src/rt/ambient.c

/* Copyright (c) 1993 Regents of the University of California */

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

/*
 *  ambient.c - routines dealing with ambient (inter-reflected) component.
 */

#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 */
static int  nunflshed = 0;      /* number of unflushed ambient values */

#define  AMBFLUSH       (BUFSIZ/AMBVALSIZ)

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

#define  newambtree()   (AMBTREE *)calloc(8, sizeof(AMBTREE))
#define  freeambtree(t) free((char *)(t))

extern long  ftell(), lseek();
static int  initambfile(), avsave(), avinsert(), loadtree();
static AMBVAL  *avstore();
#ifdef  F_SETLKW
static  aflock();
#endif


setambres(ar)                           /* set ambient resolution */
int  ar;
{
        ambres = ar;                    /* may be done already */
                                                /* 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;
}


resetambacc(newa)                       /* change ambient accuracy setting */
double  newa;
{
        AMBTREE  oldatrunk;

        if (fabs(newa - ambacc) < 0.01)
                return;                 /* insignificant -- don't bother */
        ambacc = newa;
        if (ambacc <= FTINY)
                return;                 /* cannot build new tree */
                                        /* else need to rebuild tree */
        copystruct(&oldatrunk, &atrunk);
        atrunk.alist = NULL;
        atrunk.kid = NULL;
        loadtree(&oldatrunk);
}


setambient(afile)                       /* initialize calculation */
char  *afile;
{
        long  headlen;
        AMBVAL  amb;
                                                /* init ambient limits */
        setambres(ambres);
        if (afile == NULL)
                return;
        if (ambacc <= FTINY) {
                sprintf(errmsg, "zero ambient accuracy so \"%s\" not loaded",
                                afile);
                error(WARNING, errmsg);
                return;
        }
                                                /* open ambient file */
        if ((ambfp = fopen(afile, "r+")) != NULL) {
                initambfile(0);
                headlen = ftell(ambfp);
                while (readambval(&amb, ambfp))
                        avinsert(avstore(&amb), &atrunk,
                                        thescene.cuorg, thescene.cusize);
                                                /* align */
                fseek(ambfp, -((ftell(ambfp)-headlen)%AMBVALSIZ), 1);
        } else if ((ambfp = fopen(afile, "w+")) != NULL)
                initambfile(1);
        else {
                sprintf(errmsg, "cannot open ambient file \"%s\"", afile);
                error(SYSTEM, errmsg);
        }
        nunflshed++;    /* lie */
        ambsync();
}


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;
{
        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 */
        avsave(&amb);                           /* and save 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
initambfile(creat)              /* initialize ambient file */
int  creat;
{
        extern char  *progname, *octname, VersionID[];

#ifdef  F_SETLKW
        aflock(creat ? F_WRLCK : F_RDLCK);
#endif
#ifdef MSDOS
        setmode(fileno(ambfp), O_BINARY);
#endif
        setbuf(ambfp, bmalloc(BUFSIZ));
        if (creat) {                    /* new file */
                fprintf(ambfp, "%s -av %g %g %g -ab %d -aa %g ",
                                progname, colval(ambval,RED),
                                colval(ambval,GRN), colval(ambval,BLU),
                                ambounce, ambacc);
                fprintf(ambfp, "-ad %d -as %d -ar %d %s\n",
                                ambdiv, ambssamp, ambres,
                                octname==NULL ? "" : octname);
                fprintf(ambfp, "SOFTWARE= %s\n", VersionID);
                fputformat(AMBFMT, ambfp);
                putc('\n', ambfp);
                putambmagic(ambfp);
        } else if (checkheader(ambfp, AMBFMT, NULL) < 0 || !hasambmagic(ambfp))
                error(USER, "bad ambient file");
}


