src/rt/raytrace.c

#ifndef lint
static const char RCSid[] = "$Id: raytrace.c,v 2.48 2005/04/15 04:44:51 greg Exp $";
#endif
/*
 *  raytrace.c - routines for tracing and shading rays.
 *
 *  External symbols declared in ray.h
 */

#include "copyright.h"

#include  "ray.h"
#include  "source.h"
#include  "otypes.h"
#include  "otspecial.h"

#define  MAXCSET        ((MAXSET+1)*2-1)        /* maximum check set size */

unsigned long  raynum = 0;              /* next unique ray number */
unsigned long  nrays = 0;               /* number of calls to localhit */

static RREAL  Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
OBJREC  Lamb = {
        OVOID, MAT_PLASTIC, "Lambertian",
        {0, 5, NULL, Lambfa}, NULL,
};                                      /* a Lambertian surface */

OBJREC  Aftplane;                       /* aft clipping plane object */

#define  RAYHIT         (-1)            /* return value for intercepted ray */

static int raymove(FVECT  pos, OBJECT  *cxs, int  dirf, RAY  *r, CUBE  *cu);
static int checkhit(RAY  *r, CUBE  *cu, OBJECT  *cxs);
static void checkset(OBJECT  *os, OBJECT  *cs);


extern int
rayorigin(              /* start new ray from old one */
        RAY  *r,
        int  rt,
        const RAY  *ro,
        const COLOR rc
)
{
        double  rw, re;
                                                /* assign coefficient/weight */
        if (rc == NULL) {
                rw = 1.0;
                setcolor(r->rcoef, 1., 1., 1.);
        } else {
                rw = intens(rc);
                if (rc != r->rcoef)
                        copycolor(r->rcoef, rc);
        }
        if ((r->parent = ro) == NULL) {         /* primary ray */
                r->rlvl = 0;
                r->rweight = rw;
                r->crtype = r->rtype = rt;
                r->rsrc = -1;
                r->clipset = NULL;
                copycolor(r->cext, cextinction);
                copycolor(r->albedo, salbedo);
                r->gecc = seccg;
                r->slights = NULL;
        } else {                                /* spawned ray */
                if (ro->rot >= FHUGE) {
                        memset(r, 0, sizeof(RAY));
                        return(-1);             /* illegal continuation */
                }
                r->rlvl = ro->rlvl;
                if (rt & RAYREFL) {
                        r->rlvl++;
                        r->rsrc = -1;
                        r->clipset = ro->clipset;
                        r->rmax = 0.0;
                } else {
                        r->rsrc = ro->rsrc;
                        r->clipset = ro->newcset;
                        r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
                }
                copycolor(r->cext, ro->cext);
                copycolor(r->albedo, ro->albedo);
                r->gecc = ro->gecc;
                r->slights = ro->slights;
                r->crtype = ro->crtype | (r->rtype = rt);
                VCOPY(r->rorg, ro->rop);
                r->rweight = ro->rweight * rw;
                                                /* estimate extinction */
                re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
                                colval(ro->cext,RED) : colval(ro->cext,GRN);
                if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
                re *= ro->rot;
                if (re > .1)
                        r->rweight *= exp(-re);
        }
        rayclear(r);
        return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
}


extern void
rayclear(                       /* clear a ray for (re)evaluation */
        register RAY  *r
)
{
        r->rno = raynum++;
        r->newcset = r->clipset;
        r->hitf = rayhit;
        r->robj = OVOID;
        r->ro = NULL;
        r->rox = NULL;
        r->rt = r->rot = FHUGE;
        r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
        r->uv[0] = r->uv[1] = 0.0;
        setcolor(r->pcol, 1.0, 1.0, 1.0);
        setcolor(r->rcol, 0.0, 0.0, 0.0);
}


extern void
rayvalue(                       /* trace a ray and compute its value */
        RAY  *r
)
{
        if (localhit(r, &thescene))
                raycont(r);             /* hit local surface, evaluate */
        else if (r->ro == &Aftplane) {
                r->ro = NULL;           /* hit aft clipping plane */
                r->rot = FHUGE;
        } else if (sourcehit(r))
                rayshade(r, r->ro->omod);       /* distant source */

        if (trace != NULL)
                (*trace)(r);            /* trace execution */

        rayparticipate(r);              /* for participating medium */
}


extern void
raycont(                        /* check for clipped object and continue */
        register RAY  *r
)
{
        if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) ||
                        !rayshade(r, r->ro->omod))
                raytrans(r);
}


extern void
raytrans(                       /* transmit ray as is */
        register RAY  *r
)
{
        RAY  tr;

        if (rayorigin(&tr, TRANS, r, NULL) == 0) {
                VCOPY(tr.rdir, r->rdir);
                rayvalue(&tr);
                copycolor(r->rcol, tr.rcol);
                r->rt = r->rot + tr.rt;
        }
}


extern int
rayshade(               /* shade ray r with material mod */
        register RAY  *r,
        int  mod
)
{
        register OBJREC  *m;

        r->rt = r->rot;                 /* set effective ray length */
        for ( ; mod != OVOID; mod = m->omod) {
                m = objptr(mod);
                /****** unnecessary test since modifier() is always called
                if (!ismodifier(m->otype)) {
                        sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
                        error(USER, errmsg);
                }
                ******/
                                        /* hack for irradiance calculation */
                if (do_irrad && !(r->crtype & ~(PRIMARY|TRANS)) &&
                                m->otype != MAT_CLIP &&
                                (ofun[m->otype].flags & (T_M|T_X))) {
                        if (irr_ignore(m->otype)) {
                                raytrans(r);
                                return(1);
                        }
                        if (!islight(m->otype))
                                m = &Lamb;
                }
                if ((*ofun[m->otype].funp)(m, r))
                        return(1);      /* materials call raytexture() */
        }
        return(0);                      /* no material! */
}


