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/* Copyright (c) 1996 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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|
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#define VADAPT 0.08 /* fraction of adaptation from veil */ |
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|
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extern COLOR *fovimg; /* foveal (1 degree) averaged image */ |
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extern short fvxr, fvyr; /* foveal image resolution */ |
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|
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#define fovscan(y) (fovimg+(y)*fvxr) |
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|
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static COLOR *veilimg; /* 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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/* 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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t2 = acos(t2); |
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t2 = 1./(t2*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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} |
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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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if (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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if (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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} |
