src/rt/raytrace.c

#ifndef lint
static const char RCSid[] = "$Id: raytrace.c,v 2.47 2005/04/14 18:04:12 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 */
        register RAY  *r,
        register RAY  *ro,
        int  rt,
        double  rw
)
{
        double  re;

        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 if (ro->rot >= FHUGE) {          /* illegal continuation */
                memset(r, 0, sizeof(RAY));
                return(-1);
        } else {                                /* spawned ray */
                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 absorption */
                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);
                if (re > 0.)
                        r->rweight *= exp(-re*ro->rot);
        }
        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 */

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

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


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, r, TRANS, 1.0) == 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<=0. ? 1. : re>92. ? 0. : exp(-re),
                        ge<=0. ? 1. : ge>92. ? 0. : exp(-ge),
                        be<=0. ? 1. : be>92. ? 0. : exp(-be));
        multcolor(r->rcol, ce);                 /* path absorption */
        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 RAY  *r,
        register int  flags
)
{
        double  sum = 0.0;

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


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 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:	2.48
Committed:	Fri Apr 15 04:44:51 2005 UTC (19 years ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.47:	+2 -4 lines
Log Message:	Eliminated revf member from RAY struct, as it was never really needed
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.48	static const char RCSid[] = "$Id: raytrace.c,v 2.47 2005/04/14 18:04:12 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			register RAY *r,
40			register RAY *ro,
41			int rt,
42			double rw
43			)
44	greg	1.1	{
45	gwlarson	2.31	double re;
46
47	greg	1.1	if ((r->parent = ro) == NULL) { /* primary ray */
48			r->rlvl = 0;
49			r->rweight = rw;
50			r->crtype = r->rtype = rt;
51			r->rsrc = -1;
52			r->clipset = NULL;
53	greg	2.23	copycolor(r->cext, cextinction);
54	greg	2.26	copycolor(r->albedo, salbedo);
55	greg	2.23	r->gecc = seccg;
56			r->slights = NULL;
57	greg	2.46	} else if (ro->rot >= FHUGE) { /* illegal continuation */
58			memset(r, 0, sizeof(RAY));
59			return(-1);
60	greg	1.1	} else { /* spawned ray */
61			r->rlvl = ro->rlvl;
62			if (rt & RAYREFL) {
63			r->rlvl++;
64			r->rsrc = -1;
65			r->clipset = ro->clipset;
66	greg	2.22	r->rmax = 0.0;
67	greg	1.1	} else {
68			r->rsrc = ro->rsrc;
69			r->clipset = ro->newcset;
70	greg	2.22	r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
71	greg	1.1	}
72	greg	2.23	copycolor(r->cext, ro->cext);
73	greg	2.26	copycolor(r->albedo, ro->albedo);
74	greg	2.23	r->gecc = ro->gecc;
75			r->slights = ro->slights;
76	greg	1.1	r->crtype = ro->crtype \| (r->rtype = rt);
77			VCOPY(r->rorg, ro->rop);
78	gwlarson	2.31	r->rweight = ro->rweight * rw;
79			/* estimate absorption */
80			re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
81			colval(ro->cext,RED) : colval(ro->cext,GRN);
82			if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
83			if (re > 0.)
