src/rt/m_mirror.c

/* Copyright (c) 1991 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 * Routines for mirror material supporting virtual light sources
 */

#include  "ray.h"

#include  "otypes.h"

#include  "source.h"

/*
 * The real arguments for MAT_MIRROR are simply:
 *
 *      3 rrefl grefl brefl
 *
 * Additionally, the user may specify a single string argument
 * which is interpreted as the name of the material to use
 * instead of the mirror if the ray being considered is not
 * part of the direct calculation.
 */


int  mir_proj();
VSMATERIAL  mirror_vs = {mir_proj, 1};


m_mirror(m, r)                  /* shade mirrored ray */
register OBJREC  *m;
register RAY  *r;
{
        COLOR  mcolor;
        RAY  nr;
        register int  i;
                                        /* check arguments */
        if (m->oargs.nfargs != 3 || m->oargs.nsargs > 1)
                objerror(m, USER, "bad number of arguments");
                                        /* check for substitute material */
        if (m->oargs.nsargs > 0 &&
                        (r->rsrc < 0 || source[r->rsrc].so != r->ro)) {
                if (!strcmp(m->oargs.sarg[0], VOIDID)) {
                        raytrans(r);
                        return(1);
                }
                return(rayshade(r, modifier(m->oargs.sarg[0])));
        }
                                        /* check for bad source ray */
        if (r->rsrc >= 0 && source[r->rsrc].so != r->ro)
                return(1);

        if (r->rod < 0.)                /* back is black */
                return(1);
                                        /* get modifiers */
        raytexture(r, m->omod);
                                        /* assign material color */
        setcolor(mcolor, m->oargs.farg[0],
                        m->oargs.farg[1],
                        m->oargs.farg[2]);
        multcolor(mcolor, r->pcol);
                                        /* compute reflected ray */
        if (r->rsrc >= 0) {                     /* relayed light source */
                rayorigin(&nr, r, REFLECTED, 1.);
                                        /* ignore textures */
                for (i = 0; i < 3; i++)
                        nr.rdir[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
                                        /* source we're aiming for next */
                nr.rsrc = source[r->rsrc].sa.sv.sn;
        } else {                                /* ordinary reflection */
                FVECT  pnorm;
                double  pdot;

                if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0)
                        return(1);
                pdot = raynormal(pnorm, r);     /* use textures */
                for (i = 0; i < 3; i++)
                        nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
                                                /* check for penetration */
                if (DOT(nr.rdir, r->ron) <= FTINY)
                        for (i = 0; i < 3; i++)
                                nr.rdir[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
        }
        rayvalue(&nr);
        multcolor(nr.rcol, mcolor);
        addcolor(r->rcol, nr.rcol);
        return(1);
}


mir_proj(pm, o, s, n)           /* compute a mirror's projection */
MAT4  pm;
register OBJREC  *o;
SRCREC  *s;
int  n;
{
        FVECT  nv;
        double  od;
                                /* get surface normal and offset */
        od = getplaneq(nv, o);
                                /* check for behind */
        if (DOT(s->sloc, nv) <= (s->sflags & SDISTANT ? FTINY : od+FTINY))
                return(0);
                                /* everything OK -- compute projection */
        mirrorproj(pm, nv, od);
        return(1);
}