extern void
rayparticipate(                 /* compute ray medium participation */
        register RAY  *r
)
{
        COLOR   ce, ca;
        double  re, ge, be;

        if (intens(r->cext) <= 1./FHUGE)
                return;                         /* no medium */
        re = r->rot*colval(r->cext,RED);
        ge = r->rot*colval(r->cext,GRN);
        be = r->rot*colval(r->cext,BLU);
        if (r->crtype & SHADOW) {               /* no scattering for sources */
                re *= 1. - colval(r->albedo,RED);
                ge *= 1. - colval(r->albedo,GRN);
                be *= 1. - colval(r->albedo,BLU);
        }
        setcolor(ce,    re<=FTINY ? 1. : re>92. ? 0. : exp(-re),
                        ge<=FTINY ? 1. : ge>92. ? 0. : exp(-ge),
                        be<=FTINY ? 1. : be>92. ? 0. : exp(-be));
        multcolor(r->rcol, ce);                 /* path extinction */
        if (r->crtype & SHADOW || intens(r->albedo) <= FTINY)
                return;                         /* no scattering */
        setcolor(ca,
                colval(r->albedo,RED)*colval(ambval,RED)*(1.-colval(ce,RED)),
                colval(r->albedo,GRN)*colval(ambval,GRN)*(1.-colval(ce,GRN)),
                colval(r->albedo,BLU)*colval(ambval,BLU)*(1.-colval(ce,BLU)));
        addcolor(r->rcol, ca);                  /* ambient in scattering */
        srcscatter(r);                          /* source in scattering */
}


extern void
raytexture(                     /* get material modifiers */
        RAY  *r,
        OBJECT  mod
)
{
        register OBJREC  *m;
                                        /* execute textures and patterns */
        for ( ; mod != OVOID; mod = m->omod) {
                m = objptr(mod);
                /****** unnecessary test since modifier() is always called
                if (!ismodifier(m->otype)) {
                        sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
                        error(USER, errmsg);
                }
                ******/
                if ((*ofun[m->otype].funp)(m, r)) {
                        sprintf(errmsg, "conflicting material \"%s\"",
                                        m->oname);
                        objerror(r->ro, USER, errmsg);
                }
        }
}


extern int
raymixture(             /* mix modifiers */
        register RAY  *r,
        OBJECT  fore,
        OBJECT  back,
        double  coef
)
{
        RAY  fr, br;
        int  foremat, backmat;
        register int  i;
                                        /* bound coefficient */
        if (coef > 1.0)
                coef = 1.0;
        else if (coef < 0.0)
                coef = 0.0;
                                        /* compute foreground and background */
        foremat = backmat = 0;
                                        /* foreground */
        fr = *r;
        if (coef > FTINY)
                foremat = rayshade(&fr, fore);
                                        /* background */
        br = *r;
        if (coef < 1.0-FTINY)
                backmat = rayshade(&br, back);
                                        /* check for transparency */
        if (backmat ^ foremat) {
                if (backmat && coef > FTINY)
                        raytrans(&fr);
                else if (foremat && coef < 1.0-FTINY)
                        raytrans(&br);
        }
                                        /* mix perturbations */
        for (i = 0; i < 3; i++)
                r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
                                        /* mix pattern colors */
        scalecolor(fr.pcol, coef);
        scalecolor(br.pcol, 1.0-coef);
        copycolor(r->pcol, fr.pcol);
        addcolor(r->pcol, br.pcol);
                                        /* return value tells if material */
        if (!foremat & !backmat)
                return(0);
                                        /* mix returned ray values */
        scalecolor(fr.rcol, coef);
        scalecolor(br.rcol, 1.0-coef);
        copycolor(r->rcol, fr.rcol);
        addcolor(r->rcol, br.rcol);
        r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
        return(1);
}


extern double
raydist(                /* compute (cumulative) ray distance */
        register const RAY  *r,
        register int  flags
)
{
        double  sum = 0.0;

        while (r != NULL && r->crtype&flags) {
                sum += r->rot;
                r = r->parent;
        }
        return(sum);
}


extern void
raycontrib(             /* compute (cumulative) ray contribution */
        COLOR  rc,
        const RAY  *r,
        int  flags
)
{
        COLOR   eext, ext1;
        
        setcolor(eext, 0., 0., 0.);
        setcolor(rc, 1., 1., 1.);

        while (r != NULL && r->crtype&flags) {
                multcolor(rc, r->rcoef);
                copycolor(ext1, r->cext);
                scalecolor(ext1, r->rot);
                addcolor(eext, ext1);
                r = r->parent;
        }
        if (intens(eext) > FTINY) {
                setcolor(ext1,  exp(-colval(eext,RED)),
                                exp(-colval(eext,GRN)),
                                exp(-colval(eext,BLU)));
                multcolor(rc, ext1);
        }
}


extern double
raynormal(              /* compute perturbed normal for ray */
        FVECT  norm,
        register RAY  *r
)
{
        double  newdot;
        register int  i;

