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/* Copyright (c) 1997 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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* Routines for veiling glare and loss of acuity. |
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*/ |
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|
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#include "pcond.h" |
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|
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/************** VEILING STUFF *****************/ |
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|
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#define VADAPT 0.08 /* fraction of adaptation from veil */ |
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|
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static COLOR *veilimg = NULL; /* veiling image */ |
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|
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#define veilscan(y) (veilimg+(y)*fvxr) |
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|
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static float (*raydir)[3] = NULL; /* ray direction for each pixel */ |
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|
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#define rdirscan(y) (raydir+(y)*fvxr) |
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|
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|
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compraydir() /* compute ray directions */ |
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{ |
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FVECT rorg, rdir; |
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double h, v; |
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register int x, y; |
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|
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if (raydir != NULL) /* already done? */ |
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return; |
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raydir = (float (*)[3])malloc(fvxr*fvyr*3*sizeof(float)); |
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if (raydir == NULL) |
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syserror("malloc"); |
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|
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for (y = 0; y < fvyr; y++) { |
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switch (inpres.or) { |
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case YMAJOR: case YMAJOR|XDECR: |
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v = (y+.5)/fvyr; break; |
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case YMAJOR|YDECR: case YMAJOR|YDECR|XDECR: |
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v = 1. - (y+.5)/fvyr; break; |
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case 0: case YDECR: |
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h = (y+.5)/fvyr; break; |
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case XDECR: case XDECR|YDECR: |
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h = 1. - (y+.5)/fvyr; break; |
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} |
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for (x = 0; x < fvxr; x++) { |
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switch (inpres.or) { |
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case YMAJOR: case YMAJOR|YDECR: |
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h = (x+.5)/fvxr; break; |
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case YMAJOR|XDECR: case YMAJOR|XDECR|YDECR: |
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h = 1. - (x+.5)/fvxr; break; |
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case 0: case XDECR: |
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v = (x+.5)/fvxr; break; |
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case YDECR: case YDECR|XDECR: |
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v = 1. - (x+.5)/fvxr; break; |
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} |
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if (viewray(rorg, rdir, &ourview, h, v) |
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>= -FTINY) { |
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rdirscan(y)[x][0] = rdir[0]; |
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rdirscan(y)[x][1] = rdir[1]; |
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rdirscan(y)[x][2] = rdir[2]; |
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} else { |
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rdirscan(y)[x][0] = |
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rdirscan(y)[x][1] = |
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rdirscan(y)[x][2] = 0.0; |
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} |
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} |
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} |
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} |
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|
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|
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compveil() /* compute veiling image */ |
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{ |
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double t2, t2sum; |
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COLOR ctmp, vsum; |
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int px, py; |
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register int x, y; |
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|
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if (veilimg != NULL) /* already done? */ |
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return; |
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/* compute ray directions */ |
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compraydir(); |
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/* compute veil image */ |
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veilimg = (COLOR *)malloc(fvxr*fvyr*sizeof(COLOR)); |
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if (veilimg == NULL) |
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syserror("malloc"); |
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for (py = 0; py < fvyr; py++) |
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for (px = 0; px < fvxr; px++) { |
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t2sum = 0.; |
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setcolor(vsum, 0., 0., 0.); |
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for (y = 0; y < fvyr; y++) |
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for (x = 0; x < fvxr; x++) { |
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if (x == px && y == py) continue; |
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t2 = DOT(rdirscan(py)[px], |
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rdirscan(y)[x]); |
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if (t2 <= FTINY) continue; |
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/* use approximation instead |
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t3 = acos(t2); |
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t2 = t2/(t3*t3); |
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*/ |
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t2 *= .5 / (1. - t2); |
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copycolor(ctmp, fovscan(y)[x]); |
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scalecolor(ctmp, t2); |
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addcolor(vsum, ctmp); |
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t2sum += t2; |
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} |
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/* VADAPT of original is subtracted in addveil() */ |
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scalecolor(vsum, VADAPT/t2sum); |
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copycolor(veilscan(py)[px], vsum); |
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} |
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/* modify FOV sample image */ |
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for (y = 0; y < fvyr; y++) |
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for (x = 0; x < fvxr; x++) { |
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scalecolor(fovscan(y)[x], 1.-VADAPT); |
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addcolor(fovscan(y)[x], veilscan(y)[x]); |
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} |
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comphist(); /* recompute histogram */ |
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} |
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|
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|
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addveil(sl, y) /* add veil to scanline */ |
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COLOR *sl; |
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int y; |
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{ |
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int vx, vy; |
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double dx, dy; |
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double lv, uv; |
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register int x, i; |
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|
