src/rt/raytrace.c

#ifndef lint
static const char RCSid[] = "$Id: raytrace.c,v 2.45 2004/03/30 16:13:01 schorsch 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 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;
                }
                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:	2.46
Committed:	Thu Mar 10 22:37:00 2005 UTC (19 years, 1 month ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.45:	+4 -1 lines
Log Message:	Made illum work properly with distant source objects
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.46	static const char RCSid[] = "$Id: raytrace.c,v 2.45 2004/03/30 16:13:01 schorsch 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	2.46	} else if (ro->rot >= FHUGE) { /* illegal continuation */
59			memset(r, 0, sizeof(RAY));
60			return(-1);
61	greg	1.1	} else { /* spawned ray */
62			r->rlvl = ro->rlvl;
63			if (rt & RAYREFL) {
64			r->rlvl++;
65			r->rsrc = -1;
66			r->clipset = ro->clipset;
67	greg	2.22	r->rmax = 0.0;
68	greg	1.1	} else {
69			r->rsrc = ro->rsrc;
70			r->clipset = ro->newcset;
71	greg	2.22	r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
72	greg	1.1	}
73	greg	1.21	r->revf = ro->revf;
74	greg	2.23	copycolor(r->cext, ro->cext);
75	greg	2.26	copycolor(r->albedo, ro->albedo);
76	greg	2.23	r->gecc = ro->gecc;
77			r->slights = ro->slights;
78	greg	1.1	r->crtype = ro->crtype \| (r->rtype = rt);
79			VCOPY(r->rorg, ro->rop);
80	gwlarson	2.31	r->rweight = ro->rweight * rw;
81			/* estimate absorption */
82			re = colval(ro->cext,RED) < colval(ro->cext,GRN) ?
83			colval(ro->cext,RED) : colval(ro->cext,GRN);
84			if (colval(ro->cext,BLU) < re) re = colval(ro->cext,BLU);
85			if (re > 0.)
86			r->rweight = exp(-rero->rot);
87	greg	1.1	}
88	greg	1.22	rayclear(r);
89			return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
90			}
91
92
93	schorsch	2.45	extern void
94			rayclear( /* clear a ray for (re)evaluation */
95			register RAY *r
96			)
97	greg	1.22	{
98	greg	1.20	r->rno = raynum++;
99	greg	1.1	r->newcset = r->clipset;
100	greg	2.36	r->hitf = rayhit;
101	greg	2.28	r->robj = OVOID;
102	greg	2.17	r->ro = NULL;
103	greg	2.34	r->rox = NULL;
104	gregl	2.29	r->rt = r->rot = FHUGE;
105	greg	1.1	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
106	greg	2.37	r->uv[0] = r->uv[1] = 0.0;
107	greg	1.1	setcolor(r->pcol, 1.0, 1.0, 1.0);
108			setcolor(r->rcol, 0.0, 0.0, 0.0);
109			}
110
111
112	schorsch	2.45	extern void
113			raytrace( /* trace a ray and compute its value */
114			RAY *r
115			)
116	greg	1.1	{
117	greg	1.15	if (localhit(r, &thescene))
118	greg	2.24	raycont(r); /* hit local surface, evaluate */
119	greg	2.16	else if (r->ro == &Aftplane) {
120	greg	2.23	r->ro = NULL; /* hit aft clipping plane */
121	greg	2.16	r->rot = FHUGE;
122			} else if (sourcehit(r))
123	greg	2.24	rayshade(r, r->ro->omod); /* distant source */
124	greg	1.1
125	greg	2.23	rayparticipate(r); /* for participating medium */
126
127	greg	1.1	if (trace != NULL)
128			(trace)(r); / trace execution */
129			}
130
131
132	schorsch	2.45	extern void
133			raycont( /* check for clipped object and continue */
134			register RAY *r
135			)
136	greg	1.8	{
137	greg	2.7	if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) \|\|
138	greg	2.24	!rayshade(r, r->ro->omod))
139	greg	1.8	raytrans(r);
140			}
141
142
143	schorsch	2.45	extern void
144			raytrans( /* transmit ray as is */
145			register RAY *r
146			)
147	greg	1.1	{
148			RAY tr;
149
