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 */

extern char  *shm_boundary;     /* shared memory boundary */

#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 */

#ifndef SORT_THRESH
#ifdef BIGMEM
#define SORT_THRESH     (6*(1L<<20)/sizeof(AMBVAL))
#else
#define SORT_THRESH     (2*(1L<<20)/sizeof(AMBVAL))
#endif
#endif
#ifndef SORT_INTVL
#define SORT_INTVL      (SORT_THRESH*2)
#endif

static long  ambclock = 0;      /* ambient access clock */
static int  nambvals = 0;       /* number of stored ambient values */
static long  lastsort = 0;      /* time of last value sort */
static long  sortintvl = SORT_INTVL;    /* time until next sort */

#define MAXACLOCK       (1L<<30)        /* clock turnover value */
#define tracktime       (shm_boundary == NULL || ambfp == NULL)
#define need2sort       (ambclock > lastsort+sortintvl && \
                                nambvals > SORT_THRESH)

#define  AMBFLUSH       (BUFSIZ/AMBVALSIZ)

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

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


setambres(ar)                           /* set ambient resolution */
int  ar;
{
        ambres = ar < 0 ? 0 : ar;               /* may be done already */
                                                /* set min & max radii */
        if (ar <= 0) {
                minarad = 0;
                maxarad = thescene.cusize / 2.0;
        } else {
                minarad = thescene.cusize / ar;
                maxarad = 16 * minarad;                 /* heuristic */
                if (maxarad > thescene.cusize / 2.0)
                        maxarad = thescene.cusize / 2.0;
        }
        if (minarad <= FTINY)
                minarad = 10*FTINY;
        if (maxarad <= minarad)
                maxarad = 64 * minarad;
}


setambacc(newa)                         /* set ambient accuracy */
double  newa;
{
        static double  oldambacc = -1.0;

        ambacc = newa < 0.0 ? 0.0 : newa;       /* may be done already */
        if (oldambacc < -FTINY)
                oldambacc = ambacc;     /* do nothing first call */
        if (fabs(newa - oldambacc) < 0.01)
                return;                 /* insignificant -- don't bother */
        if (ambacc <= FTINY)
                return;                 /* cannot build new tree */
                                        /* else need to rebuild tree */
        sortambvals(1);
        oldambacc = ambacc;             /* remeber setting for next call */
}


setambient(afile)                       /* initialize calculation */
char  *afile;
{
        long  headlen;
        AMBVAL  amb;
                                                /* init ambient limits */
        setambres(ambres);
        setambacc(ambacc);
        if (afile == NULL)
                return;
        if (ambacc <= FTINY) {
                sprintf(errmsg, "zero ambient accuracy so \"%s\" not opened",
                                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));
                                                /* 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 */
        if (need2sort)
                sortambvals(0);
        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) {
                if (tracktime)
                        av->latick = ambclock++;
                /*
                 *  Ambient level test.
                 */
                if (av->lvl > al)       /* list sorted, so this works */
                        break;
                if (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+8));
        if (creat) {                    /* new file */
                newheader("RADIANCE", ambfp);
                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));
        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);
        av->latick = ambclock;
        av->next = NULL;
        nambvals++;
        return(av);
}


#define ATALLOCSZ       512             /* #/8 trees to allocate at once */

static AMBTREE  *atfreelist = NULL;     /* free ambient tree structures */


static
AMBTREE *
newambtree()                            /* allocate 8 ambient tree structs */
{
        register AMBTREE  *atp, *upperlim;

        if (atfreelist == NULL) {       /* get more nodes */
                atfreelist = (AMBTREE *)bmalloc(ATALLOCSZ*8*sizeof(AMBTREE));
                if (atfreelist == NULL)
                        return(NULL);
                                        /* link new free list */
                upperlim = atfreelist + 8*(ATALLOCSZ-1);
                for (atp = atfreelist; atp < upperlim; atp += 8)
                        atp->kid = atp + 8;
                atp->kid = NULL;
        }
        atp = atfreelist;
        atfreelist = atp->kid;
        bzero((char *)atp, 8*sizeof(AMBTREE));
        return(atp);
}


static
freeambtree(atp)                        /* free 8 ambient tree structs */
AMBTREE  *atp;
{
        atp->kid = atfreelist;
        atfreelist = atp;
}


