src/rt/ambient.c

/* Copyright (c) 1991 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  ambient.c - routines dealing with ambient (inter-reflected) component.
 *
 *  The macro AMBFLUSH (if defined) is the number of ambient values
 *      to wait before flushing to the ambient file.
 *
 *     5/9/86
 */

#include  "ray.h"

#include  "octree.h"

#include  "otypes.h"

#include  "ambient.h"

#include  "random.h"

#define  OCTSCALE       0.5     /* ceil((valid rad.)/(cube size)) */

typedef struct ambtree {
        AMBVAL  *alist;         /* ambient value list */
        struct ambtree  *kid;   /* 8 child nodes */
}  AMBTREE;                     /* ambient octree */

extern CUBE  thescene;          /* contains space boundaries */

#define  MAXASET        511     /* maximum number of elements in ambient set */
OBJECT  ambset[MAXASET+1]={0};  /* ambient include/exclude set */

double  maxarad;                /* maximum ambient radius */
double  minarad;                /* minimum ambient radius */

static AMBTREE  atrunk;         /* our ambient trunk node */

static FILE  *ambfp = NULL;     /* ambient file pointer */

#define  newambval()    (AMBVAL *)bmalloc(sizeof(AMBVAL))

#define  newambtree()   (AMBTREE *)calloc(8, sizeof(AMBTREE))


setambres(ar)                           /* set ambient resolution */
int  ar;
{
                                                /* set min & max radii */
        if (ar <= 0) {
                minarad = 0.0;
                maxarad = thescene.cusize / 2.0;
        } else {
                minarad = thescene.cusize / ar;
                maxarad = 16.0 * minarad;               /* heuristic */
                if (maxarad > thescene.cusize / 2.0)
                        maxarad = thescene.cusize / 2.0;
        }
        if (maxarad <= FTINY)
                maxarad = .001;
}


setambient(afile)                       /* initialize calculation */
char  *afile;
{
        long  ftell();
        AMBVAL  amb;
                                                /* init ambient limits */
        setambres(ambres);
                                                /* open ambient file */
        if (afile != NULL)
                if ((ambfp = fopen(afile, "r+")) != NULL) {
                        while (fread((char *)&amb,sizeof(AMBVAL),1,ambfp) == 1)
                                avinsert(&amb, &atrunk, thescene.cuorg,
                                                thescene.cusize);
                                                        /* align */
                        fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1);
                } else if ((ambfp = fopen(afile, "w")) == NULL) {
                        sprintf(errmsg, "cannot open ambient file \"%s\"",
                                        afile);
                        error(SYSTEM, errmsg);
                }
}


ambnotify(obj)                  /* record new modifier */
OBJECT  obj;
{
        static int  hitlimit = 0;
        register OBJREC  *o = objptr(obj);
        register char  **amblp;

        if (hitlimit || !ismodifier(o->otype))
                return;
        for (amblp = amblist; *amblp != NULL; amblp++)
                if (!strcmp(o->oname, *amblp)) {
                        if (ambset[0] >= MAXASET) {
                                error(WARNING, "too many modifiers in ambient list");
                                hitlimit++;
                                return;         /* should this be fatal? */
                        }
                        insertelem(ambset, obj);
                        return;
                }
}


ambient(acol, r)                /* compute ambient component for ray */
COLOR  acol;
register RAY  *r;
{
        static int  rdepth = 0;                 /* ambient recursion */
        double  d;

        if (ambdiv <= 0)                        /* no ambient calculation */
                goto dumbamb;
                                                /* check number of bounces */
        if (rdepth >= ambounce)
                goto dumbamb;
                                                /* check ambient list */
        if (ambincl != -1 && r->ro != NULL &&
                        ambincl != inset(ambset, r->ro->omod))
                goto dumbamb;

        if (ambacc <= FTINY) {                  /* no ambient storage */
                rdepth++;
                d = doambient(acol, r, r->rweight, NULL, NULL);
                rdepth--;
                if (d == 0.0)
                        goto dumbamb;
                return;
        }
                                                /* get ambient value */
        setcolor(acol, 0.0, 0.0, 0.0);
        d = sumambient(acol, r, rdepth,
                        &atrunk, thescene.cuorg, thescene.cusize);
        if (d > FTINY)
                scalecolor(acol, 1.0/d);
        else {
                d = makeambient(acol, r, rdepth++);
                rdepth--;
        }
        if (d > FTINY)
                return;
dumbamb:                                        /* return global value */
        copycolor(acol, ambval);
}


