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#ifndef lint |
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static const char RCSid[] = "$Id: image.c,v 2.52 2021/02/12 00:47:08 greg Exp $"; |
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#endif |
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/* |
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* jitteraperture.c - routine to sample depth-of-field |
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* |
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* External symbols declared in view.h |
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*/ |
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|
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#include "copyright.h" |
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|
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#include <stdio.h> |
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#include "rtmath.h" |
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#include "random.h" |
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#include "view.h" |
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|
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|
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int |
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jitteraperture( /* random aperture shift for depth-of-field */ |
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FVECT orig, /* assigned previously by... */ |
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FVECT direc, /* ...viewray() call */ |
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VIEW *v, |
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double dia |
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) |
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{ |
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double vc, df[2]; |
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int i; |
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/* are we even needed? */ |
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if (dia <= FTINY) |
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return(1); |
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/* get random point on disk */ |
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SDsquare2disk(df, frandom(), frandom()); |
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df[0] *= .5*dia; |
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df[1] *= .5*dia; |
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if ((v->type == VT_PER) | (v->type == VT_PAR)) { |
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double adj = 1.0; /* basic view cases */ |
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if (v->type == VT_PER) |
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adj /= DOT(direc, v->vdir); |
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df[0] /= sqrt(v->hn2); |
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df[1] /= sqrt(v->vn2); |
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for (i = 3; i--; ) { |
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vc = v->vp[i] + adj*v->vdist*direc[i]; |
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orig[i] += df[0]*v->hvec[i] + |
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df[1]*v->vvec[i] ; |
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direc[i] = vc - orig[i]; |
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} |
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} else { /* difficult view cases */ |
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double dfd = PI/4.*dia*(.5 - frandom()); |
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if ((v->type != VT_ANG) & (v->type != VT_PLS)) { |
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if (v->type != VT_CYL) |
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df[0] /= sqrt(v->hn2); |
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df[1] /= sqrt(v->vn2); |
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} |
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for (i = 3; i--; ) { |
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vc = v->vp[i] + v->vdist*direc[i]; |
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orig[i] += df[0]*v->hvec[i] + |
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df[1]*v->vvec[i] + |
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dfd*v->vdir[i] ; |
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direc[i] = vc - orig[i]; |
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} |
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} |
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return(normalize(direc) != 0.0); |
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} |
