--- ray/src/px/pcond4.c 1996/10/03 20:14:20 3.2 +++ ray/src/px/pcond4.c 1996/10/10 16:36:39 3.9 @@ -10,6 +10,7 @@ static char SCCSid[] = "$SunId$ LBL"; #include "pcond.h" +/************** VEILING STUFF *****************/ #define VADAPT 0.08 /* fraction of adaptation from veil */ @@ -98,8 +99,11 @@ compveil() /* compute veiling image */ t2 = DOT(rdirscan(py)[px], rdirscan(y)[x]); if (t2 <= FTINY) continue; + /* use approximation instead t2 = acos(t2); t2 = 1./(t2*t2); + */ + t2 = .5 / (1. - t2); copycolor(ctmp, fovscan(y)[x]); scalecolor(ctmp, t2); addcolor(vsum, ctmp); @@ -122,11 +126,11 @@ int y; register int x, i; vy = dy = (y+.5)/numscans(&inpres)*fvyr - .5; - if (vy >= fvyr-1) vy--; + while (vy >= fvyr-1) vy--; dy -= (double)vy; for (x = 0; x < scanlen(&inpres); x++) { vx = dx = (x+.5)/scanlen(&inpres)*fvxr - .5; - if (vx >= fvxr-1) vx--; + while (vx >= fvxr-1) vx--; dx -= (double)vx; for (i = 0; i < 3; i++) { lv = (1.-dy)*colval(veilscan(vy)[vx],i) + @@ -137,4 +141,261 @@ int y; (1.-dx)*lv + dx*uv; } } +} + + +/****************** ACUITY STUFF *******************/ + +typedef struct { + short sampe; /* sample area size (exponent of 2) */ + short nscans; /* number of scanlines in this bar */ + int len; /* individual scanline length */ + int nread; /* number of scanlines loaded */ + COLOR *sdata; /* scanbar data */ +} SCANBAR; + +#define bscan(sb,y) ((COLOR *)(sb)->sdata+((y)%(sb)->nscans)*(sb)->len) + +SCANBAR *rootbar; /* root scan bar (lowest resolution) */ + +float *inpacuD; /* input acuity data (cycles/degree) */ + +#define tsampr(x,y) inpacuD[(y)*fvxr+(x)] + + +double +hacuity(La) /* return visual acuity in cycles/degree */ +double La; +{ /* data due to S. Shaler (we should fit it!) */ +#define NPOINTS 20 + static float l10lum[NPOINTS] = { + -3.10503,-2.66403,-2.37703,-2.09303,-1.64403,-1.35803, + -1.07403,-0.67203,-0.38503,-0.10103,0.29397,0.58097,0.86497, + 1.25697,1.54397,1.82797,2.27597,2.56297,2.84697,3.24897 + }; + static float resfreq[NPOINTS] = { + 2.09,3.28,3.79,4.39,6.11,8.83,10.94,18.66,23.88,31.05,37.42, + 37.68,41.60,43.16,45.30,47.00,48.43,48.32,51.06,51.09 + }; + double l10La; + register int i; + /* check limits */ + if (La <= 7.85e-4) + return(resfreq[0]); + if (La >= 1.78e3) + return(resfreq[NPOINTS-1]); + /* interpolate data */ + l10La = log10(La); + for (i = 0; i < NPOINTS-2 && l10lum[i+1] <= l10La; i++) + ; + return( ( (l10lum[i+1] - l10La)*resfreq[i] + + (l10La - l10lum[i])*resfreq[i+1] ) / + (l10lum[i+1] - l10lum[i]) ); +#undef NPOINTS +} + + +COLOR * +getascan(sb, y) /* find/read scanline y for scanbar sb */ +register SCANBAR *sb; +int y; +{ + register COLOR *sl0, *sl1, *mysl; + register int i; + + if (y < sb->nread - sb->nscans) /* too far back? */ + return(NULL); + for ( ; y >= sb->nread; sb->nread++) { /* read as necessary */ + mysl = bscan(sb, sb->nread); + if (sb->sampe == 0) { + if (freadscan(mysl, sb->len, infp) < 0) { + fprintf(stderr, "%s: %s: scanline read error\n", + progname, infn); + exit(1); + } + } else { + sl0 = getascan(sb+1, 2*y); + if (sl0 == NULL) + return(NULL); + sl1 = getascan(sb+1, 2*y+1); + for (i = 0; i < sb->len; i++) { + copycolor(mysl[i], sl0[2*i]); + addcolor(mysl[i], sl0[2*i+1]); + addcolor(mysl[i], sl1[2*i]); + addcolor(mysl[i], sl1[2*i+1]); + scalecolor(mysl[i], 0.25); + } + } + } + return(bscan(sb, y)); +} + + +acuscan(scln, y) /* get acuity-sampled scanline */ +COLOR *scln; +int y; +{ + double sr; + double dx, dy; + int ix, iy; + register int x; + /* compute foveal y position */ + iy = dy = (y+.5)/numscans(&inpres)*fvyr - .5; + while (iy >= fvyr-1) iy--; + dy -= (double)iy; + for (x = 0; x < scanlen(&inpres); x++) { + /* compute foveal x position */ + ix = dx = (x+.5)/scanlen(&inpres)*fvxr - .5; + while (ix >= fvxr-1) ix--; + dx -= (double)ix; + /* interpolate sample rate */ + sr = (1.