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vy = dy = (y+.5)/numscans(&inpres)*fvyr - .5; |
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while (vy >= fvyr-1) vy--; |
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dy -= (double)vy; |
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for (x = 0; x < scanlen(&inpres); x++) { |
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vx = dx = (x+.5)/scanlen(&inpres)*fvxr - .5; |
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while (vx >= fvxr-1) vx--; |
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dx -= (double)vx; |
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for (i = 0; i < 3; i++) { |
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lv = (1.-dy)*colval(veilscan(vy)[vx],i) + |
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dy*colval(veilscan(vy+1)[vx],i); |
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uv = (1.-dy)*colval(veilscan(vy)[vx+1],i) + |
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dy*colval(veilscan(vy+1)[vx+1],i); |
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colval(sl[x],i) = (1.-VADAPT)*colval(sl[x],i) + |
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(1.-dx)*lv + dx*uv; |
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} |
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} |
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} |
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|
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|
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/****************** ACUITY STUFF *******************/ |
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|
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typedef struct { |
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short sampe; /* sample area size (exponent of 2) */ |
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short nscans; /* number of scanlines in this bar */ |
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int len; /* individual scanline length */ |
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int nread; /* number of scanlines loaded */ |
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COLOR *sdata; /* scanbar data */ |
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} SCANBAR; |
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|
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#define bscan(sb,y) ((COLOR *)(sb)->sdata+((y)%(sb)->nscans)*(sb)->len) |
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|
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SCANBAR *rootbar; /* root scan bar (lowest resolution) */ |
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|
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float *inpacuD; /* input acuity data (cycles/degree) */ |
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|
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#define tsampr(x,y) inpacuD[(y)*fvxr+(x)] |
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|
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|
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double |
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hacuity(La) /* return visual acuity in cycles/degree */ |
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double La; |
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{ |
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/* functional fit */ |
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return(17.25*atan(1.4*log10(La) + 0.35) + 25.72); |
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} |
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|
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|
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COLOR * |
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getascan(sb, y) /* find/read scanline y for scanbar sb */ |
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register SCANBAR *sb; |
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int y; |
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{ |
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register COLOR *sl0, *sl1, *mysl; |
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register int i; |
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|
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if (y < sb->nread - sb->nscans) /* too far back? */ |
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return(NULL); |
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for ( ; y >= sb->nread; sb->nread++) { /* read as necessary */ |
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mysl = bscan(sb, sb->nread); |
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if (sb->sampe == 0) { |
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if (freadscan(mysl, sb->len, infp) < 0) { |
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fprintf(stderr, "%s: %s: scanline read error\n", |
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progname, infn); |
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exit(1); |
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} |
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} else { |
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sl0 = getascan(sb+1, 2*y); |
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if (sl0 == NULL) |
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return(NULL); |
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sl1 = getascan(sb+1, 2*y+1); |
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for (i = 0; i < sb->len; i++) { |
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copycolor(mysl[i], sl0[2*i]); |
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addcolor(mysl[i], sl0[2*i+1]); |
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addcolor(mysl[i], sl1[2*i]); |
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addcolor(mysl[i], sl1[2*i+1]); |
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scalecolor(mysl[i], 0.25); |
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} |
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} |
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} |
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return(bscan(sb, y)); |
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} |
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|
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|
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acuscan(scln, y) /* get acuity-sampled scanline */ |
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COLOR *scln; |
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int y; |
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{ |
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double sr; |
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double dx, dy; |
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int ix, iy; |
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register int x; |
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/* compute foveal y position */ |
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iy = dy = (y+.5)/numscans(&inpres)*fvyr - .5; |
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while (iy >= fvyr-1) iy--; |
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dy -= (double)iy; |
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for (x = 0; x < scanlen(&inpres); x++) { |
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/* compute foveal x position */ |
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ix = dx = (x+.5)/scanlen(&inpres)*fvxr - .5; |
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while (ix >= fvxr-1) ix--; |
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dx -= (double)ix; |
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/* interpolate sample rate */ |
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sr = (1.-dy)*((1.-dx)*tsampr(ix,iy) + dx*tsampr(ix+1,iy)) + |
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dy*((1.-dx)*tsampr(ix,iy+1) + dx*tsampr(ix+1,iy+1)); |
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|
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acusample(scln[x], x, y, sr); /* compute sample */ |
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} |
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} |
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|
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|
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acusample(col, x, y, sr) /* interpolate sample at (x,y) using rate sr */ |
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COLOR col; |
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int x, y; |
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double sr; |
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{ |
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COLOR c1; |
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double d; |
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register SCANBAR *sb0; |
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|
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for (sb0 = rootbar; sb0->sampe != 0 && 1<<sb0[1].sampe > sr; sb0++) |
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; |
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ascanval(col, x, y, sb0); |
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if (sb0->sampe == 0) /* don't extrapolate highest */ |
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return; |
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ascanval(c1, x, y, sb0+1); |