150			if (rayorigin(&tr, r, TRANS, 1.0) == 0) {
151			VCOPY(tr.rdir, r->rdir);
152			rayvalue(&tr);
153			copycolor(r->rcol, tr.rcol);
154	greg	1.10	r->rt = r->rot + tr.rt;
155	greg	1.1	}
156			}
157
158
159	schorsch	2.45	extern int
160			rayshade( /* shade ray r with material mod */
161			register RAY *r,
162			int mod
163			)
164	greg	1.1	{
165	greg	2.9	int gotmat;
166	greg	1.1	register OBJREC *m;
167	greg	1.19	r->rt = r->rot; /* set effective ray length */
168	greg	2.9	for (gotmat = 0; !gotmat && mod != OVOID; mod = m->omod) {
169	greg	1.1	m = objptr(mod);
170	greg	1.4	/****** unnecessary test since modifier() is always called
171	greg	1.1	if (!ismodifier(m->otype)) {
172			sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
173			error(USER, errmsg);
174			}
175	greg	1.4	******/
176	greg	1.16	/* hack for irradiance calculation */
177	greg	2.38	if (do_irrad && !(r->crtype & ~(PRIMARY\|TRANS)) &&
178	greg	2.43	m->otype != MAT_CLIP &&
179	greg	2.38	(ofun[m->otype].flags & (T_M\|T_X))) {
180	greg	1.16	if (irr_ignore(m->otype)) {
181			raytrans(r);
182	greg	2.15	return(1);
183	greg	1.16	}
184	greg	1.18	if (!islight(m->otype))
185	greg	1.16	m = &Lamb;
186			}
187	greg	2.9	/* materials call raytexture */
188			gotmat = (*ofun[m->otype].funp)(m, r);
189	greg	1.1	}
190	greg	2.9	return(gotmat);
191	greg	2.23	}
192
193
194	schorsch	2.45	extern void
195			rayparticipate( /* compute ray medium participation */
196			register RAY *r
197			)
198	greg	2.23	{
199			COLOR ce, ca;
200			double re, ge, be;
201
202			if (intens(r->cext) <= 1./FHUGE)
203			return; /* no medium */
204	greg	2.27	re = r->rot*colval(r->cext,RED);
205			ge = r->rot*colval(r->cext,GRN);
206			be = r->rot*colval(r->cext,BLU);
207	greg	2.26	if (r->crtype & SHADOW) { /* no scattering for sources */
208			re *= 1. - colval(r->albedo,RED);
209			ge *= 1. - colval(r->albedo,GRN);
210			be *= 1. - colval(r->albedo,BLU);
211			}
212			setcolor(ce, re<=0. ? 1. : re>92. ? 0. : exp(-re),
213			ge<=0. ? 1. : ge>92. ? 0. : exp(-ge),
214			be<=0. ? 1. : be>92. ? 0. : exp(-be));
215	greg	2.23	multcolor(r->rcol, ce); /* path absorption */
216	greg	2.26	if (r->crtype & SHADOW \|\| intens(r->albedo) <= FTINY)
217	greg	2.23	return; /* no scattering */
218	greg	2.26	setcolor(ca,
219			colval(r->albedo,RED)colval(ambval,RED)(1.-colval(ce,RED)),
220			colval(r->albedo,GRN)colval(ambval,GRN)(1.-colval(ce,GRN)),
221			colval(r->albedo,BLU)colval(ambval,BLU)(1.-colval(ce,BLU)));
222	greg	2.23	addcolor(r->rcol, ca); /* ambient in scattering */
223			srcscatter(r); /* source in scattering */
224	greg	1.1	}
225
226
227	schorsch	2.45	extern void
228			raytexture( /* get material modifiers */
229			RAY *r,
230			OBJECT mod
231			)
232	greg	1.1	{
233	gwlarson	2.33	register OBJREC *m;
234	greg	1.1	/* execute textures and patterns */
235			for ( ; mod != OVOID; mod = m->omod) {
236			m = objptr(mod);
237	greg	2.9	/****** unnecessary test since modifier() is always called
238			if (!ismodifier(m->otype)) {
239	greg	1.1	sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
240			error(USER, errmsg);
241			}
242	greg	2.9	******/
243	greg	2.20	if ((*ofun[m->otype].funp)(m, r)) {
244			sprintf(errmsg, "conflicting material \"%s\"",
245			m->oname);
246			objerror(r->ro, USER, errmsg);
247			}
248	greg	1.1	}
249			}
250
251
252	schorsch	2.45	extern int
253			raymixture( /* mix modifiers */
254			register RAY *r,
255			OBJECT fore,
256			OBJECT back,
257			double coef
258			)
