src/gen/mkillum2.c

#ifndef lint
static const char       RCSid[] = "$Id$";
#endif
/*
 * Routines to do the actual calculation for mkillum
 */

#include  "mkillum.h"

#include  "face.h"

#include  "cone.h"

#include  "random.h"


o_default(ob, il, rt, nm)       /* default illum action */
OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
        sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
                        nm, ofun[ob->otype].funame, ob->oname);
        error(WARNING, errmsg);
        printobj(il->altmat, ob);
}


o_face(ob, il, rt, nm)          /* make an illum face */
OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
#define MAXMISS         (5*n*il->nsamps)
        int  dim[3];
        int  n, nalt, nazi, h;
        float  *distarr;
        double  sp[2], r1, r2;
        FVECT  dn, org, dir;
        FVECT  u, v;
        double  ur[2], vr[2];
        int  nmisses;
        register FACE  *fa;
        register int  i, j;
                                /* get/check arguments */
        fa = getface(ob);
        if (fa->area == 0.0) {
                freeface(ob);
                o_default(ob, il, rt, nm);
                return;
        }
                                /* set up sampling */
        if (il->sampdens <= 0)
                nalt = nazi = 1;
        else {
                n = PI * il->sampdens;
                nalt = sqrt(n/PI) + .5;
                nazi = PI*nalt + .5;
        }
        n = nalt*nazi;
        distarr = (float *)calloc(n, 3*sizeof(float));
        if (distarr == NULL)
                error(SYSTEM, "out of memory in o_face");
                                /* take first edge longer than sqrt(area) */
        for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
                u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
                u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
                u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
                if ((r1 = DOT(u,u)) >= fa->area-FTINY)
                        break;
        }
        if (i < fa->nv) {       /* got one! -- let's align our axes */
                r2 = 1.0/sqrt(r1);
                u[0] *= r2; u[1] *= r2; u[2] *= r2;
                fcross(v, fa->norm, u);
        } else                  /* oh well, we'll just have to wing it */
                mkaxes(u, v, fa->norm);
                                /* now, find limits in (u,v) coordinates */
        ur[0] = vr[0] = FHUGE;
        ur[1] = vr[1] = -FHUGE;
        for (i = 0; i < fa->nv; i++) {
                r1 = DOT(VERTEX(fa,i),u);
                if (r1 < ur[0]) ur[0] = r1;
                if (r1 > ur[1]) ur[1] = r1;
                r2 = DOT(VERTEX(fa,i),v);
                if (r2 < vr[0]) vr[0] = r2;
                if (r2 > vr[1]) vr[1] = r2;
        }
        dim[0] = random();
                                /* sample polygon */
        nmisses = 0;
        for (dim[1] = 0; dim[1] < nalt; dim[1]++)
            for (dim[2] = 0; dim[2] < nazi; dim[2]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* random direction */
                    h = ilhash(dim, 3) + i;
                    multisamp(sp, 2, urand(h));
                    r1 = (dim[1] + sp[0])/nalt;
                    r2 = (dim[2] + sp[1] - .5)/nazi;
                    flatdir(dn, r1, r2);
                    for (j = 0; j < 3; j++)
                        dir[j] = -dn[0]*u[j] - dn[1]*v[j] - dn[2]*fa->norm[j];
                                        /* random location */
                    do {
                        multisamp(sp, 2, urand(h+4862+nmisses));
                        r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
                        r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
                        for (j = 0; j < 3; j++)
                            org[j] = r1*u[j] + r2*v[j]
                                        + fa->offset*fa->norm[j];
                    } while (!inface(org, fa) && nmisses++ < MAXMISS);
                    if (nmisses > MAXMISS) {
                        objerror(ob, WARNING, "bad aspect");
                        rt->nrays = 0;
                        freeface(ob);
                        free((void *)distarr);
                        o_default(ob, il, rt, nm);
                        return;
                    }
                    for (j = 0; j < 3; j++)
                        org[j] += .001*fa->norm[j];
                                        /* send sample */
                    raysamp(distarr+3*(dim[1]*nazi+dim[2]), org, dir, rt);
                }
        rayflush(rt);
                                /* write out the face and its distribution */
        if (average(il, distarr, nalt*nazi)) {
                if (il->sampdens > 0)
                        flatout(il, distarr, nalt, nazi, u, v, fa->norm);
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        freeface(ob);
        free((void *)distarr);
#undef MAXMISS
}