84			r->rweight = exp(-rero->rot);
85	greg	1.1	}
86	greg	1.22	rayclear(r);
87			return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
88			}
89
90
91	schorsch	2.45	extern void
92			rayclear( /* clear a ray for (re)evaluation */
93			register RAY *r
94			)
95	greg	1.22	{
96	greg	1.20	r->rno = raynum++;
97	greg	1.1	r->newcset = r->clipset;
98	greg	2.36	r->hitf = rayhit;
99	greg	2.28	r->robj = OVOID;
100	greg	2.17	r->ro = NULL;
101	greg	2.34	r->rox = NULL;
102	gregl	2.29	r->rt = r->rot = FHUGE;
103	greg	1.1	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
104	greg	2.37	r->uv[0] = r->uv[1] = 0.0;
105	greg	1.1	setcolor(r->pcol, 1.0, 1.0, 1.0);
106			setcolor(r->rcol, 0.0, 0.0, 0.0);
107			}
108
109
110	schorsch	2.45	extern void
111	greg	2.48	rayvalue( /* trace a ray and compute its value */
112	schorsch	2.45	RAY *r
113			)
114	greg	1.1	{
115	greg	1.15	if (localhit(r, &thescene))
116	greg	2.24	raycont(r); /* hit local surface, evaluate */
117	greg	2.16	else if (r->ro == &Aftplane) {
118	greg	2.23	r->ro = NULL; /* hit aft clipping plane */
119	greg	2.16	r->rot = FHUGE;
120			} else if (sourcehit(r))
121	greg	2.24	rayshade(r, r->ro->omod); /* distant source */
122	greg	1.1
123	greg	2.23	rayparticipate(r); /* for participating medium */
124
125	greg	1.1	if (trace != NULL)
126			(trace)(r); / trace execution */
127			}
128
129
130	schorsch	2.45	extern void
131			raycont( /* check for clipped object and continue */
132			register RAY *r
133			)
134	greg	1.8	{
135	greg	2.7	if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) \|\|
136	greg	2.24	!rayshade(r, r->ro->omod))
137	greg	1.8	raytrans(r);
138			}
139
140
141	schorsch	2.45	extern void
142			raytrans( /* transmit ray as is */
143			register RAY *r
144			)
145	greg	1.1	{
146			RAY tr;
147
148			if (rayorigin(&tr, r, TRANS, 1.0) == 0) {
149			VCOPY(tr.rdir, r->rdir);
150			rayvalue(&tr);
151			copycolor(r->rcol, tr.rcol);
152	greg	1.10	r->rt = r->rot + tr.rt;
153	greg	1.1	}
154			}
155
156
157	schorsch	2.45	extern int
158			rayshade( /* shade ray r with material mod */
159			register RAY *r,
160			int mod
161			)
162	greg	1.1	{
163			register OBJREC *m;
164	greg	2.47
165	greg	1.19	r->rt = r->rot; /* set effective ray length */
166	greg	2.47	for ( ; mod != OVOID; mod = m->omod) {
167	greg	1.1	m = objptr(mod);
168	greg	1.4	/****** unnecessary test since modifier() is always called
169	greg	1.1	if (!ismodifier(m->otype)) {
170			sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
171			error(USER, errmsg);
172			}
173	greg	1.4	******/
174	greg	1.16	/* hack for irradiance calculation */
175	greg	2.38	if (do_irrad && !(r->crtype & ~(PRIMARY\|TRANS)) &&
176	greg	2.43	m->otype != MAT_CLIP &&
177	greg	2.38	(ofun[m->otype].flags & (T_M\|T_X))) {
178	greg	1.16	if (irr_ignore(m->otype)) {
179			raytrans(r);
180	greg	2.15	return(1);
181	greg	1.16	}
182	greg	1.18	if (!islight(m->otype))
183	greg	1.16	m = &Lamb;
184			}
185	greg	2.47	if ((*ofun[m->otype].funp)(m, r))
186			return(1); /* materials call raytexture() */
187	greg	1.1	}
188	greg	2.47	return(0); /* no material! */
189	greg	2.23	}
190
191
192	schorsch	2.45	extern void
193			rayparticipate( /* compute ray medium participation */
194			register RAY *r
