--- ray/src/rt/ambcomp.c 1991/10/22 12:15:41 1.15 +++ ray/src/rt/ambcomp.c 2003/07/21 22:30:19 2.11 @@ -1,35 +1,21 @@ -/* Copyright (c) 1991 Regents of the University of California */ - #ifndef lint -static char SCCSid[] = "$SunId$ LBL"; +static const char RCSid[] = "$Id: ambcomp.c,v 2.11 2003/07/21 22:30:19 schorsch Exp $"; #endif - /* * Routines to compute "ambient" values using Monte Carlo + * + * Declarations of external symbols in ambient.h */ +#include "copyright.h" + #include "ray.h" #include "ambient.h" #include "random.h" -typedef struct { - short t, p; /* theta, phi indices */ - COLOR v; /* value sum */ - float r; /* 1/distance sum */ - float k; /* variance for this division */ - int n; /* number of subsamples */ -} AMBSAMP; /* ambient sample division */ -typedef struct { - FVECT ux, uy, uz; /* x, y and z axis directions */ - short nt, np; /* number of theta and phi directions */ -} AMBHEMI; /* ambient sample hemisphere */ - -extern double sin(), cos(), sqrt(); - - static int ambcmp(d1, d2) /* decreasing order */ AMBSAMP *d1, *d2; @@ -54,6 +40,7 @@ AMBSAMP *d1, *d2; } +int divsample(dp, h, r) /* sample a division */ register AMBSAMP *dp; AMBHEMI *h; @@ -75,8 +62,8 @@ RAY *r; multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); zd = sqrt((dp->t + spt[0])/h->nt); phi = 2.0*PI * (dp->p + spt[1])/h->np; - xd = cos(phi) * zd; - yd = sin(phi) * zd; + xd = tcos(phi) * zd; + yd = tsin(phi) * zd; zd = sqrt(1.0 - zd*zd); for (i = 0; i < 3; i++) ar.rdir[i] = xd*h->ux[i] + @@ -86,6 +73,7 @@ RAY *r; rayvalue(&ar); ndims--; addcolor(dp->v, ar.rcol); + /* use rt to improve gradient calc */ if (ar.rt > FTINY && ar.rt < FHUGE) dp->r += 1.0/ar.rt; /* (re)initialize error */ @@ -141,35 +129,37 @@ FVECT pg, dg; dp->n = 0; if (divsample(dp, &hemi, r) < 0) goto oopsy; + arad += dp->r; if (div != NULL) dp++; - else { + else addcolor(acol, dp->v); - arad += dp->r; - } } - if (ns > 0) { /* perform super-sampling */ + if (ns > 0 && arad > FTINY && ndivs/arad < minarad) + ns = 0; /* close enough */ + else if (ns > 0) { /* else perform super-sampling */ comperrs(div, &hemi); /* compute errors */ qsort(div, ndivs, sizeof(AMBSAMP), ambcmp); /* sort divs */ /* super-sample */ for (i = ns; i > 0; i--) { - copystruct(&dnew, div); + dnew = *div; if (divsample(&dnew, &hemi, r) < 0) goto oopsy; /* reinsert */ dp = div; j = ndivs < i ? ndivs : i; while (--j > 0 && dnew.k < dp[1].k) { - copystruct(dp, dp+1); + *dp = *(dp+1); dp++; } - copystruct(dp, &dnew); + *dp = dnew; } if (pg != NULL || dg != NULL) /* restore order */ qsort(div, ndivs, sizeof(AMBSAMP), ambnorm); } /* compute returned values */ if (div != NULL) { + arad = 0.0; for (i = ndivs, dp = div; i-- > 0; dp++) { arad += dp->r; if (dp->n > 1) { @@ -201,12 +191,12 @@ FVECT pg, dg; for (i = 0; i < 3; i++) dg[i] = 0.0; } - free((char *)div); + free((void *)div); } b = 1.0/ndivs; scalecolor(acol, b); if (arad <= FTINY) - arad = FHUGE; + arad = maxarad; else arad = (ndivs+ns)/arad; if (pg != NULL) { /* reduce radius if gradient