double
sumambient(acol, r, al, at, c0, s)      /* get interpolated ambient value */
COLOR  acol;
register RAY  *r;
int  al;
AMBTREE  *at;
FVECT  c0;
double  s;
{
        extern double  sqrt();
        double  d, e1, e2, wt, wsum;
        COLOR  ct;
        FVECT  ck0;
        int  i;
        register int  j;
        register AMBVAL  *av;
                                        /* do this node */
        wsum = 0.0;
        for (av = at->alist; av != NULL; av = av->next) {
                /*
                 *  Ambient level test.
                 */
                if (av->lvl > al || av->weight < r->rweight-FTINY)
                        continue;
                /*
                 *  Ambient radius test.
                 */
                e1 = 0.0;
                for (j = 0; j < 3; j++) {
                        d = av->pos[j] - r->rop[j];
                        e1 += d * d;
                }
                e1 /= av->rad * av->rad;
                if (e1 > ambacc*ambacc*1.21)
                        continue;
                /*
                 *  Normal direction test.
                 */
                e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
                if (e2 < 0.0) e2 = 0.0;
                if (e1 + e2 > ambacc*ambacc*1.21)
                        continue;
                /*
                 *  Ray behind test.
                 */
                d = 0.0;
                for (j = 0; j < 3; j++)
                        d += (r->rop[j] - av->pos[j]) *
                                        (av->dir[j] + r->ron[j]);
                if (d*0.5 < -minarad*ambacc-.001)
                        continue;
                /*
                 *  Jittering final test reduces image artifacts.
                 */
                wt = sqrt(e1) + sqrt(e2);
                wt *= .9 + .2*urand(9015+samplendx);
                if (wt > ambacc)
                        continue;
                if (wt <= 1e-3)
                        wt = 1e3;
                else
                        wt = 1.0 / wt;
                wsum += wt;
                extambient(ct, av, r->rop, r->ron);
                scalecolor(ct, wt);
                addcolor(acol, ct);
        }
        if (at->kid == NULL)
                return(wsum);
                                        /* do children */
        s *= 0.5;
        for (i = 0; i < 8; i++) {
                for (j = 0; j < 3; j++) {
                        ck0[j] = c0[j];
                        if (1<<j & i)
                                ck0[j] += s;
                        if (r->rop[j] < ck0[j] - OCTSCALE*s)
                                break;
                        if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
                                break;
                }
                if (j == 3)
                        wsum += sumambient(acol, r, al, at->kid+i, ck0, s);
        }
        return(wsum);
}


double
makeambient(acol, r, al)        /* make a new ambient value */
COLOR  acol;
register RAY  *r;
int  al;
{
        AMBVAL  amb;
        FVECT   gp, gd;
                                                /* compute weight */
        amb.weight = pow(AVGREFL, (double)al);
        if (r->rweight < 0.2*amb.weight)        /* heuristic */
                amb.weight = r->rweight;
                                                /* compute ambient */
        amb.rad = doambient(acol, r, amb.weight, gp, gd);
        if (amb.rad == 0.0)
                return(0.0);
                                                /* store it */
        VCOPY(amb.pos, r->rop);
        VCOPY(amb.dir, r->ron);
        amb.lvl = al;
        copycolor(amb.val, acol);
        VCOPY(amb.gpos, gp);
        VCOPY(amb.gdir, gd);
                                                /* insert into tree */
        avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
        avsave(&amb);                           /* write to file */
        return(amb.rad);
}


extambient(cr, ap, pv, nv)              /* extrapolate value at pv, nv */
COLOR  cr;
register AMBVAL  *ap;
FVECT  pv, nv;
{
        FVECT  v1, v2;
        register int  i;
        double  d;

        d = 1.0;                        /* zeroeth order */
                                        /* gradient due to translation */
        for (i = 0; i < 3; i++)
                d += ap->gpos[i]*(pv[i]-ap->pos[i]);
                                        /* gradient due to rotation */
        VCOPY(v1, ap->dir);
        fcross(v2, v1, nv);
        d += DOT(ap->gdir, v2);
        if (d <= 0.0) {
                setcolor(cr, 0.0, 0.0, 0.0);
                return;
        }
        copycolor(cr, ap->val);
        scalecolor(cr, d);
}


static
avsave(av)                              /* save an ambient value */
AMBVAL  *av;
{
#ifdef  AMBFLUSH
        static int  nunflshed = 0;
#endif
        if (ambfp == NULL)
                return;
        if (fwrite((char *)av, sizeof(AMBVAL), 1, ambfp) != 1)
                goto writerr;
#ifdef  AMBFLUSH
        if (++nunflshed >= AMBFLUSH) {
                if (fflush(ambfp) == EOF)
                        goto writerr;
                nunflshed = 0;
        }
#endif
        return;
writerr:
        error(SYSTEM, "error writing ambient file");
}


