src/rt/raytrace.c

/* Copyright (c) 1995 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  raytrace.c - routines for tracing and shading rays.
 *
 *     8/7/85
 */

#include  "ray.h"

#include  "octree.h"

#include  "otypes.h"

#include  "otspecial.h"

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

extern CUBE  thescene;                  /* our scene */
extern int  maxdepth;                   /* maximum recursion depth */
extern double  minweight;               /* minimum ray weight */
extern int  do_irrad;                   /* compute irradiance? */

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(), checkset(), checkhit();

#define  MAXLOOP        128             /* modifier loop detection */

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


rayorigin(r, ro, rt, rw)                /* start new ray from old one */
register RAY  *r, *ro;
int  rt;
double  rw;
{
        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;
        } 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;
                r->rweight = ro->rweight * rw;
                r->crtype = ro->crtype | (r->rtype = rt);
                VCOPY(r->rorg, ro->rop);
        }
        rayclear(r);
        return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
}


rayclear(r)                     /* clear a ray for (re)evaluation */
register RAY  *r;
{
        r->rno = raynum++;
        r->newcset = r->clipset;
        r->ro = NULL;
        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);
        r->rt = 0.0;
}


raytrace(r)                     /* trace a ray and compute its value */
RAY  *r;
{
        extern int  (*trace)();
        int  gotmat;

        if (localhit(r, &thescene))
                gotmat = raycont(r);
        else if (r->ro == &Aftplane) {
                r->ro = NULL;
                r->rot = FHUGE;
        } else if (sourcehit(r))
                gotmat = rayshade(r, r->ro->omod);

        if (r->ro != NULL && !gotmat)
                objerror(r->ro, USER, "material not found");

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


raycont(r)                      /* check for clipped object and continue */
register RAY  *r;
{
        if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) ||
                        r->ro->omod == OVOID) {
                raytrans(r);
                return(1);
        }
        return(rayshade(r, r->ro->omod));
}


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;
        }
}


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


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


raymixture(r, fore, back, coef)         /* mix modifiers */
register RAY  *r;
OBJECT  fore, back;
double  coef;
{
        RAY  fr, br;
        int  foremat, backmat;
        register int  i;
                                        /* clip coefficient */
        if (coef > 1.0)
                coef = 1.0;
        else if (coef < 0.0)
                coef = 0.0;
                                        /* compute foreground and background */
        foremat = backmat = -1;
                                        /* foreground */
        copystruct(&fr, r);
        if (fore != OVOID && coef > FTINY)
                foremat = rayshade(&fr, fore);
                                        /* background */
        copystruct(&br, r);
        if (back != OVOID && coef < 1.0-FTINY)
                backmat = rayshade(&br, back);
                                        /* check */
        if (foremat < 0)
                if (backmat < 0)
                        foremat = backmat = 0;
                else
                        foremat = backmat;
        else if (backmat < 0)
                backmat = foremat;
        if ((foremat==0) != (backmat==0))
                objerror(r->ro, USER, "mixing material with non-material");
                                        /* 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);
                                        /* mix returned ray values */
        if (foremat) {
                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 value tells if material */
        return(foremat);
}


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);
}


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 *)bmalloc(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;
}


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];
}


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
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]);
                (*ofun[o->otype].funp)(o, r);
        }
        if (r->ro == NULL)
                return(0);                      /* no scores yet */

