(MG_ETYPE);
236 if (c_cmaterial == NULL) { /* create new material */
237 lp->key = (char *)malloc(strlen(av[1])+1);
238 if (lp->key == NULL)
239 return(MG_EMEM);
240 strcpy(lp->key, av[1]);
241 lp->data = (char *)malloc(sizeof(C_MATERIAL));
242 if (lp->data == NULL)
243 return(MG_EMEM);
244 c_cmname = lp->key;
245 c_cmaterial = (C_MATERIAL *)lp->data;
246 c_cmaterial->clock = 0;
247 }
248 i = c_cmaterial->clock;
249 if (ac == 3) { /* use default template */
250 *c_cmaterial = c_dfmaterial;
251 c_cmaterial->clock = i + 1;
252 return(MG_OK);
253 }
254 lp = lu_find(&mat_tab, av[3]); /* lookup template */
255 if (lp == NULL)
256 return(MG_EMEM);
257 if (lp->data == NULL)
258 return(MG_EUNDEF);
259 *c_cmaterial = *(C_MATERIAL *)lp->data;
260 c_cmaterial->clock = i + 1;
261 return(MG_OK);
262 case MG_E_IR: /* set index of refraction */
263 if (ac != 3)
264 return(MG_EARGC);
265 if (!isflt(av[1]) | !isflt(av[2]))
266 return(MG_ETYPE);
267 c_cmaterial->nr = atof(av[1]);
268 c_cmaterial->ni = atof(av[2]);
269 if (c_cmaterial->nr <= FTINY)
270 return(MG_EILL);
271 c_cmaterial->clock++;
272 return(MG_OK);
273 case MG_E_RD: /* set diffuse reflectance */
274 if (ac != 2)
275 return(MG_EARGC);
276 if (!isflt(av[1]))
277 return(MG_ETYPE);
278 c_cmaterial->rd = atof(av[1]);
279 if (c_cmaterial->rd < 0. | c_cmaterial->rd > 1.)
280 return(MG_EILL);
281 c_cmaterial->rd_c = *c_ccolor;
282 c_cmaterial->clock++;
283 return(MG_OK);
284 case MG_E_ED: /* set diffuse emittance */
285 if (ac != 2)
286 return(MG_EARGC);
287 if (!isflt(av[1]))
288 return(MG_ETYPE);
289 c_cmaterial->ed = atof(av[1]);
290 if (c_cmaterial->ed < 0.)
291 return(MG_EILL);
292 c_cmaterial->ed_c = *c_ccolor;
293 c_cmaterial->clock++;
294 return(MG_OK);
295 case MG_E_TD: /* set diffuse transmittance */
296 if (ac != 2)
297 return(MG_EARGC);
298 if (!isflt(av[1]))
299 return(MG_ETYPE);
300 c_cmaterial->td = atof(av[1]);
301 if (c_cmaterial->td < 0. | c_cmaterial->td > 1.)
302 return(MG_EILL);
303 c_cmaterial->td_c = *c_ccolor;
304 c_cmaterial->clock++;
305 return(MG_OK);
306 case MG_E_RS: /* set specular reflectance */
307 if (ac != 3)
308 return(MG_EARGC);
309 if (!isflt(av[1]) | !isflt(av[2]))
310 return(MG_ETYPE);
311 c_cmaterial->rs = atof(av[1]);
312 c_cmaterial->rs_a = atof(av[2]);
313 if (c_cmaterial->rs < 0. | c_cmaterial->rs > 1. |
314 c_cmaterial->rs_a < 0.)
315 return(MG_EILL);
316 c_cmaterial->rs_c = *c_ccolor;
317 c_cmaterial->clock++;
318 return(MG_OK);
319 case MG_E_TS: /* set specular transmittance */
320 if (ac != 3)
321 return(MG_EARGC);
322 if (!isflt(av[1]) | !isflt(av[2]))
323 return(MG_ETYPE);
324 c_cmaterial->ts = atof(av[1]);
325 c_cmaterial->ts_a = atof(av[2]);
326 if (c_cmaterial->ts < 0. | c_cmaterial->ts > 1. |
327 c_cmaterial->ts_a < 0.)
