src/rt/m_mirror.c

#ifndef lint
static const char       RCSid[] = "$Id: m_mirror.c,v 2.20 2018/11/13 19:58:33 greg Exp $";
#endif
/*
 * Routines for mirror material supporting virtual light sources
 */

#include "copyright.h"

#include  "ray.h"
#include  "otypes.h"
#include  "rtotypes.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.
 */

static int mir_proj(MAT4  pm, OBJREC  *o, SRCREC  *s, int  n);
static void mirrorproj(MAT4  m, FVECT  nv, double  offs);

VSMATERIAL  mirror_vs = {mir_proj, 1};


int
m_mirror(                       /* shade mirrored ray */
        OBJREC  *m,
        RAY  *r
)
{
        COLOR  mcolor;
        RAY  nr;
        int  rpure = 1;
        int  i;
                                        /* check arguments */
        if (m->oargs.nfargs != 3 || m->oargs.nsargs > 1)
                objerror(m, USER, "bad number of arguments");
                                        /* check for substitute material */
                                        /* but avoid double-counting */
        if ( m->oargs.nsargs > 0 &&
                        (r->rsrc < 0 || source[r->rsrc].so != r->ro) &&
                        !(r->crtype & (AMBIENT|SPECULAR) && r->rod > 0.) ) {
                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 */
                if (!backvis)
                        raytrans(r);    /* unless back visibility is off */
                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, REFLECTED, r, mcolor);
                                        /* 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, REFLECTED, r, mcolor) < 0)
                        return(1);
                if (!(r->crtype & AMBIENT) &&
                                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];
        }
        checknorm(nr.rdir);
        rayvalue(&nr);
        multcolor(nr.rcol, nr.rcoef);
        copycolor(r->mcol, nr.rcol);
        addcolor(r->rcol, nr.rcol);
        r->rmt = r->rot;
        if (rpure && r->ro != NULL && isflat(r->ro->otype))
                r->rmt += r->rot + raydistance(&nr);
        return(1);
}


static int
mir_proj(               /* compute a mirror's projection */
        MAT4  pm,
        OBJREC  *o,
        SRCREC  *s,
        int  n
)
{
        double  corr = 1.;
        FVECT  nv, sc;
        double  od, offs;
        int  i;
                                /* get surface normal and offset */
        offs = od = getplaneq(nv, o);
        if (s->sflags & SDISTANT)
                offs = 0.;
                                /* check for extreme point behind */
        if (s->sflags & SCIR) {
                if (s->sflags & (SFLAT|SDISTANT))
                        corr = 1.12837917;      /* correct setflatss() */
                else
                        corr = 1.0/0.7236;      /* correct sphsetsrc() */
        }
        VCOPY(sc, s->sloc);
        for (i = s->sflags & SFLAT ? SV : SW; i >= 0; i--)
                if (DOT(nv, s->ss[i]) > offs)
                        VSUM(sc, sc, s->ss[i], corr);
                else
                        VSUM(sc, sc, s->ss[i], -corr);
        if (DOT(sc, nv) <= offs+FTINY)
                return(0);
                                /* everything OK -- compute projection */
        mirrorproj(pm, nv, od);
        return(1);
}