259	greg	1.1	{
260	greg	2.9	RAY fr, br;
261			int foremat, backmat;
262	greg	1.1	register int i;
263	greg	2.24	/* bound coefficient */
264	greg	1.1	if (coef > 1.0)
265			coef = 1.0;
266			else if (coef < 0.0)
267			coef = 0.0;
268	greg	2.13	/* compute foreground and background */
269	greg	2.24	foremat = backmat = 0;
270	greg	2.9	/* foreground */
271	schorsch	2.41	fr = *r;
272	greg	2.24	if (coef > FTINY)
273	greg	2.9	foremat = rayshade(&fr, fore);
274			/* background */
275	schorsch	2.41	br = *r;
276	greg	2.24	if (coef < 1.0-FTINY)
277	greg	2.9	backmat = rayshade(&br, back);
278	greg	2.24	/* check for transparency */
279	schorsch	2.41	if (backmat ^ foremat) {
280	gwlarson	2.33	if (backmat && coef > FTINY)
281	greg	2.24	raytrans(&fr);
282	gwlarson	2.33	else if (foremat && coef < 1.0-FTINY)
283	greg	2.24	raytrans(&br);
284	schorsch	2.41	}
285	greg	2.12	/* mix perturbations */
286	greg	1.1	for (i = 0; i < 3; i++)
287	greg	2.12	r->pert[i] = coeffr.pert[i] + (1.0-coef)br.pert[i];
288			/* mix pattern colors */
289	greg	2.9	scalecolor(fr.pcol, coef);
290			scalecolor(br.pcol, 1.0-coef);
291	greg	2.12	copycolor(r->pcol, fr.pcol);
292			addcolor(r->pcol, br.pcol);
293	greg	2.24	/* return value tells if material */
294			if (!foremat & !backmat)
295			return(0);
296	greg	2.12	/* mix returned ray values */
297	greg	2.24	scalecolor(fr.rcol, coef);
298			scalecolor(br.rcol, 1.0-coef);
299			copycolor(r->rcol, fr.rcol);
300			addcolor(r->rcol, br.rcol);
301			r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
302			return(1);
303	greg	1.1	}
304
305
306	schorsch	2.45	extern double
307			raydist( /* compute (cumulative) ray distance */
308			register RAY *r,
309			register int flags
310			)
311	greg	2.21	{
312			double sum = 0.0;
313
314			while (r != NULL && r->crtype&flags) {
315			sum += r->rot;
316			r = r->parent;
317			}
318			return(sum);
319			}
320
321
322	schorsch	2.45	extern double
323			raynormal( /* compute perturbed normal for ray */
324			FVECT norm,
325			register RAY *r
326			)
327	greg	1.1	{
328			double newdot;
329			register int i;
330
331			/* The perturbation is added to the surface normal to obtain
332			* the new normal. If the new normal would affect the surface
333			* orientation wrt. the ray, a correction is made. The method is
334			* still fraught with problems since reflected rays and similar
335			* directions calculated from the surface normal may spawn rays behind
336			* the surface. The only solution is to curb textures at high
337	greg	1.9	* incidence (namely, keep DOT(rdir,pert) < Rdot).
338	greg	1.1	*/
339
340			for (i = 0; i < 3; i++)
341			norm[i] = r->ron[i] + r->pert[i];
342
343			if (normalize(norm) == 0.0) {
344			objerror(r->ro, WARNING, "illegal normal perturbation");
345			VCOPY(norm, r->ron);
346			return(r->rod);
347			}
348			newdot = -DOT(norm, r->rdir);
349			if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
350			for (i = 0; i < 3; i++)
351			norm[i] += 2.0newdotr->rdir[i];
352			newdot = -newdot;
353			}
354			return(newdot);
355	greg	1.12	}
356
357
358	schorsch	2.45	extern void
359			newrayxf( /* get new tranformation matrix for ray */
360			RAY *r
361			)
362	greg	1.12	{
363			static struct xfn {
364			struct xfn *next;
365			FULLXF xf;
366			} xfseed = { &xfseed }, *xflast = &xfseed;
367			register struct xfn *xp;
368			register RAY *rp;
369
370			/*
371			* Search for transform in circular list that
372			* has no associated ray in the tree.