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

        if (av->rad <= FTINY)
                error(CONSISTENCY, "zero ambient radius in avinsert");
        at = &atrunk;
        VCOPY(ck0, thescene.cuorg);
        s = thescene.cusize;
        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;
        }
        avh.next = at->alist;           /* order by increasing level */
        for (ap = &avh; ap->next != NULL; ap = ap->next)
                if (ap->next->lvl >= av->lvl)
                        break;
        av->next = ap->next;
        ap->next = av;
        at->alist = avh.next;
}


static
unloadatree(at, f)                      /* unload an ambient value tree */
register AMBTREE  *at;
int     (*f)();
{
        register AMBVAL  *av;
        register int  i;
                                        /* transfer values at this node */
        for (av = at->alist; av != NULL; av = at->alist) {
                at->alist = av->next;
                (*f)(av);
        }
        if (at->kid == NULL)
                return;
        for (i = 0; i < 8; i++)         /* transfer and free children */
                unloadatree(at->kid+i, f);
        freeambtree(at->kid);
        at->kid = NULL;
}


static AMBVAL   **avlist1, **avlist2;   /* ambient value lists for sorting */
static int      i_avlist;               /* index for lists */


static
av2list(av)
AMBVAL  *av;
{
        if (i_avlist >= nambvals)
                error(CONSISTENCY, "too many ambient values in av2list1");
        avlist1[i_avlist] = avlist2[i_avlist] = av;
        i_avlist++;
}


static int
alatcmp(avp1, avp2)                     /* compare ambient values for MRA */
AMBVAL  **avp1, **avp2;
{
        return((**avp2).latick - (**avp1).latick);
}


static int
aposcmp(avp1, avp2)                     /* compare ambient value positions */
AMBVAL  **avp1, **avp2;
{
        return(*avp1 - *avp2);
}


static
sortambvals(always)                     /* resort ambient values */
int     always;
{
        AMBTREE  oldatrunk;
        AMBVAL  tav, *tap, *pnext;
        register int    i, j;
        /*
         * The idea here is to minimize memory thrashing
         * in VM systems by improving reference locality.
         * We do this by periodically sorting our stored ambient
         * values in memory in order of most recently to least
         * recently accessed.  This ordering was chosen so that new
         * ambient values (which tend to be less important) go into
         * higher memory with the infrequently accessed values.
         *      Since we expect our values to need sorting less
         * frequently as the process continues, we double our
         * waiting interval after each call.
         *      This routine is also called by setambacc() with
         * the "always" parameter set to 1 so that the ambient
         * tree will be rebuilt with the new accuracy parameter.
         */
        if (tracktime) {
                avlist1 = (AMBVAL **)malloc(nambvals*sizeof(AMBVAL *));
                avlist2 = (AMBVAL **)malloc(nambvals*sizeof(AMBVAL *));
        } else
                avlist1 = avlist2 = NULL;
        if (avlist2 == NULL) {          /* rebuild tree? */
                if (avlist1 != NULL)
                        free((char *)avlist1);
                if (!always)
                        return;
                copystruct(&oldatrunk, &atrunk);
                atrunk.alist = NULL;
                atrunk.kid = NULL;
                unloadatree(&oldatrunk, avinsert);
        } else {                        /* sort memory by last access time */
                i_avlist = 0;
                unloadatree(&atrunk, av2list);  /* empty current tree */
                /*
                 * Sorting memory is tricky because it isn't contiguous.
                 * We have to sort an array of pointers by MRA and also
                 * by memory position.  We then copy values in "loops"
                 * to minimize memory hits.  Nevertheless, we will visit
                 * everyone at least once, and this is an expensive process
                 * when we're thrashing, which is when we need to do it.
                 */
                qsort((char *)avlist1, nambvals, sizeof(AMBVAL *), alatcmp);
                qsort((char *)avlist2, nambvals, sizeof(AMBVAL *), aposcmp);
                for (i = 0; i < nambvals; i++) {
                        if (avlist1[i] == NULL || avlist1[i] == avlist2[i])
                                continue;
                        tap = avlist2[i];
                        copystruct(&tav, tap);
                        for (j = i; (pnext = avlist1[j]) != tap;
                                        j = (AMBVAL **)bsearch((char *)&pnext,
                                                (char *)(avlist2+i),nambvals-i,
                                                sizeof(AMBVAL *),aposcmp) -
                                                avlist2) {
                                copystruct(avlist2[j], pnext);
                                avinsert(avlist2[j]);
                                avlist1[j] = NULL;
                        }
                        copystruct(avlist2[j], &tav);
                        avinsert(avlist2[j]);
                        avlist1[j] = NULL;
                }
                free((char *)avlist1);
                free((char *)avlist2);
                if (sortintvl < MAXACLOCK/4)
                        sortintvl <<= 1;        /* wait twice as long next */
        }
        if (ambclock >= MAXACLOCK)
                ambclock = MAXACLOCK/2;
        lastsort = ambclock;
}