static void
mirrorproj(             /* get mirror projection for surface */
        MAT4  m,
        FVECT  nv,
        double  offs
)
{
        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:	2.21
Committed:	Fri Apr 19 19:01:32 2019 UTC (6 years, 6 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.20:	+3 -2 lines
Log Message:	Make sure reflected ray distance is not infinite if there's a reflection
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.21	static const char RCSid[] = "$Id: m_mirror.c,v 2.20 2018/11/13 19:58:33 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Routines for mirror material supporting virtual light sources
6			*/
7
8	greg	2.9	#include "copyright.h"
9	greg	2.8
10	greg	1.1	#include "ray.h"
11			#include "otypes.h"
12	schorsch	2.10	#include "rtotypes.h"
13	greg	1.1	#include "source.h"
14
15			/*
16			* The real arguments for MAT_MIRROR are simply:
17			*
18			* 3 rrefl grefl brefl
19			*
20			* Additionally, the user may specify a single string argument
21			* which is interpreted as the name of the material to use
22			* instead of the mirror if the ray being considered is not
23			* part of the direct calculation.
24			*/
25
26	schorsch	2.10	static int mir_proj(MAT4 pm, OBJREC o, SRCREC s, int n);
27			static void mirrorproj(MAT4 m, FVECT nv, double offs);
28	greg	2.8
29	greg	1.1	VSMATERIAL mirror_vs = {mir_proj, 1};
30
31
32	greg	2.16	int
33	schorsch	2.10	m_mirror( /* shade mirrored ray */
34	greg	2.16	OBJREC *m,
35			RAY *r
36	schorsch	2.10	)
37	greg	1.1	{
38			COLOR mcolor;
39			RAY nr;
40	greg	2.6	int rpure = 1;
41	greg	2.16	int i;
42	greg	1.1	/* check arguments */
43			if (m->oargs.nfargs != 3 \|\| m->oargs.nsargs > 1)
44			objerror(m, USER, "bad number of arguments");
45	greg	1.3	/* check for substitute material */
46	greg	2.14	/* but avoid double-counting */
47	greg	2.19	if ( m->oargs.nsargs > 0 &&
48			(r->rsrc < 0 \|\| source[r->rsrc].so != r->ro) &&
49			!(r->crtype & (AMBIENT\|SPECULAR) && r->rod > 0.) ) {
50	greg	2.4	if (!strcmp(m->oargs.sarg[0], VOIDID)) {
51			raytrans(r);
52			return(1);
53			}
54	gwlarson	2.7	return(rayshade(r, lastmod(objndx(m), m->oargs.sarg[0])));
55	greg	1.1	}
56	greg	1.3	/* check for bad source ray */
57			if (r->rsrc >= 0 && source[r->rsrc].so != r->ro)
58	greg	2.3	return(1);
59	greg	1.3
60	greg	2.15	if (r->rod < 0.) { /* back is black */
61			if (!backvis)
62			raytrans(r); /* unless back visibility is off */
63	greg	2.3	return(1);
64	greg	2.15	}
65	greg	1.1	/* get modifiers */
66			raytexture(r, m->omod);
67			/* assign material color */
68			setcolor(mcolor, m->oargs.farg[0],
69			m->oargs.farg[1],
70			m->oargs.farg[2]);
71			multcolor(mcolor, r->pcol);
72			/* compute reflected ray */
73			if (r->rsrc >= 0) { /* relayed light source */
74	greg	2.11	rayorigin(&nr, REFLECTED, r, mcolor);
75	greg	1.1	/* ignore textures */
76			for (i = 0; i < 3; i++)
77			nr.rdir[i] = r->rdir[i] + 2.r->rodr->ron[i];
78			/* source we're aiming for next */
79	greg	1.2	nr.rsrc = source[r->rsrc].sa.sv.sn;
80	greg	1.1	} else { /* ordinary reflection */
81			FVECT pnorm;
82			double pdot;
83
84	greg	2.11	if (rayorigin(&nr, REFLECTED, r, mcolor) < 0)
85	greg	2.3	return(1);
86	greg	2.16	if (!(r->crtype & AMBIENT) &&
87			DOT(r->pert,r->pert) > FTINY*FTINY) {
88	greg	2.6	pdot = raynormal(pnorm, r); /* use textures */
89			for (i = 0; i < 3; i++)
90			nr.rdir[i] = r->rdir[i] + 2.pdotpnorm[i];
91			rpure = 0;
92			}
93	greg	2.2	/* check for penetration */
94	greg	2.6	if (rpure \|\| DOT(nr.rdir, r->ron) <= FTINY)
95	greg	2.2	for (i = 0; i < 3; i++)
96			nr.rdir[i] = r->rdir[i] + 2.r->rodr->ron[i];
97	greg	1.1	}
98	greg	2.13	checknorm(nr.rdir);
99	greg	1.1	rayvalue(&nr);
100	greg	2.11	multcolor(nr.rcol, nr.rcoef);
101	greg	2.20	copycolor(r->mcol, nr.rcol);
102	greg	1.1	addcolor(r->rcol, nr.rcol);
103	greg	2.21	r->rmt = r->rot;
104	greg	2.6	if (rpure && r->ro != NULL && isflat(r->ro->otype))
105	greg	2.21	r->rmt += r->rot + raydistance(&nr);
106	greg	2.3	return(1);
107	greg	1.1	}
108
109
110	greg	2.8	static int
111	schorsch	2.10	mir_proj( /* compute a mirror's projection */
112			MAT4 pm,
113	greg	2.16	OBJREC *o,
114	schorsch	2.10	SRCREC *s,
115			int n
116			)
117	greg	1.1	{
118	greg	2.12	double corr = 1.;
119	greg	2.5	FVECT nv, sc;
120	greg	2.12	double od, offs;
121			int i;
122	greg	1.1	/* get surface normal and offset */
123	greg	2.12	offs = od = getplaneq(nv, o);
124			if (s->sflags & SDISTANT)
125			offs = 0.;
126			/* check for extreme point behind */
127			if (s->sflags & SCIR) {
128			if (s->sflags & (SFLAT\|SDISTANT))
129			corr = 1.12837917; /* correct setflatss() */
130			else
131			corr = 1.0/0.7236; /* correct sphsetsrc() */
132			}
133	greg	2.5	VCOPY(sc, s->sloc);
134			for (i = s->sflags & SFLAT ? SV : SW; i >= 0; i--)
135	greg	2.12	if (DOT(nv, s->ss[i]) > offs)
136			VSUM(sc, sc, s->ss[i], corr);
137	greg	2.5	else
138	greg	2.12	VSUM(sc, sc, s->ss[i], -corr);
139			if (DOT(sc, nv) <= offs+FTINY)
140	greg	1.1	return(0);
141			/* everything OK -- compute projection */
142			mirrorproj(pm, nv, od);
143			return(1);
144			}
145
146
147	schorsch	2.10	static void
148			mirrorproj( /* get mirror projection for surface */
149	greg	2.16	MAT4 m,
150	schorsch	2.10	FVECT nv,
151			double offs
152			)
153	greg	1.1	{
154	greg	2.16	int i, j;
155	greg	1.1	/* assign matrix */
156			setident4(m);
157	greg	1.2	for (j = 0; j < 3; j++) {
158			for (i = 0; i < 3; i++)
159	greg	1.1	m[i][j] -= 2.nv[i]nv[j];
160			m[3][j] = 2.offsnv[j];
161	greg	1.2	}
162	greg	1.1	}