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#ifndef lint |
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static const char RCSid[] = "$Id$"; |
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#endif |
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/* |
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* Routines to compute "ambient" values using Monte Carlo |
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* |
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* Declarations of external symbols in ambient.h |
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*/ |
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|
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/* ==================================================================== |
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* The Radiance Software License, Version 1.0 |
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* |
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* Copyright (c) 1990 - 2002 The Regents of the University of California, |
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* through Lawrence Berkeley National Laboratory. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* |
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* 3. The end-user documentation included with the redistribution, |
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* if any, must include the following acknowledgment: |
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* "This product includes Radiance software |
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* (http://radsite.lbl.gov/) |
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* developed by the Lawrence Berkeley National Laboratory |
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* (http://www.lbl.gov/)." |
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* Alternately, this acknowledgment may appear in the software itself, |
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* if and wherever such third-party acknowledgments normally appear. |
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* |
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* 4. The names "Radiance," "Lawrence Berkeley National Laboratory" |
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* and "The Regents of the University of California" must |
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* not be used to endorse or promote products derived from this |
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* software without prior written permission. For written |
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* permission, please contact [email protected]. |
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* |
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* 5. Products derived from this software may not be called "Radiance", |
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* nor may "Radiance" appear in their name, without prior written |
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* permission of Lawrence Berkeley National Laboratory. |
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* |
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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* DISCLAIMED. IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR |
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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* SUCH DAMAGE. |
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* ==================================================================== |
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* |
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* This software consists of voluntary contributions made by many |
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* individuals on behalf of Lawrence Berkeley National Laboratory. For more |
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* information on Lawrence Berkeley National Laboratory, please see |
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* <http://www.lbl.gov/>. |
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*/ |
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|
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#include "ray.h" |
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|
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#include "ambient.h" |
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|
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#include "random.h" |
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|
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|
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static int |
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ambcmp(d1, d2) /* decreasing order */ |
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AMBSAMP *d1, *d2; |
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{ |
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if (d1->k < d2->k) |
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return(1); |
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if (d1->k > d2->k) |
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return(-1); |
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return(0); |
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} |
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|
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|
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static int |
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ambnorm(d1, d2) /* standard order */ |
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AMBSAMP *d1, *d2; |
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{ |
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register int c; |
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|
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if (c = d1->t - d2->t) |
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return(c); |
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return(d1->p - d2->p); |
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} |
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|
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|
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int |
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divsample(dp, h, r) /* sample a division */ |
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register AMBSAMP *dp; |
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AMBHEMI *h; |
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RAY *r; |
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{ |
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RAY ar; |
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int hlist[3]; |
