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root/radiance/ray/src/cv/mgflib/context.c
Revision: 1.28
Committed: Sun Jul 27 22:12:02 2003 UTC (20 years, 8 months ago) by schorsch
Content type: text/plain
Branch: MAIN
CVS Tags: rad3R7P1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9, rad3R7P2
Changes since 1.27: +12 -12 lines
Log Message:
Added grouping parens to reduce ambiguity warnings.

File Contents

# Content
1 #ifndef lint
2 static const char RCSid[] = "$Id: context.c,v 1.27 2003/02/28 20:11:29 greg Exp $";
3 #endif
4 /*
5 * Context handlers
6 */
7
8 #include <stdio.h>
9 #include <math.h>
10 #include <stdlib.h>
11 #include <string.h>
12 #include "parser.h"
13 #include "lookup.h"
14
15 /* default context values */
16 static C_COLOR c_dfcolor = C_DEFCOLOR;
17 static C_MATERIAL c_dfmaterial = C_DEFMATERIAL;
18 static C_VERTEX c_dfvertex = C_DEFVERTEX;
19
20 /* the unnamed contexts */
21 static C_COLOR c_uncolor = C_DEFCOLOR;
22 static C_MATERIAL c_unmaterial = C_DEFMATERIAL;
23 static C_VERTEX c_unvertex = C_DEFVERTEX;
24
25 /* the current contexts */
26 C_COLOR *c_ccolor = &c_uncolor;
27 char *c_ccname = NULL;
28 C_MATERIAL *c_cmaterial = &c_unmaterial;
29 char *c_cmname = NULL;
30 C_VERTEX *c_cvertex = &c_unvertex;
31 char *c_cvname = NULL;
32
33 static LUTAB clr_tab = LU_SINIT(free,free); /* color lookup table */
34 static LUTAB mat_tab = LU_SINIT(free,free); /* material lookup table */
35 static LUTAB vtx_tab = LU_SINIT(free,free); /* vertex lookup table */
36
37 /* CIE 1931 Standard Observer curves */
38 static C_COLOR cie_xf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
39 {14,42,143,435,1344,2839,3483,3362,2908,1954,956,
40 320,49,93,633,1655,2904,4334,5945,7621,9163,10263,
41 10622,10026,8544,6424,4479,2835,1649,874,468,227,
42 114,58,29,14,7,3,2,1,0}, 106836L, .467, .368, 362.230
43 };
44 static C_COLOR cie_yf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
45 {0,1,4,12,40,116,230,380,600,910,1390,2080,3230,
46 5030,7100,8620,9540,9950,9950,9520,8700,7570,6310,
47 5030,3810,2650,1750,1070,610,320,170,82,41,21,10,
48 5,2,1,1,0,0}, 106856L, .398, .542, 493.525
49 };
50 static C_COLOR cie_zf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
51 {65,201,679,2074,6456,13856,17471,17721,16692,
52 12876,8130,4652,2720,1582,782,422,203,87,39,21,17,
53 11,8,3,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
54 106770L, .147, .077, 54.363
55 };
56 /* Derived CIE 1931 Primaries (imaginary) */
57 static C_COLOR cie_xp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
58 {-174,-198,-195,-197,-202,-213,-235,-272,-333,
59 -444,-688,-1232,-2393,-4497,-6876,-6758,-5256,
60 -3100,-815,1320,3200,4782,5998,6861,7408,7754,
61 7980,8120,8199,8240,8271,8292,8309,8283,8469,
62 8336,8336,8336,8336,8336,8336},
63 127424L, 1., .0,
64 };
65 static C_COLOR cie_yp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
66 {-451,-431,-431,-430,-427,-417,-399,-366,-312,
67 -204,57,691,2142,4990,8810,9871,9122,7321,5145,