o_sphere(ob, il, rt, nm)        /* make an illum sphere */
register OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
        int  dim[3];
        int  n, nalt, nazi;
        float  *distarr;
        double  sp[4], r1, r2, r3;
        FVECT  org, dir;
        FVECT  u, v;
        register int  i, j;
                                /* check arguments */
        if (ob->oargs.nfargs != 4)
                objerror(ob, USER, "bad # of arguments");
                                /* set up sampling */
        if (il->sampdens <= 0)
                nalt = nazi = 1;
        else {
                n = 4.*PI * il->sampdens;
                nalt = sqrt(2./PI*n) + .5;
                nazi = PI/2.*nalt + .5;
        }
        n = nalt*nazi;
        distarr = (float *)calloc(n, 3*sizeof(float));
        if (distarr == NULL)
                error(SYSTEM, "out of memory in o_sphere");
        dim[0] = random();
                                /* sample sphere */
        for (dim[1] = 0; dim[1] < nalt; dim[1]++)
            for (dim[2] = 0; dim[2] < nazi; dim[2]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* next sample point */
                    multisamp(sp, 4, urand(ilhash(dim,3)+i));
                                        /* random direction */
                    r1 = (dim[1] + sp[0])/nalt;
                    r2 = (dim[2] + sp[1] - .5)/nazi;
                    rounddir(dir, r1, r2);
                                        /* random location */
                    mkaxes(u, v, dir);          /* yuck! */
                    r3 = sqrt(sp[2]);
                    r2 = 2.*PI*sp[3];
                    r1 = r3*ob->oargs.farg[3]*cos(r2);
                    r2 = r3*ob->oargs.farg[3]*sin(r2);
                    r3 = ob->oargs.farg[3]*sqrt(1.01-r3*r3);
                    for (j = 0; j < 3; j++) {
                        org[j] = ob->oargs.farg[j] + r1*u[j] + r2*v[j] +
                                        r3*dir[j];
                        dir[j] = -dir[j];
                    }
                                        /* send sample */
                    raysamp(distarr+3*(dim[1]*nazi+dim[2]), org, dir, rt);
                }
        rayflush(rt);
                                /* write out the sphere and its distribution */
        if (average(il, distarr, nalt*nazi)) {
                if (il->sampdens > 0)
                        roundout(il, distarr, nalt, nazi);
                else
                        objerror(ob, WARNING, "diffuse distribution");
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        free((void *)distarr);
}


o_ring(ob, il, rt, nm)          /* make an illum ring */
OBJREC  *ob;
struct illum_args  *il;
struct rtproc  *rt;
char  *nm;
{
        int  dim[3];
        int  n, nalt, nazi;
        float  *distarr;
        double  sp[4], r1, r2, r3;
        FVECT  dn, org, dir;
        FVECT  u, v;
        register CONE  *co;
        register int  i, j;
                                /* get/check arguments */
        co = getcone(ob, 0);
                                /* set up sampling */
        if (il->sampdens <= 0)
                nalt = nazi = 1;
        else {
                n = PI * il->sampdens;
                nalt = sqrt(n/PI) + .5;
                nazi = PI*nalt + .5;
        }
        n = nalt*nazi;
        distarr = (float *)calloc(n, 3*sizeof(float));
        if (distarr == NULL)
                error(SYSTEM, "out of memory in o_ring");
        mkaxes(u, v, co->ad);
        dim[0] = random();
                                /* sample disk */
        for (dim[1] = 0; dim[1] < nalt; dim[1]++)
            for (dim[2] = 0; dim[2] < nazi; dim[2]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* next sample point */
                    multisamp(sp, 4, urand(ilhash(dim,3)+i));
                                        /* random direction */
                    r1 = (dim[1] + sp[0])/nalt;
                    r2 = (dim[2] + sp[1] - .5)/nazi;
                    flatdir(dn, r1, r2);
                    for (j = 0; j < 3; j++)
                        dir[j] = -dn[0]*u[j] - dn[1]*v[j] - dn[2]*co->ad[j];
                                        /* random location */
                    r3 = sqrt(CO_R0(co)*CO_R0(co) +
                            sp[2]*(CO_R1(co)*CO_R1(co) - CO_R0(co)*CO_R0(co)));
                    r2 = 2.*PI*sp[3];
                    r1 = r3*cos(r2);
                    r2 = r3*sin(r2);
                    for (j = 0; j < 3; j++)
                        org[j] = CO_P0(co)[j] + r1*u[j] + r2*v[j] +
                                        .001*co->ad[j];

