src/rt/raytrace.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 *  raytrace.c - routines for tracing and shading rays.
 *
 *  External symbols declared in ray.h
 */

#include "copyright.h"

#include  "ray.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 FLOAT  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 */

static int  raymove(), checkhit();
static void  checkset();

#ifndef  MAXLOOP
#define  MAXLOOP        0               /* modifier loop detection */
#endif

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


int
rayorigin(r, ro, rt, rw)                /* start new ray from old one */
register RAY  *r, *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;
                r->revf = raytrace;
                copycolor(r->cext, cextinction);
                copycolor(r->albedo, salbedo);
                r->gecc = seccg;
                r->slights = NULL;
        } 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;
                }
                r->revf = ro->revf;
                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);
}


void
rayclear(r)                     /* clear a ray for (re)evaluation */
register RAY  *r;
{
        r->rno = raynum++;
        r->newcset = r->clipset;
        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;
        setcolor(r->pcol, 1.0, 1.0, 1.0);
        setcolor(r->rcol, 0.0, 0.0, 0.0);
}


void
raytrace(r)                     /* 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 */
}


void
raycont(r)                      /* 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);
}


void
raytrans(r)                     /* 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;
        }
}


int
rayshade(r, mod)                /* shade ray r with material mod */
register RAY  *r;
int  mod;
{
        int  gotmat;
        register OBJREC  *m;
#if  MAXLOOP
        static int  depth = 0;
                                        /* check for infinite loop */
        if (depth++ >= MAXLOOP)
                objerror(r->ro, USER, "possible modifier loop");
#endif
        r->rt = r->rot;                 /* set effective ray length */
        for (gotmat = 0; !gotmat && 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))) {
                        if (irr_ignore(m->otype)) {
#if  MAXLOOP
                                depth--;
#endif
                                raytrans(r);
                                return(1);
                        }
                        if (!islight(m->otype))
                                m = &Lamb;
                }
                                        /* materials call raytexture */
                gotmat = (*ofun[m->otype].funp)(m, r);
        }
#if  MAXLOOP
        depth--;
#endif
        return(gotmat);
}


void
rayparticipate(r)                       /* 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 */
}


raytexture(r, mod)                      /* get material modifiers */
RAY  *r;
int  mod;
{
        register OBJREC  *m;
#if  MAXLOOP
        static int  depth = 0;
                                        /* check for infinite loop */
        if (depth++ >= MAXLOOP)
                objerror(r->ro, USER, "modifier loop");
#endif
                                        /* 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);
                }
        }
#if  MAXLOOP
        depth--;                        /* end here */
#endif
}


int
raymixture(r, fore, back, coef)         /* mix modifiers */
register RAY  *r;
OBJECT  fore, 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 */
        copystruct(&fr, r);
        if (coef > FTINY)
                foremat = rayshade(&fr, fore);
                                        /* background */
        copystruct(&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);
}


double
raydist(r, flags)               /* 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);
}


double
raynormal(norm, r)              /* 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);
}


void
newrayxf(r)                     /* 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;
}


void
flipsurface(r)                  /* 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];
}


int
localhit(r, scene)              /* 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(pos, cxs, dirf, r, cu)          /* 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(r, cu, cxs)            /* check for hit in full cube */
register RAY  *r;
CUBE  *cu;
OBJECT  *cxs;
{
        OBJECT  oset[MAXSET+1];
        register OBJREC  *o;
        register int  i;

        objset(oset, cu->cutree);
        checkset(oset, cxs);                    /* eliminate double-checking */
        for (i = oset[0]; i > 0; i--) {
                o = objptr(oset[i]);
                if ((*ofun[o->otype].funp)(o, r))
                        r->robj = oset[i];
        }
        if (r->ro == NULL)
                return(0);                      /* no scores yet */