68 3023,1123,-473,-1704,-2572,-3127,-3474,-3704,
69 -3846,-3927,-3968,-3999,-4021,-4038,-4012,-4201,
70 -4066,-4066,-4066,-4066,-4066,-4066},
71 -23035L, .0, 1.,
72 };
73 static C_COLOR cie_zp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
74 {4051,4054,4052,4053,4054,4056,4059,4064,4071,
75 4074,4056,3967,3677,2933,1492,313,-440,-795,
76 -904,-918,-898,-884,-869,-863,-855,-855,-851,
77 -848,-847,-846,-846,-846,-845,-846,-843,-845,
78 -845,-845,-845,-845,-845},
79 36057L, .0, .0,
80 };
81
82 static int setspectrum();
83 static int setbbtemp();
84 static void mixcolors();
85
86
87 int
88 c_hcolor(ac, av) /* handle color entity */
89 int ac;
90 register char **av;
91 {
92 double w, wsum;
93 register int i;
94 register LUENT *lp;
95
96 switch (mg_entity(av[0])) {
97 case MG_E_COLOR: /* get/set color context */
98 if (ac > 4)
99 return(MG_EARGC);
100 if (ac == 1) { /* set unnamed color context */
101 c_uncolor = c_dfcolor;
102 c_ccolor = &c_uncolor;
103 c_ccname = NULL;
104 return(MG_OK);
105 }
106 if (!isname(av[1]))
107 return(MG_EILL);
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 c_ccolor->client_data = NULL;
132 }
133 i = c_ccolor->clock;
134 if (ac == 3) { /* use default template */
135 *c_ccolor = c_dfcolor;
136 c_ccolor->clock = i + 1;
137 return(MG_OK);
138 }
139 lp = lu_find(&clr_tab, av[3]); /* lookup template */
140 if (lp == NULL)
141 return(MG_EMEM);
142 if (lp->data == NULL)
143 return(MG_EUNDEF);
144 *c_ccolor = *(C_COLOR *)lp->data;
145 c_ccolor->clock = i + 1;
146 return(MG_OK);
147 case MG_E_CXY: /* assign CIE XY value */
148 if (ac != 3)
149 return(MG_EARGC);
150 if (!isflt(av[1]) | !isflt(av[2]))
151 return(MG_ETYPE);
152 c_ccolor->cx = atof(av[1]);
153 c_ccolor->cy = atof(av[2]);
154 c_ccolor->flags = C_CDXY|C_CSXY;
155 if ((c_ccolor->cx < 0.) | (c_ccolor->cy < 0.) |
156 (c_ccolor->cx + c_ccolor->cy > 1.))
157 return(MG_EILL);
158 c_ccolor->clock++;
159 return(MG_OK);
160 case MG_E_CSPEC: /* assign spectral values */
161 if (ac < 5)
162 return(MG_EARGC);
163 if (!isflt(av[1]) | !isflt(av[2]))
164 return(MG_ETYPE);
165 return(setspectrum(c_ccolor, atof(av[1]), atof(av[2]),
166 ac-3, av+3));
167 case MG_E_CCT: /* assign black body spectrum */
168 if (ac != 2)
169 return(MG_EARGC);
170 if (!isflt(av[1]))
171 return(MG_ETYPE);
172 return(setbbtemp(c_ccolor, atof(av[1])));
173 case MG_E_CMIX: /* mix colors */
174 if (ac < 5 || (ac-1)%2)
175 return(MG_EARGC);
176 if (!isflt(av[1]))
177 return(MG_ETYPE);
178 wsum = atof(av[1]);
179 if ((lp = lu_find(&clr_tab, av[2])) == NULL)
180 return(MG_EMEM);
181 if (lp->data == NULL)
182 return(MG_EUNDEF);
183 *c_ccolor = *(C_COLOR *)lp->data;
184 for (i = 3; i < ac; i += 2) {
185 if (!isflt(av[i]))
186 return(MG_ETYPE);
187 w = atof(av[i]);
188 if ((lp = lu_find(&clr_tab, av[i+1])) == NULL)
189 return(MG_EMEM);
190 if (lp->data == NULL)
191 return(MG_EUNDEF);
192 mixcolors(c_ccolor, wsum, c_ccolor,
193 w, (C_COLOR *)lp->data);
194 wsum += w;
195 }
196 if (wsum <= 0.)