195			)
196	greg	2.23	{
197			COLOR ce, ca;
198			double re, ge, be;
199
200			if (intens(r->cext) <= 1./FHUGE)
201			return; /* no medium */
202	greg	2.27	re = r->rot*colval(r->cext,RED);
203			ge = r->rot*colval(r->cext,GRN);
204			be = r->rot*colval(r->cext,BLU);
205	greg	2.26	if (r->crtype & SHADOW) { /* no scattering for sources */
206			re *= 1. - colval(r->albedo,RED);
207			ge *= 1. - colval(r->albedo,GRN);
208			be *= 1. - colval(r->albedo,BLU);
209			}
210			setcolor(ce, re<=0. ? 1. : re>92. ? 0. : exp(-re),
211			ge<=0. ? 1. : ge>92. ? 0. : exp(-ge),
212			be<=0. ? 1. : be>92. ? 0. : exp(-be));
213	greg	2.23	multcolor(r->rcol, ce); /* path absorption */
214	greg	2.26	if (r->crtype & SHADOW \|\| intens(r->albedo) <= FTINY)
215	greg	2.23	return; /* no scattering */
216	greg	2.26	setcolor(ca,
217			colval(r->albedo,RED)colval(ambval,RED)(1.-colval(ce,RED)),
218			colval(r->albedo,GRN)colval(ambval,GRN)(1.-colval(ce,GRN)),
219			colval(r->albedo,BLU)colval(ambval,BLU)(1.-colval(ce,BLU)));
220	greg	2.23	addcolor(r->rcol, ca); /* ambient in scattering */
221			srcscatter(r); /* source in scattering */
222	greg	1.1	}
223
224
225	schorsch	2.45	extern void
226			raytexture( /* get material modifiers */
227			RAY *r,
228			OBJECT mod
229			)
230	greg	1.1	{
231	gwlarson	2.33	register OBJREC *m;
232	greg	1.1	/* execute textures and patterns */
233			for ( ; mod != OVOID; mod = m->omod) {
234			m = objptr(mod);
235	greg	2.9	/****** unnecessary test since modifier() is always called
236			if (!ismodifier(m->otype)) {
237	greg	1.1	sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
238			error(USER, errmsg);
239			}
240	greg	2.9	******/
241	greg	2.20	if ((*ofun[m->otype].funp)(m, r)) {
242			sprintf(errmsg, "conflicting material \"%s\"",
243			m->oname);
244			objerror(r->ro, USER, errmsg);
245			}
246	greg	1.1	}
247			}
248
249
250	schorsch	2.45	extern int
251			raymixture( /* mix modifiers */
252			register RAY *r,
253			OBJECT fore,
254			OBJECT back,
255			double coef
256			)
257	greg	1.1	{
258	greg	2.9	RAY fr, br;
259			int foremat, backmat;
260	greg	1.1	register int i;
261	greg	2.24	/* bound coefficient */
262	greg	1.1	if (coef > 1.0)
263			coef = 1.0;
264			else if (coef < 0.0)
265			coef = 0.0;
266	greg	2.13	/* compute foreground and background */
267	greg	2.24	foremat = backmat = 0;
268	greg	2.9	/* foreground */
269	schorsch	2.41	fr = *r;
270	greg	2.24	if (coef > FTINY)
271	greg	2.9	foremat = rayshade(&fr, fore);
272			/* background */
273	schorsch	2.41	br = *r;
274	greg	2.24	if (coef < 1.0-FTINY)
275	greg	2.9	backmat = rayshade(&br, back);
276	greg	2.24	/* check for transparency */
277	schorsch	2.41	if (backmat ^ foremat) {
278	gwlarson	2.33	if (backmat && coef > FTINY)
279	greg	2.24	raytrans(&fr);
280	gwlarson	2.33	else if (foremat && coef < 1.0-FTINY)
281	greg	2.24	raytrans(&br);
282	schorsch	2.41	}
283	greg	2.12	/* mix perturbations */
284	greg	1.1	for (i = 0; i < 3; i++)
285	greg	2.12	r->pert[i] = coeffr.pert[i] + (1.0-coef)br.pert[i];
286			/* mix pattern colors */
287	greg	2.9	scalecolor(fr.pcol, coef);
288			scalecolor(br.pcol, 1.0-coef);
289	greg	2.12	copycolor(r->pcol, fr.pcol);
290			addcolor(r->pcol, br.pcol);