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


static
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:	2.22
Committed:	Wed Dec 6 12:07:50 1995 UTC (28 years, 5 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.21:	+2 -3 lines
Log Message:	changed aft clipping plane to work through transparent surfaces
#	User	Rev	Content
1	greg	2.19	/* Copyright (c) 1995 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* raytrace.c - routines for tracing and shading rays.
9			*
10			* 8/7/85
11			*/
12
13			#include "ray.h"
14
15			#include "octree.h"
16
17			#include "otypes.h"
18
19	greg	1.15	#include "otspecial.h"
20
21	greg	2.3	#define MAXCSET ((MAXSET+1)2-1) / maximum check set size */
22
23	greg	1.1	extern CUBE thescene; /* our scene */
24			extern int maxdepth; /* maximum recursion depth */
25			extern double minweight; /* minimum ray weight */
26	greg	1.15	extern int do_irrad; /* compute irradiance? */
27	greg	1.1
28	greg	2.6	unsigned long raynum = 0; /* next unique ray number */
29			unsigned long nrays = 0; /* number of calls to localhit */
30	greg	1.1
31	greg	1.23	static FLOAT Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
32	greg	1.15	OBJREC Lamb = {
33			OVOID, MAT_PLASTIC, "Lambertian",
34	greg	2.2	{0, 5, NULL, Lambfa}, NULL,
35	greg	1.15	}; /* a Lambertian surface */
36
37	greg	2.17	OBJREC Aftplane; /* aft clipping plane object */
38	greg	2.16
39	greg	2.5	static int raymove(), checkset(), checkhit();
40
41	greg	1.6	#define MAXLOOP 128 /* modifier loop detection */
42	greg	1.1
43			#define RAYHIT (-1) /* return value for intercepted ray */
44
45
46			rayorigin(r, ro, rt, rw) /* start new ray from old one */
47			register RAY r, ro;
48			int rt;
49			double rw;
50			{
51			if ((r->parent = ro) == NULL) { /* primary ray */
52			r->rlvl = 0;
53			r->rweight = rw;
54			r->crtype = r->rtype = rt;
55			r->rsrc = -1;
56			r->clipset = NULL;
57	greg	1.21	r->revf = raytrace;
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	1.1	r->rweight = ro->rweight * rw;
72			r->crtype = ro->crtype \| (r->rtype = rt);
73			VCOPY(r->rorg, ro->rop);
74			}
75	greg	1.22	rayclear(r);
76			return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
77			}
78
79
80			rayclear(r) /* clear a ray for (re)evaluation */
81			register RAY *r;
82			{
83	greg	1.20	r->rno = raynum++;
84	greg	1.1	r->newcset = r->clipset;
85	greg	2.17	r->ro = NULL;
86			r->rot = FHUGE;
87	greg	1.1	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
88			setcolor(r->pcol, 1.0, 1.0, 1.0);
89			setcolor(r->rcol, 0.0, 0.0, 0.0);
90	greg	1.10	r->rt = 0.0;
91	greg	1.1	}
92
93
94	greg	1.21	raytrace(r) /* trace a ray and compute its value */
95	greg	1.8	RAY *r;
96	greg	1.1	{
97			extern int (*trace)();
98	greg	2.9	int gotmat;
99	greg	1.1
100	greg	1.15	if (localhit(r, &thescene))
101	greg	2.9	gotmat = raycont(r);
102	greg	2.16	else if (r->ro == &Aftplane) {
103			r->ro = NULL;
104			r->rot = FHUGE;
105			} else if (sourcehit(r))
106	greg	2.9	gotmat = rayshade(r, r->ro->omod);
107	greg	1.1
108	greg	2.14	if (r->ro != NULL && !gotmat)
109	greg	2.9	objerror(r->ro, USER, "material not found");
110
111	greg	1.1	if (trace != NULL)
112			(trace)(r); / trace execution */
113			}
114
115
116	greg	1.8	raycont(r) /* check for clipped object and continue */