197 return(MG_EILL);
198 c_ccolor->clock++;
199 return(MG_OK);
200 }
201 return(MG_EUNK);
202 }
203
204
205 int
206 c_hmaterial(ac, av) /* handle material entity */
207 int ac;
208 register char **av;
209 {
210 int i;
211 register LUENT *lp;
212
213 switch (mg_entity(av[0])) {
214 case MG_E_MATERIAL: /* get/set material context */
215 if (ac > 4)
216 return(MG_EARGC);
217 if (ac == 1) { /* set unnamed material context */
218 c_unmaterial = c_dfmaterial;
219 c_cmaterial = &c_unmaterial;
220 c_cmname = NULL;
221 return(MG_OK);
222 }
223 if (!isname(av[1]))
224 return(MG_EILL);
225 lp = lu_find(&mat_tab, av[1]); /* lookup context */
226 if (lp == NULL)
227 return(MG_EMEM);
228 c_cmname = lp->key;
229 c_cmaterial = (C_MATERIAL *)lp->data;
230 if (ac == 2) { /* reestablish previous context */
231 if (c_cmaterial == NULL)
232 return(MG_EUNDEF);
233 return(MG_OK);
234 }
235 if (av[2][0] != '=' || av[2][1])
236 return(MG_ETYPE);
237 if (c_cmaterial == NULL) { /* create new material */
238 lp->key = (char *)malloc(strlen(av[1])+1);
239 if (lp->key == NULL)
240 return(MG_EMEM);
241 strcpy(lp->key, av[1]);
242 lp->data = (char *)malloc(sizeof(C_MATERIAL));
243 if (lp->data == NULL)
244 return(MG_EMEM);
245 c_cmname = lp->key;
246 c_cmaterial = (C_MATERIAL *)lp->data;
247 c_cmaterial->clock = 0;
248 c_cmaterial->client_data = NULL;
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 c_cvertex->clock = 0;
396 c_cvertex->client_data = NULL;
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 = w1/c1->cy + w2/c2->cy;
671 if (scale == 0.)
672 return;
673 scale = 1. / scale;
674 cres->cx = (c1->cx*w1/c1->cy + c2->cx*w2/c2->cy) * scale;
675 cres->cy = (w1 + w2) * scale;
676 cres->flags = C_CDXY|C_CSXY;
677 }
678 }
679
680
681 #define C1 3.741832e-16 /* W-m^2 */
682 #define C2 1.4388e-2 /* m-K */
683
684 #define bbsp(l,t) (C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.)))
685 #define bblm(t) (C2/5./(t))
686
687 static int
688 setbbtemp(clr, tk) /* set black body spectrum */
689 register C_COLOR *clr;
690 double tk;
691 {
692 double sf, wl;
693 register int i;
694
695 if (tk < 1000)
696 return(MG_EILL);
697 wl = bblm(tk); /* scalefactor based on peak */
698 if (wl < C_CMINWL*1e-9)
699 wl = C_CMINWL*1e-9;
700 else if (wl > C_CMAXWL*1e-9)
701 wl = C_CMAXWL*1e-9;
702 sf = C_CMAXV/bbsp(wl,tk);
703 clr->ssum = 0;
704 for (i = 0; i < C_CNSS; i++) {
705 wl = (C_CMINWL + i*C_CWLI)*1e-9;
706 clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5;
707 }
708 clr->flags = C_CDSPEC|C_CSSPEC;
709 clr->clock++;
710 return(MG_OK);
711 }
712
713 #undef C1
714 #undef C2
715 #undef bbsp
716 #undef bblm