                                        /* send sample */
                    raysamp(distarr+3*(dim[1]*nazi+dim[2]), org, dir, rt);
                }
        rayflush(rt);
                                /* write out the ring and its distribution */
        if (average(il, distarr, nalt*nazi)) {
                if (il->sampdens > 0)
                        flatout(il, distarr, nalt, nazi, u, v, co->ad);
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        freecone(ob);
        free((void *)distarr);
}


raysamp(res, org, dir, rt)      /* compute a ray sample */
float  res[3];
FVECT  org, dir;
register struct rtproc  *rt;
{
        register float  *fp;

        if (rt->nrays == rt->bsiz)
                rayflush(rt);
        rt->dest[rt->nrays] = res;
        fp = rt->buf + 6*rt->nrays++;
        *fp++ = org[0]; *fp++ = org[1]; *fp++ = org[2];
        *fp++ = dir[0]; *fp++ = dir[1]; *fp = dir[2];
}


rayflush(rt)                    /* flush buffered rays */
register struct rtproc  *rt;
{
        register int  i;

        if (rt->nrays <= 0)
                return;
        bzero(rt->buf+6*rt->nrays, 6*sizeof(float));
        errno = 0;
        if ( process(rt->pd, (char *)rt->buf, (char *)rt->buf,
                        3*sizeof(float)*(rt->nrays+1),
                        6*sizeof(float)*(rt->nrays+1)) <
                        3*sizeof(float)*(rt->nrays+1) )
                error(SYSTEM, "error reading from rtrace process");
        i = rt->nrays;
        while (i--) {
                rt->dest[i][0] += rt->buf[3*i];
                rt->dest[i][1] += rt->buf[3*i+1];
                rt->dest[i][2] += rt->buf[3*i+2];
        }
        rt->nrays = 0;
}


mkaxes(u, v, n)                 /* compute u and v to go with n */
FVECT  u, v, n;
{
        register int  i;

        v[0] = v[1] = v[2] = 0.0;
        for (i = 0; i < 3; i++)
                if (n[i] < 0.6 && n[i] > -0.6)
                        break;
        v[i] = 1.0;
        fcross(u, v, n);
        normalize(u);
        fcross(v, n, u);
}


rounddir(dv, alt, azi)          /* compute uniform spherical direction */
register FVECT  dv;
double  alt, azi;
{
        double  d1, d2;

        dv[2] = 1. - 2.*alt;
        d1 = sqrt(1. - dv[2]*dv[2]);
        d2 = 2.*PI * azi;
        dv[0] = d1*cos(d2);
        dv[1] = d1*sin(d2);
}


flatdir(dv, alt, azi)           /* compute uniform hemispherical direction */
register FVECT  dv;
double  alt, azi;
{
        double  d1, d2;