#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)
                goto seekerr;
        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)
                        goto seekerr;
                while (n >= AMBVALSIZ) {        /* load contributed values */
                        readambval(&avs, ambinp);
                        avinsert(avstore(&avs));
                        n -= AMBVALSIZ;
                }
                /*** seek always as safety measure
                if (n) ***/                     /* alignment */
                        if (lseek(fileno(ambfp), flen-n, 0) < 0)
                                goto seekerr;
        }
#ifdef  DEBUG
        if (ambfp->_ptr - ambfp->_base != nunflshed*AMBVALSIZ) {
                sprintf(errmsg, "ambient file buffer at %d rather than %d",
                                ambfp->_ptr - ambfp->_base,
                                nunflshed*AMBVALSIZ);
                error(CONSISTENCY, errmsg);
        }
#endif
syncend:
        n = fflush(ambfp);                      /* calls write() at last */
        if ((lastpos = lseek(fileno(ambfp), 0L, 1)) < 0)
                goto seekerr;
        aflock(F_UNLCK);                        /* release file */
        nunflshed = 0;
        return(n);
seekerr:
        error(SYSTEM, "seek failed in ambsync");
}

#else

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

#endif
Revision:	2.26
Committed:	Thu Apr 27 14:12:05 1995 UTC (29 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.25:	+183 -12 lines
Log Message:	added memory sorting to ambient caching module
#	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	2.26	extern char shm_boundary; / shared memory boundary */
31
32	greg	2.12	#define MAXASET 511 /* maximum number of elements in ambient set */
33			OBJECT ambset[MAXASET+1]={0}; /* ambient include/exclude set */
34	greg	1.1
35	greg	2.12	double maxarad; /* maximum ambient radius */
36			double minarad; /* minimum ambient radius */
37	greg	1.1
38	greg	2.12	static AMBTREE atrunk; /* our ambient trunk node */
39	greg	1.1
40			static FILE ambfp = NULL; / ambient file pointer */
41	greg	2.16	static int nunflshed = 0; /* number of unflushed ambient values */
42	greg	1.1
43	greg	2.26	#ifndef SORT_THRESH
44			#ifdef BIGMEM
45			#define SORT_THRESH (6*(1L<<20)/sizeof(AMBVAL))
46			#else
47			#define SORT_THRESH (2*(1L<<20)/sizeof(AMBVAL))
48			#endif
49			#endif
50			#ifndef SORT_INTVL
51			#define SORT_INTVL (SORT_THRESH*2)
52			#endif
53
54			static long ambclock = 0; /* ambient access clock */
55			static int nambvals = 0; /* number of stored ambient values */
56			static long lastsort = 0; /* time of last value sort */
57			static long sortintvl = SORT_INTVL; /* time until next sort */
58
59			#define MAXACLOCK (1L<<30) /* clock turnover value */
60			#define tracktime (shm_boundary == NULL \|\| ambfp == NULL)
61			#define need2sort (ambclock > lastsort+sortintvl && \
62			nambvals > SORT_THRESH)
63
64	greg	2.12	#define AMBFLUSH (BUFSIZ/AMBVALSIZ)
65	greg	2.6
66	greg	2.12	#define newambval() (AMBVAL *)bmalloc(sizeof(AMBVAL))
67	greg	1.1
68	greg	2.7	extern long ftell(), lseek();
69	greg	2.26	static int initambfile(), avsave(), avinsert(), sortambvals();
70	greg	2.20	static AMBVAL *avstore();
71	greg	2.19	#ifdef F_SETLKW
72			static aflock();
73			#endif
74	greg	1.1
75	greg	2.7
76	greg	2.3	setambres(ar) /* set ambient resolution */
77			int ar;
78			{
79	greg	2.21	ambres = ar < 0 ? 0 : ar; /* may be done already */
80	greg	2.3	/* set min & max radii */
81			if (ar <= 0) {
82	greg	2.25	minarad = 0;
83	greg	2.3	maxarad = thescene.cusize / 2.0;
84			} else {
85			minarad = thescene.cusize / ar;