291	greg	2.24	/* return value tells if material */
292			if (!foremat & !backmat)
293			return(0);
294	greg	2.12	/* mix returned ray values */
295	greg	2.24	scalecolor(fr.rcol, coef);
296			scalecolor(br.rcol, 1.0-coef);
297			copycolor(r->rcol, fr.rcol);
298			addcolor(r->rcol, br.rcol);
299			r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
300			return(1);
301	greg	1.1	}
302
303
304	schorsch	2.45	extern double
305			raydist( /* compute (cumulative) ray distance */
306			register RAY *r,
307			register int flags
308			)
309	greg	2.21	{
310			double sum = 0.0;
311
312			while (r != NULL && r->crtype&flags) {
313			sum += r->rot;
314			r = r->parent;
315			}
316			return(sum);
317			}
318
319
320	schorsch	2.45	extern double
321			raynormal( /* compute perturbed normal for ray */
322			FVECT norm,
323			register RAY *r
324			)
325	greg	1.1	{
326			double newdot;
327			register int i;
328
329			/* The perturbation is added to the surface normal to obtain
330			* the new normal. If the new normal would affect the surface
331			* orientation wrt. the ray, a correction is made. The method is
332			* still fraught with problems since reflected rays and similar
333			* directions calculated from the surface normal may spawn rays behind
334			* the surface. The only solution is to curb textures at high
335	greg	1.9	* incidence (namely, keep DOT(rdir,pert) < Rdot).
336	greg	1.1	*/
337
338			for (i = 0; i < 3; i++)
339			norm[i] = r->ron[i] + r->pert[i];
340
341			if (normalize(norm) == 0.0) {
342			objerror(r->ro, WARNING, "illegal normal perturbation");
343			VCOPY(norm, r->ron);
344			return(r->rod);
345			}
346			newdot = -DOT(norm, r->rdir);
347			if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
348			for (i = 0; i < 3; i++)
349			norm[i] += 2.0newdotr->rdir[i];
350			newdot = -newdot;
351			}
352			return(newdot);
353	greg	1.12	}
354
355
356	schorsch	2.45	extern void
357			newrayxf( /* get new tranformation matrix for ray */
358			RAY *r
359			)
360	greg	1.12	{
361			static struct xfn {
362			struct xfn *next;
363			FULLXF xf;
364			} xfseed = { &xfseed }, *xflast = &xfseed;
365			register struct xfn *xp;
366			register RAY *rp;
367
368			/*
369			* Search for transform in circular list that
370			* has no associated ray in the tree.
371			*/
372			xp = xflast;
373			for (rp = r->parent; rp != NULL; rp = rp->parent)
374			if (rp->rox == &xp->xf) { /* xp in use */
375			xp = xp->next; /* move to next */
376			if (xp == xflast) { /* need new one */
377	greg	2.34	xp = (struct xfn *)malloc(sizeof(struct xfn));
378	greg	1.12	if (xp == NULL)
379			error(SYSTEM,
380			"out of memory in newrayxf");
381			/* insert in list */
382			xp->next = xflast->next;
383			xflast->next = xp;
384			break; /* we're done */
385			}
386			rp = r; /* start check over */
387			}
388			/* got it */
389			r->rox = &xp->xf;
390			xflast = xp;
391	greg	1.1	}
392
393
394	schorsch	2.45	extern void
395			flipsurface( /* reverse surface orientation */
396			register RAY *r
397			)
398	greg	1.1	{
399			r->rod = -r->rod;
400			r->ron[0] = -r->ron[0];
401			r->ron[1] = -r->ron[1];
402			r->ron[2] = -r->ron[2];
403			r->pert[0] = -r->pert[0];
404			r->pert[1] = -r->pert[1];