static
avinsert(aval, at, c0, s)               /* insert ambient value in a tree */
AMBVAL  *aval;
register AMBTREE  *at;
FVECT  c0;
double  s;
{
        FVECT  ck0;
        int  branch;
        register AMBVAL  *av;
        register int  i;

        if ((av = newambval()) == NULL)
                goto memerr;
        copystruct(av, aval);
        VCOPY(ck0, c0);
        while (s*(OCTSCALE/2) > av->rad*ambacc) {
                if (at->kid == NULL)
                        if ((at->kid = newambtree()) == NULL)
                                goto memerr;
                s *= 0.5;
                branch = 0;
                for (i = 0; i < 3; i++)
                        if (av->pos[i] > ck0[i] + s) {
                                ck0[i] += s;
                                branch |= 1 << i;
                        }
                at = at->kid + branch;
        }
        av->next = at->alist;
        at->alist = av;
        return;
memerr:
        error(SYSTEM, "out of memory in avinsert");
}
Revision:	2.4
Committed:	Fri Apr 10 16:14:34 1992 UTC (32 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.3:	+2 -0 lines
Log Message:	avoid zero maxarad for scenes with no local objects
#	User	Rev	Content
1	greg	1.14	/* Copyright (c) 1991 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* ambient.c - routines dealing with ambient (inter-reflected) component.
9			*
10			* The macro AMBFLUSH (if defined) is the number of ambient values
11			* to wait before flushing to the ambient file.
12			*
13			* 5/9/86
14			*/
15
16			#include "ray.h"
17
18			#include "octree.h"
19
20	greg	1.8	#include "otypes.h"
21
22	greg	1.14	#include "ambient.h"
23
24	greg	1.1	#include "random.h"
25
26			#define OCTSCALE 0.5 /* ceil((valid rad.)/(cube size)) */
27
28	greg	1.14	typedef struct ambtree {
29			AMBVAL alist; / ambient value list */
30			struct ambtree kid; / 8 child nodes */
31			} AMBTREE; /* ambient octree */
32
33	greg	1.1	extern CUBE thescene; /* contains space boundaries */
34
35	greg	1.11	#define MAXASET 511 /* maximum number of elements in ambient set */
36			OBJECT ambset[MAXASET+1]={0}; /* ambient include/exclude set */
37	greg	1.1
38			double maxarad; /* maximum ambient radius */
39			double minarad; /* minimum ambient radius */
40
41			static AMBTREE atrunk; /* our ambient trunk node */
42
43			static FILE ambfp = NULL; / ambient file pointer */
44
45			#define newambval() (AMBVAL *)bmalloc(sizeof(AMBVAL))
46
47			#define newambtree() (AMBTREE *)calloc(8, sizeof(AMBTREE))
48
49
50	greg	2.3	setambres(ar) /* set ambient resolution */
51			int ar;
52			{
53			/* set min & max radii */
54			if (ar <= 0) {
55			minarad = 0.0;
56			maxarad = thescene.cusize / 2.0;
57			} else {
58			minarad = thescene.cusize / ar;
59			maxarad = 16.0 * minarad; /* heuristic */
60			if (maxarad > thescene.cusize / 2.0)
61			maxarad = thescene.cusize / 2.0;
62			}
63	greg	2.4	if (maxarad <= FTINY)
64			maxarad = .001;
65	greg	2.3	}
66
67
68	greg	1.1	setambient(afile) /* initialize calculation */
69			char *afile;
70			{
71			long ftell();
72			AMBVAL amb;
73	greg	2.3	/* init ambient limits */
74			setambres(ambres);
75			/* open ambient file */
76	greg	1.1	if (afile != NULL)
77			if ((ambfp = fopen(afile, "r+")) != NULL) {
78	greg	1.9	while (fread((char *)&amb,sizeof(AMBVAL),1,ambfp) == 1)
79	greg	1.1	avinsert(&amb, &atrunk, thescene.cuorg,
80			thescene.cusize);
81			/* align */
82			fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1);
83			} else if ((ambfp = fopen(afile, "w")) == NULL) {