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double spt[2]; |
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double xd, yd, zd; |
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double b2; |
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double phi; |
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register int i; |
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|
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if (rayorigin(&ar, r, AMBIENT, AVGREFL) < 0) |
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return(-1); |
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hlist[0] = r->rno; |
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hlist[1] = dp->t; |
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hlist[2] = dp->p; |
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multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); |
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zd = sqrt((dp->t + spt[0])/h->nt); |
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phi = 2.0*PI * (dp->p + spt[1])/h->np; |
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xd = tcos(phi) * zd; |
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yd = tsin(phi) * zd; |
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zd = sqrt(1.0 - zd*zd); |
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for (i = 0; i < 3; i++) |
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ar.rdir[i] = xd*h->ux[i] + |
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yd*h->uy[i] + |
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zd*h->uz[i]; |
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dimlist[ndims++] = dp->t*h->np + dp->p + 90171; |
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rayvalue(&ar); |
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ndims--; |
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addcolor(dp->v, ar.rcol); |
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/* use rt to improve gradient calc */ |
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if (ar.rt > FTINY && ar.rt < FHUGE) |
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dp->r += 1.0/ar.rt; |
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/* (re)initialize error */ |
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if (dp->n++) { |
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b2 = bright(dp->v)/dp->n - bright(ar.rcol); |
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b2 = b2*b2 + dp->k*((dp->n-1)*(dp->n-1)); |
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dp->k = b2/(dp->n*dp->n); |
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} else |
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dp->k = 0.0; |
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return(0); |
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} |
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|
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|
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double |
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doambient(acol, r, wt, pg, dg) /* compute ambient component */ |
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COLOR acol; |
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RAY *r; |
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double wt; |
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FVECT pg, dg; |
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{ |
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double b, d; |
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AMBHEMI hemi; |
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AMBSAMP *div; |
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AMBSAMP dnew; |
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register AMBSAMP *dp; |
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double arad; |
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int ndivs, ns; |
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register int i, j; |
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/* initialize color */ |
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setcolor(acol, 0.0, 0.0, 0.0); |
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/* initialize hemisphere */ |
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inithemi(&hemi, r, wt); |
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ndivs = hemi.nt * hemi.np; |
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if (ndivs == 0) |
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return(0.0); |
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/* set number of super-samples */ |
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ns = ambssamp * wt + 0.5; |
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if (ns > 0 || pg != NULL || dg != NULL) { |
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div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP)); |
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if (div == NULL) |
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error(SYSTEM, "out of memory in doambient"); |
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} else |
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div = NULL; |
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/* sample the divisions */ |
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arad = 0.0; |
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if ((dp = div) == NULL) |
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dp = &dnew; |
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for (i = 0; i < hemi.nt; i++) |
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for (j = 0; j < hemi.np; j++) { |
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dp->t = i; dp->p = j; |
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setcolor(dp->v, 0.0, 0.0, 0.0); |
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dp->r = 0.0; |
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dp->n = 0; |
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if (divsample(dp, &hemi, r) < 0) |
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goto oopsy; |
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arad += dp->r; |
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if (div != NULL) |
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dp++; |
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else |
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addcolor(acol, dp->v); |
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} |
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if (ns > 0 && arad > FTINY && ndivs/arad < minarad) |
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ns = 0; /* close enough */ |
