src/rt/raytrace.c

#ifndef lint
static const char RCSid[] = "$Id: raytrace.c,v 2.44 2003/12/31 01:50:02 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;
                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);
}


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
raytrace(                       /* 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
)
{
        int  gotmat;
        register OBJREC  *m;
        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)) &&
                                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;
                }
                                        /* materials call raytexture */
                gotmat = (*ofun[m->otype].funp)(m, r);
        }
        return(gotmat);
}


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:	2.45
Committed:	Tue Mar 30 16:13:01 2004 UTC (20 years, 1 month ago) by schorsch
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R6, rad3R6P1
Changes since 2.44:	+94 -74 lines
Log Message:	Continued ANSIfication. There are only bits and pieces left now.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.45	static const char RCSid[] = "$Id: raytrace.c,v 2.44 2003/12/31 01:50:02 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	1.21	r->revf = raytrace;
54	greg	2.23	copycolor(r->cext, cextinction);
55	greg	2.26	copycolor(r->albedo, salbedo);
56	greg	2.23	r->gecc = seccg;
57			r->slights = NULL;
58	greg	1.1	} else { /* spawned ray */
59			r->rlvl = ro->rlvl;
60			if (rt & RAYREFL) {
61			r->rlvl++;
62			r->rsrc = -1;
63			r->clipset = ro->clipset;
64	greg	2.22	r->rmax = 0.0;
65	greg	1.1	} else {
66			r->rsrc = ro->rsrc;
67			r->clipset = ro->newcset;
68	greg	2.22	r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
69	greg	1.1	}
70	greg	1.21	r->revf = ro->revf;
71	greg	2.23	copycolor(r->cext, ro->cext);
72	greg	2.26	copycolor(r->albedo, ro->albedo);
73	greg	2.23	r->gecc = ro->gecc;
74			r->slights = ro->slights;
75	greg	1.1	r->crtype = ro->crtype \| (r->rtype = rt);
76			VCOPY(r->rorg, ro->rop);
77	gwlarson	2.31	r->rweight = ro->rweight * rw;
78			/* estimate absorption */
79			re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
80			colval(ro->cext,RED) : colval(ro->cext,GRN);
81			if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
82			if (re > 0.)
83			r->rweight = exp(-rero->rot);
84	greg	1.1	}
85	greg	1.22	rayclear(r);
86			return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
87			}
88
89
90	schorsch	2.45	extern void
91			rayclear( /* clear a ray for (re)evaluation */
92			register RAY *r
93			)
94	greg	1.22	{
95	greg	1.20	r->rno = raynum++;
96	greg	1.1	r->newcset = r->clipset;
97	greg	2.36	r->hitf = rayhit;
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	greg	2.37	r->uv[0] = r->uv[1] = 0.0;
104	greg	1.1	setcolor(r->pcol, 1.0, 1.0, 1.0);
105			setcolor(r->rcol, 0.0, 0.0, 0.0);
106			}
107
108
109	schorsch	2.45	extern void
110			raytrace( /* trace a ray and compute its value */
111			RAY *r
112			)
113	greg	1.1	{
114	greg	1.15	if (localhit(r, &thescene))
115	greg	2.24	raycont(r); /* hit local surface, evaluate */
116	greg	2.16	else if (r->ro == &Aftplane) {
117	greg	2.23	r->ro = NULL; /* hit aft clipping plane */
118	greg	2.16	r->rot = FHUGE;
119			} else if (sourcehit(r))
120	greg	2.24	rayshade(r, r->ro->omod); /* distant source */
121	greg	1.1
122	greg	2.23	rayparticipate(r); /* for participating medium */
123
124	greg	1.1	if (trace != NULL)
125			(trace)(r); / trace execution */
126			}
127
128
129	schorsch	2.45	extern void
130			raycont( /* check for clipped object and continue */
131			register RAY *r