373			*/
374			xp = xflast;
375			for (rp = r->parent; rp != NULL; rp = rp->parent)
376			if (rp->rox == &xp->xf) { /* xp in use */
377			xp = xp->next; /* move to next */
378			if (xp == xflast) { /* need new one */
379	greg	2.34	xp = (struct xfn *)malloc(sizeof(struct xfn));
380	greg	1.12	if (xp == NULL)
381			error(SYSTEM,
382			"out of memory in newrayxf");
383			/* insert in list */
384			xp->next = xflast->next;
385			xflast->next = xp;
386			break; /* we're done */
387			}
388			rp = r; /* start check over */
389			}
390			/* got it */
391			r->rox = &xp->xf;
392			xflast = xp;
393	greg	1.1	}
394
395
396	schorsch	2.45	extern void
397			flipsurface( /* reverse surface orientation */
398			register RAY *r
399			)
400	greg	1.1	{
401			r->rod = -r->rod;
402			r->ron[0] = -r->ron[0];
403			r->ron[1] = -r->ron[1];
404			r->ron[2] = -r->ron[2];
405			r->pert[0] = -r->pert[0];
406			r->pert[1] = -r->pert[1];
407			r->pert[2] = -r->pert[2];
408			}
409
410
411	schorsch	2.45	extern void
412			rayhit( /* standard ray hit test */
413			OBJECT *oset,
414			RAY *r
415			)
416	greg	2.36	{
417			OBJREC *o;
418			int i;
419
420			for (i = oset[0]; i > 0; i--) {
421			o = objptr(oset[i]);
422			if ((*ofun[o->otype].funp)(o, r))
423			r->robj = oset[i];
424			}
425			}
426
427
428	schorsch	2.45	extern int
429			localhit( /* check for hit in the octree */
430			register RAY *r,
431			register CUBE *scene
432			)
433	greg	1.1	{
434	greg	2.3	OBJECT cxset[MAXCSET+1]; /* set of checked objects */
435	greg	1.1	FVECT curpos; /* current cube position */
436	greg	1.11	int sflags; /* sign flags */
437	greg	1.1	double t, dt;
438			register int i;
439
440	greg	1.21	nrays++; /* increment trace counter */
441	greg	1.11	sflags = 0;
442	greg	1.1	for (i = 0; i < 3; i++) {
443			curpos[i] = r->rorg[i];
444	greg	2.8	if (r->rdir[i] > 1e-7)
445	greg	1.11	sflags \|= 1 << i;
446	greg	2.8	else if (r->rdir[i] < -1e-7)
447	greg	1.11	sflags \|= 0x10 << i;
448	greg	1.1	}
449	greg	1.17	if (sflags == 0)
450			error(CONSISTENCY, "zero ray direction in localhit");
451	greg	2.17	/* start off assuming nothing hit */
452			if (r->rmax > FTINY) { /* except aft plane if one */
453			r->ro = &Aftplane;
454			r->rot = r->rmax;
455			for (i = 0; i < 3; i++)
456			r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
457			}
458			/* find global cube entrance point */
459	greg	1.1	t = 0.0;
460			if (!incube(scene, curpos)) {
461			/* find distance to entry */
462			for (i = 0; i < 3; i++) {
463			/* plane in our direction */
464	greg	1.11	if (sflags & 1<<i)
465	greg	1.1	dt = scene->cuorg[i];
466	greg	1.11	else if (sflags & 0x10<<i)
467	greg	1.1	dt = scene->cuorg[i] + scene->cusize;
468			else
469			continue;
470			/* distance to the plane */
471			dt = (dt - r->rorg[i])/r->rdir[i];
472			if (dt > t)
473			t = dt; /* farthest face is the one */
474			}
475			t += FTINY; /* fudge to get inside cube */
476	greg	2.17	if (t >= r->rot) /* clipped already */
477			return(0);
478	greg	1.1	/* advance position */
479			for (i = 0; i < 3; i++)
480			curpos[i] += r->rdir[i]*t;
481
482			if (!incube(scene, curpos)) /* non-intersecting ray */
483			return(0);
484			}
485	greg	2.3	cxset[0] = 0;
486	greg	2.19	raymove(curpos, cxset, sflags, r, scene);
487	schorsch	2.42	return((r->ro != NULL) & (r->ro != &Aftplane));
488	greg	1.1	}
489
490
491			static int
492	schorsch	2.45	raymove( /* check for hit as we move */
493			FVECT pos, /* current position, modified herein */
494			OBJECT cxs, / checked objects, modified by checkhit */
495			int dirf, /* direction indicators to speed tests */
496			register RAY *r,
497			register CUBE *cu
498			)
499	greg	1.1	{
500			int ax;