84			sprintf(errmsg, "cannot open ambient file \"%s\"",
85			afile);
86			error(SYSTEM, errmsg);
87	greg	1.8	}
88			}
89
90
91			ambnotify(obj) /* record new modifier */
92			OBJECT obj;
93			{
94	greg	1.11	static int hitlimit = 0;
95	greg	1.8	register OBJREC *o = objptr(obj);
96			register char **amblp;
97
98	greg	1.11	if (hitlimit \|\| !ismodifier(o->otype))
99	greg	1.8	return;
100			for (amblp = amblist; *amblp != NULL; amblp++)
101			if (!strcmp(o->oname, *amblp)) {
102	greg	1.11	if (ambset[0] >= MAXASET) {
103			error(WARNING, "too many modifiers in ambient list");
104			hitlimit++;
105			return; /* should this be fatal? */
106			}
107	greg	1.8	insertelem(ambset, obj);
108			return;
109	greg	1.1	}
110			}
111
112
113			ambient(acol, r) /* compute ambient component for ray */
114			COLOR acol;
115			register RAY *r;
116			{
117			static int rdepth = 0; /* ambient recursion */
118	greg	1.16	double d;
119	greg	1.1
120			if (ambdiv <= 0) /* no ambient calculation */
121			goto dumbamb;
122			/* check number of bounces */
123	greg	1.16	if (rdepth >= ambounce)
124	greg	1.1	goto dumbamb;
125			/* check ambient list */
126			if (ambincl != -1 && r->ro != NULL &&
127			ambincl != inset(ambset, r->ro->omod))
128			goto dumbamb;
129
130			if (ambacc <= FTINY) { /* no ambient storage */
131	greg	1.16	rdepth++;
132			d = doambient(acol, r, r->rweight, NULL, NULL);
133			rdepth--;
134			if (d == 0.0)
135	greg	1.1	goto dumbamb;
136	greg	1.16	return;
137	greg	1.1	}
138			/* get ambient value */
139			setcolor(acol, 0.0, 0.0, 0.0);
140	greg	1.16	d = sumambient(acol, r, rdepth,
141			&atrunk, thescene.cuorg, thescene.cusize);
142			if (d > FTINY)
143			scalecolor(acol, 1.0/d);
144			else {
145			d = makeambient(acol, r, rdepth++);
146			rdepth--;
147			}
148			if (d > FTINY)
149			return;
150	greg	1.1	dumbamb: /* return global value */
151			copycolor(acol, ambval);
152			}
153
154
155			double
156	greg	1.16	sumambient(acol, r, al, at, c0, s) /* get interpolated ambient value */
157	greg	1.1	COLOR acol;
158			register RAY *r;
159	greg	1.16	int al;
160	greg	1.1	AMBTREE *at;
161			FVECT c0;
162			double s;
163			{
164			extern double sqrt();
165			double d, e1, e2, wt, wsum;
166			COLOR ct;
167			FVECT ck0;
168			int i;
169			register int j;
170			register AMBVAL *av;
171	greg	1.7	/* do this node */
172	greg	1.1	wsum = 0.0;
173			for (av = at->alist; av != NULL; av = av->next) {
174			/*
175	greg	1.16	* Ambient level test.
176	greg	1.1	*/
177	greg	1.16	if (av->lvl > al \|\| av->weight < r->rweight-FTINY)
178	greg	1.1	continue;
179			/*
180			* Ambient radius test.
181			*/
182			e1 = 0.0;
183			for (j = 0; j < 3; j++) {
184			d = av->pos[j] - r->rop[j];
185			e1 += d * d;
186			}
187			e1 /= av->rad * av->rad;
188			if (e1 > ambaccambacc1.21)
189			continue;
190			/*
191			* Normal direction test.
192			*/
193			e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
194			if (e2 < 0.0) e2 = 0.0;
195			if (e1 + e2 > ambaccambacc1.21)
196			continue;
197			/*
198			* Ray behind test.
199			*/
200			d = 0.0;
201			for (j = 0; j < 3; j++)
202			d += (r->rop[j] - av->pos[j]) *
203			(av->dir[j] + r->ron[j]);
204	greg	1.18	if (d0.5 < -minaradambacc-.001)
205	greg	1.1	continue;
206			/*
207			* Jittering final test reduces image artifacts.
208			*/
209			wt = sqrt(e1) + sqrt(e2);
210	greg	2.2	wt = .9 + .2urand(9015+samplendx);
211	greg	1.6	if (wt > ambacc)
212	greg	1.1	continue;
213			if (wt <= 1e-3)
214			wt = 1e3;
215			else
216			wt = 1.0 / wt;
217			wsum += wt;