        d1 = sqrt(alt);
        d2 = 2.*PI * azi;
        dv[0] = d1*cos(d2);
        dv[1] = d1*sin(d2);
        dv[2] = sqrt(1. - alt);
}
Revision:	2.9
Committed:	Sat Feb 22 02:07:24 2003 UTC (21 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R5
Changes since 2.8:	+5 -8 lines
Log Message:	Changes and check-in for 3.5 release Includes new source files and modifications not recorded for many years See ray/doc/notes/ReleaseNotes for notes between 3.1 and 3.5 release
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.9	static const char RCSid[] = "$Id$";
3	greg	1.1	#endif
4			/*
5	greg	1.4	* Routines to do the actual calculation for mkillum
6	greg	1.1	*/
7
8			#include "mkillum.h"
9
10			#include "face.h"
11
12			#include "cone.h"
13
14	greg	1.2	#include "random.h"
15	greg	1.1
16	greg	1.2
17			o_default(ob, il, rt, nm) /* default illum action */
18	greg	1.1	OBJREC *ob;
19			struct illum_args *il;
20			struct rtproc *rt;
21	greg	1.2	char *nm;
22	greg	1.1	{
23	greg	1.2	sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
24			nm, ofun[ob->otype].funame, ob->oname);
25			error(WARNING, errmsg);
26	greg	2.2	printobj(il->altmat, ob);
27	greg	1.2	}
28
29
30			o_face(ob, il, rt, nm) /* make an illum face */
31			OBJREC *ob;
32			struct illum_args *il;
33			struct rtproc *rt;
34			char *nm;
35			{
36	greg	1.3	#define MAXMISS (5nil->nsamps)
37	greg	1.10	int dim[3];
38			int n, nalt, nazi, h;
39	greg	1.3	float *distarr;
40	greg	1.10	double sp[2], r1, r2;
41	greg	1.4	FVECT dn, org, dir;
42	greg	1.3	FVECT u, v;
43			double ur[2], vr[2];
44			int nmisses;
45			register FACE *fa;
46			register int i, j;
47			/* get/check arguments */
48			fa = getface(ob);
49			if (fa->area == 0.0) {
50			freeface(ob);
51			o_default(ob, il, rt, nm);
52			return;
53			}
54			/* set up sampling */
55	greg	1.11	if (il->sampdens <= 0)
56			nalt = nazi = 1;
57			else {
58			n = PI * il->sampdens;
59			nalt = sqrt(n/PI) + .5;
60			nazi = PI*nalt + .5;
61			}
62	greg	1.3	n = nalt*nazi;
63			distarr = (float )calloc(n, 3sizeof(float));
64			if (distarr == NULL)
65			error(SYSTEM, "out of memory in o_face");
66	greg	2.3	/* take first edge longer than sqrt(area) */
67	greg	2.4	for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
68			u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
69			u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
70			u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
71	greg	2.5	if ((r1 = DOT(u,u)) >= fa->area-FTINY)
72	greg	2.3	break;
73			}
74			if (i < fa->nv) { /* got one! -- let's align our axes */
75	greg	2.5	r2 = 1.0/sqrt(r1);
76			u[0] = r2; u[1] = r2; u[2] *= r2;
77	greg	2.3	fcross(v, fa->norm, u);
78			} else /* oh well, we'll just have to wing it */
79			mkaxes(u, v, fa->norm);
80			/* now, find limits in (u,v) coordinates */
81	greg	1.3	ur[0] = vr[0] = FHUGE;
82			ur[1] = vr[1] = -FHUGE;
83			for (i = 0; i < fa->nv; i++) {
84			r1 = DOT(VERTEX(fa,i),u);
85			if (r1 < ur[0]) ur[0] = r1;
86			if (r1 > ur[1]) ur[1] = r1;
87			r2 = DOT(VERTEX(fa,i),v);
88			if (r2 < vr[0]) vr[0] = r2;
89			if (r2 > vr[1]) vr[1] = r2;
90			}
91			dim[0] = random();
92			/* sample polygon */
93			nmisses = 0;
94			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
95			for (dim[2] = 0; dim[2] < nazi; dim[2]++)
96			for (i = 0; i < il->nsamps; i++) {
97			/* random direction */
98	greg	1.10	h = ilhash(dim, 3) + i;