        /*      The perturbation is added to the surface normal to obtain
         *  the new normal.  If the new normal would affect the surface
         *  orientation wrt. the ray, a correction is made.  The method is
         *  still fraught with problems since reflected rays and similar
         *  directions calculated from the surface normal may spawn rays behind
         *  the surface.  The only solution is to curb textures at high
         *  incidence (namely, keep DOT(rdir,pert) < Rdot).
         */

        for (i = 0; i < 3; i++)
                norm[i] = r->ron[i] + r->pert[i];

        if (normalize(norm) == 0.0) {
                objerror(r->ro, WARNING, "illegal normal perturbation");
                VCOPY(norm, r->ron);
                return(r->rod);
        }
        newdot = -DOT(norm, r->rdir);
        if ((newdot > 0.0) != (r->rod > 0.0)) {         /* fix orientation */
                for (i = 0; i < 3; i++)
                        norm[i] += 2.0*newdot*r->rdir[i];
                newdot = -newdot;
        }
        return(newdot);
}


extern void
newrayxf(                       /* get new tranformation matrix for ray */
        RAY  *r
)
{
        static struct xfn {
                struct xfn  *next;
                FULLXF  xf;
        }  xfseed = { &xfseed }, *xflast = &xfseed;
        register struct xfn  *xp;
        register const RAY  *rp;

        /*
         * Search for transform in circular list that
         * has no associated ray in the tree.
         */
        xp = xflast;
        for (rp = r->parent; rp != NULL; rp = rp->parent)
                if (rp->rox == &xp->xf) {               /* xp in use */
                        xp = xp->next;                  /* move to next */
                        if (xp == xflast) {             /* need new one */
                                xp = (struct xfn *)malloc(sizeof(struct xfn));
                                if (xp == NULL)
                                        error(SYSTEM,
                                                "out of memory in newrayxf");
                                                        /* insert in list */
                                xp->next = xflast->next;
                                xflast->next = xp;
                                break;                  /* we're done */
                        }
                        rp = r;                 /* start check over */
                }
                                        /* got it */
        r->rox = &xp->xf;
        xflast = xp;
}


extern void
flipsurface(                    /* reverse surface orientation */
        register RAY  *r
)
{
        r->rod = -r->rod;
        r->ron[0] = -r->ron[0];
        r->ron[1] = -r->ron[1];
        r->ron[2] = -r->ron[2];
        r->pert[0] = -r->pert[0];
        r->pert[1] = -r->pert[1];
        r->pert[2] = -r->pert[2];
}


extern void
rayhit(                 /* standard ray hit test */
        OBJECT  *oset,
        RAY  *r
)
{
        OBJREC  *o;
        int     i;

        for (i = oset[0]; i > 0; i--) {
                o = objptr(oset[i]);
                if ((*ofun[o->otype].funp)(o, r))
                        r->robj = oset[i];
        }
}


extern int
localhit(               /* check for hit in the octree */
        register RAY  *r,
        register CUBE  *scene
)
{
        OBJECT  cxset[MAXCSET+1];       /* set of checked objects */
        FVECT  curpos;                  /* current cube position */
        int  sflags;                    /* sign flags */
        double  t, dt;
        register int  i;

        nrays++;                        /* increment trace counter */
        sflags = 0;
        for (i = 0; i < 3; i++) {
                curpos[i] = r->rorg[i];
                if (r->rdir[i] > 1e-7)
                        sflags |= 1 << i;
                else if (r->rdir[i] < -1e-7)
                        sflags |= 0x10 << i;
        }
        if (sflags == 0)
                error(CONSISTENCY, "zero ray direction in localhit");
                                        /* start off assuming nothing hit */
        if (r->rmax > FTINY) {          /* except aft plane if one */
                r->ro = &Aftplane;
                r->rot = r->rmax;
                for (i = 0; i < 3; i++)
                        r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
        }
                                        /* find global cube entrance point */
        t = 0.0;
        if (!incube(scene, curpos)) {
                                        /* find distance to entry */
                for (i = 0; i < 3; i++) {
                                        /* plane in our direction */
                        if (sflags & 1<<i)
                                dt = scene->cuorg[i];
                        else if (sflags & 0x10<<i)
                                dt = scene->cuorg[i] + scene->cusize;
                        else
                                continue;
                                        /* distance to the plane */
                        dt = (dt - r->rorg[i])/r->rdir[i];
                        if (dt > t)
                                t = dt; /* farthest face is the one */
                }
                t += FTINY;             /* fudge to get inside cube */
                if (t >= r->rot)        /* clipped already */
                        return(0);
                                        /* advance position */
                for (i = 0; i < 3; i++)
                        curpos[i] += r->rdir[i]*t;

                if (!incube(scene, curpos))     /* non-intersecting ray */
                        return(0);
        }
        cxset[0] = 0;
        raymove(curpos, cxset, sflags, r, scene);
        return((r->ro != NULL) & (r->ro != &Aftplane));
}


static int
raymove(                /* check for hit as we move */
        FVECT  pos,                     /* current position, modified herein */
        OBJECT  *cxs,                   /* checked objects, modified by checkhit */
        int  dirf,                      /* direction indicators to speed tests */
        register RAY  *r,
        register CUBE  *cu
)
{
        int  ax;
        double  dt, t;

        if (istree(cu->cutree)) {               /* recurse on subcubes */
                CUBE  cukid;
                register int  br, sgn;