132			)
133	greg	1.8	{
134	greg	2.7	if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) \|\|
135	greg	2.24	!rayshade(r, r->ro->omod))
136	greg	1.8	raytrans(r);
137			}
138
139
140	schorsch	2.45	extern void
141			raytrans( /* transmit ray as is */
142			register RAY *r
143			)
144	greg	1.1	{
145			RAY tr;
146
147			if (rayorigin(&tr, r, TRANS, 1.0) == 0) {
148			VCOPY(tr.rdir, r->rdir);
149			rayvalue(&tr);
150			copycolor(r->rcol, tr.rcol);
151	greg	1.10	r->rt = r->rot + tr.rt;
152	greg	1.1	}
153			}
154
155
156	schorsch	2.45	extern int
157			rayshade( /* shade ray r with material mod */
158			register RAY *r,
159			int mod
160			)
161	greg	1.1	{
162	greg	2.9	int gotmat;
163	greg	1.1	register OBJREC *m;
164	greg	1.19	r->rt = r->rot; /* set effective ray length */
165	greg	2.9	for (gotmat = 0; !gotmat && mod != OVOID; mod = m->omod) {
166	greg	1.1	m = objptr(mod);
167	greg	1.4	/****** unnecessary test since modifier() is always called
168	greg	1.1	if (!ismodifier(m->otype)) {
169			sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
170			error(USER, errmsg);
171			}
172	greg	1.4	******/
173	greg	1.16	/* hack for irradiance calculation */
174	greg	2.38	if (do_irrad && !(r->crtype & ~(PRIMARY\|TRANS)) &&
175	greg	2.43	m->otype != MAT_CLIP &&
176	greg	2.38	(ofun[m->otype].flags & (T_M\|T_X))) {
177	greg	1.16	if (irr_ignore(m->otype)) {
178			raytrans(r);
179	greg	2.15	return(1);
180	greg	1.16	}
181	greg	1.18	if (!islight(m->otype))
182	greg	1.16	m = &Lamb;
183			}
184	greg	2.9	/* materials call raytexture */
185			gotmat = (*ofun[m->otype].funp)(m, r);
186	greg	1.1	}
187	greg	2.9	return(gotmat);
188	greg	2.23	}
189
190
191	schorsch	2.45	extern void
192			rayparticipate( /* compute ray medium participation */
193			register RAY *r
194			)
195	greg	2.23	{
196			COLOR ce, ca;
197			double re, ge, be;
198
199			if (intens(r->cext) <= 1./FHUGE)
200			return; /* no medium */
201	greg	2.27	re = r->rot*colval(r->cext,RED);
202			ge = r->rot*colval(r->cext,GRN);
203			be = r->rot*colval(r->cext,BLU);
204	greg	2.26	if (r->crtype & SHADOW) { /* no scattering for sources */
205			re *= 1. - colval(r->albedo,RED);
206			ge *= 1. - colval(r->albedo,GRN);
207			be *= 1. - colval(r->albedo,BLU);
208			}
209			setcolor(ce, re<=0. ? 1. : re>92. ? 0. : exp(-re),
210			ge<=0. ? 1. : ge>92. ? 0. : exp(-ge),
211			be<=0. ? 1. : be>92. ? 0. : exp(-be));
212	greg	2.23	multcolor(r->rcol, ce); /* path absorption */
213	greg	2.26	if (r->crtype & SHADOW \|\| intens(r->albedo) <= FTINY)
214	greg	2.23	return; /* no scattering */
215	greg	2.26	setcolor(ca,
216			colval(r->albedo,RED)colval(ambval,RED)(1.-colval(ce,RED)),
217			colval(r->albedo,GRN)colval(ambval,GRN)(1.-colval(ce,GRN)),
218			colval(r->albedo,BLU)colval(ambval,BLU)(1.-colval(ce,BLU)));
219	greg	2.23	addcolor(r->rcol, ca); /* ambient in scattering */
220			srcscatter(r); /* source in scattering */
221	greg	1.1	}
222
223
224	schorsch	2.45	extern void
225			raytexture( /* get material modifiers */
226			RAY *r,
227			OBJECT mod
228			)
229	greg	1.1	{
230	gwlarson	2.33	register OBJREC *m;
231	greg	1.1	/* execute textures and patterns */
232			for ( ; mod != OVOID; mod = m->omod) {
233			m = objptr(mod);
234	greg	2.9	/****** unnecessary test since modifier() is always called
235			if (!ismodifier(m->otype)) {
236	greg	1.1	sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
237			error(USER, errmsg);
238			}
239	greg	2.9	******/
240	greg	2.20	if ((*ofun[m->otype].funp)(m, r)) {
241			sprintf(errmsg, "conflicting material \"%s\"",
242			m->oname);
243			objerror(r->ro, USER, errmsg);
244			}
245	greg	1.1	}
246			}