86	greg	2.25	maxarad = 16 * minarad; /* heuristic */
87	greg	2.3	if (maxarad > thescene.cusize / 2.0)
88			maxarad = thescene.cusize / 2.0;
89			}
90	greg	2.25	if (minarad <= FTINY)
91			minarad = 10*FTINY;
92			if (maxarad <= minarad)
93			maxarad = 64 * minarad;
94	greg	2.3	}
95
96
97	greg	2.21	setambacc(newa) /* set ambient accuracy */
98	greg	2.20	double newa;
99			{
100	greg	2.21	static double oldambacc = -1.0;
101	greg	2.20
102	greg	2.21	ambacc = newa < 0.0 ? 0.0 : newa; /* may be done already */
103			if (oldambacc < -FTINY)
104			oldambacc = ambacc; /* do nothing first call */
105			if (fabs(newa - oldambacc) < 0.01)
106	greg	2.20	return; /* insignificant -- don't bother */
107			if (ambacc <= FTINY)
108			return; /* cannot build new tree */
109			/* else need to rebuild tree */
110	greg	2.26	sortambvals(1);
111	greg	2.21	oldambacc = ambacc; /* remeber setting for next call */
112	greg	2.20	}
113
114
115	greg	1.1	setambient(afile) /* initialize calculation */
116			char *afile;
117			{
118	greg	2.9	long headlen;
119	greg	2.12	AMBVAL amb;
120	greg	2.3	/* init ambient limits */
121			setambres(ambres);
122	greg	2.21	setambacc(ambacc);
123	greg	2.19	if (afile == NULL)
124			return;
125	greg	2.20	if (ambacc <= FTINY) {
126	greg	2.21	sprintf(errmsg, "zero ambient accuracy so \"%s\" not opened",
127	greg	2.20	afile);
128			error(WARNING, errmsg);
129			return;
130			}
131	greg	2.3	/* open ambient file */
132	greg	2.19	if ((ambfp = fopen(afile, "r+")) != NULL) {
133			initambfile(0);
134			headlen = ftell(ambfp);
135			while (readambval(&amb, ambfp))
136	greg	2.21	avinsert(avstore(&amb));
137	greg	2.19	/* align */
138			fseek(ambfp, -((ftell(ambfp)-headlen)%AMBVALSIZ), 1);
139			} else if ((ambfp = fopen(afile, "w+")) != NULL)
140			initambfile(1);
141			else {
142			sprintf(errmsg, "cannot open ambient file \"%s\"", afile);
143			error(SYSTEM, errmsg);
144	greg	2.16	}
145	greg	2.19	nunflshed++; /* lie */
146			ambsync();
147	greg	1.8	}
148
149
150			ambnotify(obj) /* record new modifier */
151	greg	2.12	OBJECT obj;
152	greg	1.8	{
153	greg	1.11	static int hitlimit = 0;
154	greg	2.12	register OBJREC *o = objptr(obj);
155	greg	1.8	register char **amblp;
156
157	greg	1.11	if (hitlimit \|\| !ismodifier(o->otype))
158	greg	1.8	return;
159			for (amblp = amblist; *amblp != NULL; amblp++)
160			if (!strcmp(o->oname, *amblp)) {
161	greg	1.11	if (ambset[0] >= MAXASET) {
162			error(WARNING, "too many modifiers in ambient list");
163			hitlimit++;
164			return; /* should this be fatal? */
165			}
166	greg	1.8	insertelem(ambset, obj);
167			return;
168	greg	1.1	}
169			}
170
171
172			ambient(acol, r) /* compute ambient component for ray */
173			COLOR acol;
174			register RAY *r;
175			{
176			static int rdepth = 0; /* ambient recursion */
177	greg	2.12	double d;
178	greg	1.1
179			if (ambdiv <= 0) /* no ambient calculation */
180			goto dumbamb;
181			/* check number of bounces */
182	greg	1.16	if (rdepth >= ambounce)
183	greg	1.1	goto dumbamb;
184			/* check ambient list */
185			if (ambincl != -1 && r->ro != NULL &&
186			ambincl != inset(ambset, r->ro->omod))
187			goto dumbamb;
188
189			if (ambacc <= FTINY) { /* no ambient storage */
190	greg	1.16	rdepth++;
191			d = doambient(acol, r, r->rweight, NULL, NULL);
192			rdepth--;
193			if (d == 0.0)
194	greg	1.1	goto dumbamb;
195	greg	1.16	return;
196	greg	1.1	}
197			/* get ambient value */
198	greg	2.26	if (need2sort)
199			sortambvals(0);
200	greg	1.1	setcolor(acol, 0.0, 0.0, 0.0);
201	greg	1.16	d = sumambient(acol, r, rdepth,
202			&atrunk, thescene.cuorg, thescene.cusize);
203			if (d > FTINY)
204			scalecolor(acol, 1.0/d);
205			else {
206			d = makeambient(acol, r, rdepth++);
207			rdepth--;