                cukid.cusize = cu->cusize * 0.5;        /* find subcube */
                VCOPY(cukid.cuorg, cu->cuorg);
                br = 0;
                if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
                        cukid.cuorg[0] += cukid.cusize;
                        br |= 1;
                }
                if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
                        cukid.cuorg[1] += cukid.cusize;
                        br |= 2;
                }
                if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
                        cukid.cuorg[2] += cukid.cusize;
                        br |= 4;
                }
                for ( ; ; ) {
                        cukid.cutree = octkid(cu->cutree, br);
                        if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
                                return(RAYHIT);
                        sgn = 1 << ax;
                        if (sgn & dirf)                 /* positive axis? */
                                if (sgn & br)
                                        return(ax);     /* overflow */
                                else {
                                        cukid.cuorg[ax] += cukid.cusize;
                                        br |= sgn;
                                }
                        else
                                if (sgn & br) {
                                        cukid.cuorg[ax] -= cukid.cusize;
                                        br &= ~sgn;
                                } else
                                        return(ax);     /* underflow */
                }
                /*NOTREACHED*/
        }
        if (isfull(cu->cutree)) {
                if (checkhit(r, cu, cxs))
                        return(RAYHIT);
        } else if (r->ro == &Aftplane && incube(cu, r->rop))
                return(RAYHIT);
                                        /* advance to next cube */
        if (dirf&0x11) {
                dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
                t = (dt - pos[0])/r->rdir[0];
                ax = 0;
        } else
                t = FHUGE;
        if (dirf&0x22) {
                dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
                dt = (dt - pos[1])/r->rdir[1];
                if (dt < t) {
                        t = dt;
                        ax = 1;
                }
        }
        if (dirf&0x44) {
                dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
                dt = (dt - pos[2])/r->rdir[2];
                if (dt < t) {
                        t = dt;
                        ax = 2;
                }
        }
        pos[0] += r->rdir[0]*t;
        pos[1] += r->rdir[1]*t;
        pos[2] += r->rdir[2]*t;
        return(ax);
}


static int
checkhit(               /* check for hit in full cube */
        register RAY  *r,
        CUBE  *cu,
        OBJECT  *cxs
)
{
        OBJECT  oset[MAXSET+1];

        objset(oset, cu->cutree);
        checkset(oset, cxs);                    /* avoid double-checking */

        (*r->hitf)(oset, r);                    /* test for hit in set */

        if (r->robj == OVOID)
                return(0);                      /* no scores yet */