-dy)*((1.-dx)*tsampr(ix,iy) + dx*tsampr(ix+1,iy)) + + dy*((1.-dx)*tsampr(ix,iy+1) + dx*tsampr(ix+1,iy+1)); + + acusample(scln[x], x, y, sr); /* compute sample */ + } +} + + +acusample(col, x, y, sr) /* interpolate sample at (x,y) using rate sr */ +COLOR col; +int x, y; +double sr; +{ + COLOR c1; + double d; + register SCANBAR *sb0; + + for (sb0 = rootbar; sb0->sampe != 0 && 1< sr; sb0++) + ; + ascanval(col, x, y, sb0); + if (sb0->sampe == 0) /* don't extrapolate highest */ + return; + ascanval(c1, x, y, sb0+1); + d = ((1<sampe) - sr)/(1<sampe == 0) { /* no need to interpolate */ + sl0 = getascan(sb, y); + copycolor(col, sl0[x]); + return; + } + /* compute coordinates for sb */ + ix = dx = (x+.5)/(1<sampe) - .5; + while (ix >= sb->len-1) ix--; + dx -= (double)ix; + iy = dy = (y+.5)/(1<sampe) - .5; + while (iy >= (numscans(&inpres)>>sb->sampe)-1) iy--; + dy -= (double)iy; + /* get scanlines */ + sl0 = getascan(sb, iy); +#ifdef DEBUG + if (sl0 == NULL) { + fprintf(stderr, "%s: internal - cannot backspace in ascanval\n", + progname); + abort(); + } +#endif + sl1 = getascan(sb, iy+1); + /* 2D linear interpolation */ + copycolor(col, sl0[ix]); + scalecolor(col, 1.-dx); + copycolor(c1, sl0[ix+1]); + scalecolor(c1, dx); + addcolor(col, c1); + copycolor(c1y, sl1[ix]); + scalecolor(c1y, 1.-dx); + copycolor(c1, sl1[ix+1]); + scalecolor(c1, dx); + addcolor(c1y, c1); + scalecolor(col, 1.-dy); + scalecolor(c1y, dy); + addcolor(col, c1y); + for (ix = 0; ix < 3; ix++) /* make sure no negative */ + if (colval(col,ix) < 0.) + colval(col,ix) = 0.; +} + + +SCANBAR * +sballoc(se, ns, sl) /* allocate scanbar */ +int se; /* sampling rate exponent */ +int ns; /* number of scanlines */ +int sl; /* original scanline length */ +{ + SCANBAR *sbarr; + register SCANBAR *sb; + + sbarr = sb = (SCANBAR *)malloc((se+1)*sizeof(SCANBAR)); + if (sb == NULL) + syserror("malloc"); + do { + sb->sampe = se; + sb->len = sl>>se; + sb->nscans = ns; + sb->sdata = (COLOR *)malloc(sb->len*ns*sizeof(COLOR)); + if (sb->sdata == NULL) + syserror("malloc"); + sb->nread = 0; + ns <<= 1; + sb++; + } while (--se >= 0); + return(sbarr); +} + + +initacuity() /* initialize variable acuity sampling */ +{ + FVECT diffx, diffy, cp; + double omega, maxsr; + register int x, y, i; + + compraydir(); /* compute ray directions */ + + inpacuD = (float *)malloc(fvxr*fvyr*sizeof(float)); + if (inpacuD == NULL) + syserror("malloc"); + maxsr = 1.; /* compute internal sample rates */ + for (y = 1; y < fvyr-1; y++) + for (x = 1; x < fvxr-1; x++) { + for (i = 0; i < 3; i++) { + diffx[i] = 0.5*fvxr/scanlen(&inpres) * + (rdirscan(y)[x+1][i] - + rdirscan(y)[x-1][i]); + diffy[i] = 0.5*fvyr/numscans(&inpres) * + (rdirscan(y+1)[x][i] - + rdirscan(y-1)[x][i]); + } + fcross(cp, diffx, diffy); + omega = 0.5 * sqrt(DOT(cp,cp)); + if (omega <= FTINY) + tsampr(x,y) = 1.; + else if ((tsampr(x,y) = PI/180. / sqrt(omega) / + hacuity(plum(fovscan(y)[x]))) > maxsr) + maxsr = tsampr(x,y); + } + /* copy perimeter (easier) */ + for (x = 1; x < fvxr-1; x++) { + tsampr(x,0) = tsampr(x,1); + tsampr(x,fvyr-1) = tsampr(x,fvyr-2); + } + for (y = 0; y < fvyr; y++) { + tsampr(0,y) = tsampr(1,y); + tsampr(fvxr-1,y) = tsampr(fvxr-2,y); + } + /* initialize with next power of two */ + rootbar = sballoc((int)(log(maxsr)/log(2.))+1, 2, scanlen(&inpres)); }