405			r->pert[2] = -r->pert[2];
406			}
407
408
409	schorsch	2.45	extern void
410			rayhit( /* standard ray hit test */
411			OBJECT *oset,
412			RAY *r
413			)
414	greg	2.36	{
415			OBJREC *o;
416			int i;
417
418			for (i = oset[0]; i > 0; i--) {
419			o = objptr(oset[i]);
420			if ((*ofun[o->otype].funp)(o, r))
421			r->robj = oset[i];
422			}
423			}
424
425
426	schorsch	2.45	extern int
427			localhit( /* check for hit in the octree */
428			register RAY *r,
429			register CUBE *scene
430			)
431	greg	1.1	{
432	greg	2.3	OBJECT cxset[MAXCSET+1]; /* set of checked objects */
433	greg	1.1	FVECT curpos; /* current cube position */
434	greg	1.11	int sflags; /* sign flags */
435	greg	1.1	double t, dt;
436			register int i;
437
438	greg	1.21	nrays++; /* increment trace counter */
439	greg	1.11	sflags = 0;
440	greg	1.1	for (i = 0; i < 3; i++) {
441			curpos[i] = r->rorg[i];
442	greg	2.8	if (r->rdir[i] > 1e-7)
443	greg	1.11	sflags \|= 1 << i;
444	greg	2.8	else if (r->rdir[i] < -1e-7)
445	greg	1.11	sflags \|= 0x10 << i;
446	greg	1.1	}
447	greg	1.17	if (sflags == 0)
448			error(CONSISTENCY, "zero ray direction in localhit");
449	greg	2.17	/* start off assuming nothing hit */
450			if (r->rmax > FTINY) { /* except aft plane if one */
451			r->ro = &Aftplane;
452			r->rot = r->rmax;
453			for (i = 0; i < 3; i++)
454			r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
455			}
456			/* find global cube entrance point */
457	greg	1.1	t = 0.0;
458			if (!incube(scene, curpos)) {
459			/* find distance to entry */
460			for (i = 0; i < 3; i++) {
461			/* plane in our direction */
462	greg	1.11	if (sflags & 1<<i)
463	greg	1.1	dt = scene->cuorg[i];
464	greg	1.11	else if (sflags & 0x10<<i)
465	greg	1.1	dt = scene->cuorg[i] + scene->cusize;
466			else
467			continue;
468			/* distance to the plane */
469			dt = (dt - r->rorg[i])/r->rdir[i];
470			if (dt > t)
471			t = dt; /* farthest face is the one */
472			}
473			t += FTINY; /* fudge to get inside cube */
474	greg	2.17	if (t >= r->rot) /* clipped already */
475			return(0);
476	greg	1.1	/* advance position */
477			for (i = 0; i < 3; i++)
478			curpos[i] += r->rdir[i]*t;
479
480			if (!incube(scene, curpos)) /* non-intersecting ray */
481			return(0);
482			}
483	greg	2.3	cxset[0] = 0;
484	greg	2.19	raymove(curpos, cxset, sflags, r, scene);
485	schorsch	2.42	return((r->ro != NULL) & (r->ro != &Aftplane));
486	greg	1.1	}
487
488
489			static int
490	schorsch	2.45	raymove( /* check for hit as we move */
491			FVECT pos, /* current position, modified herein */
492			OBJECT cxs, / checked objects, modified by checkhit */
493			int dirf, /* direction indicators to speed tests */
494			register RAY *r,
495			register CUBE *cu
496			)
497	greg	1.1	{
498			int ax;
499			double dt, t;
500
501			if (istree(cu->cutree)) { /* recurse on subcubes */
502			CUBE cukid;
503	greg	1.11	register int br, sgn;
504	greg	1.1
505			cukid.cusize = cu->cusize * 0.5; /* find subcube */
506			VCOPY(cukid.cuorg, cu->cuorg);
507			br = 0;
508			if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
509			cukid.cuorg[0] += cukid.cusize;
510			br \|= 1;
511			}
512			if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
513			cukid.cuorg[1] += cukid.cusize;