mirrorproj(m, nv, offs)         /* get mirror projection for surface */
register MAT4  m;
FVECT  nv;
double  offs;
{
        register int  i, j;
                                        /* assign matrix */
        setident4(m);
        for (j = 0; j < 3; j++) {
                for (i = 0; i < 3; i++)
                        m[i][j] -= 2.*nv[i]*nv[j];
                m[3][j] = 2.*offs*nv[j];
        }
}
Revision:	2.4
Committed:	Wed Jul 26 16:53:25 1995 UTC (28 years, 9 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.3:	+5 -2 lines
Log Message:	changed behavior of mirror so that void alternate makes transparent
#	User	Rev	Content
1	greg	1.1	/* Copyright (c) 1991 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* Routines for mirror material supporting virtual light sources
9			*/
10
11			#include "ray.h"
12
13			#include "otypes.h"
14
15			#include "source.h"
16
17			/*
18			* The real arguments for MAT_MIRROR are simply:
19			*
20			* 3 rrefl grefl brefl
21			*
22			* Additionally, the user may specify a single string argument
23			* which is interpreted as the name of the material to use
24			* instead of the mirror if the ray being considered is not
25			* part of the direct calculation.
26			*/
27
28
29			int mir_proj();
30			VSMATERIAL mirror_vs = {mir_proj, 1};
31
32
33			m_mirror(m, r) /* shade mirrored ray */
34			register OBJREC *m;
35			register RAY *r;
36			{
37			COLOR mcolor;
38			RAY nr;
39			register int i;
40			/* check arguments */
41			if (m->oargs.nfargs != 3 \|\| m->oargs.nsargs > 1)
42			objerror(m, USER, "bad number of arguments");
43	greg	1.3	/* check for substitute material */
44			if (m->oargs.nsargs > 0 &&
45			(r->rsrc < 0 \|\| source[r->rsrc].so != r->ro)) {
46	greg	2.4	if (!strcmp(m->oargs.sarg[0], VOIDID)) {
47			raytrans(r);
48			return(1);
49			}
50			return(rayshade(r, modifier(m->oargs.sarg[0])));
51	greg	1.1	}
52	greg	1.3	/* check for bad source ray */
53			if (r->rsrc >= 0 && source[r->rsrc].so != r->ro)
54	greg	2.3	return(1);
55	greg	1.3
56	greg	1.1	if (r->rod < 0.) /* back is black */
57	greg	2.3	return(1);
58	greg	1.1	/* get modifiers */
59			raytexture(r, m->omod);
60			/* assign material color */
61			setcolor(mcolor, m->oargs.farg[0],
62			m->oargs.farg[1],
63			m->oargs.farg[2]);
64			multcolor(mcolor, r->pcol);
65			/* compute reflected ray */
66			if (r->rsrc >= 0) { /* relayed light source */
67			rayorigin(&nr, r, REFLECTED, 1.);
68			/* ignore textures */
69			for (i = 0; i < 3; i++)
70			nr.rdir[i] = r->rdir[i] + 2.r->rodr->ron[i];
71			/* source we're aiming for next */
72	greg	1.2	nr.rsrc = source[r->rsrc].sa.sv.sn;
73	greg	1.1	} else { /* ordinary reflection */
74			FVECT pnorm;
75			double pdot;
76
77			if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0)
78	greg	2.3	return(1);
79	greg	1.1	pdot = raynormal(pnorm, r); /* use textures */
80			for (i = 0; i < 3; i++)
81			nr.rdir[i] = r->rdir[i] + 2.pdotpnorm[i];
82	greg	2.2	/* check for penetration */
83			if (DOT(nr.rdir, r->ron) <= FTINY)
84			for (i = 0; i < 3; i++)
85			nr.rdir[i] = r->rdir[i] + 2.r->rodr->ron[i];
86	greg	1.1	}
87			rayvalue(&nr);
88			multcolor(nr.rcol, mcolor);
89			addcolor(r->rcol, nr.rcol);
90	greg	2.3	return(1);
91	greg	1.1	}
92
93
94			mir_proj(pm, o, s, n) /* compute a mirror's projection */
95			MAT4 pm;
96			register OBJREC *o;
97	greg	1.2	SRCREC *s;
98	greg	1.1	int n;
99			{
100			FVECT nv;
101			double od;
102			/* get surface normal and offset */
103	greg	1.2	od = getplaneq(nv, o);
104	greg	1.1	/* check for behind */
105			if (DOT(s->sloc, nv) <= (s->sflags & SDISTANT ? FTINY : od+FTINY))
106			return(0);
107			/* everything OK -- compute projection */
108			mirrorproj(pm, nv, od);
109			return(1);
110			}
111
112
113			mirrorproj(m, nv, offs) /* get mirror projection for surface */
114			register MAT4 m;
115			FVECT nv;
116			double offs;
117			{
118			register int i, j;
119			/* assign matrix */
120			setident4(m);
121	greg	1.2	for (j = 0; j < 3; j++) {
122			for (i = 0; i < 3; i++)
123	greg	1.1	m[i][j] -= 2.nv[i]nv[j];
124			m[3][j] = 2.offsnv[j];
125	greg	1.2	}
126	greg	1.1	}