99	greg	1.11	multisamp(sp, 2, urand(h));
100	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
101	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
102	greg	1.3	flatdir(dn, r1, r2);
103			for (j = 0; j < 3; j++)
104	greg	1.5	dir[j] = -dn[0]u[j] - dn[1]v[j] - dn[2]*fa->norm[j];
105	greg	1.3	/* random location */
106			do {
107	greg	1.11	multisamp(sp, 2, urand(h+4862+nmisses));
108	greg	1.10	r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
109			r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
110	greg	1.3	for (j = 0; j < 3; j++)
111			org[j] = r1u[j] + r2v[j]
112			+ fa->offset*fa->norm[j];
113			} while (!inface(org, fa) && nmisses++ < MAXMISS);
114			if (nmisses > MAXMISS) {
115			objerror(ob, WARNING, "bad aspect");
116			rt->nrays = 0;
117			freeface(ob);
118	greg	2.9	free((void *)distarr);
119	greg	1.3	o_default(ob, il, rt, nm);
120			return;
121			}
122			for (j = 0; j < 3; j++)
123			org[j] += .001*fa->norm[j];
124			/* send sample */
125	greg	1.7	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt);
126	greg	1.3	}
127			rayflush(rt);
128	greg	1.11	/* write out the face and its distribution */
129	greg	1.12	if (average(il, distarr, nalt*nazi)) {
130			if (il->sampdens > 0)
131			flatout(il, distarr, nalt, nazi, u, v, fa->norm);
132			illumout(il, ob);
133	greg	2.2	} else
134	greg	1.12	printobj(il->altmat, ob);
135	greg	1.3	/* clean up */
136			freeface(ob);
137	greg	2.9	free((void *)distarr);
138	greg	1.3	#undef MAXMISS
139	greg	1.2	}
140
141
142			o_sphere(ob, il, rt, nm) /* make an illum sphere */
143	greg	1.3	register OBJREC *ob;
144	greg	1.2	struct illum_args *il;
145			struct rtproc *rt;
146			char *nm;
147			{
148	greg	1.10	int dim[3];
149	greg	1.2	int n, nalt, nazi;
150			float *distarr;
151	greg	1.10	double sp[4], r1, r2, r3;
152	greg	1.4	FVECT org, dir;
153	greg	1.2	FVECT u, v;
154			register int i, j;
155			/* check arguments */
156			if (ob->oargs.nfargs != 4)
157			objerror(ob, USER, "bad # of arguments");
158			/* set up sampling */
159	greg	1.11	if (il->sampdens <= 0)
160			nalt = nazi = 1;
161			else {
162			n = 4.PI il->sampdens;
163	greg	2.7	nalt = sqrt(2./PI*n) + .5;
164			nazi = PI/2.*nalt + .5;
165	greg	1.11	}
166	greg	1.2	n = nalt*nazi;
167			distarr = (float )calloc(n, 3sizeof(float));
168			if (distarr == NULL)
169			error(SYSTEM, "out of memory in o_sphere");
170			dim[0] = random();
171			/* sample sphere */
172			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
173	greg	1.8	for (dim[2] = 0; dim[2] < nazi; dim[2]++)
174	greg	1.2	for (i = 0; i < il->nsamps; i++) {
175	greg	1.10	/* next sample point */
176	greg	1.11	multisamp(sp, 4, urand(ilhash(dim,3)+i));
177	greg	1.2	/* random direction */
178	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
179	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
180	greg	1.2	rounddir(dir, r1, r2);
181			/* random location */
182	greg	1.8	mkaxes(u, v, dir); /* yuck! */
183	greg	1.10	r3 = sqrt(sp[2]);
184			r2 = 2.PIsp[3];
185	greg	1.5	r1 = r3ob->oargs.farg[3]cos(r2);
186			r2 = r3ob->oargs.farg[3]sin(r2);
187			r3 = ob->oargs.farg[3]sqrt(1.01-r3r3);
188			for (j = 0; j < 3; j++) {
189			org[j] = ob->oargs.farg[j] + r1u[j] + r2v[j] +
190			r3*dir[j];
191			dir[j] = -dir[j];
192			}
193	greg	1.2	/* send sample */
194	greg	1.7	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt);
195	greg	1.2	}
196			rayflush(rt);