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d = ((1<<sb0->sampe) - sr)/(1<<sb0[1].sampe); |
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scalecolor(col, 1.-d); |
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scalecolor(c1, d); |
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addcolor(col, c1); |
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} |
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|
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|
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ascanval(col, x, y, sb) /* interpolate scanbar at orig. coords (x,y) */ |
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COLOR col; |
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int x, y; |
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SCANBAR *sb; |
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{ |
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COLOR *sl0, *sl1, c1, c1y; |
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double dx, dy; |
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int ix, iy; |
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|
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if (sb->sampe == 0) { /* no need to interpolate */ |
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sl0 = getascan(sb, y); |
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copycolor(col, sl0[x]); |
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return; |
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} |
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/* compute coordinates for sb */ |
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ix = dx = (x+.5)/(1<<sb->sampe) - .5; |
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while (ix >= sb->len-1) ix--; |
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dx -= (double)ix; |
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iy = dy = (y+.5)/(1<<sb->sampe) - .5; |
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while (iy >= (numscans(&inpres)>>sb->sampe)-1) iy--; |
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dy -= (double)iy; |
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/* get scanlines */ |
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sl0 = getascan(sb, iy); |
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#ifdef DEBUG |
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if (sl0 == NULL) |
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error(INTERNAL, "cannot backspace in ascanval"); |
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#endif |
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sl1 = getascan(sb, iy+1); |
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/* 2D linear interpolation */ |
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copycolor(col, sl0[ix]); |
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scalecolor(col, 1.-dx); |
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copycolor(c1, sl0[ix+1]); |
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scalecolor(c1, dx); |
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addcolor(col, c1); |
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copycolor(c1y, sl1[ix]); |
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scalecolor(c1y, 1.-dx); |
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copycolor(c1, sl1[ix+1]); |
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scalecolor(c1, dx); |
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addcolor(c1y, c1); |
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scalecolor(col, 1.-dy); |
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scalecolor(c1y, dy); |
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addcolor(col, c1y); |
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for (ix = 0; ix < 3; ix++) /* make sure no negative */ |
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if (colval(col,ix) < 0.) |
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colval(col,ix) = 0.; |
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} |
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|
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|
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SCANBAR * |
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sballoc(se, ns, sl) /* allocate scanbar */ |
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int se; /* sampling rate exponent */ |
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int ns; /* number of scanlines */ |
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int sl; /* original scanline length */ |
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{ |
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SCANBAR *sbarr; |
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register SCANBAR *sb; |
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|
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sbarr = sb = (SCANBAR *)malloc((se+1)*sizeof(SCANBAR)); |
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if (sb == NULL) |
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syserror("malloc"); |
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do { |
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sb->sampe = se; |
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sb->len = sl>>se; |
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sb->nscans = ns; |
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sb->sdata = (COLOR *)malloc(sb->len*ns*sizeof(COLOR)); |
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if (sb->sdata == NULL) |
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syserror("malloc"); |
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sb->nread = 0; |
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ns <<= 1; |
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sb++; |
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} while (--se >= 0); |
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return(sbarr); |
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} |
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|
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|
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initacuity() /* initialize variable acuity sampling */ |
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{ |
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FVECT diffx, diffy, cp; |
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double omega, maxsr; |
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register int x, y, i; |
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|
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compraydir(); /* compute ray directions */ |
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|
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inpacuD = (float *)malloc(fvxr*fvyr*sizeof(float)); |
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if (inpacuD == NULL) |
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syserror("malloc"); |
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maxsr = 1.; /* compute internal sample rates */ |
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for (y = 1; y < fvyr-1; y++) |
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for (x = 1; x < fvxr-1; x++) { |
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for (i = 0; i < 3; i++) { |
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diffx[i] = 0.5*fvxr/scanlen(&inpres) * |
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(rdirscan(y)[x+1][i] - |
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rdirscan(y)[x-1][i]); |
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diffy[i] = 0.5*fvyr/numscans(&inpres) * |
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(rdirscan(y+1)[x][i] - |
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rdirscan(y-1)[x][i]); |
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} |
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fcross(cp, diffx, diffy); |
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omega = 0.5 * sqrt(DOT(cp,cp)); |
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if (omega <= FTINY*FTINY) |
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tsampr(x,y) = 1.; |
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else if ((tsampr(x,y) = PI/180. / sqrt(omega) / |
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hacuity(plum(fovscan(y)[x]))) > maxsr) |
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maxsr = tsampr(x,y); |
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} |
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/* copy perimeter (easier) */ |
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for (x = 1; x < fvxr-1; x++) { |
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tsampr(x,0) = tsampr(x,1); |
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tsampr(x,fvyr-1) = tsampr(x,fvyr-2); |
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} |
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for (y = 0; y < fvyr; y++) { |
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tsampr(0,y) = tsampr(1,y); |
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tsampr(fvxr-1,y) = tsampr(fvxr-2,y); |
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} |
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/* initialize with next power of two */ |
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rootbar = sballoc((int)(log(maxsr)/log(2.))+1, 2, scanlen(&inpres)); |
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} |
