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/* Copyright (c) 1991 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* Gather samples and compute glare sources. |
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*/ |
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|
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#include "glare.h" |
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|
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#define vcont(vd,vu) ((vu)-(vd)<=SEPS) |
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#define hcont(s1,s2) ((s1)->r-(s2)->l>=-SEPS&&(s2)->r-(s1)->l>=-SEPS) |
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|
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struct source *curlist = NULL; /* current source list */ |
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struct source *donelist = NULL; /* finished sources */ |
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|
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|
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struct srcspan * |
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newspan(l, r, v, sb) /* allocate a new source span */ |
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int l, r, v; |
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float *sb; |
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{ |
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register struct srcspan *ss; |
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register int i; |
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|
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ss = (struct srcspan *)malloc(sizeof(struct srcspan)); |
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if (ss == NULL) |
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memerr("source spans"); |
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ss->l = l; |
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ss->r = r; |
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ss->v = v; |
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ss->brsum = 0.0; |
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for (i = l; i < r; i++) |
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ss->brsum += sb[i+hsize]; |
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return(ss); |
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} |
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|
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|
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analyze() /* analyze our scene */ |
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{ |
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int h, v; |
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int left; |
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float *spanbr; |
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|
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spanbr = (float *)malloc((2*hsize+1)*sizeof(float)); |
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if (spanbr == NULL) |
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memerr("view span brightness buffer"); |
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for (v = vsize; v >= -vsize; v--) { |
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close_sources(v); |
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getviewspan(v, spanbr); |
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left = hsize + 1; |
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for (h = -hsize; h <= hsize; h++) { |
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if (spanbr[h+hsize] < 0.0) { /* off view */ |
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if (left < h) { |
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addsrcspan(newspan(left,h,v,spanbr)); |
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left = hsize + 1; |
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} |
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continue; |
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} |
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if (spanbr[h+hsize] > threshold) { /* in source */ |
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if (left > h) |
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left = h; |
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} else { /* out of source */ |
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if (left < h) { |
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addsrcspan(newspan(left,h,v,spanbr)); |
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left = hsize + 1; |
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} |
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addindirect(h, spanbr[h+hsize]); |
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} |
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} |
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if (left < h) |
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addsrcspan(newspan(left,h,v,spanbr)); |
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} |
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free((char *)spanbr); |
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close_allsrcs(); |
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absorb_specks(); |
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} |
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|
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|
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addindirect(h, br) /* add brightness to indirect illuminances */ |
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int h; |
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double br; |
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{ |
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double tanb, d; |
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register int i; |
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|
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if (h <= -hlim) { /* left region */ |
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d = (double)(h+hlim)/sampdens; |
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if (d <= -1.0+FTINY) |
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return; |
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tanb = d/sqrt(1.0-d*d); |
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for (i = 0; i < nglardirs; i++) { |
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d = indirect[i].lcos - tanb*indirect[i].lsin; |
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if (d > 0.0) { |
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indirect[i].sum += d * br; |
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indirect[i].n++; |
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} |
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} |
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return; |
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} |
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if (h >= hlim) { /* right region */ |
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d = (double)(h-hlim)/sampdens; |
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if (d >= 1.0-FTINY) |
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return; |
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tanb = d/sqrt(1.0-d*d); |
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for (i = 0; i < nglardirs; i++) { |
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d = indirect[i].rcos - tanb*indirect[i].rsin; |
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if (d > 0.0) { |
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indirect[i].sum += d * br; |
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indirect[i].n++; |
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} |
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} |
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return; |
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} |
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/* central region */ |
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for (i = 0; i < nglardirs; i++) { |
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d = cos(h_theta(h) - indirect[i].theta); |
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if (d > 0.0) { |
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indirect[i].sum += d * br; |
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indirect[i].n++; |
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} |
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} |
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} |
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|
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|
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comp_thresh() /* compute glare threshold */ |
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{ |
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int h, v; |
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int nsamps; |
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double brsum, br; |
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|
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if (verbose) |
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fprintf(stderr, "%s: computing glare threshold...\n", |
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progname); |
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brsum = 0.0; |
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nsamps = 0; |
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for (v = vsize; v >= -vsize; v -= TSAMPSTEP) |
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for (h = -hsize; h <= hsize; h += TSAMPSTEP) { |
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if ((br = getviewpix(h, v)) < 0.0) |
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continue; |
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brsum += br; |
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nsamps++; |
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} |
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if (nsamps == 0) { |
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fprintf(stderr, "%s: no viewable scene!\n", progname); |
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exit(1); |
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} |
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threshold = GLAREBR * brsum / nsamps; |
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if (threshold <= FTINY) { |
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fprintf(stderr, "%s: threshold zero!\n", progname); |
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exit(1); |
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} |
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if (verbose) { |
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pict_stats(); |
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fprintf(stderr, |
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"%s: threshold set to %f cd/m2 from %d samples\n", |
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progname, threshold, nsamps); |
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} |
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} |
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|
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|
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addsrcspan(nss) /* add new source span to our list */ |
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struct srcspan *nss; |
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{ |
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struct source *last, *cs, *this; |
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register struct srcspan *ss; |
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|
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cs = NULL; |
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for (this = curlist; this != NULL; this = this->next) { |
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for (ss = this->first; ss != NULL; ss = ss->next) { |
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if (!vcont(nss->v, ss->v)) |
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break; |
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if (hcont(ss, nss)) { |
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if (cs == NULL) |
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cs = this; |
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else { |
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last->next = this->next; |
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mergesource(cs, this); |
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this = last; |
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} |
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break; |
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} |
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} |
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last = this; |
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} |
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if (cs == NULL) { |