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


static void
checkset(os, cs)                /* 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:	2.35
Committed:	Tue Feb 25 02:47:23 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.34:	+1 -56 lines
Log Message:	Replaced inline copyright notice with #include "copyright.h"
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.34	static const char RCSid[] = "$Id$";
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
14			#include "otypes.h"
15
16	greg	1.15	#include "otspecial.h"
17
18	greg	2.3	#define MAXCSET ((MAXSET+1)2-1) / maximum check set size */
19
20	greg	2.6	unsigned long raynum = 0; /* next unique ray number */
21			unsigned long nrays = 0; /* number of calls to localhit */
22	greg	1.1
23	greg	1.23	static FLOAT Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
24	greg	1.15	OBJREC Lamb = {
25			OVOID, MAT_PLASTIC, "Lambertian",
26	greg	2.2	{0, 5, NULL, Lambfa}, NULL,
27	greg	1.15	}; /* a Lambertian surface */
28
29	greg	2.17	OBJREC Aftplane; /* aft clipping plane object */
30	greg	2.16
31	greg	2.34	static int raymove(), checkhit();
32			static void checkset();
33	greg	2.5
34	gwlarson	2.33	#ifndef MAXLOOP
35			#define MAXLOOP 0 /* modifier loop detection */
36			#endif
37	greg	1.1
38			#define RAYHIT (-1) /* return value for intercepted ray */
39
40
41	greg	2.34	int
42	greg	1.1	rayorigin(r, ro, rt, rw) /* start new ray from old one */
43			register RAY r, ro;
44			int rt;
45			double rw;
46			{
47	gwlarson	2.31	double re;
48
49	greg	1.1	if ((r->parent = ro) == NULL) { /* primary ray */
50			r->rlvl = 0;
51			r->rweight = rw;
52			r->crtype = r->rtype = rt;
53			r->rsrc = -1;
54			r->clipset = NULL;
55	greg	1.21	r->revf = raytrace;
56	greg	2.23	copycolor(r->cext, cextinction);
57	greg	2.26	copycolor(r->albedo, salbedo);
58	greg	2.23	r->gecc = seccg;
59			r->slights = NULL;
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	1.21	r->revf = ro->revf;
73	greg	2.23	copycolor(r->cext, ro->cext);
74	greg	2.26	copycolor(r->albedo, ro->albedo);
75	greg	2.23	r->gecc = ro->gecc;
76			r->slights = ro->slights;
77	greg	1.1	r->crtype = ro->crtype \| (r->rtype = rt);
78			VCOPY(r->rorg, ro->rop);
79	gwlarson	2.31	r->rweight = ro->rweight * rw;
80			/* estimate absorption */
81			re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
82			colval(ro->cext,RED) : colval(ro->cext,GRN);
83			if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
84			if (re > 0.)
85			r->rweight = exp(-rero->rot);
86	greg	1.1	}
87	greg	1.22	rayclear(r);
88			return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
89			}
90
91
92	greg	2.34	void
93	greg	1.22	rayclear(r) /* clear a ray for (re)evaluation */
94			register RAY *r;
95			{
96	greg	1.20	r->rno = raynum++;
97	greg	1.1	r->newcset = r->clipset;
98	greg	2.28	r->robj = OVOID;
99	greg	2.17	r->ro = NULL;
100	greg	2.34	r->rox = NULL;
101	gregl	2.29	r->rt = r->rot = FHUGE;
102	greg	1.1	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
103			setcolor(r->pcol, 1.0, 1.0, 1.0);
104			setcolor(r->rcol, 0.0, 0.0, 0.0);
105			}
106
107
108	greg	2.34	void
109	greg	1.21	raytrace(r) /* trace a ray and compute its value */
110	greg	1.8	RAY *r;
111	greg	1.1	{
112	greg	1.15	if (localhit(r, &thescene))
113	greg	2.24	raycont(r); /* hit local surface, evaluate */
114	greg	2.16	else if (r->ro == &Aftplane) {
115	greg	2.23	r->ro = NULL; /* hit aft clipping plane */
116	greg	2.16	r->rot = FHUGE;
117			} else if (sourcehit(r))
118	greg	2.24	rayshade(r, r->ro->omod); /* distant source */
119	greg	1.1
120	greg	2.23	rayparticipate(r); /* for participating medium */
121
122	greg	1.1	if (trace != NULL)