247
248
249	schorsch	2.45	extern int
250			raymixture( /* mix modifiers */
251			register RAY *r,
252			OBJECT fore,
253			OBJECT back,
254			double coef
255			)
256	greg	1.1	{
257	greg	2.9	RAY fr, br;
258			int foremat, backmat;
259	greg	1.1	register int i;
260	greg	2.24	/* bound coefficient */
261	greg	1.1	if (coef > 1.0)
262			coef = 1.0;
263			else if (coef < 0.0)
264			coef = 0.0;
265	greg	2.13	/* compute foreground and background */
266	greg	2.24	foremat = backmat = 0;
267	greg	2.9	/* foreground */
268	schorsch	2.41	fr = *r;
269	greg	2.24	if (coef > FTINY)
270	greg	2.9	foremat = rayshade(&fr, fore);
271			/* background */
272	schorsch	2.41	br = *r;
273	greg	2.24	if (coef < 1.0-FTINY)
274	greg	2.9	backmat = rayshade(&br, back);
275	greg	2.24	/* check for transparency */
276	schorsch	2.41	if (backmat ^ foremat) {
277	gwlarson	2.33	if (backmat && coef > FTINY)
278	greg	2.24	raytrans(&fr);
279	gwlarson	2.33	else if (foremat && coef < 1.0-FTINY)
280	greg	2.24	raytrans(&br);
281	schorsch	2.41	}
282	greg	2.12	/* mix perturbations */
283	greg	1.1	for (i = 0; i < 3; i++)
284	greg	2.12	r->pert[i] = coeffr.pert[i] + (1.0-coef)br.pert[i];
285			/* mix pattern colors */
286	greg	2.9	scalecolor(fr.pcol, coef);
287			scalecolor(br.pcol, 1.0-coef);
288	greg	2.12	copycolor(r->pcol, fr.pcol);
289			addcolor(r->pcol, br.pcol);
290	greg	2.24	/* return value tells if material */
291			if (!foremat & !backmat)
292			return(0);
293	greg	2.12	/* mix returned ray values */
294	greg	2.24	scalecolor(fr.rcol, coef);
295			scalecolor(br.rcol, 1.0-coef);
296			copycolor(r->rcol, fr.rcol);
297			addcolor(r->rcol, br.rcol);
298			r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
299			return(1);
300	greg	1.1	}
301
302
303	schorsch	2.45	extern double
304			raydist( /* compute (cumulative) ray distance */
305			register RAY *r,
306			register int flags
307			)
308	greg	2.21	{
309			double sum = 0.0;
310
311			while (r != NULL && r->crtype&flags) {
312			sum += r->rot;
313			r = r->parent;
314			}
315			return(sum);
316			}
317
318
319	schorsch	2.45	extern double
320			raynormal( /* compute perturbed normal for ray */
321			FVECT norm,
322			register RAY *r
323			)
324	greg	1.1	{
325			double newdot;
326			register int i;
327
328			/* The perturbation is added to the surface normal to obtain
329			* the new normal. If the new normal would affect the surface
330			* orientation wrt. the ray, a correction is made. The method is
331			* still fraught with problems since reflected rays and similar
332			* directions calculated from the surface normal may spawn rays behind
333			* the surface. The only solution is to curb textures at high
334	greg	1.9	* incidence (namely, keep DOT(rdir,pert) < Rdot).
335	greg	1.1	*/
336
337			for (i = 0; i < 3; i++)
338			norm[i] = r->ron[i] + r->pert[i];
339
340			if (normalize(norm) == 0.0) {
341			objerror(r->ro, WARNING, "illegal normal perturbation");
342			VCOPY(norm, r->ron);
343			return(r->rod);
344			}
345			newdot = -DOT(norm, r->rdir);
346			if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
347			for (i = 0; i < 3; i++)
348			norm[i] += 2.0newdotr->rdir[i];
349			newdot = -newdot;
350			}
351			return(newdot);
352	greg	1.12	}
353
354
355	schorsch	2.45	extern void
356			newrayxf( /* get new tranformation matrix for ray */
357			RAY *r
358			)
359	greg	1.12	{
360			static struct xfn {
361			struct xfn *next;
362			FULLXF xf;
363			} xfseed = { &xfseed }, *xflast = &xfseed;
364			register struct xfn *xp;
365			register RAY *rp;
366
367			/*
368			* Search for transform in circular list that
369			* has no associated ray in the tree.