117			register RAY *r;
118			{
119	greg	2.7	if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) \|\|
120	greg	2.9	r->ro->omod == OVOID) {
121	greg	1.8	raytrans(r);
122	greg	2.9	return(1);
123			}
124			return(rayshade(r, r->ro->omod));
125	greg	1.8	}
126
127
128	greg	1.1	raytrans(r) /* transmit ray as is */
129	greg	1.8	register RAY *r;
130	greg	1.1	{
131			RAY tr;
132
133			if (rayorigin(&tr, r, TRANS, 1.0) == 0) {
134			VCOPY(tr.rdir, r->rdir);
135			rayvalue(&tr);
136			copycolor(r->rcol, tr.rcol);
137	greg	1.10	r->rt = r->rot + tr.rt;
138	greg	1.1	}
139			}
140
141
142			rayshade(r, mod) /* shade ray r with material mod */
143			register RAY *r;
144			int mod;
145			{
146			static int depth = 0;
147	greg	2.9	int gotmat;
148	greg	1.1	register OBJREC *m;
149			/* check for infinite loop */
150			if (depth++ >= MAXLOOP)
151	greg	1.4	objerror(r->ro, USER, "possible modifier loop");
152	greg	1.19	r->rt = r->rot; /* set effective ray length */
153	greg	2.9	for (gotmat = 0; !gotmat && mod != OVOID; mod = m->omod) {
154	greg	1.1	m = objptr(mod);
155	greg	1.4	/****** unnecessary test since modifier() is always called
156	greg	1.1	if (!ismodifier(m->otype)) {
157			sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
158			error(USER, errmsg);
159			}
160	greg	1.4	******/
161	greg	1.16	/* hack for irradiance calculation */
162			if (do_irrad && !(r->crtype & ~(PRIMARY\|TRANS))) {
163			if (irr_ignore(m->otype)) {
164			depth--;
165			raytrans(r);
166	greg	2.15	return(1);
167	greg	1.16	}
168	greg	1.18	if (!islight(m->otype))
169	greg	1.16	m = &Lamb;
170			}
171	greg	2.9	/* materials call raytexture */
172			gotmat = (*ofun[m->otype].funp)(m, r);
173	greg	1.1	}
174	greg	2.9	depth--;
175			return(gotmat);
176	greg	1.1	}
177
178
179			raytexture(r, mod) /* get material modifiers */
180			RAY *r;
181			int mod;
182			{
183			static int depth = 0;
184			register OBJREC *m;
185			/* check for infinite loop */
186			if (depth++ >= MAXLOOP)
187			objerror(r->ro, USER, "modifier loop");
188			/* execute textures and patterns */
189			for ( ; mod != OVOID; mod = m->omod) {
190			m = objptr(mod);
191	greg	2.9	/****** unnecessary test since modifier() is always called
192			if (!ismodifier(m->otype)) {
193	greg	1.1	sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
194			error(USER, errmsg);
195			}
196	greg	2.9	******/
197	greg	2.20	if ((*ofun[m->otype].funp)(m, r)) {
198			sprintf(errmsg, "conflicting material \"%s\"",
199			m->oname);
200			objerror(r->ro, USER, errmsg);
201			}
202	greg	1.1	}
203			depth--; /* end here */
204			}
205
206
207			raymixture(r, fore, back, coef) /* mix modifiers */
208			register RAY *r;
209			OBJECT fore, back;
210			double coef;
211			{
212	greg	2.9	RAY fr, br;
213			int foremat, backmat;
214	greg	1.1	register int i;
215			/* clip coefficient */
216			if (coef > 1.0)
217			coef = 1.0;
218			else if (coef < 0.0)
219			coef = 0.0;
220	greg	2.13	/* compute foreground and background */
221			foremat = backmat = -1;
222	greg	2.9	/* foreground */
223			copystruct(&fr, r);
224	greg	1.1	if (fore != OVOID && coef > FTINY)
225	greg	2.9	foremat = rayshade(&fr, fore);
226			/* background */
227			copystruct(&br, r);
228	greg	1.1	if (back != OVOID && coef < 1.0-FTINY)
229	greg	2.9	backmat = rayshade(&br, back);