        return(incube(cu, r->rop));             /* hit OK if in current cube */
}


static void
checkset(               /* modify checked set and set to check */
        register OBJECT  *os,                   /* os' = os - cs */
        register OBJECT  *cs                    /* cs' = cs + os */
)
{
        OBJECT  cset[MAXCSET+MAXSET+1];
        register int  i, j;
        int  k;
                                        /* copy os in place, cset <- cs */
        cset[0] = 0;
        k = 0;
        for (i = j = 1; i <= os[0]; i++) {
                while (j <= cs[0] && cs[j] < os[i])
                        cset[++cset[0]] = cs[j++];
                if (j > cs[0] || os[i] != cs[j]) {      /* object to check */
                        os[++k] = os[i];
                        cset[++cset[0]] = os[i];
                }
        }
        if (!(os[0] = k))               /* new "to check" set size */
                return;                 /* special case */
        while (j <= cs[0])              /* get the rest of cs */
                cset[++cset[0]] = cs[j++];
        if (cset[0] > MAXCSET)          /* truncate "checked" set if nec. */
                cset[0] = MAXCSET;
        /* setcopy(cs, cset); */        /* copy cset back to cs */
        os = cset;
        for (i = os[0]; i-- >= 0; )
                *cs++ = *os++;
}
Revision:	2.49
Committed:	Tue Apr 19 01:15:06 2005 UTC (19 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.48:	+59 -21 lines
Log Message:	Extensive changes to enable rtrace -oTW option for tracking ray contributions
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.49	static const char RCSid[] = "$Id: raytrace.c,v 2.48 2005/04/15 04:44:51 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* raytrace.c - routines for tracing and shading rays.
6			*
7	greg	2.34	* External symbols declared in ray.h
8			*/
9
10	greg	2.35	#include "copyright.h"
11	greg	1.1
12			#include "ray.h"
13	schorsch	2.45	#include "source.h"
14	greg	1.1	#include "otypes.h"
15	greg	1.15	#include "otspecial.h"
16
17	greg	2.3	#define MAXCSET ((MAXSET+1)2-1) / maximum check set size */
18
19	greg	2.6	unsigned long raynum = 0; /* next unique ray number */
20			unsigned long nrays = 0; /* number of calls to localhit */
21	greg	1.1
22	schorsch	2.40	static RREAL Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
23	greg	1.15	OBJREC Lamb = {
24			OVOID, MAT_PLASTIC, "Lambertian",
25	greg	2.2	{0, 5, NULL, Lambfa}, NULL,
26	greg	1.15	}; /* a Lambertian surface */
27
28	greg	2.17	OBJREC Aftplane; /* aft clipping plane object */
29	greg	2.16
30	schorsch	2.45	#define RAYHIT (-1) /* return value for intercepted ray */
31	greg	2.5
32	schorsch	2.45	static int raymove(FVECT pos, OBJECT cxs, int dirf, RAY r, CUBE *cu);
33			static int checkhit(RAY r, CUBE cu, OBJECT *cxs);
34			static void checkset(OBJECT os, OBJECT cs);
35	greg	1.1
36
37	schorsch	2.45	extern int
38			rayorigin( /* start new ray from old one */
39	greg	2.49	RAY *r,
40	schorsch	2.45	int rt,
41	greg	2.49	const RAY *ro,
42			const COLOR rc
43	schorsch	2.45	)
44	greg	1.1	{
45	greg	2.49	double rw, re;
46			/* assign coefficient/weight */
47			if (rc == NULL) {
48			rw = 1.0;
49			setcolor(r->rcoef, 1., 1., 1.);
50			} else {
51			rw = intens(rc);
52			if (rc != r->rcoef)
53			copycolor(r->rcoef, rc);
54			}
55	greg	1.1	if ((r->parent = ro) == NULL) { /* primary ray */
56			r->rlvl = 0;
57			r->rweight = rw;
58			r->crtype = r->rtype = rt;
59			r->rsrc = -1;
60			r->clipset = NULL;
61	greg	2.23	copycolor(r->cext, cextinction);
62	greg	2.26	copycolor(r->albedo, salbedo);
63	greg	2.23	r->gecc = seccg;
64			r->slights = NULL;
65	greg	1.1	} else { /* spawned ray */
66	greg	2.49	if (ro->rot >= FHUGE) {
67			memset(r, 0, sizeof(RAY));
68			return(-1); /* illegal continuation */
69			}
70	greg	1.1	r->rlvl = ro->rlvl;
71			if (rt & RAYREFL) {
72			r->rlvl++;
73			r->rsrc = -1;
74			r->clipset = ro->clipset;
75	greg	2.22	r->rmax = 0.0;
76	greg	1.1	} else {
77			r->rsrc = ro->rsrc;
78			r->clipset = ro->newcset;
79	greg	2.22	r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
80	greg	1.1	}
81	greg	2.23	copycolor(r->cext, ro->cext);
82	greg	2.26	copycolor(r->albedo, ro->albedo);
83	greg	2.23	r->gecc = ro->gecc;
84			r->slights = ro->slights;
85	greg	1.1	r->crtype = ro->crtype \| (r->rtype = rt);
86			VCOPY(r->rorg, ro->rop);
87	gwlarson	2.31	r->rweight = ro->rweight * rw;
88	greg	2.49	/* estimate extinction */
89	gwlarson	2.31	re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
90			colval(ro->cext,RED) : colval(ro->cext,GRN);
91			if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
92	greg	2.49	re *= ro->rot;
93			if (re > .1)
94			r->rweight *= exp(-re);
95	greg	1.1	}
96	greg	1.22	rayclear(r);
97			return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
98			}
99
100
101	schorsch	2.45	extern void
102			rayclear( /* clear a ray for (re)evaluation */
103			register RAY *r
104			)
105	greg	1.22	{
106	greg	1.20	r->rno = raynum++;
107	greg	1.1	r->newcset = r->clipset;
108	greg	2.36	r->hitf = rayhit;
109	greg	2.28	r->robj = OVOID;
110	greg	2.17	r->ro = NULL;
111	greg	2.34	r->rox = NULL;
112	gregl	2.29	r->rt = r->rot = FHUGE;
113	greg	1.1	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
114	greg	2.37	r->uv[0] = r->uv[1] = 0.0;
115	greg	1.1	setcolor(r->pcol, 1.0, 1.0, 1.0);
116			setcolor(r->rcol, 0.0, 0.0, 0.0);