123			(trace)(r); / trace execution */
124			}
125
126
127	greg	2.34	void
128	greg	1.8	raycont(r) /* check for clipped object and continue */
129			register RAY *r;
130			{
131	greg	2.7	if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) \|\|
132	greg	2.24	!rayshade(r, r->ro->omod))
133	greg	1.8	raytrans(r);
134			}
135
136
137	greg	2.34	void
138	greg	1.1	raytrans(r) /* transmit ray as is */
139	greg	1.8	register RAY *r;
140	greg	1.1	{
141			RAY tr;
142
143			if (rayorigin(&tr, r, TRANS, 1.0) == 0) {
144			VCOPY(tr.rdir, r->rdir);
145			rayvalue(&tr);
146			copycolor(r->rcol, tr.rcol);
147	greg	1.10	r->rt = r->rot + tr.rt;
148	greg	1.1	}
149			}
150
151
152	greg	2.34	int
153	greg	1.1	rayshade(r, mod) /* shade ray r with material mod */
154			register RAY *r;
155			int mod;
156			{
157	greg	2.9	int gotmat;
158	greg	1.1	register OBJREC *m;
159	gwlarson	2.33	#if MAXLOOP
160			static int depth = 0;
161	greg	1.1	/* check for infinite loop */
162			if (depth++ >= MAXLOOP)
163	greg	1.4	objerror(r->ro, USER, "possible modifier loop");
164	gwlarson	2.33	#endif
165	greg	1.19	r->rt = r->rot; /* set effective ray length */
166	greg	2.9	for (gotmat = 0; !gotmat && 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			if (do_irrad && !(r->crtype & ~(PRIMARY\|TRANS))) {
176			if (irr_ignore(m->otype)) {
177	gwlarson	2.33	#if MAXLOOP
178	greg	1.16	depth--;
179	gwlarson	2.33	#endif
180	greg	1.16	raytrans(r);
181	greg	2.15	return(1);
182	greg	1.16	}
183	greg	1.18	if (!islight(m->otype))
184	greg	1.16	m = &Lamb;
185			}
186	greg	2.9	/* materials call raytexture */
187			gotmat = (*ofun[m->otype].funp)(m, r);
188	greg	1.1	}
189	gwlarson	2.33	#if MAXLOOP
190	greg	2.9	depth--;
191	gwlarson	2.33	#endif
192	greg	2.9	return(gotmat);
193	greg	2.23	}
194
195
196	greg	2.34	void
197	greg	2.23	rayparticipate(r) /* compute ray medium participation */
198			register RAY *r;
199			{
200			COLOR ce, ca;
201			double re, ge, be;
202
203			if (intens(r->cext) <= 1./FHUGE)
204			return; /* no medium */
205	greg	2.27	re = r->rot*colval(r->cext,RED);
206			ge = r->rot*colval(r->cext,GRN);
207			be = r->rot*colval(r->cext,BLU);
208	greg	2.26	if (r->crtype & SHADOW) { /* no scattering for sources */
209			re *= 1. - colval(r->albedo,RED);
210			ge *= 1. - colval(r->albedo,GRN);
211			be *= 1. - colval(r->albedo,BLU);
212			}
213			setcolor(ce, re<=0. ? 1. : re>92. ? 0. : exp(-re),
214			ge<=0. ? 1. : ge>92. ? 0. : exp(-ge),
215			be<=0. ? 1. : be>92. ? 0. : exp(-be));
216	greg	2.23	multcolor(r->rcol, ce); /* path absorption */
217	greg	2.26	if (r->crtype & SHADOW \|\| intens(r->albedo) <= FTINY)
218	greg	2.23	return; /* no scattering */
219	greg	2.26	setcolor(ca,
220			colval(r->albedo,RED)colval(ambval,RED)(1.-colval(ce,RED)),
221			colval(r->albedo,GRN)colval(ambval,GRN)(1.-colval(ce,GRN)),
222			colval(r->albedo,BLU)colval(ambval,BLU)(1.-colval(ce,BLU)));
223	greg	2.23	addcolor(r->rcol, ca); /* ambient in scattering */
224			srcscatter(r); /* source in scattering */
225	greg	1.1	}
226
227
228			raytexture(r, mod) /* get material modifiers */
229			RAY *r;
230			int mod;
231			{
232	gwlarson	2.33	register OBJREC *m;
233			#if MAXLOOP
234	greg	1.1	static int depth = 0;
235			/* check for infinite loop */
236			if (depth++ >= MAXLOOP)
237			objerror(r->ro, USER, "modifier loop");
238	gwlarson	2.33	#endif
239	greg	1.1	/* execute textures and patterns */
240			for ( ; mod != OVOID; mod = m->omod) {
241			m = objptr(mod);
242	greg	2.9	/****** unnecessary test since modifier() is always called
243			if (!ismodifier(m->otype)) {
244	greg	1.1	sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
245			error(USER, errmsg);
246			}
247	greg	2.9	******/