large */ @@ -214,18 +204,25 @@ FVECT pg, dg; if (d*arad*arad > 1.0) arad = 1.0/sqrt(d); } - if (arad > maxarad) - arad = maxarad; - else if (arad < minarad) + if (arad < minarad) { arad = minarad; - return(arad/sqrt(wt)); + if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ + d = 1.0/arad/sqrt(d); + for (i = 0; i < 3; i++) + pg[i] *= d; + } + } + if ((arad /= sqrt(wt)) > maxarad) + arad = maxarad; + return(arad); oopsy: if (div != NULL) - free((char *)div); + free((void *)div); return(0.0); } +void inithemi(hp, r, wt) /* initialize sampling hemisphere */ register AMBHEMI *hp; RAY *r; @@ -254,6 +251,7 @@ double wt; } +void comperrs(da, hp) /* compute initial error estimates */ AMBSAMP *da; /* assumes standard ordering */ register AMBHEMI *hp; @@ -304,13 +302,14 @@ register AMBHEMI *hp; } +void posgradient(gv, da, hp) /* compute position gradient */ FVECT gv; AMBSAMP *da; /* assumes standard ordering */ -AMBHEMI *hp; +register AMBHEMI *hp; { register int i, j; - double b, d; + double nextsine, lastsine, b, d; double mag0, mag1; double phi, cosp, sinp, xd, yd; register AMBSAMP *dp; @@ -319,6 +318,7 @@ AMBHEMI *hp; for (j = 0; j < hp->np; j++) { dp = da + j; mag0 = mag1 = 0.0; + lastsine = 0.0; for (i = 0; i < hp->nt; i++) { #ifdef DEBUG if (dp->t != i || dp->p != j) @@ -329,26 +329,28 @@ AMBHEMI *hp; if (i > 0) { d = dp[-hp->np].r; if (dp[0].r > d) d = dp[0].r; - d *= 1.0 - (double)i/hp->nt; /* cos(t)^2 */ + /* sin(t)*cos(t)^2 */ + d *= lastsine * (1.0 - (double)i/hp->nt); mag0 += d*(b - bright(dp[-hp->np].v)); } + nextsine = sqrt((double)(i+1)/hp->nt); if (j > 0) { d = dp[-1].r; if (dp[0].r > d) d = dp[0].r; - mag1 += d*(b - bright(dp[-1].v)); + mag1 += d * (nextsine - lastsine) * + (b - bright(dp[-1].v)); } else { d = dp[hp->np-1].r; if (dp[0].r > d) d = dp[0].r; - mag1 += d*(b - bright(dp[hp->np-1].v)); + mag1 += d * (nextsine - lastsine) * + (b - bright(dp[hp->np-1].v)); } dp += hp->np; + lastsine = nextsine; } - if (hp->nt > 1) { - mag0 /= (double)hp->np; - mag1 /= (double)hp->nt; - } + mag0 *= 2.0*PI / hp->np; phi = 2.0*PI * (double)j/hp->np; - cosp = cos(phi); sinp = sin(phi); + cosp = tcos(phi); sinp = tsin(phi); xd += mag0*cosp - mag1*sinp; yd += mag0*sinp + mag1*cosp; } @@ -357,10 +359,11 @@ AMBHEMI *hp; } +void dirgradient(gv, da, hp) /* compute direction gradient */ FVECT gv; AMBSAMP *da; /* assumes standard ordering */ -AMBHEMI *hp; +register AMBHEMI *hp; { register int i, j; double mag; @@ -377,13 +380,14 @@ AMBHEMI *hp; error(CONSISTENCY, "division order in dirgradient"); #endif - mag += sqrt((i+.5)/hp->nt)*bright(dp->v); /* sin(t) */ + /* tan(t) */ + mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); dp += hp->np; } phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; - xd += mag * cos(phi); - yd += mag * sin(phi); + xd += mag * tcos(phi); + yd += mag * tsin(phi); } for (i = 0; i < 3; i++) - gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*PI/(hp->nt*hp->np); + gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np); }