370			*/
371			xp = xflast;
372			for (rp = r->parent; rp != NULL; rp = rp->parent)
373			if (rp->rox == &xp->xf) { /* xp in use */
374			xp = xp->next; /* move to next */
375			if (xp == xflast) { /* need new one */
376	greg	2.34	xp = (struct xfn *)malloc(sizeof(struct xfn));
377	greg	1.12	if (xp == NULL)
378			error(SYSTEM,
379			"out of memory in newrayxf");
380			/* insert in list */
381			xp->next = xflast->next;
382			xflast->next = xp;
383			break; /* we're done */
384			}
385			rp = r; /* start check over */
386			}
387			/* got it */
388			r->rox = &xp->xf;
389			xflast = xp;
390	greg	1.1	}
391
392
393	schorsch	2.45	extern void
394			flipsurface( /* reverse surface orientation */
395			register RAY *r
396			)
397	greg	1.1	{
398			r->rod = -r->rod;
399			r->ron[0] = -r->ron[0];
400			r->ron[1] = -r->ron[1];
401			r->ron[2] = -r->ron[2];
402			r->pert[0] = -r->pert[0];
403			r->pert[1] = -r->pert[1];
404			r->pert[2] = -r->pert[2];
405			}
406
407
408	schorsch	2.45	extern void
409			rayhit( /* standard ray hit test */
410			OBJECT *oset,
411			RAY *r
412			)
413	greg	2.36	{
414			OBJREC *o;
415			int i;
416
417			for (i = oset[0]; i > 0; i--) {
418			o = objptr(oset[i]);
419			if ((*ofun[o->otype].funp)(o, r))
420			r->robj = oset[i];
421			}
422			}
423
424
425	schorsch	2.45	extern int
426			localhit( /* check for hit in the octree */
427			register RAY *r,
428			register CUBE *scene
429			)
430	greg	1.1	{
431	greg	2.3	OBJECT cxset[MAXCSET+1]; /* set of checked objects */
432	greg	1.1	FVECT curpos; /* current cube position */
433	greg	1.11	int sflags; /* sign flags */
434	greg	1.1	double t, dt;
435			register int i;
436
437	greg	1.21	nrays++; /* increment trace counter */
438	greg	1.11	sflags = 0;
439	greg	1.1	for (i = 0; i < 3; i++) {
440			curpos[i] = r->rorg[i];
441	greg	2.8	if (r->rdir[i] > 1e-7)
442	greg	1.11	sflags \|= 1 << i;
443	greg	2.8	else if (r->rdir[i] < -1e-7)
444	greg	1.11	sflags \|= 0x10 << i;
445	greg	1.1	}
446	greg	1.17	if (sflags == 0)
447			error(CONSISTENCY, "zero ray direction in localhit");
448	greg	2.17	/* start off assuming nothing hit */
449			if (r->rmax > FTINY) { /* except aft plane if one */
450			r->ro = &Aftplane;
451			r->rot = r->rmax;
452			for (i = 0; i < 3; i++)
453			r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
454			}
455			/* find global cube entrance point */
456	greg	1.1	t = 0.0;
457			if (!incube(scene, curpos)) {
458			/* find distance to entry */
459			for (i = 0; i < 3; i++) {
460			/* plane in our direction */
461	greg	1.11	if (sflags & 1<<i)
462	greg	1.1	dt = scene->cuorg[i];
463	greg	1.11	else if (sflags & 0x10<<i)
464	greg	1.1	dt = scene->cuorg[i] + scene->cusize;
465			else
466			continue;
467			/* distance to the plane */
468			dt = (dt - r->rorg[i])/r->rdir[i];
469			if (dt > t)
470			t = dt; /* farthest face is the one */
471			}
472			t += FTINY; /* fudge to get inside cube */
473	greg	2.17	if (t >= r->rot) /* clipped already */
474			return(0);
475	greg	1.1	/* advance position */
476			for (i = 0; i < 3; i++)
477			curpos[i] += r->rdir[i]*t;
478
479			if (!incube(scene, curpos)) /* non-intersecting ray */
480			return(0);
481			}
482	greg	2.3	cxset[0] = 0;
483	greg	2.19	raymove(curpos, cxset, sflags, r, scene);
484	schorsch	2.42	return((r->ro != NULL) & (r->ro != &Aftplane));
485	greg	1.1	}
486
487
488			static int
489	schorsch	2.45	raymove( /* check for hit as we move */
490			FVECT pos, /* current position, modified herein */
491			OBJECT cxs, / checked objects, modified by checkhit */
492			int dirf, /* direction indicators to speed tests */
493			register RAY *r,
494			register CUBE *cu
495			)
496	greg	1.1	{
497			int ax;