514			br \|= 2;
515			}
516			if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
517			cukid.cuorg[2] += cukid.cusize;
518			br \|= 4;
519			}
520			for ( ; ; ) {
521			cukid.cutree = octkid(cu->cutree, br);
522	greg	2.3	if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
523	greg	1.1	return(RAYHIT);
524			sgn = 1 << ax;
525	greg	1.11	if (sgn & dirf) /* positive axis? */
526	greg	1.1	if (sgn & br)
527			return(ax); /* overflow */
528			else {
529			cukid.cuorg[ax] += cukid.cusize;
530			br \|= sgn;
531			}
532	greg	1.11	else
533			if (sgn & br) {
534			cukid.cuorg[ax] -= cukid.cusize;
535			br &= ~sgn;
536			} else
537			return(ax); /* underflow */
538	greg	1.1	}
539			/NOTREACHED/
540			}
541	greg	2.18	if (isfull(cu->cutree)) {
542			if (checkhit(r, cu, cxs))
543			return(RAYHIT);
544			} else if (r->ro == &Aftplane && incube(cu, r->rop))
545	greg	1.1	return(RAYHIT);
546			/* advance to next cube */
547	greg	1.11	if (dirf&0x11) {
548			dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
549	greg	1.1	t = (dt - pos[0])/r->rdir[0];
550			ax = 0;
551			} else
552			t = FHUGE;
553	greg	1.11	if (dirf&0x22) {
554			dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
555	greg	1.1	dt = (dt - pos[1])/r->rdir[1];
556			if (dt < t) {
557			t = dt;
558			ax = 1;
559			}
560			}
561	greg	1.11	if (dirf&0x44) {
562			dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
563	greg	1.1	dt = (dt - pos[2])/r->rdir[2];
564			if (dt < t) {
565			t = dt;
566			ax = 2;
567			}
568			}
569			pos[0] += r->rdir[0]*t;
570			pos[1] += r->rdir[1]*t;
571			pos[2] += r->rdir[2]*t;
572			return(ax);
573			}
574
575
576	greg	2.34	static int
577	schorsch	2.45	checkhit( /* check for hit in full cube */
578			register RAY *r,
579			CUBE *cu,
580			OBJECT *cxs
581			)
582	greg	1.1	{
583			OBJECT oset[MAXSET+1];
584
585			objset(oset, cu->cutree);
586	greg	2.36	checkset(oset, cxs); /* avoid double-checking */
587
588			(r->hitf)(oset, r); / test for hit in set */
589
590			if (r->robj == OVOID)
591	greg	1.1	return(0); /* no scores yet */
592
593			return(incube(cu, r->rop)); /* hit OK if in current cube */
594	greg	2.2	}
595
596
597	greg	2.34	static void
598	schorsch	2.45	checkset( /* modify checked set and set to check */
599			register OBJECT os, / os' = os - cs */
600			register OBJECT cs / cs' = cs + os */
601			)
602	greg	2.2	{
603			OBJECT cset[MAXCSET+MAXSET+1];
604	greg	2.3	register int i, j;
605			int k;
606	greg	2.2	/* copy os in place, cset <- cs */
607			cset[0] = 0;
608			k = 0;
609			for (i = j = 1; i <= os[0]; i++) {
610			while (j <= cs[0] && cs[j] < os[i])
611			cset[++cset[0]] = cs[j++];
612			if (j > cs[0] \|\| os[i] != cs[j]) { /* object to check */
613			os[++k] = os[i];
614			cset[++cset[0]] = os[i];
615			}
616			}
617	greg	2.3	if (!(os[0] = k)) /* new "to check" set size */
618			return; /* special case */
619	greg	2.2	while (j <= cs[0]) /* get the rest of cs */
620			cset[++cset[0]] = cs[j++];
621	greg	2.3	if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
622	greg	2.2	cset[0] = MAXCSET;
623	greg	2.3	/* setcopy(cs, cset); / / copy cset back to cs */
624			os = cset;
625			for (i = os[0]; i-- >= 0; )
626			cs++ = os++;
627	greg	1.1	}