501			double dt, t;
502
503			if (istree(cu->cutree)) { /* recurse on subcubes */
504			CUBE cukid;
505	greg	1.11	register int br, sgn;
506	greg	1.1
507			cukid.cusize = cu->cusize * 0.5; /* find subcube */
508			VCOPY(cukid.cuorg, cu->cuorg);
509			br = 0;
510			if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
511			cukid.cuorg[0] += cukid.cusize;
512			br \|= 1;
513			}
514			if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
515			cukid.cuorg[1] += cukid.cusize;
516			br \|= 2;
517			}
518			if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
519			cukid.cuorg[2] += cukid.cusize;
520			br \|= 4;
521			}
522			for ( ; ; ) {
523			cukid.cutree = octkid(cu->cutree, br);
524	greg	2.3	if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
525	greg	1.1	return(RAYHIT);
526			sgn = 1 << ax;
527	greg	1.11	if (sgn & dirf) /* positive axis? */
528	greg	1.1	if (sgn & br)
529			return(ax); /* overflow */
530			else {
531			cukid.cuorg[ax] += cukid.cusize;
532			br \|= sgn;
533			}
534	greg	1.11	else
535			if (sgn & br) {
536			cukid.cuorg[ax] -= cukid.cusize;
537			br &= ~sgn;
538			} else
539			return(ax); /* underflow */
540	greg	1.1	}
541			/NOTREACHED/
542			}
543	greg	2.18	if (isfull(cu->cutree)) {
544			if (checkhit(r, cu, cxs))
545			return(RAYHIT);
546			} else if (r->ro == &Aftplane && incube(cu, r->rop))
547	greg	1.1	return(RAYHIT);
548			/* advance to next cube */
549	greg	1.11	if (dirf&0x11) {
550			dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
551	greg	1.1	t = (dt - pos[0])/r->rdir[0];
552			ax = 0;
553			} else
554			t = FHUGE;
555	greg	1.11	if (dirf&0x22) {
556			dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
557	greg	1.1	dt = (dt - pos[1])/r->rdir[1];
558			if (dt < t) {
559			t = dt;
560			ax = 1;
561			}
562			}
563	greg	1.11	if (dirf&0x44) {
564			dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
565	greg	1.1	dt = (dt - pos[2])/r->rdir[2];
566			if (dt < t) {
567			t = dt;
568			ax = 2;
569			}
570			}
571			pos[0] += r->rdir[0]*t;
572			pos[1] += r->rdir[1]*t;
573			pos[2] += r->rdir[2]*t;
574			return(ax);
575			}
576
577
578	greg	2.34	static int
579	schorsch	2.45	checkhit( /* check for hit in full cube */
580			register RAY *r,
581			CUBE *cu,
582			OBJECT *cxs
583			)
584	greg	1.1	{
585			OBJECT oset[MAXSET+1];
586
587			objset(oset, cu->cutree);
588	greg	2.36	checkset(oset, cxs); /* avoid double-checking */
589
590			(r->hitf)(oset, r); / test for hit in set */
591
592			if (r->robj == OVOID)
593	greg	1.1	return(0); /* no scores yet */
594
595			return(incube(cu, r->rop)); /* hit OK if in current cube */
596	greg	2.2	}
597
598
599	greg	2.34	static void
600	schorsch	2.45	checkset( /* modify checked set and set to check */
601			register OBJECT os, / os' = os - cs */
602			register OBJECT cs / cs' = cs + os */
603			)
604	greg	2.2	{
605			OBJECT cset[MAXCSET+MAXSET+1];
606	greg	2.3	register int i, j;
607			int k;
608	greg	2.2	/* copy os in place, cset <- cs */
609			cset[0] = 0;
610			k = 0;
611			for (i = j = 1; i <= os[0]; i++) {
612			while (j <= cs[0] && cs[j] < os[i])
613			cset[++cset[0]] = cs[j++];
614			if (j > cs[0] \|\| os[i] != cs[j]) { /* object to check */
615			os[++k] = os[i];
616			cset[++cset[0]] = os[i];
617			}
618			}
619	greg	2.3	if (!(os[0] = k)) /* new "to check" set size */
620			return; /* special case */
621	greg	2.2	while (j <= cs[0]) /* get the rest of cs */
622			cset[++cset[0]] = cs[j++];
623	greg	2.3	if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
624	greg	2.2	cset[0] = MAXCSET;
625	greg	2.3	/* setcopy(cs, cset); / / copy cset back to cs */
626			os = cset;
627			for (i = os[0]; i-- >= 0; )
628			cs++ = os++;
629	greg	1.1	}