static
avsave(av)                              /* insert and save an ambient value */
AMBVAL  *av;
{
        avinsert(avstore(av), &atrunk, thescene.cuorg, thescene.cusize);
        if (ambfp == NULL)
                return;
        if (writambval(av, ambfp) < 0)
                goto writerr;
        if (++nunflshed >= AMBFLUSH)
                if (ambsync() == EOF)
                        goto writerr;
        return;
writerr:
        error(SYSTEM, "error writing ambient file");
}


static AMBVAL *
avstore(aval)                           /* allocate memory and store aval */
register AMBVAL  *aval;
{
        register AMBVAL  *av;

        if ((av = newambval()) == NULL)
                error(SYSTEM, "out of memory in avstore");
        copystruct(av, aval);
        return(av);
}


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

        if (av->rad <= FTINY)
                error(CONSISTENCY, "zero ambient radius in avinsert");
        VCOPY(ck0, c0);
        while (s*(OCTSCALE/2) > av->rad*ambacc) {
                if (at->kid == NULL)
                        if ((at->kid = newambtree()) == NULL)
                                error(SYSTEM, "out of memory in avinsert");
                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;
}


static
loadtree(at)                            /* move tree to main store */
register AMBTREE  *at;
{
        register AMBVAL  *av;
        register int  i;
                                        /* transfer values at this node */
        for (av = at->alist; av != NULL; av = at->alist) {
                at->alist = av->next;
                avinsert(av, &atrunk, thescene.cuorg, thescene.cusize);
        }
        for (i = 0; i < 8; i++)         /* transfer and free children */
                loadtree(at->kid+i);
        freeambtree(at->kid);
}


#ifdef  F_SETLKW

static
aflock(typ)                     /* lock/unlock ambient file */
int  typ;
{
        static struct flock  fls;       /* static so initialized to zeroes */

        fls.l_type = typ;
        if (fcntl(fileno(ambfp), F_SETLKW, &fls) < 0)
                error(SYSTEM, "cannot (un)lock ambient file");
}


int
ambsync()                       /* synchronize ambient file */
{
        static FILE  *ambinp = NULL;
        static long  lastpos = -1;
        long  flen;
        AMBVAL  avs;
        register int  n;

        if (nunflshed == 0)
                return(0);
        if (lastpos < 0)        /* initializing (locked in initambfile) */
                goto syncend;
                                /* gain exclusive access */
        aflock(F_WRLCK);
                                /* see if file has grown */
        if ((flen = lseek(fileno(ambfp), 0L, 2)) < 0)
                error(SYSTEM, "cannot seek on ambient file");
        if (n = flen - lastpos) {               /* file has grown */
                if (ambinp == NULL) {           /* use duplicate filedes */
                        ambinp = fdopen(dup(fileno(ambfp)), "r");
                        if (ambinp == NULL)
                                error(SYSTEM, "fdopen failed in ambsync");
                }
                if (fseek(ambinp, lastpos, 0) < 0)
                        error(SYSTEM, "fseek failed in ambsync");
                while (n >= AMBVALSIZ) {        /* load contributed values */
                        readambval(&avs, ambinp);
                        avinsert(avstore(&avs), &atrunk,
                                        thescene.cuorg, thescene.cusize);
                        n -= AMBVALSIZ;
                }
                if (n)                          /* alignment */
                        lseek(fileno(ambfp), flen-n, 0);
        }
syncend:
        n = fflush(ambfp);                      /* calls write() at last */
        lastpos = lseek(fileno(ambfp), 0L, 1);
        aflock(F_UNLCK);                        /* release file */
        nunflshed = 0;
        return(n);
}

#else

int
ambsync()                       /* flush ambient file */
{
        if (nunflshed == 0)
                return(0);
        nunflshed = 0;
        return(fflush(ambfp));
}

