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root/radiance/ray/src/rt/ambient.c
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Comparing ray/src/rt/ambient.c (file contents):
Revision 2.25 by greg, Thu Jun 2 11:45:27 1994 UTC vs.
Revision 2.26 by greg, Thu Apr 27 14:12:05 1995 UTC

# Line 27 | Line 27 | typedef struct ambtree {
27  
28   extern CUBE  thescene;          /* contains space boundaries */
29  
30 + extern char  *shm_boundary;     /* shared memory boundary */
31 +
32   #define  MAXASET        511     /* maximum number of elements in ambient set */
33   OBJECT  ambset[MAXASET+1]={0};  /* ambient include/exclude set */
34  
# Line 38 | Line 40 | static AMBTREE atrunk;         /* our ambient trunk node */
40   static FILE  *ambfp = NULL;     /* ambient file pointer */
41   static int  nunflshed = 0;      /* number of unflushed ambient values */
42  
43 + #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   #define  AMBFLUSH       (BUFSIZ/AMBVALSIZ)
65  
66   #define  newambval()    (AMBVAL *)bmalloc(sizeof(AMBVAL))
67  
45 – #define  newambtree()   (AMBTREE *)calloc(8, sizeof(AMBTREE))
46 – #define  freeambtree(t) free((char *)(t))
47 –
68   extern long  ftell(), lseek();
69 < static int  initambfile(), avsave(), avinsert(), loadatree();
69 > static int  initambfile(), avsave(), avinsert(), sortambvals();
70   static AMBVAL  *avstore();
71   #ifdef  F_SETLKW
72   static  aflock();
# Line 78 | Line 98 | setambacc(newa)                                /* set ambient accuracy */
98   double  newa;
99   {
100          static double  oldambacc = -1.0;
81 –        AMBTREE  oldatrunk;
101  
102          ambacc = newa < 0.0 ? 0.0 : newa;       /* may be done already */
103          if (oldambacc < -FTINY)
# Line 88 | Line 107 | double  newa;
107          if (ambacc <= FTINY)
108                  return;                 /* cannot build new tree */
109                                          /* else need to rebuild tree */
110 <        copystruct(&oldatrunk, &atrunk);
92 <        atrunk.alist = NULL;
93 <        atrunk.kid = NULL;
94 <        loadatree(&oldatrunk);
110 >        sortambvals(1);
111          oldambacc = ambacc;             /* remeber setting for next call */
112   }
113  
# Line 179 | Line 195 | register RAY  *r;
195                  return;
196          }
197                                                  /* get ambient value */
198 +        if (need2sort)
199 +                sortambvals(0);
200          setcolor(acol, 0.0, 0.0, 0.0);
201          d = sumambient(acol, r, rdepth,
202                          &atrunk, thescene.cuorg, thescene.cusize);
# Line 213 | Line 231 | double s;
231                                          /* do this node */
232          wsum = 0.0;
233          for (av = at->alist; av != NULL; av = av->next) {
234 +                if (tracktime)
235 +                        av->latick = ambclock++;
236                  /*
237                   *  Ambient level test.
238                   */
# Line 397 | Line 417 | register AMBVAL  *aval;
417          if ((av = newambval()) == NULL)
418                  error(SYSTEM, "out of memory in avstore");
419          copystruct(av, aval);
420 +        av->latick = ambclock;
421 +        av->next = NULL;
422 +        nambvals++;
423          return(av);
424   }
425  
426  
427 + #define ATALLOCSZ       512             /* #/8 trees to allocate at once */
428 +
429 + static AMBTREE  *atfreelist = NULL;     /* free ambient tree structures */
430 +
431 +
432   static
433 + 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(ATALLOCSZ*8*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, 8*sizeof(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   avinsert(av)                            /* insert ambient value in our tree */
466   register AMBVAL  *av;
467   {
# Line 442 | Line 502 | register AMBVAL         *av;
502  
503  
504   static
505 < loadatree(at)                           /* move tree to main store */
505 > unloadatree(at, f)                      /* unload an ambient value tree */
506   register AMBTREE  *at;
507 + int     (*f)();
508   {
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 <                avinsert(av);
514 >                (*f)(av);
515          }
516          if (at->kid == NULL)
517                  return;
518          for (i = 0; i < 8; i++)         /* transfer and free children */
519 <                loadatree(at->kid+i);
519 >                unloadatree(at->kid+i, f);
520          freeambtree(at->kid);
521 +        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(nambvals*sizeof(AMBVAL *));
580 +                avlist2 = (AMBVAL **)malloc(nambvals*sizeof(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   }
632  
633  

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