328 return(MG_EILL);
329 c_cmaterial->ts_c = *c_ccolor;
330 c_cmaterial->clock++;
331 return(MG_OK);
332 case MG_E_SIDES: /* set number of sides */
333 if (ac != 2)
334 return(MG_EARGC);
335 if (!isint(av[1]))
336 return(MG_ETYPE);
337 i = atoi(av[1]);
338 if (i == 1)
339 c_cmaterial->sided = 1;
340 else if (i == 2)
341 c_cmaterial->sided = 0;
342 else
343 return(MG_EILL);
344 c_cmaterial->clock++;
345 return(MG_OK);
346 }
347 return(MG_EUNK);
348 }
349
350
351 int
352 c_hvertex(ac, av) /* handle a vertex entity */
353 int ac;
354 register char **av;
355 {
356 int i;
357 register LUENT *lp;
358
359 switch (mg_entity(av[0])) {
360 case MG_E_VERTEX: /* get/set vertex context */
361 if (ac > 4)
362 return(MG_EARGC);
363 if (ac == 1) { /* set unnamed vertex context */
364 c_unvertex = c_dfvertex;
365 c_cvertex = &c_unvertex;
366 c_cvname = NULL;
367 return(MG_OK);
368 }
369 lp = lu_find(&vtx_tab, av[1]); /* lookup context */
370 if (lp == NULL)
371 return(MG_EMEM);
372 c_cvname = lp->key;
373 c_cvertex = (C_VERTEX *)lp->data;
374 if (ac == 2) { /* reestablish previous context */
375 if (c_cvertex == NULL)
376 return(MG_EUNDEF);
377 return(MG_OK);
378 }
379 if (av[2][0] != '=' || av[2][1])
380 return(MG_ETYPE);
381 if (c_cvertex == NULL) { /* create new vertex context */
382 lp->key = (char *)malloc(strlen(av[1])+1);
383 if (lp->key == NULL)
384 return(MG_EMEM);
385 strcpy(lp->key, av[1]);
386 lp->data = (char *)malloc(sizeof(C_VERTEX));
387 if (lp->data == NULL)
388 return(MG_EMEM);
389 c_cvname = lp->key;
390 c_cvertex = (C_VERTEX *)lp->data;
391 }
392 i = c_cvertex->clock;
393 if (ac == 3) { /* use default template */
394 *c_cvertex = c_dfvertex;
395 c_cvertex->clock = i + 1;
396 return(MG_OK);
397 }
398 lp = lu_find(&vtx_tab, av[3]); /* lookup template */
399 if (lp == NULL)
400 return(MG_EMEM);
401 if (lp->data == NULL)
402 return(MG_EUNDEF);
403 *c_cvertex = *(C_VERTEX *)lp->data;
404 c_cvertex->clock = i + 1;
405 return(MG_OK);
406 case MG_E_POINT: /* set point */
407 if (ac != 4)
408 return(MG_EARGC);
409 if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
410 return(MG_ETYPE);
411 c_cvertex->p[0] = atof(av[1]);
412 c_cvertex->p[1] = atof(av[2]);
413 c_cvertex->p[2] = atof(av[3]);
414 c_cvertex->clock++;
415 return(MG_OK);
416 case MG_E_NORMAL: /* set normal */
417 if (ac != 4)
418 return(MG_EARGC);
419 if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
420 return(MG_ETYPE);
421 c_cvertex->n[0] = atof(av[1]);
422 c_cvertex->n[1] = atof(av[2]);
423 c_cvertex->n[2] = atof(av[3]);
424 (void)normalize(c_cvertex->n);
425 c_cvertex->clock++;
426 return(MG_OK);
427 }
428 return(MG_EUNK);
429 }
430
431
432 void
433 c_clearall() /* empty context tables */
434 {
435 c_uncolor = c_dfcolor;
436 c_ccolor = &c_uncolor;
437 c_ccname = NULL;
438 lu_done(&clr_tab);
439 c_unmaterial = c_dfmaterial;
440 c_cmaterial = &c_unmaterial;
441 c_cmname = NULL;
442 lu_done(&mat_tab);
443 c_unvertex = c_dfvertex;
444 c_cvertex = &c_unvertex;
445 c_cvname = NULL;
446 lu_done(&vtx_tab);
447 }
448
449
450 C_MATERIAL *
451 c_getmaterial(name) /* get a named material */
452 char *name;
453 {
454 register LUENT *lp;
455
456 if ((lp = lu_find(&mat_tab, name)) == NULL)
457 return(NULL);
458 return((C_MATERIAL *)lp->data);
459 }
460
461
462 C_VERTEX *
463 c_getvert(name) /* get a named vertex */
464 char *name;
465 {
466 register LUENT *lp;
467