#endif
Revision:	2.20
Committed:	Thu Aug 5 10:02:00 1993 UTC (30 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.19:	+68 -15 lines
Log Message:	corrected flaws in setting and resetting of ambient accuracy
#	User	Rev	Content
1	greg	2.15	/* Copyright (c) 1993 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
11			#include "ray.h"
12
13			#include "octree.h"
14
15	greg	1.8	#include "otypes.h"
16
17	greg	1.14	#include "ambient.h"
18
19	greg	1.1	#include "random.h"
20
21	greg	2.12	#define OCTSCALE 0.5 /* ceil((valid rad.)/(cube size)) */
22	greg	1.1
23	greg	1.14	typedef struct ambtree {
24	greg	2.12	AMBVAL alist; / ambient value list */
25			struct ambtree kid; / 8 child nodes */
26	greg	1.14	} AMBTREE; /* ambient octree */
27
28	greg	1.1	extern CUBE thescene; /* contains space boundaries */
29
30	greg	2.12	#define MAXASET 511 /* maximum number of elements in ambient set */
31			OBJECT ambset[MAXASET+1]={0}; /* ambient include/exclude set */
32	greg	1.1
33	greg	2.12	double maxarad; /* maximum ambient radius */
34			double minarad; /* minimum ambient radius */
35	greg	1.1
36	greg	2.12	static AMBTREE atrunk; /* our ambient trunk node */
37	greg	1.1
38			static FILE ambfp = NULL; / ambient file pointer */
39	greg	2.16	static int nunflshed = 0; /* number of unflushed ambient values */
40	greg	1.1
41	greg	2.12	#define AMBFLUSH (BUFSIZ/AMBVALSIZ)
42	greg	2.6
43	greg	2.12	#define newambval() (AMBVAL *)bmalloc(sizeof(AMBVAL))
44	greg	1.1
45	greg	2.12	#define newambtree() (AMBTREE *)calloc(8, sizeof(AMBTREE))
46	greg	2.20	#define freeambtree(t) free((char *)(t))
47	greg	1.1
48	greg	2.7	extern long ftell(), lseek();
49	greg	2.20	static int initambfile(), avsave(), avinsert(), loadtree();
50			static AMBVAL *avstore();
51	greg	2.19	#ifdef F_SETLKW
52			static aflock();
53			#endif
54	greg	1.1
55	greg	2.7
56	greg	2.3	setambres(ar) /* set ambient resolution */
57			int ar;
58			{
59	greg	2.20	ambres = ar; /* may be done already */
60	greg	2.3	/* set min & max radii */
61			if (ar <= 0) {
62			minarad = 0.0;
63			maxarad = thescene.cusize / 2.0;
64			} else {
65			minarad = thescene.cusize / ar;
66			maxarad = 16.0 * minarad; /* heuristic */
67			if (maxarad > thescene.cusize / 2.0)
68			maxarad = thescene.cusize / 2.0;
69			}
70	greg	2.4	if (maxarad <= FTINY)
71			maxarad = .001;
72	greg	2.3	}
73
74
75	greg	2.20	resetambacc(newa) /* change ambient accuracy setting */
76			double newa;
77			{
78			AMBTREE oldatrunk;
79
80			if (fabs(newa - ambacc) < 0.01)
81			return; /* insignificant -- don't bother */
82			ambacc = newa;
83			if (ambacc <= FTINY)
84			return; /* cannot build new tree */
85			/* else need to rebuild tree */
86			copystruct(&oldatrunk, &atrunk);
87			atrunk.alist = NULL;
88			atrunk.kid = NULL;
89			loadtree(&oldatrunk);
90			}
91
92
93	greg	1.1	setambient(afile) /* initialize calculation */
94			char *afile;
95			{
96	greg	2.9	long headlen;
97	greg	2.12	AMBVAL amb;