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else if (ns > 0) { /* else perform super-sampling */ |
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comperrs(div, &hemi); /* compute errors */ |
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qsort(div, ndivs, sizeof(AMBSAMP), ambcmp); /* sort divs */ |
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/* super-sample */ |
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for (i = ns; i > 0; i--) { |
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copystruct(&dnew, div); |
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if (divsample(&dnew, &hemi, r) < 0) |
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goto oopsy; |
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/* reinsert */ |
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dp = div; |
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j = ndivs < i ? ndivs : i; |
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while (--j > 0 && dnew.k < dp[1].k) { |
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copystruct(dp, dp+1); |
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dp++; |
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} |
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copystruct(dp, &dnew); |
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} |
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if (pg != NULL || dg != NULL) /* restore order */ |
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qsort(div, ndivs, sizeof(AMBSAMP), ambnorm); |
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} |
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/* compute returned values */ |
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if (div != NULL) { |
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arad = 0.0; |
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for (i = ndivs, dp = div; i-- > 0; dp++) { |
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arad += dp->r; |
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if (dp->n > 1) { |
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b = 1.0/dp->n; |
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scalecolor(dp->v, b); |
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dp->r *= b; |
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dp->n = 1; |
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} |
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addcolor(acol, dp->v); |
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} |
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b = bright(acol); |
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if (b > FTINY) { |
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b = ndivs/b; |
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if (pg != NULL) { |
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posgradient(pg, div, &hemi); |
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for (i = 0; i < 3; i++) |
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pg[i] *= b; |
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} |
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if (dg != NULL) { |
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dirgradient(dg, div, &hemi); |
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for (i = 0; i < 3; i++) |
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dg[i] *= b; |
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} |
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} else { |
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if (pg != NULL) |
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for (i = 0; i < 3; i++) |
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pg[i] = 0.0; |
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if (dg != NULL) |
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for (i = 0; i < 3; i++) |
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dg[i] = 0.0; |
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} |
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free((void *)div); |
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} |
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b = 1.0/ndivs; |
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scalecolor(acol, b); |
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if (arad <= FTINY) |
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arad = maxarad; |
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else |
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arad = (ndivs+ns)/arad; |
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if (pg != NULL) { /* reduce radius if gradient large */ |
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d = DOT(pg,pg); |
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if (d*arad*arad > 1.0) |
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arad = 1.0/sqrt(d); |
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} |
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if (arad < minarad) { |
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arad = minarad; |
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if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
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d = 1.0/arad/sqrt(d); |
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for (i = 0; i < 3; i++) |
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pg[i] *= d; |
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} |
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} |
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if ((arad /= sqrt(wt)) > maxarad) |
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arad = maxarad; |
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return(arad); |
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oopsy: |
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if (div != NULL) |
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free((void *)div); |
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return(0.0); |
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} |
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|
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|
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void |
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inithemi(hp, r, wt) /* initialize sampling hemisphere */ |
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register AMBHEMI *hp; |
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RAY *r; |
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double wt; |
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{ |
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register int i; |
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/* set number of divisions */ |
| 288 |