208			}
209			if (d > FTINY)
210			return;
211	greg	1.1	dumbamb: /* return global value */
212			copycolor(acol, ambval);
213			}
214
215
216			double
217	greg	1.16	sumambient(acol, r, al, at, c0, s) /* get interpolated ambient value */
218	greg	1.1	COLOR acol;
219			register RAY *r;
220	greg	1.16	int al;
221	greg	2.12	AMBTREE *at;
222	greg	1.1	FVECT c0;
223	greg	2.12	double s;
224	greg	1.1	{
225	greg	2.12	double d, e1, e2, wt, wsum;
226	greg	1.1	COLOR ct;
227			FVECT ck0;
228			int i;
229			register int j;
230	greg	2.12	register AMBVAL *av;
231	greg	1.7	/* do this node */
232	greg	1.1	wsum = 0.0;
233			for (av = at->alist; av != NULL; av = av->next) {
234	greg	2.26	if (tracktime)
235			av->latick = ambclock++;
236	greg	1.1	/*
237	greg	1.16	* Ambient level test.
238	greg	1.1	*/
239	greg	2.23	if (av->lvl > al) /* list sorted, so this works */
240			break;
241			if (av->weight < r->rweight-FTINY)
242	greg	1.1	continue;
243			/*
244			* Ambient radius test.
245			*/
246			e1 = 0.0;
247			for (j = 0; j < 3; j++) {
248			d = av->pos[j] - r->rop[j];
249			e1 += d * d;
250			}
251			e1 /= av->rad * av->rad;
252			if (e1 > ambaccambacc1.21)
253			continue;
254			/*
255			* Normal direction test.
256			*/
257			e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight;
258			if (e2 < 0.0) e2 = 0.0;
259			if (e1 + e2 > ambaccambacc1.21)
260			continue;
261			/*
262			* Ray behind test.
263			*/
264			d = 0.0;
265			for (j = 0; j < 3; j++)
266			d += (r->rop[j] - av->pos[j]) *
267			(av->dir[j] + r->ron[j]);
268	greg	1.18	if (d0.5 < -minaradambacc-.001)
269	greg	1.1	continue;
270			/*
271			* Jittering final test reduces image artifacts.
272			*/
273			wt = sqrt(e1) + sqrt(e2);
274	greg	2.2	wt = .9 + .2urand(9015+samplendx);
275	greg	1.6	if (wt > ambacc)
276	greg	1.1	continue;
277			if (wt <= 1e-3)
278			wt = 1e3;
279			else
280			wt = 1.0 / wt;
281			wsum += wt;
282	greg	1.15	extambient(ct, av, r->rop, r->ron);
283	greg	1.1	scalecolor(ct, wt);
284			addcolor(acol, ct);
285	greg	1.7	}
286			if (at->kid == NULL)
287			return(wsum);
288			/* do children */
289			s *= 0.5;
290			for (i = 0; i < 8; i++) {
291			for (j = 0; j < 3; j++) {
292			ck0[j] = c0[j];
293			if (1<<j & i)
294			ck0[j] += s;
295			if (r->rop[j] < ck0[j] - OCTSCALE*s)
296			break;
297			if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s)
298			break;
299			}
300			if (j == 3)
301	greg	1.16	wsum += sumambient(acol, r, al, at->kid+i, ck0, s);
302	greg	1.1	}
303			return(wsum);
304			}
305
306
307			double
308	greg	1.16	makeambient(acol, r, al) /* make a new ambient value */
309	greg	1.1	COLOR acol;
310			register RAY *r;
311	greg	1.16	int al;
312	greg	1.1	{
313	greg	2.12	AMBVAL amb;
314	greg	1.14	FVECT gp, gd;
315	greg	1.16	/* compute weight */
316			amb.weight = pow(AVGREFL, (double)al);
317	greg	1.17	if (r->rweight < 0.2amb.weight) / heuristic */
318	greg	1.16	amb.weight = r->rweight;
319			/* compute ambient */
320			amb.rad = doambient(acol, r, amb.weight, gp, gd);
321	greg	1.1	if (amb.rad == 0.0)
322			return(0.0);
323			/* store it */
324			VCOPY(amb.pos, r->rop);
325			VCOPY(amb.dir, r->ron);
326	greg	1.16	amb.lvl = al;
327	greg	1.1	copycolor(amb.val, acol);
328	greg	1.14	VCOPY(amb.gpos, gp);
329			VCOPY(amb.gdir, gd);
330	greg	1.1	/* insert into tree */
331	greg	2.7	avsave(&amb); /* and save to file */
332	greg	1.1	return(amb.rad);
333	greg	1.15	}
334
335
336			extambient(cr, ap, pv, nv) /* extrapolate value at pv, nv */
337			COLOR cr;
338	greg	2.12	register AMBVAL *ap;
339	greg	1.15	FVECT pv, nv;
340			{
341			FVECT v1, v2;
342			register int i;
343	greg	2.12	double d;
344	greg	1.15
345			d = 1.0; /* zeroeth order */
346			/* gradient due to translation */