98	greg	2.3	/* init ambient limits */
99			setambres(ambres);
100	greg	2.19	if (afile == NULL)
101			return;
102	greg	2.20	if (ambacc <= FTINY) {
103			sprintf(errmsg, "zero ambient accuracy so \"%s\" not loaded",
104			afile);
105			error(WARNING, errmsg);
106			return;
107			}
108	greg	2.3	/* open ambient file */
109	greg	2.19	if ((ambfp = fopen(afile, "r+")) != NULL) {
110			initambfile(0);
111			headlen = ftell(ambfp);
112			while (readambval(&amb, ambfp))
113	greg	2.20	avinsert(avstore(&amb), &atrunk,
114			thescene.cuorg, thescene.cusize);
115	greg	2.19	/* align */
116			fseek(ambfp, -((ftell(ambfp)-headlen)%AMBVALSIZ), 1);
117			} else if ((ambfp = fopen(afile, "w+")) != NULL)
118			initambfile(1);
119			else {
120			sprintf(errmsg, "cannot open ambient file \"%s\"", afile);
121			error(SYSTEM, errmsg);
122	greg	2.16	}
123	greg	2.19	nunflshed++; /* lie */
124			ambsync();
125	greg	1.8	}
126
127
128			ambnotify(obj) /* record new modifier */
129	greg	2.12	OBJECT obj;
130	greg	1.8	{
131	greg	1.11	static int hitlimit = 0;
132	greg	2.12	register OBJREC *o = objptr(obj);
133	greg	1.8	register char **amblp;
134
135	greg	1.11	if (hitlimit \|\| !ismodifier(o->otype))
136	greg	1.8	return;
137			for (amblp = amblist; *amblp != NULL; amblp++)
138			if (!strcmp(o->oname, *amblp)) {
139	greg	1.11	if (ambset[0] >= MAXASET) {
140			error(WARNING, "too many modifiers in ambient list");
141			hitlimit++;
142			return; /* should this be fatal? */
143			}
144	greg	1.8	insertelem(ambset, obj);
145			return;
146	greg	1.1	}
147			}
148
149
150			ambient(acol, r) /* compute ambient component for ray */
151			COLOR acol;
152			register RAY *r;
153			{
154			static int rdepth = 0; /* ambient recursion */
155	greg	2.12	double d;
156	greg	1.1
157			if (ambdiv <= 0) /* no ambient calculation */
158			goto dumbamb;
159			/* check number of bounces */
160	greg	1.16	if (rdepth >= ambounce)
161	greg	1.1	goto dumbamb;
162			/* check ambient list */
163			if (ambincl != -1 && r->ro != NULL &&
164			ambincl != inset(ambset, r->ro->omod))
165			goto dumbamb;
166
167			if (ambacc <= FTINY) { /* no ambient storage */
168	greg	1.16	rdepth++;
169			d = doambient(acol, r, r->rweight, NULL, NULL);
170			rdepth--;
171			if (d == 0.0)
172	greg	1.1	goto dumbamb;
173	greg	1.16	return;
174	greg	1.1	}
175			/* get ambient value */
176			setcolor(acol, 0.0, 0.0, 0.0);
177	greg	1.16	d = sumambient(acol, r, rdepth,
178			&atrunk, thescene.cuorg, thescene.cusize);
179			if (d > FTINY)
180			scalecolor(acol, 1.0/d);
181			else {
182			d = makeambient(acol, r, rdepth++);
183			rdepth--;
184			}
185			if (d > FTINY)
186			return;
187	greg	1.1	dumbamb: /* return global value */
188			copycolor(acol, ambval);
189			}
190
191
192			double
193	greg	1.16	sumambient(acol, r, al, at, c0, s) /* get interpolated ambient value */
194	greg	1.1	COLOR acol;
195			register RAY *r;
196	greg	1.16	int al;
197	greg	2.12	AMBTREE *at;
198	greg	1.1	FVECT c0;