if (wt < (.25*PI)/ambdiv+FTINY) { |
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hp->nt = hp->np = 0; |
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return; /* zero samples */ |
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} |
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hp->nt = sqrt(ambdiv * wt / PI) + 0.5; |
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hp->np = PI * hp->nt + 0.5; |
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/* make axes */ |
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VCOPY(hp->uz, r->ron); |
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hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
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for (i = 0; i < 3; i++) |
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if (hp->uz[i] < 0.6 && hp->uz[i] > -0.6) |
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break; |
| 300 |
if (i >= 3) |
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error(CONSISTENCY, "bad ray direction in inithemi"); |
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hp->uy[i] = 1.0; |
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fcross(hp->ux, hp->uy, hp->uz); |
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normalize(hp->ux); |
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fcross(hp->uy, hp->uz, hp->ux); |
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} |
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|
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|
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void |
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comperrs(da, hp) /* compute initial error estimates */ |
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AMBSAMP *da; /* assumes standard ordering */ |
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register AMBHEMI *hp; |
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{ |
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double b, b2; |
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int i, j; |
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register AMBSAMP *dp; |
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/* sum differences from neighbors */ |
| 318 |
dp = da; |
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for (i = 0; i < hp->nt; i++) |
| 320 |
for (j = 0; j < hp->np; j++) { |
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#ifdef DEBUG |
| 322 |
if (dp->t != i || dp->p != j) |
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error(CONSISTENCY, |
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"division order in comperrs"); |
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#endif |
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b = bright(dp[0].v); |
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if (i > 0) { /* from above */ |
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b2 = bright(dp[-hp->np].v) - b; |
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b2 *= b2 * 0.25; |
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dp[0].k += b2; |
| 331 |
dp[-hp->np].k += b2; |
| 332 |
} |
| 333 |
if (j > 0) { /* from behind */ |
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b2 = bright(dp[-1].v) - b; |
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b2 *= b2 * 0.25; |
| 336 |
dp[0].k += b2; |
| 337 |
dp[-1].k += b2; |
| 338 |
} else { /* around */ |
| 339 |
b2 = bright(dp[hp->np-1].v) - b; |
| 340 |
b2 *= b2 * 0.25; |
| 341 |
dp[0].k += b2; |
| 342 |
dp[hp->np-1].k += b2; |
| 343 |
} |
| 344 |
dp++; |
| 345 |
} |
| 346 |
/* divide by number of neighbors */ |
| 347 |
dp = da; |
| 348 |
for (j = 0; j < hp->np; j++) /* top row */ |
| 349 |
(dp++)->k *= 1.0/3.0; |
| 350 |
if (hp->nt < 2) |
| 351 |
return; |
| 352 |
for (i = 1; i < hp->nt-1; i++) /* central region */ |
| 353 |
for (j = 0; j < hp->np; j++) |
| 354 |
(dp++)->k *= 0.25; |
| 355 |
for (j = 0; j < hp->np; j++) /* bottom row */ |
| 356 |
(dp++)->k *= 1.0/3.0; |
| 357 |
} |
| 358 |
|
| 359 |
|
| 360 |
void |
| 361 |
posgradient(gv, da, hp) /* compute position gradient */ |
| 362 |
FVECT gv; |
| 363 |
AMBSAMP *da; /* assumes standard ordering */ |
| 364 |
register AMBHEMI *hp; |
| 365 |
{ |
| 366 |
register int i, j; |
| 367 |
double nextsine, lastsine, b, d; |
| 368 |
double mag0, mag1; |
| 369 |
double phi, cosp, sinp, xd, yd; |
| 370 |
register AMBSAMP *dp; |
| 371 |
|
| 372 |
xd = yd = 0.0; |
| 373 |
for (j = 0; j < hp->np; j++) { |
| 374 |
dp = da + j; |
| 375 |
mag0 = mag1 = 0.0; |
| 376 |
lastsine = 0.0; |
| 377 |
for (i = 0; i < hp->nt; i++) { |
| 378 |
#ifdef DEBUG |
| 379 |
if (dp->t != i || dp->p != j) |
| 380 |
error(CONSISTENCY, |
| 381 |
"division order in posgradient"); |
| 382 |
#endif |
| 383 |
b = bright(dp->v); |
| 384 |
if (i > 0) { |
| 385 |
d = dp[-hp->np].r; |
| 386 |
if (dp[0].r > d) d = dp[0].r; |
| 387 |
/* sin(t)*cos(t)^2 */ |
| 388 |
d *= lastsine * (1.0 - (double)i/hp->nt); |
| 389 |
mag0 += d*(b - bright(dp[-hp->np].v)); |
| 390 |
} |
| 391 |
nextsine = sqrt((double)(i+1)/hp->nt); |
| 392 |
if (j > 0) { |
| 393 |
d = dp[-1].r; |
| 394 |
if (dp[0].r > d) d = dp[0].r; |
| 395 |
mag1 += d * (nextsine - lastsine) * |
| 396 |
(b - bright(dp[-1].v)); |
| 397 |
} else { |
| 398 |
d = dp[hp->np-1].r; |
| 399 |
if (dp[0].r > d) d = dp[0].r; |
| 400 |
mag1 += d * (nextsine - lastsine) * |
| 401 |
(b - bright(dp[hp->np-1].v)); |
| 402 |
} |
| 403 |
dp += hp->np; |
| 404 |
lastsine = nextsine; |
| 405 |
} |
| 406 |
mag0 *= 2.0*PI / hp->np; |
| 407 |
phi = 2.0*PI * (double)j/hp->np; |
| 408 |
cosp = tcos(phi); sinp = tsin(phi); |
| 409 |
xd += mag0*cosp - mag1*sinp; |
| 410 |
yd += mag0*sinp + mag1*cosp; |
| 411 |
} |
| 412 |
for (i = 0; i < 3; i++) |
| 413 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/PI; |
| 414 |
} |
| 415 |
|
| 416 |
|
| 417 |
void |
| 418 |
dirgradient(gv, da, hp) /* compute direction gradient */ |
| 419 |
FVECT gv; |
| 420 |
AMBSAMP *da; /* assumes standard ordering */ |
| 421 |
register AMBHEMI *hp; |
| 422 |
{ |
| 423 |
register int i, j; |
| 424 |
double mag; |
| 425 |
double phi, xd, yd; |
| 426 |
register AMBSAMP *dp; |
| 427 |
|
| 428 |
xd = yd = 0.0; |
| 429 |
for (j = 0; j < hp->np; j++) { |
| 430 |
dp = da + j; |
| 431 |
mag = 0.0; |
| 432 |
for (i = 0; i < hp->nt; i++) { |
| 433 |
#ifdef DEBUG |
| 434 |
if (dp->t != i || dp->p != j) |
| 435 |
error(CONSISTENCY, |
| 436 |
"division order in dirgradient"); |
| 437 |
#endif |
| 438 |
/* tan(t) */ |
| 439 |
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); |
| 440 |
dp += hp->np; |
| 441 |
} |
| 442 |
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
| 443 |
xd += mag * tcos(phi); |
| 444 |
yd += mag * tsin(phi); |
| 445 |
} |
| 446 |
for (i = 0; i < 3; i++) |
| 447 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np); |
| 448 |
} |