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cs = (struct source *)malloc(sizeof(struct source)); |
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if (cs == NULL) |
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memerr("source records"); |
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cs->dom = 0.0; |
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cs->first = NULL; |
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cs->next = curlist; |
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curlist = cs; |
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} |
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nss->next = cs->first; |
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cs->first = nss; |
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} |
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|
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|
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mergesource(sp, ap) /* merge source ap into source sp */ |
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struct source *sp, *ap; |
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{ |
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struct srcspan head; |
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register struct srcspan *alp, *prev, *tp; |
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|
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head.next = sp->first; |
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prev = &head; |
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alp = ap->first; |
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while (alp != NULL && prev->next != NULL) { |
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if (prev->next->v > alp->v) { |
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tp = alp->next; |
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alp->next = prev->next; |
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prev->next = alp; |
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alp = tp; |
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} |
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prev = prev->next; |
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} |
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if (prev->next == NULL) |
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prev->next = alp; |
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sp->first = head.next; |
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if (ap->dom > 0.0 && sp->dom > 0.0) { /* sources are done */ |
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sp->dir[0] *= sp->dom; |
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sp->dir[1] *= sp->dom; |
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sp->dir[2] *= sp->dom; |
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fvsum(sp->dir, sp->dir, ap->dir, ap->dom); |
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normalize(sp->dir); |
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sp->brt = (sp->brt*sp->dom + ap->brt*ap->dom) |
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/ (sp->dom + ap->dom); |
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} |
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free((char *)ap); |
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} |
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|
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|
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close_sources(v) /* close sources above v */ |
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int v; |
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{ |
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struct source head; |
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register struct source *last, *this; |
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|
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head.next = curlist; |
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last = &head; |
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for (this = curlist; this != NULL; this = this->next) |
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if (!vcont(v, this->first->v)) { |
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last->next = this->next; |
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donesource(this); |
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this = last; |
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} else |
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last = this; |
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curlist = head.next; |
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} |
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|
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|
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close_allsrcs() /* done with everything */ |
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{ |
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register struct source *this, *next; |
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|
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this = curlist; |
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while (this != NULL) { |
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next = this->next; |
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donesource(this); |
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this = next; |
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} |
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curlist = NULL; |
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} |
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|
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|
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donesource(sp) /* finished with this source */ |
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register struct source *sp; |
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{ |
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FVECT dthis, dright; |
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register struct srcspan *ss; |
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int h, n; |
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double d; |
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|
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sp->dom = 0.0; |
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sp->dir[0] = sp->dir[1] = sp->dir[2] = 0.0; |
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sp->brt = 0.0; |
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n = 0; |
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for (ss = sp->first; ss != NULL; ss = ss->next) { |
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sp->brt += ss->brsum; |
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n += ss->r - ss->l; |
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if (compdir(dright, ss->r, ss->v) < 0) |
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compdir(dright, ss->r-2, ss->v); |
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for (h = ss->r-1; h >= ss->l; h--) |
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if (compdir(dthis, h, ss->v) == 0) { |
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d = dist2(dthis, dright); |
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fvsum(sp->dir, sp->dir, dthis, d); |
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sp->dom += d; |
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VCOPY(dright, dthis); |
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} |
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free((char *)ss); |
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} |
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sp->first = NULL; |
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sp->brt /= (double)n; |
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normalize(sp->dir); |
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sp->next = donelist; |
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donelist = sp; |
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if (verbose) |
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fprintf(stderr, |
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"%s: found source at (%.3f,%.3f,%.3f), dw %.5f, br %.1f (%d samps)\n", |
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progname, sp->dir[0], sp->dir[1], sp->dir[2], |
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sp->dom, sp->brt, n); |
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} |
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|
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|
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struct source * |
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findbuddy(s, l) /* find close enough source to s in l*/ |
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register struct source *s, *l; |
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{ |
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struct source *bestbuddy = NULL; |
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double d, r, mindist = MAXBUDDY; |
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|
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r = sqrt(s->dom/PI); |
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for ( ; l != NULL; l = l->next) { |
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d = sqrt(dist2(l->dir, s->dir)) - sqrt(l->dom/PI) - r; |
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if (d < mindist) { |
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bestbuddy = l; |
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mindist = d; |
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} |
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} |
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return(bestbuddy); |
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} |
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|
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|
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absorb_specks() /* eliminate too-small sources */ |
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{ |
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struct source head, *buddy; |
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register struct source *last, *this; |
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|
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if (verbose) |
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fprintf(stderr, "%s: absorbing small sources...\n", progname); |
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head.next = donelist; |
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last = &head; |
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for (this = donelist; this != NULL; this = this->next) |
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if (TOOSMALL(this)) { |
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last->next = this->next; |
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buddy = findbuddy(this, donelist); |
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if (buddy != NULL) |
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mergesource(buddy, this); |
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else |
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absorb(this); |
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this = last; |
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} else |
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last = this; |
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donelist = head.next; |
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} |
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|
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|
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absorb(s) /* absorb a source into indirect */ |
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register struct source *s; |
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{ |
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FVECT dir; |
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register int i, n; |
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|
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for (i = 0; i < nglardirs; i++) { |
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spinvector(dir, ourview.vdir, ourview.vup, indirect[i].theta); |
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n = DOT(dir,s->dir)*s->dom*(sampdens*sampdens) + 0.5; |
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if (n == 0) |
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continue; |
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indirect[i].sum += n * s->brt; |
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indirect[i].n += n; |
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} |
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for ( ; s->first != NULL; s->first = s->first->next) |
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free((char *)s->first); |
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free((char *)s); |
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} |