199	greg	2.12	double s;
200	greg	1.1	{
201	greg	2.12	double d, e1, e2, wt, wsum;
202	greg	1.1	COLOR ct;
203			FVECT ck0;
204			int i;
205			register int j;
206	greg	2.12	register AMBVAL *av;
207	greg	1.7	/* do this node */
208	greg	1.1	wsum = 0.0;
209			for (av = at->alist; av != NULL; av = av->next) {
210			/*
211	greg	1.16	* Ambient level test.
212	greg	1.1	*/
213	greg	1.16	if (av->lvl > al \|\| av->weight < r->rweight-FTINY)
214	greg	1.1	continue;
215			/*
216			* Ambient radius test.
217			*/
218			e1 = 0.0;
219			for (j = 0; j < 3; j++) {
220			d = av->pos[j] - r->rop[j];
221			e1 += d * d;
222			}
223			e1 /= av->rad * av->rad;
224			if (e1 > ambaccambacc1.21)
225			continue;
226			/*
227			* Normal direction test.
228			*/
229			e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
230			if (e2 < 0.0) e2 = 0.0;
231			if (e1 + e2 > ambaccambacc1.21)
232			continue;
233			/*
234			* Ray behind test.
235			*/
236			d = 0.0;
237			for (j = 0; j < 3; j++)
238			d += (r->rop[j] - av->pos[j]) *
239			(av->dir[j] + r->ron[j]);
240	greg	1.18	if (d0.5 < -minaradambacc-.001)
241	greg	1.1	continue;
242			/*
243			* Jittering final test reduces image artifacts.
244			*/
245			wt = sqrt(e1) + sqrt(e2);
246	greg	2.2	wt = .9 + .2urand(9015+samplendx);
247	greg	1.6	if (wt > ambacc)
248	greg	1.1	continue;
249			if (wt <= 1e-3)
250			wt = 1e3;
251			else
252			wt = 1.0 / wt;
253			wsum += wt;
254	greg	1.15	extambient(ct, av, r->rop, r->ron);
255	greg	1.1	scalecolor(ct, wt);
256			addcolor(acol, ct);
257	greg	1.7	}
258			if (at->kid == NULL)
259			return(wsum);
260			/* do children */
261			s *= 0.5;
262			for (i = 0; i < 8; i++) {
263			for (j = 0; j < 3; j++) {
264			ck0[j] = c0[j];
265			if (1<<j & i)
266			ck0[j] += s;
267			if (r->rop[j] < ck0[j] - OCTSCALE*s)
268			break;
269			if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
270			break;
271			}
272			if (j == 3)
273	greg	1.16	wsum += sumambient(acol, r, al, at->kid+i, ck0, s);
274	greg	1.1	}
275			return(wsum);
276			}
277
278
279			double
280	greg	1.16	makeambient(acol, r, al) /* make a new ambient value */
281	greg	1.1	COLOR acol;
282			register RAY *r;
283	greg	1.16	int al;
284	greg	1.1	{
285	greg	2.12	AMBVAL amb;
286	greg	1.14	FVECT gp, gd;
287	greg	1.16	/* compute weight */
288			amb.weight = pow(AVGREFL, (double)al);
289	greg	1.17	if (r->rweight < 0.2amb.weight) / heuristic */
290	greg	1.16	amb.weight = r->rweight;
291			/* compute ambient */
292			amb.rad = doambient(acol, r, amb.weight, gp, gd);
293	greg	1.1	if (amb.rad == 0.0)
294			return(0.0);
295			/* store it */
296			VCOPY(amb.pos, r->rop);
297			VCOPY(amb.dir, r->ron);
298	greg	1.16	amb.lvl = al;
299	greg	1.1	copycolor(amb.val, acol);
300	greg	1.14	VCOPY(amb.gpos, gp);
301			VCOPY(amb.gdir, gd);
302	greg	1.1	/* insert into tree */
303	greg	2.7	avsave(&amb); /* and save to file */
304	greg	1.1	return(amb.rad);
305	greg	1.15	}
306
307
