src/rt/m_mirror.c

/* Copyright (c) 1998 Silicon Graphics, Inc. */

#ifndef lint
static char SCCSid[] = "$SunId$ SGI";
#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;
        int  rpure = 1;
        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, lastmod(objndx(m), 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);
                if (DOT(r->pert,r->pert) > FTINY*FTINY) {
                        pdot = raynormal(pnorm, r);     /* use textures */
                        for (i = 0; i < 3; i++)
                                nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
                        rpure = 0;
                }
                                                /* check for penetration */
                if (rpure || 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);
        if (rpure && r->ro != NULL && isflat(r->ro->otype))
                r->rt = r->rot + nr.rt;
        return(1);
}


mir_proj(pm, o, s, n)           /* compute a mirror's projection */
MAT4  pm;
register OBJREC  *o;
SRCREC  *s;
int  n;
{
        FVECT  nv, sc;
        double  od;
        register int  i, j;
                                /* get surface normal and offset */
        od = getplaneq(nv, o);
                                /* check for extreme point for behind */
        VCOPY(sc, s->sloc);
        for (i = s->sflags & SFLAT ? SV : SW; i >= 0; i--)
                if (DOT(nv, s->ss[i]) > 0.)
                        for (j = 0; j < 3; j++)
                                sc[j] += s->ss[i][j];
                else
                        for (j = 0; j < 3; j++)
                                sc[j] -= s->ss[i][j];
        if (DOT(sc, 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:	2.7
Committed:	Mon Aug 10 18:37:05 1998 UTC (27 years, 2 months ago) by gwlarson
Content type:	text/plain
Branch:	MAIN
Changes since 2.6:	+3 -3 lines
Log Message:	changed modifier checking to take most recent definition
#	User	Rev	Content
1	gwlarson	2.7	/* Copyright (c) 1998 Silicon Graphics, Inc. */
2	greg	1.1
3			#ifndef lint
4	gwlarson	2.7	static char SCCSid[] = "$SunId$ SGI";
5	greg	1.1	#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	greg	2.6	int rpure = 1;
40	greg	1.1	register int i;
41			/* check arguments */
42			if (m->oargs.nfargs != 3 \|\| m->oargs.nsargs > 1)
43			objerror(m, USER, "bad number of arguments");
44	greg	1.3	/* check for substitute material */
45			if (m->oargs.nsargs > 0 &&
46			(r->rsrc < 0 \|\| source[r->rsrc].so != r->ro)) {
47	greg	2.4	if (!strcmp(m->oargs.sarg[0], VOIDID)) {
48			raytrans(r);
49			return(1);
50			}
51	gwlarson	2.7	return(rayshade(r, lastmod(objndx(m), m->oargs.sarg[0])));
52	greg	1.1	}
53	greg	1.3	/* check for bad source ray */
54			if (r->rsrc >= 0 && source[r->rsrc].so != r->ro)
55	greg	2.3	return(1);
56	greg	1.3
57	greg	1.1	if (r->rod < 0.) /* back is black */
58	greg	2.3	return(1);
59	greg	1.1	/* get modifiers */
60			raytexture(r, m->omod);
61			/* assign material color */
62			setcolor(mcolor, m->oargs.farg[0],
63			m->oargs.farg[1],
64			m->oargs.farg[2]);
65			multcolor(mcolor, r->pcol);
66			/* compute reflected ray */
67			if (r->rsrc >= 0) { /* relayed light source */
68			rayorigin(&nr, r, REFLECTED, 1.);
69			/* ignore textures */
70			for (i = 0; i < 3; i++)
71			nr.rdir[i] = r->rdir[i] + 2.r->rodr->ron[i];
72			/* source we're aiming for next */
73	greg	1.2	nr.rsrc = source[r->rsrc].sa.sv.sn;
74	greg	1.1	} else { /* ordinary reflection */
75			FVECT pnorm;
76			double pdot;
77
78			if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0)
79	greg	2.3	return(1);
80	greg	2.6	if (DOT(r->pert,r->pert) > FTINY*FTINY) {
81			pdot = raynormal(pnorm, r); /* use textures */
82			for (i = 0; i < 3; i++)
83			nr.rdir[i] = r->rdir[i] + 2.pdotpnorm[i];
84			rpure = 0;
85			}
86	greg	2.2	/* check for penetration */
87	greg	2.6	if (rpure \|\| DOT(nr.rdir, r->ron) <= FTINY)
88	greg	2.2	for (i = 0; i < 3; i++)
89			nr.rdir[i] = r->rdir[i] + 2.r->rodr->ron[i];
90	greg	1.1	}
91			rayvalue(&nr);
92			multcolor(nr.rcol, mcolor);
93			addcolor(r->rcol, nr.rcol);
94	greg	2.6	if (rpure && r->ro != NULL && isflat(r->ro->otype))
95			r->rt = r->rot + nr.rt;
96	greg	2.3	return(1);
97	greg	1.1	}
98
99
100			mir_proj(pm, o, s, n) /* compute a mirror's projection */
101			MAT4 pm;
102			register OBJREC *o;
103	greg	1.2	SRCREC *s;
104	greg	1.1	int n;
105			{
106	greg	2.5	FVECT nv, sc;
107	greg	1.1	double od;
108	greg	2.5	register int i, j;
109	greg	1.1	/* get surface normal and offset */
110	greg	1.2	od = getplaneq(nv, o);
111	greg	2.5	/* check for extreme point for behind */
112			VCOPY(sc, s->sloc);
113			for (i = s->sflags & SFLAT ? SV : SW; i >= 0; i--)
114			if (DOT(nv, s->ss[i]) > 0.)
115			for (j = 0; j < 3; j++)
116			sc[j] += s->ss[i][j];
117			else
118			for (j = 0; j < 3; j++)
119			sc[j] -= s->ss[i][j];
120			if (DOT(sc, nv) <= (s->sflags & SDISTANT ? FTINY : od+FTINY))
121	greg	1.1	return(0);
122			/* everything OK -- compute projection */
123			mirrorproj(pm, nv, od);
124			return(1);
125			}
126
127
128			mirrorproj(m, nv, offs) /* get mirror projection for surface */
129			register MAT4 m;
130			FVECT nv;
131			double offs;
132			{
133			register int i, j;
134			/* assign matrix */
135			setident4(m);
136	greg	1.2	for (j = 0; j < 3; j++) {
137			for (i = 0; i < 3; i++)
138	greg	1.1	m[i][j] -= 2.nv[i]nv[j];
139			m[3][j] = 2.offsnv[j];
140	greg	1.2	}
141	greg	1.1	}