468 if ((lp = lu_find(&vtx_tab, name)) == NULL)
469 return(NULL);
470 return((C_VERTEX *)lp->data);
471 }
472
473
474 C_COLOR *
475 c_getcolor(name) /* get a named color */
476 char *name;
477 {
478 register LUENT *lp;
479
480 if ((lp = lu_find(&clr_tab, name)) == NULL)
481 return(NULL);
482 return((C_COLOR *)lp->data);
483 }
484
485
486 int
487 c_isgrey(clr) /* check if color is grey */
488 register C_COLOR *clr;
489 {
490 if (!(clr->flags & (C_CSXY|C_CSSPEC)))
491 return(1); /* no settings == grey */
492 c_ccvt(clr, C_CSXY);
493 return(clr->cx >= .323 && clr->cx <= .343 &&
494 clr->cy >= .323 && clr->cy <= .343);
495 }
496
497
498 void
499 c_ccvt(clr, fl) /* convert color representations */
500 register C_COLOR *clr;
501 int fl;
502 {
503 double x, y, z;
504 register int i;
505
506 fl &= ~clr->flags; /* ignore what's done */
507 if (!fl) /* everything's done! */
508 return;
509 if (!(clr->flags & (C_CSXY|C_CSSPEC))) /* nothing set! */
510 *clr = c_dfcolor;
511 if (fl & C_CSXY) { /* cspec -> cxy */
512 x = y = z = 0.;
513 for (i = 0; i < C_CNSS; i++) {
514 x += cie_xf.ssamp[i] * clr->ssamp[i];
515 y += cie_yf.ssamp[i] * clr->ssamp[i];
516 z += cie_zf.ssamp[i] * clr->ssamp[i];
517 }
518 x /= (double)cie_xf.ssum;
519 y /= (double)cie_yf.ssum;
520 z /= (double)cie_zf.ssum;
521 z += x + y;
522 clr->cx = x / z;
523 clr->cy = y / z;
524 clr->flags |= C_CSXY;
525 } else if (fl & C_CSSPEC) { /* cxy -> cspec */
526 x = clr->cx;
527 y = clr->cy;
528 z = 1. - x - y;
529 clr->ssum = 0;
530 for (i = 0; i < C_CNSS; i++) {
531 clr->ssamp[i] = x*cie_xp.ssamp[i] + y*cie_yp.ssamp[i]
532 + z*cie_zp.ssamp[i] + .5;
533 if (clr->ssamp[i] < 0) /* out of gamut! */
534 clr->ssamp[i] = 0;
535 else
536 clr->ssum += clr->ssamp[i];
537 }
538 clr->flags |= C_CSSPEC;
539 }
540 if (fl & C_CSEFF) { /* compute efficacy */
541 if (clr->flags & C_CSSPEC) { /* from spectrum */
542 y = 0.;
543 for (i = 0; i < C_CNSS; i++)
544 y += cie_yf.ssamp[i] * clr->ssamp[i];
545 clr->eff = C_CLPWM * y / clr->ssum;
546 } else /* clr->flags & C_CSXY */ { /* from (x,y) */
547 clr->eff = clr->cx*cie_xf.eff + clr->cy*cie_yf.eff +
548 (1. - clr->cx - clr->cy)*cie_zf.eff;
549 }
550 clr->flags |= C_CSEFF;
551 }
552 }
553
554
555 static int
556 setspectrum(clr, wlmin, wlmax, ac, av) /* convert a spectrum */
557 register C_COLOR *clr;
558 double wlmin, wlmax;
559 int ac;
560 char **av;
561 {
562 double scale;
563 float va[C_CNSS];
564 register int i, pos;
565 int n, imax;
566 int wl;
567 double wl0, wlstep;
568 double boxpos, boxstep;
569 /* check bounds */
570 if (wlmax <= C_CMINWL | wlmax <= wlmin | wlmin >= C_CMAXWL)
571 return(MG_EILL);
572 wlstep = (wlmax - wlmin)/(ac-1);
573 while (wlmin < C_CMINWL) {
574 wlmin += wlstep;
575 ac--; av++;
576 }
577 while (wlmax > C_CMAXWL) {
578 wlmax -= wlstep;
579 ac--;
580 }
581 imax = ac; /* box filter if necessary */
582 boxpos = 0;
583 boxstep = 1;
584 if (wlstep < C_CWLI) {
585 imax = (wlmax - wlmin)/C_CWLI + (1-FTINY);
586 boxpos = (wlmin - C_CMINWL)/C_CWLI;
587 boxstep = wlstep/C_CWLI;
588 wlstep = C_CWLI;
589 }
590 scale = 0.; /* get values and maximum */
591 pos = 0;
592 for (i = 0; i < imax; i++) {
593 va[i] = 0.; n = 0;
594 while (boxpos < i+.5 && pos < ac) {
595 if (!isflt(av[pos]))
596 return(MG_ETYPE);
597 va[i] += atof(av[pos++]);
598 n++;
599 boxpos += boxstep;
600 }
601 if (n > 1)
602 va[i] /= (double)n;
603 if (va[i] < 0.)