308			extambient(cr, ap, pv, nv) /* extrapolate value at pv, nv */
309			COLOR cr;
310	greg	2.12	register AMBVAL *ap;
311	greg	1.15	FVECT pv, nv;
312			{
313			FVECT v1, v2;
314			register int i;
315	greg	2.12	double d;
316	greg	1.15
317			d = 1.0; /* zeroeth order */
318			/* gradient due to translation */
319			for (i = 0; i < 3; i++)
320			d += ap->gpos[i]*(pv[i]-ap->pos[i]);
321			/* gradient due to rotation */
322			VCOPY(v1, ap->dir);
323			fcross(v2, v1, nv);
324			d += DOT(ap->gdir, v2);
325			if (d <= 0.0) {
326			setcolor(cr, 0.0, 0.0, 0.0);
327			return;
328			}
329			copycolor(cr, ap->val);
330			scalecolor(cr, d);
331	greg	1.1	}
332
333
334			static
335	greg	2.9	initambfile(creat) /* initialize ambient file */
336			int creat;
337			{
338			extern char progname, octname, VersionID[];
339
340	greg	2.19	#ifdef F_SETLKW
341			aflock(creat ? F_WRLCK : F_RDLCK);
342			#endif
343	greg	2.12	#ifdef MSDOS
344			setmode(fileno(ambfp), O_BINARY);
345			#endif
346	greg	2.9	setbuf(ambfp, bmalloc(BUFSIZ));
347			if (creat) { /* new file */
348			fprintf(ambfp, "%s -av %g %g %g -ab %d -aa %g ",
349			progname, colval(ambval,RED),
350			colval(ambval,GRN), colval(ambval,BLU),
351			ambounce, ambacc);
352			fprintf(ambfp, "-ad %d -as %d -ar %d %s\n",
353			ambdiv, ambssamp, ambres,
354			octname==NULL ? "" : octname);
355			fprintf(ambfp, "SOFTWARE= %s\n", VersionID);
356			fputformat(AMBFMT, ambfp);
357			putc('\n', ambfp);
358			putambmagic(ambfp);
359	greg	2.17	} else if (checkheader(ambfp, AMBFMT, NULL) < 0 \|\| !hasambmagic(ambfp))
360			error(USER, "bad ambient file");
361	greg	2.9	}
362
363
364			static
365	greg	2.7	avsave(av) /* insert and save an ambient value */
366	greg	2.12	AMBVAL *av;
367	greg	1.1	{
368	greg	2.20	avinsert(avstore(av), &atrunk, thescene.cuorg, thescene.cusize);
369	greg	1.1	if (ambfp == NULL)
370			return;
371	greg	2.5	if (writambval(av, ambfp) < 0)
372	greg	1.1	goto writerr;
373	greg	2.16	if (++nunflshed >= AMBFLUSH)
374	greg	2.7	if (ambsync() == EOF)
375	greg	1.1	goto writerr;
376			return;
377			writerr:
378	greg	2.17	error(SYSTEM, "error writing ambient file");
379	greg	1.1	}
380
381
382	greg	2.20	static AMBVAL *
383			avstore(aval) /* allocate memory and store aval */
384			register AMBVAL *aval;
385			{
386			register AMBVAL *av;
387
388			if ((av = newambval()) == NULL)
389			error(SYSTEM, "out of memory in avstore");
390			copystruct(av, aval);
391			return(av);
392			}
393
394
395	greg	1.1	static
396	greg	2.20	avinsert(av, at, c0, s) /* insert ambient value in a tree */
397			register AMBVAL *av;
398	greg	1.1	register AMBTREE *at;
399			FVECT c0;
400	greg	2.12	double s;
401	greg	1.1	{
402			FVECT ck0;
403			int branch;
404			register int i;
405
406	greg	2.20	if (av->rad <= FTINY)
407			error(CONSISTENCY, "zero ambient radius in avinsert");
408	greg	1.1	VCOPY(ck0, c0);
409			while (s(OCTSCALE/2) > av->radambacc) {
410			if (at->kid == NULL)
411			if ((at->kid = newambtree()) == NULL)
