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))


setambient(afile)                       /* initialize calculation */
char  *afile;
{
        long  ftell();
        AMBVAL  amb;

        maxarad = thescene.cusize / 2.0;                /* maximum radius */
                                                        /* minimum radius */
        minarad = ambres > 0 ? thescene.cusize/ambres : 0.0;

                                        /* 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:	2.2
Committed:	Wed Jan 15 10:36:42 1992 UTC (33 years, 9 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.1:	+1 -1 lines
Log Message:	changed jittering test to use urand
#	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			setambient(afile) /* initialize calculation */
51			char *afile;
52			{
53			long ftell();
54			AMBVAL amb;
55	greg	1.8
56	greg	1.1	maxarad = thescene.cusize / 2.0; /* maximum radius */
57			/* minimum radius */
58			minarad = ambres > 0 ? thescene.cusize/ambres : 0.0;
59
60			/* open ambient file */
61			if (afile != NULL)
62			if ((ambfp = fopen(afile, "r+")) != NULL) {
63	greg	1.9	while (fread((char *)&amb,sizeof(AMBVAL),1,ambfp) == 1)
64	greg	1.1	avinsert(&amb, &atrunk, thescene.cuorg,
65			thescene.cusize);
66			/* align */
67			fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1);
68			} else if ((ambfp = fopen(afile, "w")) == NULL) {
69			sprintf(errmsg, "cannot open ambient file \"%s\"",
70			afile);
71			error(SYSTEM, errmsg);
72	greg	1.8	}
73			}
74
75
76			ambnotify(obj) /* record new modifier */
77			OBJECT obj;
78			{
79	greg	1.11	static int hitlimit = 0;
80	greg	1.8	register OBJREC *o = objptr(obj);
81			register char **amblp;
82
83	greg	1.11	if (hitlimit \|\| !ismodifier(o->otype))
84	greg	1.8	return;
85			for (amblp = amblist; *amblp != NULL; amblp++)
86			if (!strcmp(o->oname, *amblp)) {
87	greg	1.11	if (ambset[0] >= MAXASET) {
88			error(WARNING, "too many modifiers in ambient list");
89			hitlimit++;
90			return; /* should this be fatal? */
91			}
92	greg	1.8	insertelem(ambset, obj);
93			return;
94	greg	1.1	}
95			}
96
97
98			ambient(acol, r) /* compute ambient component for ray */
99			COLOR acol;
100			register RAY *r;
101			{
102			static int rdepth = 0; /* ambient recursion */
103	greg	1.16	double d;
104	greg	1.1
105			if (ambdiv <= 0) /* no ambient calculation */
106			goto dumbamb;
107			/* check number of bounces */
108	greg	1.16	if (rdepth >= ambounce)
109	greg	1.1	goto dumbamb;
110			/* check ambient list */
111			if (ambincl != -1 && r->ro != NULL &&
112			ambincl != inset(ambset, r->ro->omod))
113			goto dumbamb;
114
115			if (ambacc <= FTINY) { /* no ambient storage */
116	greg	1.16	rdepth++;
117			d = doambient(acol, r, r->rweight, NULL, NULL);
118			rdepth--;
119			if (d == 0.0)
120	greg	1.1	goto dumbamb;
121	greg	1.16	return;
122	greg	1.1	}
123			/* get ambient value */
124			setcolor(acol, 0.0, 0.0, 0.0);
125	greg	1.16	d = sumambient(acol, r, rdepth,
126			&atrunk, thescene.cuorg, thescene.cusize);
127			if (d > FTINY)
128			scalecolor(acol, 1.0/d);
129			else {
130			d = makeambient(acol, r, rdepth++);
131			rdepth--;
132			}
133			if (d > FTINY)
134			return;
135	greg	1.1	dumbamb: /* return global value */
136			copycolor(acol, ambval);
137			}
138
139
140			double
141	greg	1.16	sumambient(acol, r, al, at, c0, s) /* get interpolated ambient value */
142	greg	1.1	COLOR acol;
143			register RAY *r;
144	greg	1.16	int al;
145	greg	1.1	AMBTREE *at;
146			FVECT c0;
147			double s;
148			{
149			extern double sqrt();
150			double d, e1, e2, wt, wsum;
151			COLOR ct;
152			FVECT ck0;
153			int i;
154			register int j;
155			register AMBVAL *av;
156	greg	1.7	/* do this node */
157	greg	1.1	wsum = 0.0;
158			for (av = at->alist; av != NULL; av = av->next) {
159			/*
160	greg	1.16	* Ambient level test.
161	greg	1.1	*/
162	greg	1.16	if (av->lvl > al \|\| av->weight < r->rweight-FTINY)
163	greg	1.1	continue;
164			/*
165			* Ambient radius test.
166			*/
167			e1 = 0.0;
168			for (j = 0; j < 3; j++) {
169			d = av->pos[j] - r->rop[j];
170			e1 += d * d;
171			}
172			e1 /= av->rad * av->rad;
173			if (e1 > ambaccambacc1.21)
174			continue;
175			/*
176			* Normal direction test.