347			for (i = 0; i < 3; i++)
348			d += ap->gpos[i]*(pv[i]-ap->pos[i]);
349			/* gradient due to rotation */
350			VCOPY(v1, ap->dir);
351			fcross(v2, v1, nv);
352			d += DOT(ap->gdir, v2);
353			if (d <= 0.0) {
354			setcolor(cr, 0.0, 0.0, 0.0);
355			return;
356			}
357			copycolor(cr, ap->val);
358			scalecolor(cr, d);
359	greg	1.1	}
360
361
362			static
363	greg	2.9	initambfile(creat) /* initialize ambient file */
364			int creat;
365			{
366			extern char progname, octname, VersionID[];
367
368	greg	2.19	#ifdef F_SETLKW
369			aflock(creat ? F_WRLCK : F_RDLCK);
370			#endif
371	greg	2.12	#ifdef MSDOS
372			setmode(fileno(ambfp), O_BINARY);
373			#endif
374	greg	2.21	setbuf(ambfp, bmalloc(BUFSIZ+8));
375	greg	2.9	if (creat) { /* new file */
376	greg	2.24	newheader("RADIANCE", ambfp);
377	greg	2.9	fprintf(ambfp, "%s -av %g %g %g -ab %d -aa %g ",
378			progname, colval(ambval,RED),
379			colval(ambval,GRN), colval(ambval,BLU),
380			ambounce, ambacc);
381			fprintf(ambfp, "-ad %d -as %d -ar %d %s\n",
382			ambdiv, ambssamp, ambres,
383			octname==NULL ? "" : octname);
384			fprintf(ambfp, "SOFTWARE= %s\n", VersionID);
385			fputformat(AMBFMT, ambfp);
386			putc('\n', ambfp);
387			putambmagic(ambfp);
388	greg	2.17	} else if (checkheader(ambfp, AMBFMT, NULL) < 0 \|\| !hasambmagic(ambfp))
389			error(USER, "bad ambient file");
390	greg	2.9	}
391
392
393			static
394	greg	2.7	avsave(av) /* insert and save an ambient value */
395	greg	2.12	AMBVAL *av;
396	greg	1.1	{
397	greg	2.21	avinsert(avstore(av));
398	greg	1.1	if (ambfp == NULL)
399			return;
400	greg	2.5	if (writambval(av, ambfp) < 0)
401	greg	1.1	goto writerr;
402	greg	2.16	if (++nunflshed >= AMBFLUSH)
403	greg	2.7	if (ambsync() == EOF)
404	greg	1.1	goto writerr;
405			return;
406			writerr:
407	greg	2.17	error(SYSTEM, "error writing ambient file");
408	greg	1.1	}
409
410
411	greg	2.20	static AMBVAL *
412			avstore(aval) /* allocate memory and store aval */
413			register AMBVAL *aval;
414			{
415			register AMBVAL *av;
416
417			if ((av = newambval()) == NULL)
418			error(SYSTEM, "out of memory in avstore");
419			copystruct(av, aval);
420	greg	2.26	av->latick = ambclock;
421			av->next = NULL;
422			nambvals++;
423	greg	2.20	return(av);
424			}
425
426
427	greg	2.26	#define ATALLOCSZ 512 /* #/8 trees to allocate at once */
428
429			static AMBTREE atfreelist = NULL; / free ambient tree structures */
430
431
432	greg	1.1	static
433	greg	2.26	AMBTREE *
434			newambtree() /* allocate 8 ambient tree structs */
435			{
436			register AMBTREE atp, upperlim;
437
438			if (atfreelist == NULL) { /* get more nodes */
439			atfreelist = (AMBTREE )bmalloc(ATALLOCSZ8*sizeof(AMBTREE));
440			if (atfreelist == NULL)
441			return(NULL);
442			/* link new free list */
443			upperlim = atfreelist + 8*(ATALLOCSZ-1);
444			for (atp = atfreelist; atp < upperlim; atp += 8)
445			atp->kid = atp + 8;
446			atp->kid = NULL;
447			}
448			atp = atfreelist;
449			atfreelist = atp->kid;
450			bzero((char )atp, 8sizeof(AMBTREE));
451			return(atp);
452			}
453
454
455			static
456			freeambtree(atp) /* free 8 ambient tree structs */
457			AMBTREE *atp;
458			{
459			atp->kid = atfreelist;
460			atfreelist = atp;
461			}
462
463
464			static
465	greg	2.21	avinsert(av) /* insert ambient value in our tree */
466	greg	2.20	register AMBVAL *av;
467	greg	1.1	{
468	greg	2.21	register AMBTREE *at;
469	greg	2.23	register AMBVAL *ap;
470			AMBVAL avh;
471	greg	1.1	FVECT ck0;
472	greg	2.21	double s;
473	greg	1.1	int branch;
474			register int i;
475
476	greg	2.20	if (av->rad <= FTINY)
477			error(CONSISTENCY, "zero ambient radius in avinsert");
478	greg	2.21	at = &atrunk;
479			VCOPY(ck0, thescene.cuorg);