412	greg	2.20	error(SYSTEM, "out of memory in avinsert");
413	greg	1.1	s *= 0.5;
414			branch = 0;
415			for (i = 0; i < 3; i++)
416			if (av->pos[i] > ck0[i] + s) {
417			ck0[i] += s;
418			branch \|= 1 << i;
419			}
420			at = at->kid + branch;
421			}
422			av->next = at->alist;
423			at->alist = av;
424	greg	2.7	}
425
426
427	greg	2.20	static
428			loadtree(at) /* move tree to main store */
429			register AMBTREE *at;
430			{
431			register AMBVAL *av;
432			register int i;
433			/* transfer values at this node */
434			for (av = at->alist; av != NULL; av = at->alist) {
435			at->alist = av->next;
436			avinsert(av, &atrunk, thescene.cuorg, thescene.cusize);
437			}
438			for (i = 0; i < 8; i++) /* transfer and free children */
439			loadtree(at->kid+i);
440			freeambtree(at->kid);
441			}
442
443
444	greg	2.18	#ifdef F_SETLKW
445	greg	2.10
446	greg	2.19	static
447			aflock(typ) /* lock/unlock ambient file */
448			int typ;
449			{
450			static struct flock fls; /* static so initialized to zeroes */
451
452			fls.l_type = typ;
453			if (fcntl(fileno(ambfp), F_SETLKW, &fls) < 0)
454			error(SYSTEM, "cannot (un)lock ambient file");
455			}
456
457
458	greg	2.16	int
459	greg	2.7	ambsync() /* synchronize ambient file */
460			{
461			static FILE *ambinp = NULL;
462	greg	2.15	static long lastpos = -1;
463			long flen;
464	greg	2.12	AMBVAL avs;
465	greg	2.7	register int n;
466	greg	2.16
467			if (nunflshed == 0)
468			return(0);
469	greg	2.19	if (lastpos < 0) /* initializing (locked in initambfile) */
470			goto syncend;
471	greg	2.7	/* gain exclusive access */
472	greg	2.19	aflock(F_WRLCK);
473	greg	2.7	/* see if file has grown */
474	greg	2.15	if ((flen = lseek(fileno(ambfp), 0L, 2)) < 0)
475			error(SYSTEM, "cannot seek on ambient file");
476			if (n = flen - lastpos) { /* file has grown */
477	greg	2.17	if (ambinp == NULL) { /* use duplicate filedes */
478			ambinp = fdopen(dup(fileno(ambfp)), "r");
479	greg	2.14	if (ambinp == NULL)
480	greg	2.17	error(SYSTEM, "fdopen failed in ambsync");
481	greg	2.14	}
482	greg	2.15	if (fseek(ambinp, lastpos, 0) < 0)
483			error(SYSTEM, "fseek failed in ambsync");
484			while (n >= AMBVALSIZ) { /* load contributed values */
485	greg	2.7	readambval(&avs, ambinp);
486	greg	2.20	avinsert(avstore(&avs), &atrunk,
487			thescene.cuorg, thescene.cusize);
488	greg	2.15	n -= AMBVALSIZ;
489			}
490			if (n) /* alignment */
491	greg	2.10	lseek(fileno(ambfp), flen-n, 0);
492	greg	2.7	}
493	greg	2.15	syncend:
494	greg	2.7	n = fflush(ambfp); /* calls write() at last */
495	greg	2.15	lastpos = lseek(fileno(ambfp), 0L, 1);
496	greg	2.19	aflock(F_UNLCK); /* release file */
497	greg	2.16	nunflshed = 0;
498	greg	2.7	return(n);
499	greg	2.18	}
500
501			#else
502
503			int
504			ambsync() /* flush ambient file */
505			{
506			if (nunflshed == 0)
507			return(0);
508			nunflshed = 0;
509			return(fflush(ambfp));
510	greg	1.1	}
511	greg	2.10
512			#endif