498			double dt, t;
499
500			if (istree(cu->cutree)) { /* recurse on subcubes */
501			CUBE cukid;
502	greg	1.11	register int br, sgn;
503	greg	1.1
504			cukid.cusize = cu->cusize * 0.5; /* find subcube */
505			VCOPY(cukid.cuorg, cu->cuorg);
506			br = 0;
507			if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
508			cukid.cuorg[0] += cukid.cusize;
509			br \|= 1;
510			}
511			if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
512			cukid.cuorg[1] += cukid.cusize;
513			br \|= 2;
514			}
515			if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
516			cukid.cuorg[2] += cukid.cusize;
517			br \|= 4;
518			}
519			for ( ; ; ) {
520			cukid.cutree = octkid(cu->cutree, br);
521	greg	2.3	if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
522	greg	1.1	return(RAYHIT);
523			sgn = 1 << ax;
524	greg	1.11	if (sgn & dirf) /* positive axis? */
525	greg	1.1	if (sgn & br)
526			return(ax); /* overflow */
527			else {
528			cukid.cuorg[ax] += cukid.cusize;
529			br \|= sgn;
530			}
531	greg	1.11	else
532			if (sgn & br) {
533			cukid.cuorg[ax] -= cukid.cusize;
534			br &= ~sgn;
535			} else
536			return(ax); /* underflow */
537	greg	1.1	}
538			/NOTREACHED/
539			}
540	greg	2.18	if (isfull(cu->cutree)) {
541			if (checkhit(r, cu, cxs))
542			return(RAYHIT);
543			} else if (r->ro == &Aftplane && incube(cu, r->rop))
544	greg	1.1	return(RAYHIT);
545			/* advance to next cube */
546	greg	1.11	if (dirf&0x11) {
547			dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
548	greg	1.1	t = (dt - pos[0])/r->rdir[0];
549			ax = 0;
550			} else
551			t = FHUGE;
552	greg	1.11	if (dirf&0x22) {
553			dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
554	greg	1.1	dt = (dt - pos[1])/r->rdir[1];
555			if (dt < t) {
556			t = dt;
557			ax = 1;
558			}
559			}
560	greg	1.11	if (dirf&0x44) {
561			dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
562	greg	1.1	dt = (dt - pos[2])/r->rdir[2];
563			if (dt < t) {
564			t = dt;
565			ax = 2;
566			}
567			}
568			pos[0] += r->rdir[0]*t;
569			pos[1] += r->rdir[1]*t;
570			pos[2] += r->rdir[2]*t;
571			return(ax);
572			}
573
574
575	greg	2.34	static int
576	schorsch	2.45	checkhit( /* check for hit in full cube */
577			register RAY *r,
578			CUBE *cu,
579			OBJECT *cxs
580			)
581	greg	1.1	{
582			OBJECT oset[MAXSET+1];
583
584			objset(oset, cu->cutree);
585	greg	2.36	checkset(oset, cxs); /* avoid double-checking */
586
587			(r->hitf)(oset, r); / test for hit in set */
588
589			if (r->robj == OVOID)
590	greg	1.1	return(0); /* no scores yet */
591
592			return(incube(cu, r->rop)); /* hit OK if in current cube */
593	greg	2.2	}
594
595
596	greg	2.34	static void
597	schorsch	2.45	checkset( /* modify checked set and set to check */
598			register OBJECT os, / os' = os - cs */
599			register OBJECT cs / cs' = cs + os */
600			)
601	greg	2.2	{
602			OBJECT cset[MAXCSET+MAXSET+1];
603	greg	2.3	register int i, j;
604			int k;
605	greg	2.2	/* copy os in place, cset <- cs */
606			cset[0] = 0;
607			k = 0;
608			for (i = j = 1; i <= os[0]; i++) {
609			while (j <= cs[0] && cs[j] < os[i])
610			cset[++cset[0]] = cs[j++];
611			if (j > cs[0] \|\| os[i] != cs[j]) { /* object to check */
612			os[++k] = os[i];
613			cset[++cset[0]] = os[i];
614			}
615			}
616	greg	2.3	if (!(os[0] = k)) /* new "to check" set size */
617			return; /* special case */
618	greg	2.2	while (j <= cs[0]) /* get the rest of cs */
619			cset[++cset[0]] = cs[j++];
620	greg	2.3	if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
621	greg	2.2	cset[0] = MAXCSET;
622	greg	2.3	/* setcopy(cs, cset); / / copy cset back to cs */
623			os = cset;
624			for (i = os[0]; i-- >= 0; )
625			cs++ = os++;
626	greg	1.1	}