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/* Copyright (c) 1986 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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* image.c - routines for image generation. |
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* |
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* 10/17/85 |
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*/ |
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|
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#include "standard.h" |
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|
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#include "view.h" |
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|
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VIEW stdview = STDVIEW; /* default view parameters */ |
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|
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|
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char * |
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setview(v) /* set hvec and vvec, return message on error */ |
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register VIEW *v; |
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{ |
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extern double tan(), normalize(); |
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|
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if (normalize(v->vdir) == 0.0) /* normalize direction */ |
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return("zero view direction"); |
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|
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fcross(v->hvec, v->vdir, v->vup); /* compute horiz dir */ |
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|
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if (normalize(v->hvec) == 0.0) |
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return("illegal view up vector"); |
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|
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fcross(v->vvec, v->hvec, v->vdir); /* compute vert dir */ |
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|
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if (v->type == VT_PAR) |
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v->hn2 = v->horiz; |
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else if (v->type == VT_PER) |
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v->hn2 = 2.0 * tan(v->horiz*(PI/180.0/2.0)); |
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else |
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return("unknown view type"); |
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|
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if (v->hn2 <= FTINY || v->hn2 >= FHUGE) |
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return("illegal horizontal view size"); |
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|
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v->hvec[0] *= v->hn2; |
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v->hvec[1] *= v->hn2; |
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v->hvec[2] *= v->hn2; |
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v->hn2 *= v->hn2; |
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|
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if (v->type == VT_PAR) |
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v->vn2 = v->vert; |
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else |
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v->vn2 = 2.0 * tan(v->vert*(PI/180.0/2.0)); |
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|
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if (v->vn2 <= FTINY || v->vn2 >= FHUGE) |
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return("illegal vertical view size"); |
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|
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v->vvec[0] *= v->vn2; |
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v->vvec[1] *= v->vn2; |
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v->vvec[2] *= v->vn2; |
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v->vn2 *= v->vn2; |
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|
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return(NULL); |
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} |
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|
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|
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normaspect(vp, ap, xp, yp) /* fix pixel aspect or resolution */ |
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VIEW *vp; |
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double *ap; |
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int *xp, *yp; |
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{ |
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double va = viewaspect(vp); |
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|
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if (*ap <= FTINY) |
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*ap = (double)*yp / *xp / va; /* compute pixel aspect */ |
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else if (va * *xp > *ap * *yp) |
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*xp = *yp / va * *ap; /* reduce x resolution */ |
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else |
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*yp = *xp * va / *ap; /* reduce y resolution */ |
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} |
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|
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|
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viewray(orig, direc, v, x, y) /* compute ray origin and direction */ |
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FVECT orig, direc; |
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register VIEW *v; |
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double x, y; |
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{ |
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x += v->hoff - 0.5; |
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y += v->voff - 0.5; |
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|
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if (v->type == VT_PAR) { /* parallel view */ |
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orig[0] = v->vp[0] + x*v->hvec[0] + y*v->vvec[0]; |
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orig[1] = v->vp[1] + x*v->hvec[1] + y*v->vvec[1]; |
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orig[2] = v->vp[2] + x*v->hvec[2] + y*v->vvec[2]; |
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VCOPY(direc, v->vdir); |
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} else { /* perspective view */ |
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VCOPY(orig, v->vp); |
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direc[0] = v->vdir[0] + x*v->hvec[0] + y*v->vvec[0]; |
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direc[1] = v->vdir[1] + x*v->hvec[1] + y*v->vvec[1]; |
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direc[2] = v->vdir[2] + x*v->hvec[2] + y*v->vvec[2]; |
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normalize(direc); |
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} |
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} |
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|
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|
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viewpixel(xp, yp, zp, v, p) /* find image location for point */ |
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double *xp, *yp, *zp; |
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register VIEW *v; |
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FVECT p; |
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{ |
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extern double sqrt(); |
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double d; |
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FVECT disp; |
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|
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disp[0] = p[0] - v->vp[0]; |
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disp[1] = p[1] - v->vp[1]; |
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disp[2] = p[2] - v->vp[2]; |
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|
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if (v->type == VT_PAR) { /* parallel view */ |
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if (zp != NULL) |
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*zp = DOT(disp,v->vdir); |
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} else { /* perspective view */ |
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d = 1.0/DOT(disp,v->vdir); |
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if (zp != NULL) { |
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*zp = sqrt(DOT(disp,disp)); |
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if (d < 0.0) |
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*zp = -*zp; |
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} |
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disp[0] *= d; |
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disp[1] *= d; |
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disp[2] *= d; |
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} |
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*xp = DOT(disp,v->hvec)/v->hn2 + 0.5 - v->hoff; |
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*yp = DOT(disp,v->vvec)/v->vn2 + 0.5 - v->voff; |
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} |
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|
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|
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int |
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getviewopt(v, ac, av) /* process view argument */ |
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register VIEW *v; |