480			s = thescene.cusize;
481	greg	1.1	while (s(OCTSCALE/2) > av->radambacc) {
482			if (at->kid == NULL)
483			if ((at->kid = newambtree()) == NULL)
484	greg	2.20	error(SYSTEM, "out of memory in avinsert");
485	greg	1.1	s *= 0.5;
486			branch = 0;
487			for (i = 0; i < 3; i++)
488			if (av->pos[i] > ck0[i] + s) {
489			ck0[i] += s;
490			branch \|= 1 << i;
491			}
492			at = at->kid + branch;
493			}
494	greg	2.23	avh.next = at->alist; /* order by increasing level */
495			for (ap = &avh; ap->next != NULL; ap = ap->next)
496			if (ap->next->lvl >= av->lvl)
497			break;
498			av->next = ap->next;
499			ap->next = av;
500			at->alist = avh.next;
501	greg	2.7	}
502
503
504	greg	2.20	static
505	greg	2.26	unloadatree(at, f) /* unload an ambient value tree */
506	greg	2.20	register AMBTREE *at;
507	greg	2.26	int (*f)();
508	greg	2.20	{
509			register AMBVAL *av;
510			register int i;
511			/* transfer values at this node */
512			for (av = at->alist; av != NULL; av = at->alist) {
513			at->alist = av->next;
514	greg	2.26	(*f)(av);
515	greg	2.20	}
516	greg	2.21	if (at->kid == NULL)
517			return;
518	greg	2.20	for (i = 0; i < 8; i++) /* transfer and free children */
519	greg	2.26	unloadatree(at->kid+i, f);
520	greg	2.20	freeambtree(at->kid);
521	greg	2.26	at->kid = NULL;
522			}
523
524
525			static AMBVAL avlist1, avlist2; /* ambient value lists for sorting */
526			static int i_avlist; /* index for lists */
527
528
529			static
530			av2list(av)
531			AMBVAL *av;
532			{
533			if (i_avlist >= nambvals)
534			error(CONSISTENCY, "too many ambient values in av2list1");
535			avlist1[i_avlist] = avlist2[i_avlist] = av;
536			i_avlist++;
537			}
538
539
540			static int
541			alatcmp(avp1, avp2) /* compare ambient values for MRA */
542			AMBVAL avp1, avp2;
543			{
544			return((avp2).latick - (avp1).latick);
545			}
546
547
548			static int
549			aposcmp(avp1, avp2) /* compare ambient value positions */
550			AMBVAL avp1, avp2;
551			{
552			return(avp1 - avp2);
553			}
554
555
556			static
557			sortambvals(always) /* resort ambient values */
558			int always;
559			{
560			AMBTREE oldatrunk;
561			AMBVAL tav, tap, pnext;
562			register int i, j;
563			/*
564			* The idea here is to minimize memory thrashing
565			* in VM systems by improving reference locality.
566			* We do this by periodically sorting our stored ambient
567			* values in memory in order of most recently to least
568			* recently accessed. This ordering was chosen so that new
569			* ambient values (which tend to be less important) go into
570			* higher memory with the infrequently accessed values.
571			* Since we expect our values to need sorting less
572			* frequently as the process continues, we double our
573			* waiting interval after each call.
574			* This routine is also called by setambacc() with
575			* the "always" parameter set to 1 so that the ambient
576			* tree will be rebuilt with the new accuracy parameter.
577			*/
578			if (tracktime) {
579			avlist1 = (AMBVAL *)malloc(nambvalssizeof(AMBVAL *));
580			avlist2 = (AMBVAL *)malloc(nambvalssizeof(AMBVAL *));
581			} else
582			avlist1 = avlist2 = NULL;
583			if (avlist2 == NULL) { /* rebuild tree? */
584			if (avlist1 != NULL)
585			free((char *)avlist1);
586			if (!always)
587			return;
588			copystruct(&oldatrunk, &atrunk);
589			atrunk.alist = NULL;
590			atrunk.kid = NULL;
591			unloadatree(&oldatrunk, avinsert);
592			} else { /* sort memory by last access time */
593			i_avlist = 0;
594			unloadatree(&atrunk, av2list); /* empty current tree */
595			/*
596			* Sorting memory is tricky because it isn't contiguous.
597			* We have to sort an array of pointers by MRA and also
