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;
        }
}


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