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int ac; |
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register char *av[]; |
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{ |
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#define check(c,n) if ((av[0][c]&&av[0][c]!=' ') || n>=ac) return(-1) |
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extern double atof(); |
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|
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if (av[0][0] != '-' || av[0][1] != 'v') |
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return(-1); |
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switch (av[0][2]) { |
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case 't': /* type */ |
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if (!av[0][3] || av[0][3]==' ') |
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return(-1); |
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check(4,0); |
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v->type = av[0][3]; |
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return(0); |
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case 'p': /* point */ |
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check(3,3); |
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v->vp[0] = atof(av[1]); |
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v->vp[1] = atof(av[2]); |
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v->vp[2] = atof(av[3]); |
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return(3); |
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case 'd': /* direction */ |
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check(3,3); |
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v->vdir[0] = atof(av[1]); |
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v->vdir[1] = atof(av[2]); |
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v->vdir[2] = atof(av[3]); |
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return(3); |
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case 'u': /* up */ |
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check(3,3); |
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v->vup[0] = atof(av[1]); |
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v->vup[1] = atof(av[2]); |
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v->vup[2] = atof(av[3]); |
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return(3); |
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case 'h': /* horizontal size */ |
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check(3,1); |
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v->horiz = atof(av[1]); |
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return(1); |
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case 'v': /* vertical size */ |
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check(3,1); |
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v->vert = atof(av[1]); |
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return(1); |
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case 's': /* shift */ |
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check(3,1); |
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v->hoff = atof(av[1]); |
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return(1); |
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case 'l': /* lift */ |
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check(3,1); |
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v->voff = atof(av[1]); |
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return(1); |
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default: |
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return(-1); |
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} |
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#undef check |
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} |
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|
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|
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int |
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sscanview(vp, s) /* get view parameters from string */ |
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VIEW *vp; |
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register char *s; |
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{ |
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int ac; |
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char *av[4]; |
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int na; |
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int nvopts = 0; |
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|
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while (*s == ' ') |
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s++; |
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do { |
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ac = 0; |
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do { |
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av[ac++] = s; |
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while (*s && *s != ' ') |
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s++; |
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while (*s == ' ') |
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s++; |
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} while (*s && ac < 4); |
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if ((na = getviewopt(vp, ac, av)) >= 0) { |
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if (na+1 < ac) |
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s = av[na+1]; |
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nvopts++; |
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} |
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} while (*s); |
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return(nvopts); |
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} |
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|
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|
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fprintview(vp, fp) /* write out view parameters */ |
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register VIEW *vp; |
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FILE *fp; |
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{ |
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fprintf(fp, " -vt%c", vp->type); |
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fprintf(fp, " -vp %.6g %.6g %.6g", vp->vp[0], vp->vp[1], vp->vp[2]); |
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fprintf(fp, " -vd %.6g %.6g %.6g", vp->vdir[0], vp->vdir[1], vp->vdir[2]); |
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fprintf(fp, " -vu %.6g %.6g %.6g", vp->vup[0], vp->vup[1], vp->vup[2]); |
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fprintf(fp, " -vh %.6g -vv %.6g", vp->horiz, vp->vert); |
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fprintf(fp, " -vs %d -vl %d", vp->hoff, vp->voff); |
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} |
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|
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|
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static VIEW *hview; /* view from header */ |
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static int gothview; /* success indicator */ |
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static char *altname[] = {NULL,"rpict","rview","pinterp",VIEWSTR,NULL}; |
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|
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|
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static |
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gethview(s) /* get view from header */ |
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char *s; |
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{ |
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register char **an; |
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|
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for (an = altname; *an != NULL; an++) |
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if (!strncmp(*an, s, strlen(*an))) { |
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if (sscanview(hview, s+strlen(*an)) > 0) |
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gothview++; |
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return; |
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} |
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} |
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|
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|
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int |
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viewfile(fname, vp) /* get view from file */ |
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char *fname; |
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VIEW *vp; |
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{ |
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extern char *progname; |
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FILE *fp; |
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|
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if ((fp = fopen(fname, "r")) == NULL) |
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return(-1); |
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|
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altname[0] = progname; |
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hview = vp; |
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gothview = 0; |
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|
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getheader(fp, gethview); |
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|
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fclose(fp); |
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|
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return(gothview); |
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} |