598			* by memory position. We then copy values in "loops"
599			* to minimize memory hits. Nevertheless, we will visit
600			* everyone at least once, and this is an expensive process
601			* when we're thrashing, which is when we need to do it.
602			*/
603			qsort((char )avlist1, nambvals, sizeof(AMBVAL ), alatcmp);
604			qsort((char )avlist2, nambvals, sizeof(AMBVAL ), aposcmp);
605			for (i = 0; i < nambvals; i++) {
606			if (avlist1[i] == NULL \|\| avlist1[i] == avlist2[i])
607			continue;
608			tap = avlist2[i];
609			copystruct(&tav, tap);
610			for (j = i; (pnext = avlist1[j]) != tap;
611			j = (AMBVAL *)bsearch((char )&pnext,
612			(char *)(avlist2+i),nambvals-i,
613			sizeof(AMBVAL *),aposcmp) -
614			avlist2) {
615			copystruct(avlist2[j], pnext);
616			avinsert(avlist2[j]);
617			avlist1[j] = NULL;
618			}
619			copystruct(avlist2[j], &tav);
620			avinsert(avlist2[j]);
621			avlist1[j] = NULL;
622			}
623			free((char *)avlist1);
624			free((char *)avlist2);
625			if (sortintvl < MAXACLOCK/4)
626			sortintvl <<= 1; /* wait twice as long next */
627			}
628			if (ambclock >= MAXACLOCK)
629			ambclock = MAXACLOCK/2;
630			lastsort = ambclock;
631	greg	2.20	}
632
633
634	greg	2.18	#ifdef F_SETLKW
635	greg	2.10
636	greg	2.19	static
637			aflock(typ) /* lock/unlock ambient file */
638			int typ;
639			{
640			static struct flock fls; /* static so initialized to zeroes */
641
642			fls.l_type = typ;
643			if (fcntl(fileno(ambfp), F_SETLKW, &fls) < 0)
644			error(SYSTEM, "cannot (un)lock ambient file");
645			}
646
647
648	greg	2.16	int
649	greg	2.7	ambsync() /* synchronize ambient file */
650			{
651			static FILE *ambinp = NULL;
652	greg	2.15	static long lastpos = -1;
653			long flen;
654	greg	2.12	AMBVAL avs;
655	greg	2.7	register int n;
656	greg	2.16
657			if (nunflshed == 0)
658			return(0);
659	greg	2.19	if (lastpos < 0) /* initializing (locked in initambfile) */
660			goto syncend;
661	greg	2.7	/* gain exclusive access */
662	greg	2.19	aflock(F_WRLCK);
663	greg	2.7	/* see if file has grown */
664	greg	2.15	if ((flen = lseek(fileno(ambfp), 0L, 2)) < 0)
665	greg	2.21	goto seekerr;
666	greg	2.15	if (n = flen - lastpos) { /* file has grown */
667	greg	2.17	if (ambinp == NULL) { /* use duplicate filedes */
668			ambinp = fdopen(dup(fileno(ambfp)), "r");
669	greg	2.14	if (ambinp == NULL)
670	greg	2.17	error(SYSTEM, "fdopen failed in ambsync");
671	greg	2.14	}
672	greg	2.15	if (fseek(ambinp, lastpos, 0) < 0)
673	greg	2.21	goto seekerr;
674	greg	2.15	while (n >= AMBVALSIZ) { /* load contributed values */
675	greg	2.7	readambval(&avs, ambinp);
676	greg	2.21	avinsert(avstore(&avs));
677	greg	2.15	n -= AMBVALSIZ;
678			}
679	greg	2.22	/*** seek always as safety measure
680			if (n) **/ / alignment */
681	greg	2.21	if (lseek(fileno(ambfp), flen-n, 0) < 0)
682			goto seekerr;
683	greg	2.7	}
684	greg	2.21	#ifdef DEBUG
685			if (ambfp->_ptr - ambfp->_base != nunflshed*AMBVALSIZ) {
686			sprintf(errmsg, "ambient file buffer at %d rather than %d",
687			ambfp->_ptr - ambfp->_base,
688			nunflshed*AMBVALSIZ);
689			error(CONSISTENCY, errmsg);
690			}
691			#endif
692	greg	2.15	syncend:
693	greg	2.7	n = fflush(ambfp); /* calls write() at last */
694	greg	2.21	if ((lastpos = lseek(fileno(ambfp), 0L, 1)) < 0)
695			goto seekerr;
696	greg	2.19	aflock(F_UNLCK); /* release file */
697	greg	2.16	nunflshed = 0;
698	greg	2.7	return(n);
699	greg	2.21	seekerr:
700			error(SYSTEM, "seek failed in ambsync");
701	greg	2.18	}
702
703			#else
704
705			int
706			ambsync() /* flush ambient file */
707			{
708			if (nunflshed == 0)
709			return(0);
710			nunflshed = 0;
711			return(fflush(ambfp));
712	greg	1.1	}
713	greg	2.10
714			#endif