604 return(MG_EILL);
605 if (va[i] > scale)
606 scale = va[i];
607 }
608 if (scale <= FTINY)
609 return(MG_EILL);
610 scale = C_CMAXV / scale;
611 clr->ssum = 0; /* convert to our spacing */
612 wl0 = wlmin;
613 pos = 0;
614 for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI)
615 if (wl < wlmin | wl > wlmax)
616 clr->ssamp[i] = 0;
617 else {
618 while (wl0 + wlstep < wl+FTINY) {
619 wl0 += wlstep;
620 pos++;
621 }
622 if (wl+FTINY >= wl0 & wl-FTINY <= wl0)
623 clr->ssamp[i] = scale*va[pos] + .5;
624 else /* interpolate if necessary */
625 clr->ssamp[i] = .5 + scale / wlstep *
626 ( va[pos]*(wl0+wlstep - wl) +
627 va[pos+1]*(wl - wl0) );
628 clr->ssum += clr->ssamp[i];
629 }
630 clr->flags = C_CDSPEC|C_CSSPEC;
631 clr->clock++;
632 return(MG_OK);
633 }
634
635
636 static void
637 mixcolors(cres, w1, c1, w2, c2) /* mix two colors according to weights given */
638 register C_COLOR *cres, *c1, *c2;
639 double w1, w2;
640 {
641 double scale;
642 float cmix[C_CNSS];
643 register int i;
644
645 if ((c1->flags|c2->flags) & C_CDSPEC) { /* spectral mixing */
646 c_ccvt(c1, C_CSSPEC|C_CSEFF);
647 c_ccvt(c2, C_CSSPEC|C_CSEFF);
648 w1 /= c1->eff*c1->ssum;
649 w2 /= c2->eff*c2->ssum;
650 scale = 0.;
651 for (i = 0; i < C_CNSS; i++) {
652 cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i];
653 if (cmix[i] > scale)
654 scale = cmix[i];
655 }
656 scale = C_CMAXV / scale;
657 cres->ssum = 0;
658 for (i = 0; i < C_CNSS; i++)
659 cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5;
660 cres->flags = C_CDSPEC|C_CSSPEC;
661 } else { /* CIE xy mixing */
662 c_ccvt(c1, C_CSXY);
663 c_ccvt(c2, C_CSXY);
664 scale = 1. / (w1/c1->cy + w2/c2->cy);
665 cres->cx = (c1->cx*w1/c1->cy + c2->cx*w2/c2->cy) * scale;
666 cres->cy = (w1 + w2) * scale;
667 cres->flags = C_CDXY|C_CSXY;
668 }
669 }
670
671
672 #define C1 3.741832e-16 /* W-m^2 */
673 #define C2 1.4388e-2 /* m-K */
674
675 #define bbsp(l,t) (C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.)))
676 #define bblm(t) (C2/5./(t))
677
678 static int
679 setbbtemp(clr, tk) /* set black body spectrum */
680 register C_COLOR *clr;
681 double tk;
682 {
683 double sf, wl;
684 register int i;
685
686 if (tk < 1000)
687 return(MG_EILL);
688 wl = bblm(tk); /* scalefactor based on peak */
689 if (wl < C_CMINWL*1e-9)
690 wl = C_CMINWL*1e-9;
691 else if (wl > C_CMAXWL*1e-9)
692 wl = C_CMAXWL*1e-9;
693 sf = C_CMAXV/bbsp(wl,tk);
694 clr->ssum = 0;
695 for (i = 0; i < C_CNSS; i++) {
696 wl = (C_CMINWL + i*C_CWLI)*1e-9;
697 clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5;
698 }
699 clr->flags = C_CDSPEC|C_CSSPEC;
700 clr->clock++;
701 return(MG_OK);
702 }
703
704 #undef C1
705 #undef C2
706 #undef bbsp
707 #undef bblm