117			}
118
119
120	schorsch	2.45	extern void
121	greg	2.48	rayvalue( /* trace a ray and compute its value */
122	schorsch	2.45	RAY *r
123			)
124	greg	1.1	{
125	greg	1.15	if (localhit(r, &thescene))
126	greg	2.24	raycont(r); /* hit local surface, evaluate */
127	greg	2.16	else if (r->ro == &Aftplane) {
128	greg	2.23	r->ro = NULL; /* hit aft clipping plane */
129	greg	2.16	r->rot = FHUGE;
130			} else if (sourcehit(r))
131	greg	2.24	rayshade(r, r->ro->omod); /* distant source */
132	greg	1.1
133			if (trace != NULL)
134			(trace)(r); / trace execution */
135	greg	2.49
136			rayparticipate(r); /* for participating medium */
137	greg	1.1	}
138
139
140	schorsch	2.45	extern void
141			raycont( /* check for clipped object and continue */
142			register RAY *r
143			)
144	greg	1.8	{
145	greg	2.7	if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) \|\|
146	greg	2.24	!rayshade(r, r->ro->omod))
147	greg	1.8	raytrans(r);
148			}
149
150
151	schorsch	2.45	extern void
152			raytrans( /* transmit ray as is */
153			register RAY *r
154			)
155	greg	1.1	{
156			RAY tr;
157
158	greg	2.49	if (rayorigin(&tr, TRANS, r, NULL) == 0) {
159	greg	1.1	VCOPY(tr.rdir, r->rdir);
160			rayvalue(&tr);
161			copycolor(r->rcol, tr.rcol);
162	greg	1.10	r->rt = r->rot + tr.rt;
163	greg	1.1	}
164			}
165
166
167	schorsch	2.45	extern int
168			rayshade( /* shade ray r with material mod */
169			register RAY *r,
170			int mod
171			)
172	greg	1.1	{
173			register OBJREC *m;
174	greg	2.47
175	greg	1.19	r->rt = r->rot; /* set effective ray length */
176	greg	2.47	for ( ; mod != OVOID; mod = m->omod) {
177	greg	1.1	m = objptr(mod);
178	greg	1.4	/****** unnecessary test since modifier() is always called
179	greg	1.1	if (!ismodifier(m->otype)) {
180			sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
181			error(USER, errmsg);
182			}
183	greg	1.4	******/
184	greg	1.16	/* hack for irradiance calculation */
185	greg	2.38	if (do_irrad && !(r->crtype & ~(PRIMARY\|TRANS)) &&
186	greg	2.43	m->otype != MAT_CLIP &&
187	greg	2.38	(ofun[m->otype].flags & (T_M\|T_X))) {
188	greg	1.16	if (irr_ignore(m->otype)) {
189			raytrans(r);
190	greg	2.15	return(1);
191	greg	1.16	}
192	greg	1.18	if (!islight(m->otype))
193	greg	1.16	m = &Lamb;
194			}
195	greg	2.47	if ((*ofun[m->otype].funp)(m, r))
196			return(1); /* materials call raytexture() */
197	greg	1.1	}
198	greg	2.47	return(0); /* no material! */
199	greg	2.23	}
200
201
202	schorsch	2.45	extern void
203			rayparticipate( /* compute ray medium participation */
204			register RAY *r
205			)
206	greg	2.23	{
207			COLOR ce, ca;
208			double re, ge, be;
209
210			if (intens(r->cext) <= 1./FHUGE)
211			return; /* no medium */
212	greg	2.27	re = r->rot*colval(r->cext,RED);
213			ge = r->rot*colval(r->cext,GRN);
214			be = r->rot*colval(r->cext,BLU);
215	greg	2.26	if (r->crtype & SHADOW) { /* no scattering for sources */
216			re *= 1. - colval(r->albedo,RED);
217			ge *= 1. - colval(r->albedo,GRN);
218			be *= 1. - colval(r->albedo,BLU);
219			}
220	greg	2.49	setcolor(ce, re<=FTINY ? 1. : re>92. ? 0. : exp(-re),
221			ge<=FTINY ? 1. : ge>92. ? 0. : exp(-ge),
222			be<=FTINY ? 1. : be>92. ? 0. : exp(-be));
223			multcolor(r->rcol, ce); /* path extinction */
224	greg	2.26	if (r->crtype & SHADOW \|\| intens(r->albedo) <= FTINY)
225	greg	2.23	return; /* no scattering */
226	greg	2.26	setcolor(ca,
227			colval(r->albedo,RED)colval(ambval,RED)(1.-colval(ce,RED)),
228			colval(r->albedo,GRN)colval(ambval,GRN)(1.-colval(ce,GRN)),
229			colval(r->albedo,BLU)colval(ambval,BLU)(1.-colval(ce,BLU)));
230	greg	2.23	addcolor(r->rcol, ca); /* ambient in scattering */
231			srcscatter(r); /* source in scattering */
232	greg	1.1	}
233
234
235	schorsch	2.45	extern void
236			raytexture( /* get material modifiers */
237			RAY *r,
238			OBJECT mod
239			)
240	greg	1.1	{
241	gwlarson	2.33	register OBJREC *m;
242	greg	1.1	/* execute textures and patterns */
243			for ( ; mod != OVOID; mod = m->omod) {
244			m = objptr(mod);
245	greg	2.9	/****** unnecessary test since modifier() is always called
246			if (!ismodifier(m->otype)) {
247	greg	1.1	sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
248			error(USER, errmsg);
249			}
250	greg	2.9	******/
251	greg	2.20	if ((*ofun[m->otype].funp)(m, r)) {
252			sprintf(errmsg, "conflicting material \"%s\"",
253			m->oname);
254			objerror(r->ro, USER, errmsg);
255			}
256	greg	1.1	}
257			}
258
259
260	schorsch	2.45	extern int
261			raymixture( /* mix modifiers */
262			register RAY *r,
263			OBJECT fore,
264			OBJECT back,
265			double coef
266			)
267	greg	1.1	{
268	greg	2.9	RAY fr, br;
269			int foremat, backmat;
270	greg	1.1	register int i;
271	greg	2.24	/* bound coefficient */
272	greg	1.1	if (coef > 1.0)
273			coef = 1.0;
274			else if (coef < 0.0)
275			coef = 0.0;
276	greg	2.13	/* compute foreground and background */
277	greg	2.24	foremat = backmat = 0;
278	greg	2.9	/* foreground */
279	schorsch	2.41	fr = *r;
280	greg	2.24	if (coef > FTINY)
281	greg	2.9	foremat = rayshade(&fr, fore);
282			/* background */
283	schorsch	2.41	br = *r;
284	greg	2.24	if (coef < 1.0-FTINY)
285	greg	2.9	backmat = rayshade(&br, back);
286	greg	2.24	/* check for transparency */
287	schorsch	2.41	if (backmat ^ foremat) {
288	gwlarson	2.33	if (backmat && coef > FTINY)
289	greg	2.24	raytrans(&fr);
290	gwlarson	2.33	else if (foremat && coef < 1.0-FTINY)