218	greg	1.15	extambient(ct, av, r->rop, r->ron);
219	greg	1.1	scalecolor(ct, wt);
220			addcolor(acol, ct);
221	greg	1.7	}
222			if (at->kid == NULL)
223			return(wsum);
224			/* do children */
225			s *= 0.5;
226			for (i = 0; i < 8; i++) {
227			for (j = 0; j < 3; j++) {
228			ck0[j] = c0[j];
229			if (1<<j & i)
230			ck0[j] += s;
231			if (r->rop[j] < ck0[j] - OCTSCALE*s)
232			break;
233			if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
234			break;
235			}
236			if (j == 3)
237	greg	1.16	wsum += sumambient(acol, r, al, at->kid+i, ck0, s);
238	greg	1.1	}
239			return(wsum);
240			}
241
242
243			double
244	greg	1.16	makeambient(acol, r, al) /* make a new ambient value */
245	greg	1.1	COLOR acol;
246			register RAY *r;
247	greg	1.16	int al;
248	greg	1.1	{
249			AMBVAL amb;
250	greg	1.14	FVECT gp, gd;
251	greg	1.16	/* compute weight */
252			amb.weight = pow(AVGREFL, (double)al);
253	greg	1.17	if (r->rweight < 0.2amb.weight) / heuristic */
254	greg	1.16	amb.weight = r->rweight;
255			/* compute ambient */
256			amb.rad = doambient(acol, r, amb.weight, gp, gd);
257	greg	1.1	if (amb.rad == 0.0)
258			return(0.0);
259			/* store it */
260			VCOPY(amb.pos, r->rop);
261			VCOPY(amb.dir, r->ron);
262	greg	1.16	amb.lvl = al;
263	greg	1.1	copycolor(amb.val, acol);
264	greg	1.14	VCOPY(amb.gpos, gp);
265			VCOPY(amb.gdir, gd);
266	greg	1.1	/* insert into tree */
267			avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
268			avsave(&amb); /* write to file */
269			return(amb.rad);
270	greg	1.15	}
271
272
273			extambient(cr, ap, pv, nv) /* extrapolate value at pv, nv */
274			COLOR cr;
275			register AMBVAL *ap;
276			FVECT pv, nv;
277			{
278			FVECT v1, v2;
279			register int i;
280			double d;
281
282			d = 1.0; /* zeroeth order */
283			/* gradient due to translation */
284			for (i = 0; i < 3; i++)
285			d += ap->gpos[i]*(pv[i]-ap->pos[i]);
286			/* gradient due to rotation */
287			VCOPY(v1, ap->dir);
288			fcross(v2, v1, nv);
289			d += DOT(ap->gdir, v2);
290			if (d <= 0.0) {
291			setcolor(cr, 0.0, 0.0, 0.0);
292			return;
293			}
294			copycolor(cr, ap->val);
295			scalecolor(cr, d);
296	greg	1.1	}
297
298
299			static
300			avsave(av) /* save an ambient value */
301			AMBVAL *av;
302			{
303			#ifdef AMBFLUSH
304			static int nunflshed = 0;
305			#endif
306			if (ambfp == NULL)
307			return;
308	greg	1.9	if (fwrite((char *)av, sizeof(AMBVAL), 1, ambfp) != 1)
309	greg	1.1	goto writerr;
310			#ifdef AMBFLUSH
311			if (++nunflshed >= AMBFLUSH) {
312			if (fflush(ambfp) == EOF)
313			goto writerr;
314			nunflshed = 0;
315			}
316			#endif
317			return;
318			writerr:
319			error(SYSTEM, "error writing ambient file");
320			}
321
322
323			static
324			avinsert(aval, at, c0, s) /* insert ambient value in a tree */
325			AMBVAL *aval;
326			register AMBTREE *at;
327			FVECT c0;
328			double s;
329			{
330			FVECT ck0;
331			int branch;
332			register AMBVAL *av;
333			register int i;
334
335			if ((av = newambval()) == NULL)
336			goto memerr;
337	greg	1.9	copystruct(av, aval);
338	greg	1.1	VCOPY(ck0, c0);
339			while (s(OCTSCALE/2) > av->radambacc) {
340			if (at->kid == NULL)
341			if ((at->kid = newambtree()) == NULL)
342			goto memerr;
343			s *= 0.5;
344			branch = 0;
345			for (i = 0; i < 3; i++)
346			if (av->pos[i] > ck0[i] + s) {
347			ck0[i] += s;
348			branch \|= 1 << i;
349			}
350			at = at->kid + branch;
351			}
352			av->next = at->alist;
353			at->alist = av;
354			return;
355			memerr:
356			error(SYSTEM, "out of memory in avinsert");
357			}