230	greg	2.13	/* check */
231			if (foremat < 0)
232			if (backmat < 0)
233			foremat = backmat = 0;
234			else
235			foremat = backmat;
236			else if (backmat < 0)
237	greg	2.9	backmat = foremat;
238	greg	2.12	if ((foremat==0) != (backmat==0))
239	greg	2.10	objerror(r->ro, USER, "mixing material with non-material");
240	greg	2.12	/* mix perturbations */
241	greg	1.1	for (i = 0; i < 3; i++)
242	greg	2.12	r->pert[i] = coeffr.pert[i] + (1.0-coef)br.pert[i];
243			/* mix pattern colors */
244	greg	2.9	scalecolor(fr.pcol, coef);
245			scalecolor(br.pcol, 1.0-coef);
246	greg	2.12	copycolor(r->pcol, fr.pcol);
247			addcolor(r->pcol, br.pcol);
248			/* mix returned ray values */
249			if (foremat) {
250			scalecolor(fr.rcol, coef);
251			scalecolor(br.rcol, 1.0-coef);
252			copycolor(r->rcol, fr.rcol);
253			addcolor(r->rcol, br.rcol);
254	greg	2.10	r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
255	greg	2.12	}
256	greg	2.9	/* return value tells if material */
257			return(foremat);
258	greg	1.1	}
259
260
261			double
262	greg	2.21	raydist(r, flags) /* compute (cumulative) ray distance */
263			register RAY *r;
264			register int flags;
265			{
266			double sum = 0.0;
267
268			while (r != NULL && r->crtype&flags) {
269			sum += r->rot;
270			r = r->parent;
271			}
272			return(sum);
273			}
274
275
276			double
277	greg	1.1	raynormal(norm, r) /* compute perturbed normal for ray */
278			FVECT norm;
279			register RAY *r;
280			{
281			double newdot;
282			register int i;
283
284			/* The perturbation is added to the surface normal to obtain
285			* the new normal. If the new normal would affect the surface
286			* orientation wrt. the ray, a correction is made. The method is
287			* still fraught with problems since reflected rays and similar
288			* directions calculated from the surface normal may spawn rays behind
289			* the surface. The only solution is to curb textures at high
290	greg	1.9	* incidence (namely, keep DOT(rdir,pert) < Rdot).
291	greg	1.1	*/
292
293			for (i = 0; i < 3; i++)
294			norm[i] = r->ron[i] + r->pert[i];
295
296			if (normalize(norm) == 0.0) {
297			objerror(r->ro, WARNING, "illegal normal perturbation");
298			VCOPY(norm, r->ron);
299			return(r->rod);
300			}
301			newdot = -DOT(norm, r->rdir);
302			if ((newdot > 0.0) != (r->rod > 0.0)) { /* fix orientation */
303			for (i = 0; i < 3; i++)
304			norm[i] += 2.0newdotr->rdir[i];
305			newdot = -newdot;
306			}
307			return(newdot);
308	greg	1.12	}
309
310
311			newrayxf(r) /* get new tranformation matrix for ray */
312			RAY *r;
313			{
314			static struct xfn {
315			struct xfn *next;
316			FULLXF xf;
317			} xfseed = { &xfseed }, *xflast = &xfseed;
318			register struct xfn *xp;
319			register RAY *rp;
320
321			/*
322			* Search for transform in circular list that
323			* has no associated ray in the tree.
324			*/
325			xp = xflast;
326			for (rp = r->parent; rp != NULL; rp = rp->parent)
327			if (rp->rox == &xp->xf) { /* xp in use */
328			xp = xp->next; /* move to next */
329			if (xp == xflast) { /* need new one */
330	greg	1.14	xp = (struct xfn *)bmalloc(sizeof(struct xfn));
331	greg	1.12	if (xp == NULL)
332			error(SYSTEM,
333			"out of memory in newrayxf");
334			/* insert in list */
335			xp->next = xflast->next;
336			xflast->next = xp;