177			*/
178			e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
179			if (e2 < 0.0) e2 = 0.0;
180			if (e1 + e2 > ambaccambacc1.21)
181			continue;
182			/*
183			* Ray behind test.
184			*/
185			d = 0.0;
186			for (j = 0; j < 3; j++)
187			d += (r->rop[j] - av->pos[j]) *
188			(av->dir[j] + r->ron[j]);
189	greg	1.18	if (d0.5 < -minaradambacc-.001)
190	greg	1.1	continue;
191			/*
192			* Jittering final test reduces image artifacts.
193			*/
194			wt = sqrt(e1) + sqrt(e2);
195	greg	2.2	wt = .9 + .2urand(9015+samplendx);
196	greg	1.6	if (wt > ambacc)
197	greg	1.1	continue;
198			if (wt <= 1e-3)
199			wt = 1e3;
200			else
201			wt = 1.0 / wt;
202			wsum += wt;
203	greg	1.15	extambient(ct, av, r->rop, r->ron);
204	greg	1.1	scalecolor(ct, wt);
205			addcolor(acol, ct);
206	greg	1.7	}
207			if (at->kid == NULL)
208			return(wsum);
209			/* do children */
210			s *= 0.5;
211			for (i = 0; i < 8; i++) {
212			for (j = 0; j < 3; j++) {
213			ck0[j] = c0[j];
214			if (1<<j & i)
215			ck0[j] += s;
216			if (r->rop[j] < ck0[j] - OCTSCALE*s)
217			break;
218			if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
219			break;
220			}
221			if (j == 3)
222	greg	1.16	wsum += sumambient(acol, r, al, at->kid+i, ck0, s);
223	greg	1.1	}
224			return(wsum);
225			}
226
227
228			double
229	greg	1.16	makeambient(acol, r, al) /* make a new ambient value */
230	greg	1.1	COLOR acol;
231			register RAY *r;
232	greg	1.16	int al;
233	greg	1.1	{
234			AMBVAL amb;
235	greg	1.14	FVECT gp, gd;
236	greg	1.16	/* compute weight */
237			amb.weight = pow(AVGREFL, (double)al);
238	greg	1.17	if (r->rweight < 0.2amb.weight) / heuristic */
239	greg	1.16	amb.weight = r->rweight;
240			/* compute ambient */
241			amb.rad = doambient(acol, r, amb.weight, gp, gd);
242	greg	1.1	if (amb.rad == 0.0)
243			return(0.0);
244			/* store it */
245			VCOPY(amb.pos, r->rop);
246			VCOPY(amb.dir, r->ron);
247	greg	1.16	amb.lvl = al;
248	greg	1.1	copycolor(amb.val, acol);
249	greg	1.14	VCOPY(amb.gpos, gp);
250			VCOPY(amb.gdir, gd);
251	greg	1.1	/* insert into tree */
252			avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize);
253			avsave(&amb); /* write to file */
254			return(amb.rad);
255	greg	1.15	}
256
257
258			extambient(cr, ap, pv, nv) /* extrapolate value at pv, nv */
259			COLOR cr;
260			register AMBVAL *ap;
261			FVECT pv, nv;
262			{
263			FVECT v1, v2;
264			register int i;
265			double d;
266
267			d = 1.0; /* zeroeth order */
268			/* gradient due to translation */
269			for (i = 0; i < 3; i++)
270			d += ap->gpos[i]*(pv[i]-ap->pos[i]);
271			/* gradient due to rotation */
272			VCOPY(v1, ap->dir);
273			fcross(v2, v1, nv);
274			d += DOT(ap->gdir, v2);
275			if (d <= 0.0) {
276			setcolor(cr, 0.0, 0.0, 0.0);
277			return;
278			}
279			copycolor(cr, ap->val);
280			scalecolor(cr, d);
281	greg	1.1	}
282
283
284			static
285			avsave(av) /* save an ambient value */
286			AMBVAL *av;
287			{
288			#ifdef AMBFLUSH
289			static int nunflshed = 0;
290			#endif
291			if (ambfp == NULL)
292			return;
293	greg	1.9	if (fwrite((char *)av, sizeof(AMBVAL), 1, ambfp) != 1)
294	greg	1.1	goto writerr;
295			#ifdef AMBFLUSH
296			if (++nunflshed >= AMBFLUSH) {
297			if (fflush(ambfp) == EOF)
298			goto writerr;
299			nunflshed = 0;
300			}
301			#endif
302			return;
303			writerr:
304			error(SYSTEM, "error writing ambient file");
305			}
306
307
308			static
309			avinsert(aval, at, c0, s) /* insert ambient value in a tree */
310			AMBVAL *aval;
311			register AMBTREE *at;
312			FVECT c0;
313			double s;
314			{
315			FVECT ck0;
316			int branch;
317			register AMBVAL *av;
318			register int i;
319
320			if ((av = newambval()) == NULL)
321			goto memerr;
322	greg	1.9	copystruct(av, aval);
323	greg	1.1	VCOPY(ck0, c0);
324			while (s(OCTSCALE/2) > av->radambacc) {
325			if (at->kid == NULL)
326			if ((at->kid = newambtree()) == NULL)
327			goto memerr;
328			s *= 0.5;
329			branch = 0;
330			for (i = 0; i < 3; i++)
331			if (av->pos[i] > ck0[i] + s) {
332			ck0[i] += s;
333			branch \|= 1 << i;
334			}
335			at = at->kid + branch;
336			}
337			av->next = at->alist;
338			at->alist = av;
339			return;
340			memerr:
341			error(SYSTEM, "out of memory in avinsert");
342			}