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greg |
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/* Copyright (c) 1991 Regents of the University of California */ |
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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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* Routines for mirror material supporting virtual light sources |
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*/ |
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#include "ray.h" |
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#include "otypes.h" |
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#include "source.h" |
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/* |
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* The real arguments for MAT_MIRROR are simply: |
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* |
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* 3 rrefl grefl brefl |
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* |
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* Additionally, the user may specify a single string argument |
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* which is interpreted as the name of the material to use |
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* instead of the mirror if the ray being considered is not |
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* part of the direct calculation. |
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*/ |
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int mir_proj(); |
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VSMATERIAL mirror_vs = {mir_proj, 1}; |
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m_mirror(m, r) /* shade mirrored ray */ |
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register OBJREC *m; |
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register RAY *r; |
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{ |
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COLOR mcolor; |
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RAY nr; |
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register int i; |
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/* check arguments */ |
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if (m->oargs.nfargs != 3 || m->oargs.nsargs > 1) |
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objerror(m, USER, "bad number of arguments"); |
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/* check if source ray */ |
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if (r->rsrc >= 0) { /* aiming for somebody */ |
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if (source[r->rsrc].so != r->ro) |
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return; /* but not us */ |
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} else if (m->oargs.nsargs > 0) { /* else call substitute? */ |
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rayshade(r, modifier(m->oargs.sarg[0])); |
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return; |
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} |
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if (r->rod < 0.) /* back is black */ |
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return; |
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/* get modifiers */ |
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raytexture(r, m->omod); |
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/* assign material color */ |
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setcolor(mcolor, m->oargs.farg[0], |
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m->oargs.farg[1], |
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m->oargs.farg[2]); |
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multcolor(mcolor, r->pcol); |
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/* compute reflected ray */ |
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if (r->rsrc >= 0) { /* relayed light source */ |
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rayorigin(&nr, r, REFLECTED, 1.); |
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/* ignore textures */ |
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for (i = 0; i < 3; i++) |
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nr.rdir[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
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/* source we're aiming for next */ |
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greg |
1.2 |
nr.rsrc = source[r->rsrc].sa.sv.sn; |
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} else { /* ordinary reflection */ |
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FVECT pnorm; |
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double pdot; |
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if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0) |
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return; |
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pdot = raynormal(pnorm, r); /* use textures */ |
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for (i = 0; i < 3; i++) |
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nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i]; |
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} |
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rayvalue(&nr); |
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multcolor(nr.rcol, mcolor); |
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addcolor(r->rcol, nr.rcol); |
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} |
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mir_proj(pm, o, s, n) /* compute a mirror's projection */ |
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MAT4 pm; |
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register OBJREC *o; |
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greg |
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SRCREC *s; |
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greg |
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int n; |
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{ |
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FVECT nv; |
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double od; |
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/* get surface normal and offset */ |
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od = getplaneq(nv, o); |
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/* check for behind */ |
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if (DOT(s->sloc, nv) <= (s->sflags & SDISTANT ? FTINY : od+FTINY)) |
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return(0); |
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/* everything OK -- compute projection */ |
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mirrorproj(pm, nv, od); |
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return(1); |
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} |
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mirrorproj(m, nv, offs) /* get mirror projection for surface */ |
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register MAT4 m; |
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FVECT nv; |
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double offs; |
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{ |
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register int i, j; |
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/* assign matrix */ |
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setident4(m); |
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for (j = 0; j < 3; j++) { |
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for (i = 0; i < 3; i++) |
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m[i][j] -= 2.*nv[i]*nv[j]; |
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m[3][j] = 2.*offs*nv[j]; |
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greg |
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} |
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greg |
1.1 |
} |