248	greg	2.20	if ((*ofun[m->otype].funp)(m, r)) {
249			sprintf(errmsg, "conflicting material \"%s\"",
250			m->oname);
251			objerror(r->ro, USER, errmsg);
252			}
253	greg	1.1	}
254	gwlarson	2.33	#if MAXLOOP
255	greg	1.1	depth--; /* end here */
256	gwlarson	2.33	#endif
257	greg	1.1	}
258
259
260	greg	2.34	int
261	greg	1.1	raymixture(r, fore, back, coef) /* mix modifiers */
262			register RAY *r;
263			OBJECT fore, back;
264			double coef;
265			{
266	greg	2.9	RAY fr, br;
267			int foremat, backmat;
268	greg	1.1	register int i;
269	greg	2.24	/* bound coefficient */
270	greg	1.1	if (coef > 1.0)
271			coef = 1.0;
272			else if (coef < 0.0)
273			coef = 0.0;
274	greg	2.13	/* compute foreground and background */
275	greg	2.24	foremat = backmat = 0;
276	greg	2.9	/* foreground */
277			copystruct(&fr, r);
278	greg	2.24	if (coef > FTINY)
279	greg	2.9	foremat = rayshade(&fr, fore);
280			/* background */
281			copystruct(&br, r);
282	greg	2.24	if (coef < 1.0-FTINY)
283	greg	2.9	backmat = rayshade(&br, back);
284	greg	2.24	/* check for transparency */
285			if (backmat ^ foremat)
286	gwlarson	2.33	if (backmat && coef > FTINY)
287	greg	2.24	raytrans(&fr);
288	gwlarson	2.33	else if (foremat && coef < 1.0-FTINY)
289	greg	2.24	raytrans(&br);
290	greg	2.12	/* mix perturbations */
291	greg	1.1	for (i = 0; i < 3; i++)
292	greg	2.12	r->pert[i] = coeffr.pert[i] + (1.0-coef)br.pert[i];
293			/* mix pattern colors */
294	greg	2.9	scalecolor(fr.pcol, coef);
295			scalecolor(br.pcol, 1.0-coef);
296	greg	2.12	copycolor(r->pcol, fr.pcol);
297			addcolor(r->pcol, br.pcol);
298	greg	2.24	/* return value tells if material */
299			if (!foremat & !backmat)
300			return(0);
301	greg	2.12	/* mix returned ray values */
302	greg	2.24	scalecolor(fr.rcol, coef);
303			scalecolor(br.rcol, 1.0-coef);
304			copycolor(r->rcol, fr.rcol);
305			addcolor(r->rcol, br.rcol);
306			r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
307			return(1);
308	greg	1.1	}
309
310
311			double
312	greg	2.21	raydist(r, flags) /* compute (cumulative) ray distance */
313			register RAY *r;
314			register int flags;
315			{
316			double sum = 0.0;
317
318			while (r != NULL && r->crtype&flags) {
319			sum += r->rot;
320			r = r->parent;
321			}
322			return(sum);
323			}
324
325
326			double
327	greg	1.1	raynormal(norm, r) /* compute perturbed normal for ray */
328			FVECT norm;
329			register RAY *r;
330			{
331			double newdot;
332			register int i;
333
334			/* The perturbation is added to the surface normal to obtain
335			* the new normal. If the new normal would affect the surface
336			* orientation wrt. the ray, a correction is made. The method is
337			* still fraught with problems since reflected rays and similar
338			* directions calculated from the surface normal may spawn rays behind
339			* the surface. The only solution is to curb textures at high
340	greg	1.9	* incidence (namely, keep DOT(rdir,pert) < Rdot).
341	greg	1.1	*/
342
343			for (i = 0; i < 3; i++)
344			norm[i] = r->ron[i] + r->pert[i];
345
346			if (normalize(norm) == 0.0) {
347			objerror(r->ro, WARNING, "illegal normal perturbation");
348			VCOPY(norm, r->ron);
349			return(r->rod);
350			}
351			newdot = -DOT(norm, r->rdir);
352			if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
353			for (i = 0; i < 3; i++)
354			norm[i] += 2.0newdotr->rdir[i];
355			newdot = -newdot;
356			}
357			return(newdot);
358	greg	1.12	}
359
360
361	greg	2.34	void
362	greg	1.12	newrayxf(r) /* get new tranformation matrix for ray */
363			RAY *r;
364			{
365			static struct xfn {
366			struct xfn *next;
367			FULLXF xf;
368			} xfseed = { &xfseed }, *xflast = &xfseed;