291	greg	2.24	raytrans(&br);
292	schorsch	2.41	}
293	greg	2.12	/* mix perturbations */
294	greg	1.1	for (i = 0; i < 3; i++)
295	greg	2.12	r->pert[i] = coeffr.pert[i] + (1.0-coef)br.pert[i];
296			/* mix pattern colors */
297	greg	2.9	scalecolor(fr.pcol, coef);
298			scalecolor(br.pcol, 1.0-coef);
299	greg	2.12	copycolor(r->pcol, fr.pcol);
300			addcolor(r->pcol, br.pcol);
301	greg	2.24	/* return value tells if material */
302			if (!foremat & !backmat)
303			return(0);
304	greg	2.12	/* mix returned ray values */
305	greg	2.24	scalecolor(fr.rcol, coef);
306			scalecolor(br.rcol, 1.0-coef);
307			copycolor(r->rcol, fr.rcol);
308			addcolor(r->rcol, br.rcol);
309			r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
310			return(1);
311	greg	1.1	}
312
313
314	schorsch	2.45	extern double
315			raydist( /* compute (cumulative) ray distance */
316	greg	2.49	register const RAY *r,
317	schorsch	2.45	register int flags
318			)
319	greg	2.21	{
320			double sum = 0.0;
321
322			while (r != NULL && r->crtype&flags) {
323			sum += r->rot;
324			r = r->parent;
325			}
326			return(sum);
327			}
328
329
330	greg	2.49	extern void
331			raycontrib( /* compute (cumulative) ray contribution */
332			COLOR rc,
333			const RAY *r,
334			int flags
335			)
336			{
337			COLOR eext, ext1;
338
339			setcolor(eext, 0., 0., 0.);
340			setcolor(rc, 1., 1., 1.);
341
342			while (r != NULL && r->crtype&flags) {
343			multcolor(rc, r->rcoef);
344			copycolor(ext1, r->cext);
345			scalecolor(ext1, r->rot);
346			addcolor(eext, ext1);
347			r = r->parent;
348			}
349			if (intens(eext) > FTINY) {
350			setcolor(ext1, exp(-colval(eext,RED)),
351			exp(-colval(eext,GRN)),
352			exp(-colval(eext,BLU)));
353			multcolor(rc, ext1);
354			}
355			}
356
357
358	schorsch	2.45	extern double
359			raynormal( /* compute perturbed normal for ray */
360			FVECT norm,
361			register RAY *r
362			)
363	greg	1.1	{
364			double newdot;
365			register int i;
366
367			/* The perturbation is added to the surface normal to obtain
368			* the new normal. If the new normal would affect the surface
369			* orientation wrt. the ray, a correction is made. The method is
370			* still fraught with problems since reflected rays and similar
371			* directions calculated from the surface normal may spawn rays behind
372			* the surface. The only solution is to curb textures at high
373	greg	1.9	* incidence (namely, keep DOT(rdir,pert) < Rdot).
374	greg	1.1	*/
375
376			for (i = 0; i < 3; i++)
377			norm[i] = r->ron[i] + r->pert[i];
378
379			if (normalize(norm) == 0.0) {
380			objerror(r->ro, WARNING, "illegal normal perturbation");
381			VCOPY(norm, r->ron);
382			return(r->rod);
383			}
384			newdot = -DOT(norm, r->rdir);
385			if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
386			for (i = 0; i < 3; i++)
387			norm[i] += 2.0newdotr->rdir[i];
388			newdot = -newdot;
389			}
390			return(newdot);
391	greg	1.12	}
392
393
394	schorsch	2.45	extern void
395			newrayxf( /* get new tranformation matrix for ray */
396			RAY *r
397			)
398	greg	1.12	{
399			static struct xfn {
400			struct xfn *next;
401			FULLXF xf;
402			} xfseed = { &xfseed }, *xflast = &xfseed;
403			register struct xfn *xp;
404	greg	2.49	register const RAY *rp;
405	greg	1.12
406			/*
407			* Search for transform in circular list that
408			* has no associated ray in the tree.
409			*/
410			xp = xflast;
411			for (rp = r->parent; rp != NULL; rp = rp->parent)
412			if (rp->rox == &xp->xf) { /* xp in use */
413			xp = xp->next; /* move to next */
414			if (xp == xflast) { /* need new one */
415	greg	2.34	xp = (struct xfn *)malloc(sizeof(struct xfn));
416	greg	1.12	if (xp == NULL)
417			error(SYSTEM,
418			"out of memory in newrayxf");
419			/* insert in list */
420			xp->next = xflast->next;
421			xflast->next = xp;
422			break; /* we're done */
423			}
424			rp = r; /* start check over */
425			}
426			/* got it */
427			r->rox = &xp->xf;
428			xflast = xp;
429	greg	1.1	}
430
431
432	schorsch	2.45	extern void
433			flipsurface( /* reverse surface orientation */
434			register RAY *r
435			)
436	greg	1.1	{
437			r->rod = -r->rod;
438			r->ron[0] = -r->ron[0];
439			r->ron[1] = -r->ron[1];
440			r->ron[2] = -r->ron[2];
441			r->pert[0] = -r->pert[0];
442			r->pert[1] = -r->pert[1];
443			r->pert[2] = -r->pert[2];
444			}
445
446
447	schorsch	2.45	extern void
448			rayhit( /* standard ray hit test */
449			OBJECT *oset,
450			RAY *r
451			)
452	greg	2.36	{
453			OBJREC *o;
454			int i;
455
456			for (i = oset[0]; i > 0; i--) {
457			o = objptr(oset[i]);
458			if ((*ofun[o->otype].funp)(o, r))
459			r->robj = oset[i];
460			}
461			}
462
463
464	schorsch	2.45	extern int
465			localhit( /* check for hit in the octree */
466			register RAY *r,
467			register CUBE *scene
468			)
469	greg	1.1	{
470	greg	2.3	OBJECT cxset[MAXCSET+1]; /* set of checked objects */
471	greg	1.1	FVECT curpos; /* current cube position */
472	greg	1.11	int sflags; /* sign flags */
473	greg	1.1	double t, dt;
474			register int i;
475
476	greg	1.21	nrays++; /* increment trace counter */
477	greg	1.11	sflags = 0;
478	greg	1.1	for (i = 0; i < 3; i++) {
479			curpos[i] = r->rorg[i];
480	greg	2.8	if (r->rdir[i] > 1e-7)
481	greg	1.11	sflags \|= 1 << i;
482	greg	2.8	else if (r->rdir[i] < -1e-7)
483	greg	1.11	sflags \|= 0x10 << i;
484	greg	1.1	}
485	greg	1.17	if (sflags == 0)