337			break; /* we're done */
338			}
339			rp = r; /* start check over */
340			}
341			/* got it */
342			r->rox = &xp->xf;
343			xflast = xp;
344	greg	1.1	}
345
346
347			flipsurface(r) /* reverse surface orientation */
348			register RAY *r;
349			{
350			r->rod = -r->rod;
351			r->ron[0] = -r->ron[0];
352			r->ron[1] = -r->ron[1];
353			r->ron[2] = -r->ron[2];
354			r->pert[0] = -r->pert[0];
355			r->pert[1] = -r->pert[1];
356			r->pert[2] = -r->pert[2];
357			}
358
359
360			localhit(r, scene) /* check for hit in the octree */
361			register RAY *r;
362			register CUBE *scene;
363			{
364	greg	2.3	OBJECT cxset[MAXCSET+1]; /* set of checked objects */
365	greg	1.1	FVECT curpos; /* current cube position */
366	greg	1.11	int sflags; /* sign flags */
367	greg	1.1	double t, dt;
368			register int i;
369
370	greg	1.21	nrays++; /* increment trace counter */
371	greg	1.11	sflags = 0;
372	greg	1.1	for (i = 0; i < 3; i++) {
373			curpos[i] = r->rorg[i];
374	greg	2.8	if (r->rdir[i] > 1e-7)
375	greg	1.11	sflags \|= 1 << i;
376	greg	2.8	else if (r->rdir[i] < -1e-7)
377	greg	1.11	sflags \|= 0x10 << i;
378	greg	1.1	}
379	greg	1.17	if (sflags == 0)
380			error(CONSISTENCY, "zero ray direction in localhit");
381	greg	2.17	/* start off assuming nothing hit */
382			if (r->rmax > FTINY) { /* except aft plane if one */
383			r->ro = &Aftplane;
384			r->rot = r->rmax;
385			for (i = 0; i < 3; i++)
386			r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
387			}
388			/* find global cube entrance point */
389	greg	1.1	t = 0.0;
390			if (!incube(scene, curpos)) {
391			/* find distance to entry */
392			for (i = 0; i < 3; i++) {
393			/* plane in our direction */
394	greg	1.11	if (sflags & 1<<i)
395	greg	1.1	dt = scene->cuorg[i];
396	greg	1.11	else if (sflags & 0x10<<i)
397	greg	1.1	dt = scene->cuorg[i] + scene->cusize;
398			else
399			continue;
400			/* distance to the plane */
401			dt = (dt - r->rorg[i])/r->rdir[i];
402			if (dt > t)
403			t = dt; /* farthest face is the one */
404			}
405			t += FTINY; /* fudge to get inside cube */
406	greg	2.17	if (t >= r->rot) /* clipped already */
407			return(0);
408	greg	1.1	/* advance position */
409			for (i = 0; i < 3; i++)
410			curpos[i] += r->rdir[i]*t;
411
412			if (!incube(scene, curpos)) /* non-intersecting ray */
413			return(0);
414			}
415	greg	2.3	cxset[0] = 0;
416	greg	2.19	raymove(curpos, cxset, sflags, r, scene);
417			return(r->ro != NULL & r->ro != &Aftplane);
418	greg	1.1	}
419
420
421			static int
422	greg	2.3	raymove(pos, cxs, dirf, r, cu) /* check for hit as we move */
423			FVECT pos; /* current position, modified herein */
424			OBJECT cxs; / checked objects, modified by checkhit */
425	greg	1.11	int dirf; /* direction indicators to speed tests */
426	greg	1.1	register RAY *r;
427			register CUBE *cu;
428			{
429			int ax;
430			double dt, t;
431
432			if (istree(cu->cutree)) { /* recurse on subcubes */
433			CUBE cukid;
434	greg	1.11	register int br, sgn;
435	greg	1.1
436			cukid.cusize = cu->cusize * 0.5; /* find subcube */
437			VCOPY(cukid.cuorg, cu->cuorg);
438			br = 0;
439			if (pos[0] >= cukid.cuorg[0]+cukid.cusize) {
440			cukid.cuorg[0] += cukid.cusize;
441			br \|= 1;
442			}
443			if (pos[1] >= cukid.cuorg[1]+cukid.cusize) {
444			cukid.cuorg[1] += cukid.cusize;