369			register struct xfn *xp;
370			register RAY *rp;
371
372			/*
373			* Search for transform in circular list that
374			* has no associated ray in the tree.
375			*/
376			xp = xflast;
377			for (rp = r->parent; rp != NULL; rp = rp->parent)
378			if (rp->rox == &xp->xf) { /* xp in use */
379			xp = xp->next; /* move to next */
380			if (xp == xflast) { /* need new one */
381	greg	2.34	xp = (struct xfn *)malloc(sizeof(struct xfn));
382	greg	1.12	if (xp == NULL)
383			error(SYSTEM,
384			"out of memory in newrayxf");
385			/* insert in list */
386			xp->next = xflast->next;
387			xflast->next = xp;
388			break; /* we're done */
389			}
390			rp = r; /* start check over */
391			}
392			/* got it */
393			r->rox = &xp->xf;
394			xflast = xp;
395	greg	1.1	}
396
397
398	greg	2.34	void
399	greg	1.1	flipsurface(r) /* reverse surface orientation */
400			register RAY *r;
401			{
402			r->rod = -r->rod;
403			r->ron[0] = -r->ron[0];
404			r->ron[1] = -r->ron[1];
405			r->ron[2] = -r->ron[2];
406			r->pert[0] = -r->pert[0];
407			r->pert[1] = -r->pert[1];
408			r->pert[2] = -r->pert[2];
409			}
410
411
412	greg	2.34	int
413	greg	1.1	localhit(r, scene) /* check for hit in the octree */
414			register RAY *r;
415			register CUBE *scene;
416			{
417	greg	2.3	OBJECT cxset[MAXCSET+1]; /* set of checked objects */
418	greg	1.1	FVECT curpos; /* current cube position */
419	greg	1.11	int sflags; /* sign flags */
420	greg	1.1	double t, dt;
421			register int i;
422
423	greg	1.21	nrays++; /* increment trace counter */
424	greg	1.11	sflags = 0;
425	greg	1.1	for (i = 0; i < 3; i++) {
426			curpos[i] = r->rorg[i];
427	greg	2.8	if (r->rdir[i] > 1e-7)
428	greg	1.11	sflags \|= 1 << i;
429	greg	2.8	else if (r->rdir[i] < -1e-7)
430	greg	1.11	sflags \|= 0x10 << i;
431	greg	1.1	}
432	greg	1.17	if (sflags == 0)
433			error(CONSISTENCY, "zero ray direction in localhit");
434	greg	2.17	/* start off assuming nothing hit */
435			if (r->rmax > FTINY) { /* except aft plane if one */
436			r->ro = &Aftplane;
437			r->rot = r->rmax;
438			for (i = 0; i < 3; i++)
439			r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
440			}
441			/* find global cube entrance point */
442	greg	1.1	t = 0.0;
443			if (!incube(scene, curpos)) {
444			/* find distance to entry */
445			for (i = 0; i < 3; i++) {
446			/* plane in our direction */
447	greg	1.11	if (sflags & 1<<i)
448	greg	1.1	dt = scene->cuorg[i];
449	greg	1.11	else if (sflags & 0x10<<i)
450	greg	1.1	dt = scene->cuorg[i] + scene->cusize;
451			else
452			continue;
453			/* distance to the plane */
454			dt = (dt - r->rorg[i])/r->rdir[i];
455			if (dt > t)
456			t = dt; /* farthest face is the one */
457			}
458			t += FTINY; /* fudge to get inside cube */
459	greg	2.17	if (t >= r->rot) /* clipped already */
460			return(0);
461	greg	1.1	/* advance position */
462			for (i = 0; i < 3; i++)
463			curpos[i] += r->rdir[i]*t;
464
465			if (!incube(scene, curpos)) /* non-intersecting ray */
466			return(0);
467			}
468	greg	2.3	cxset[0] = 0;
469	greg	2.19	raymove(curpos, cxset, sflags, r, scene);
470			return(r->ro != NULL & r->ro != &Aftplane);
471	greg	1.1	}
472
473
474			static int
475	greg	2.3	raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */
476			FVECT pos; /* current position, modified herein */
477			OBJECT cxs; / checked objects, modified by checkhit */
478	greg	1.11	int dirf; /* direction indicators to speed tests */
479	greg	1.1	register RAY *r;
480			register CUBE *cu;
481			{
482			int ax;
483			double dt, t;
484
485			if (istree(cu->cutree)) { /* recurse on subcubes */
486			CUBE cukid;
487	greg	1.11	register int br, sgn;
488	greg	1.1