486			error(CONSISTENCY, "zero ray direction in localhit");
487	greg	2.17	/* start off assuming nothing hit */
488			if (r->rmax > FTINY) { /* except aft plane if one */
489			r->ro = &Aftplane;
490			r->rot = r->rmax;
491			for (i = 0; i < 3; i++)
492			r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
493			}
494			/* find global cube entrance point */
495	greg	1.1	t = 0.0;
496			if (!incube(scene, curpos)) {
497			/* find distance to entry */
498			for (i = 0; i < 3; i++) {
499			/* plane in our direction */
500	greg	1.11	if (sflags & 1<<i)
501	greg	1.1	dt = scene->cuorg[i];
502	greg	1.11	else if (sflags & 0x10<<i)
503	greg	1.1	dt = scene->cuorg[i] + scene->cusize;
504			else
505			continue;
506			/* distance to the plane */
507			dt = (dt - r->rorg[i])/r->rdir[i];
508			if (dt > t)
509			t = dt; /* farthest face is the one */
510			}
511			t += FTINY; /* fudge to get inside cube */
512	greg	2.17	if (t >= r->rot) /* clipped already */
513			return(0);
514	greg	1.1	/* advance position */
515			for (i = 0; i < 3; i++)
516			curpos[i] += r->rdir[i]*t;
517
518			if (!incube(scene, curpos)) /* non-intersecting ray */
519			return(0);
520			}
521	greg	2.3	cxset[0] = 0;
522	greg	2.19	raymove(curpos, cxset, sflags, r, scene);
523	schorsch	2.42	return((r->ro != NULL) & (r->ro != &Aftplane));
524	greg	1.1	}
525
526
527			static int
528	schorsch	2.45	raymove( /* check for hit as we move */
529			FVECT pos, /* current position, modified herein */
530			OBJECT cxs, / checked objects, modified by checkhit */
531			int dirf, /* direction indicators to speed tests */
532			register RAY *r,
533			register CUBE *cu
534			)
535	greg	1.1	{
536			int ax;
537			double dt, t;
538
539			if (istree(cu->cutree)) { /* recurse on subcubes */
540			CUBE cukid;
541	greg	1.11	register int br, sgn;
542	greg	1.1
543			cukid.cusize = cu->cusize * 0.5; /* find subcube */
544			VCOPY(cukid.cuorg, cu->cuorg);
545			br = 0;
546			if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
547			cukid.cuorg[0] += cukid.cusize;
548			br \|= 1;
549			}
550			if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
551			cukid.cuorg[1] += cukid.cusize;
552			br \|= 2;
553			}
554			if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
555			cukid.cuorg[2] += cukid.cusize;
556			br \|= 4;
557			}
558			for ( ; ; ) {
559			cukid.cutree = octkid(cu->cutree, br);
560	greg	2.3	if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
561	greg	1.1	return(RAYHIT);
562			sgn = 1 << ax;
563	greg	1.11	if (sgn & dirf) /* positive axis? */
564	greg	1.1	if (sgn & br)
565			return(ax); /* overflow */
566			else {
567			cukid.cuorg[ax] += cukid.cusize;
568			br \|= sgn;
569			}
570	greg	1.11	else
571			if (sgn & br) {
572			cukid.cuorg[ax] -= cukid.cusize;
573			br &= ~sgn;
574			} else
575			return(ax); /* underflow */
576	greg	1.1	}
577			/NOTREACHED/
578			}
579	greg	2.18	if (isfull(cu->cutree)) {
580			if (checkhit(r, cu, cxs))
581			return(RAYHIT);
582			} else if (r->ro == &Aftplane && incube(cu, r->rop))
583	greg	1.1	return(RAYHIT);
584			/* advance to next cube */
585	greg	1.11	if (dirf&0x11) {
586			dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
587	greg	1.1	t = (dt - pos[0])/r->rdir[0];
588			ax = 0;
589			} else
590			t = FHUGE;
591	greg	1.11	if (dirf&0x22) {
592			dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
593	greg	1.1	dt = (dt - pos[1])/r->rdir[1];
594			if (dt < t) {
595			t = dt;
596			ax = 1;
597			}
598			}
599	greg	1.11	if (dirf&0x44) {
600			dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
601	greg	1.1	dt = (dt - pos[2])/r->rdir[2];
602			if (dt < t) {
603			t = dt;
604			ax = 2;
605			}
606			}
607			pos[0] += r->rdir[0]*t;
608			pos[1] += r->rdir[1]*t;
609			pos[2] += r->rdir[2]*t;
610			return(ax);
611			}
612
613
614	greg	2.34	static int
615	schorsch	2.45	checkhit( /* check for hit in full cube */
616			register RAY *r,
617			CUBE *cu,
618			OBJECT *cxs
619			)
620	greg	1.1	{
621			OBJECT oset[MAXSET+1];
622
623			objset(oset, cu->cutree);
624	greg	2.36	checkset(oset, cxs); /* avoid double-checking */
625
626			(r->hitf)(oset, r); / test for hit in set */
627
628			if (r->robj == OVOID)
629	greg	1.1	return(0); /* no scores yet */
630
631			return(incube(cu, r->rop)); /* hit OK if in current cube */
632	greg	2.2	}
633
634
635	greg	2.34	static void
636	schorsch	2.45	checkset( /* modify checked set and set to check */
637			register OBJECT os, / os' = os - cs */
638			register OBJECT cs / cs' = cs + os */
639			)
640	greg	2.2	{
641			OBJECT cset[MAXCSET+MAXSET+1];
642	greg	2.3	register int i, j;
643			int k;
644	greg	2.2	/* copy os in place, cset <- cs */
645			cset[0] = 0;
646			k = 0;
647			for (i = j = 1; i <= os[0]; i++) {
648			while (j <= cs[0] && cs[j] < os[i])
649			cset[++cset[0]] = cs[j++];
650			if (j > cs[0] \|\| os[i] != cs[j]) { /* object to check */
651			os[++k] = os[i];
652			cset[++cset[0]] = os[i];
653			}
654			}
655	greg	2.3	if (!(os[0] = k)) /* new "to check" set size */
656			return; /* special case */
657	greg	2.2	while (j <= cs[0]) /* get the rest of cs */
658			cset[++cset[0]] = cs[j++];
659	greg	2.3	if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
660	greg	2.2	cset[0] = MAXCSET;
661	greg	2.3	/* setcopy(cs, cset); / / copy cset back to cs */
662			os = cset;
663			for (i = os[0]; i-- >= 0; )
664			cs++ = os++;
665	greg	1.1	}