445			br \|= 2;
446			}
447			if (pos[2] >= cukid.cuorg[2]+cukid.cusize) {
448			cukid.cuorg[2] += cukid.cusize;
449			br \|= 4;
450			}
451			for ( ; ; ) {
452			cukid.cutree = octkid(cu->cutree, br);
453	greg	2.3	if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
454	greg	1.1	return(RAYHIT);
455			sgn = 1 << ax;
456	greg	1.11	if (sgn & dirf) /* positive axis? */
457	greg	1.1	if (sgn & br)
458			return(ax); /* overflow */
459			else {
460			cukid.cuorg[ax] += cukid.cusize;
461			br \|= sgn;
462			}
463	greg	1.11	else
464			if (sgn & br) {
465			cukid.cuorg[ax] -= cukid.cusize;
466			br &= ~sgn;
467			} else
468			return(ax); /* underflow */
469	greg	1.1	}
470			/NOTREACHED/
471			}
472	greg	2.18	if (isfull(cu->cutree)) {
473			if (checkhit(r, cu, cxs))
474			return(RAYHIT);
475			} else if (r->ro == &Aftplane && incube(cu, r->rop))
476	greg	1.1	return(RAYHIT);
477			/* advance to next cube */
478	greg	1.11	if (dirf&0x11) {
479			dt = dirf&1 ? cu->cuorg[0] + cu->cusize : cu->cuorg[0];
480	greg	1.1	t = (dt - pos[0])/r->rdir[0];
481			ax = 0;
482			} else
483			t = FHUGE;
484	greg	1.11	if (dirf&0x22) {
485			dt = dirf&2 ? cu->cuorg[1] + cu->cusize : cu->cuorg[1];
486	greg	1.1	dt = (dt - pos[1])/r->rdir[1];
487			if (dt < t) {
488			t = dt;
489			ax = 1;
490			}
491			}
492	greg	1.11	if (dirf&0x44) {
493			dt = dirf&4 ? cu->cuorg[2] + cu->cusize : cu->cuorg[2];
494	greg	1.1	dt = (dt - pos[2])/r->rdir[2];
495			if (dt < t) {
496			t = dt;
497			ax = 2;
498			}
499			}
500			pos[0] += r->rdir[0]*t;
501			pos[1] += r->rdir[1]*t;
502			pos[2] += r->rdir[2]*t;
503			return(ax);
504			}
505
506
507			static
508	greg	2.3	checkhit(r, cu, cxs) /* check for hit in full cube */
509	greg	1.1	register RAY *r;
510			CUBE *cu;
511	greg	2.3	OBJECT *cxs;
512	greg	1.1	{
513			OBJECT oset[MAXSET+1];
514			register OBJREC *o;
515			register int i;
516
517			objset(oset, cu->cutree);
518	greg	2.3	checkset(oset, cxs); /* eliminate double-checking */
519	greg	1.1	for (i = oset[0]; i > 0; i--) {
520			o = objptr(oset[i]);
521			(*ofun[o->otype].funp)(o, r);
522			}
523			if (r->ro == NULL)
524			return(0); /* no scores yet */
525
526			return(incube(cu, r->rop)); /* hit OK if in current cube */
527	greg	2.2	}
528
529
530			static
531			checkset(os, cs) /* modify checked set and set to check */
532	greg	2.3	register OBJECT os; / os' = os - cs */
533			register OBJECT cs; / cs' = cs + os */
534	greg	2.2	{
535			OBJECT cset[MAXCSET+MAXSET+1];
536	greg	2.3	register int i, j;
537			int k;
538	greg	2.2	/* copy os in place, cset <- cs */
539			cset[0] = 0;
540			k = 0;
541			for (i = j = 1; i <= os[0]; i++) {
542			while (j <= cs[0] && cs[j] < os[i])
543			cset[++cset[0]] = cs[j++];
544			if (j > cs[0] \|\| os[i] != cs[j]) { /* object to check */
545			os[++k] = os[i];
546			cset[++cset[0]] = os[i];
547			}
548			}
549	greg	2.3	if (!(os[0] = k)) /* new "to check" set size */
550			return; /* special case */
551	greg	2.2	while (j <= cs[0]) /* get the rest of cs */
552			cset[++cset[0]] = cs[j++];
553	greg	2.3	if (cset[0] > MAXCSET) /* truncate "checked" set if nec. */
554	greg	2.2	cset[0] = MAXCSET;
555	greg	2.3	/* setcopy(cs, cset); / / copy cset back to cs */
556			os = cset;
557			for (i = os[0]; i-- >= 0; )
558			cs++ = os++;
559	greg	1.1	}