489			cukid.cusize = cu->cusize * 0.5; /* find subcube */
490			VCOPY(cukid.cuorg, cu->cuorg);
491			br = 0;
492			if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
493			cukid.cuorg[0] += cukid.cusize;
494			br \|= 1;
495			}
496			if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
497			cukid.cuorg[1] += cukid.cusize;
498			br \|= 2;
499			}
500			if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
501			cukid.cuorg[2] += cukid.cusize;
502			br \|= 4;
503			}
504			for ( ; ; ) {
505			cukid.cutree = octkid(cu->cutree, br);
506	greg	2.3	if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
507	greg	1.1	return(RAYHIT);
508			sgn = 1 << ax;
509	greg	1.11	if (sgn & dirf) /* positive axis? */
510	greg	1.1	if (sgn & br)
511			return(ax); /* overflow */
512			else {
513			cukid.cuorg[ax] += cukid.cusize;
514			br \|= sgn;
515			}
516	greg	1.11	else
517			if (sgn & br) {
518			cukid.cuorg[ax] -= cukid.cusize;
519			br &= ~sgn;
520			} else
521			return(ax); /* underflow */
522	greg	1.1	}
523			/NOTREACHED/
524			}
525	greg	2.18	if (isfull(cu->cutree)) {
526			if (checkhit(r, cu, cxs))
527			return(RAYHIT);
528			} else if (r->ro == &Aftplane && incube(cu, r->rop))
529	greg	1.1	return(RAYHIT);
530			/* advance to next cube */
531	greg	1.11	if (dirf&0x11) {
532			dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
533	greg	1.1	t = (dt - pos[0])/r->rdir[0];
534			ax = 0;
535			} else
536			t = FHUGE;
537	greg	1.11	if (dirf&0x22) {
538			dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
539	greg	1.1	dt = (dt - pos[1])/r->rdir[1];
540			if (dt < t) {
541			t = dt;
542			ax = 1;
543			}
544			}
545	greg	1.11	if (dirf&0x44) {
546			dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
547	greg	1.1	dt = (dt - pos[2])/r->rdir[2];
548			if (dt < t) {
549			t = dt;
550			ax = 2;
551			}
552			}
553			pos[0] += r->rdir[0]*t;
554			pos[1] += r->rdir[1]*t;
555			pos[2] += r->rdir[2]*t;
556			return(ax);
557			}
558
559
560	greg	2.34	static int
561	greg	2.3	checkhit(r, cu, cxs) /* check for hit in full cube */
562	greg	1.1	register RAY *r;
563			CUBE *cu;
564	greg	2.3	OBJECT *cxs;
565	greg	1.1	{
566			OBJECT oset[MAXSET+1];
567			register OBJREC *o;
568			register int i;
569
570			objset(oset, cu->cutree);
571	greg	2.3	checkset(oset, cxs); /* eliminate double-checking */
572	greg	1.1	for (i = oset[0]; i > 0; i--) {
573			o = objptr(oset[i]);
574	greg	2.28	if ((*ofun[o->otype].funp)(o, r))
575			r->robj = oset[i];
576	greg	1.1	}
577			if (r->ro == NULL)
578			return(0); /* no scores yet */
579
580			return(incube(cu, r->rop)); /* hit OK if in current cube */
581	greg	2.2	}
582
583
584	greg	2.34	static void
585	greg	2.2	checkset(os, cs) /* modify checked set and set to check */
586	greg	2.3	register OBJECT os; / os' = os - cs */
587			register OBJECT cs; / cs' = cs + os */
588	greg	2.2	{
589			OBJECT cset[MAXCSET+MAXSET+1];
590	greg	2.3	register int i, j;
591			int k;
592	greg	2.2	/* copy os in place, cset <- cs */
593			cset[0] = 0;
594			k = 0;
595			for (i = j = 1; i <= os[0]; i++) {
596			while (j <= cs[0] && cs[j] < os[i])
597			cset[++cset[0]] = cs[j++];
598			if (j > cs[0] \|\| os[i] != cs[j]) { /* object to check */
599			os[++k] = os[i];
600			cset[++cset[0]] = os[i];
601			}
602			}
603	greg	2.3	if (!(os[0] = k)) /* new "to check" set size */
604			return; /* special case */
605	greg	2.2	while (j <= cs[0]) /* get the rest of cs */
606			cset[++cset[0]] = cs[j++];
607	greg	2.3	if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
608	greg	2.2	cset[0] = MAXCSET;
609	greg	2.3	/* setcopy(cs, cset); / / copy cset back to cs */
610			os = cset;
611			for (i = os[0]; i-- >= 0; )
612			cs++ = os++;
613	greg	1.1	}