197	greg	1.11	/* write out the sphere and its distribution */
198	greg	1.12	if (average(il, distarr, nalt*nazi)) {
199			if (il->sampdens > 0)
200			roundout(il, distarr, nalt, nazi);
201			else
202			objerror(ob, WARNING, "diffuse distribution");
203			illumout(il, ob);
204	greg	2.2	} else
205	greg	1.12	printobj(il->altmat, ob);
206	greg	1.2	/* clean up */
207	greg	2.9	free((void *)distarr);
208	greg	1.2	}
209
210
211			o_ring(ob, il, rt, nm) /* make an illum ring */
212			OBJREC *ob;
213			struct illum_args *il;
214			struct rtproc *rt;
215			char *nm;
216			{
217	greg	1.10	int dim[3];
218	greg	1.3	int n, nalt, nazi;
219			float *distarr;
220	greg	1.10	double sp[4], r1, r2, r3;
221	greg	1.4	FVECT dn, org, dir;
222	greg	1.3	FVECT u, v;
223			register CONE *co;
224			register int i, j;
225			/* get/check arguments */
226			co = getcone(ob, 0);
227			/* set up sampling */
228	greg	1.11	if (il->sampdens <= 0)
229			nalt = nazi = 1;
230			else {
231			n = PI * il->sampdens;
232			nalt = sqrt(n/PI) + .5;
233			nazi = PI*nalt + .5;
234			}
235	greg	1.3	n = nalt*nazi;
236			distarr = (float )calloc(n, 3sizeof(float));
237			if (distarr == NULL)
238			error(SYSTEM, "out of memory in o_ring");
239			mkaxes(u, v, co->ad);
240			dim[0] = random();
241			/* sample disk */
242			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
243			for (dim[2] = 0; dim[2] < nazi; dim[2]++)
244			for (i = 0; i < il->nsamps; i++) {
245	greg	1.10	/* next sample point */
246	greg	1.11	multisamp(sp, 4, urand(ilhash(dim,3)+i));
247	greg	1.3	/* random direction */
248	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
249	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
250	greg	1.3	flatdir(dn, r1, r2);
251			for (j = 0; j < 3; j++)
252	greg	1.5	dir[j] = -dn[0]u[j] - dn[1]v[j] - dn[2]*co->ad[j];
253	greg	1.3	/* random location */
254	greg	1.5	r3 = sqrt(CO_R0(co)*CO_R0(co) +
255	greg	1.10	sp[2](CO_R1(co)CO_R1(co) - CO_R0(co)*CO_R0(co)));
256			r2 = 2.PIsp[3];
257	greg	1.5	r1 = r3*cos(r2);
258			r2 = r3*sin(r2);
259	greg	1.3	for (j = 0; j < 3; j++)
260	greg	2.6	org[j] = CO_P0(co)[j] + r1u[j] + r2v[j] +
261	greg	1.5	.001*co->ad[j];
262	greg	1.3
263			/* send sample */
264	greg	1.7	raysamp(distarr+3(dim[1]nazi+dim[2]), org, dir, rt);
265	greg	1.3	}
266			rayflush(rt);
267	greg	1.11	/* write out the ring and its distribution */
268	greg	1.12	if (average(il, distarr, nalt*nazi)) {
269			if (il->sampdens > 0)
270			flatout(il, distarr, nalt, nazi, u, v, co->ad);
271			illumout(il, ob);
272	greg	2.2	} else
273	greg	1.12	printobj(il->altmat, ob);
274	greg	1.3	/* clean up */
275			freecone(ob);
276	greg	2.9	free((void *)distarr);
277	greg	1.2	}
278
279
280			raysamp(res, org, dir, rt) /* compute a ray sample */
281			float res[3];
282			FVECT org, dir;
283			register struct rtproc *rt;
284			{
285			register float *fp;
286
287			if (rt->nrays == rt->bsiz)
288			rayflush(rt);
289			rt->dest[rt->nrays] = res;
290			fp = rt->buf + 6*rt->nrays++;
291			fp++ = org[0]; fp++ = org[1]; *fp++ = org[2];
292			fp++ = dir[0]; fp++ = dir[1]; *fp = dir[2];
293			}
294
295
296			rayflush(rt) /* flush buffered rays */
297			register struct rtproc *rt;
298			{
299			register int i;
300
301			if (rt->nrays <= 0)
302			return;
303	greg	1.9	bzero(rt->buf+6rt->nrays, 6sizeof(float));
304	greg	1.14	errno = 0;
305	greg	1.2	if ( process(rt->pd, (char )rt->buf, (char )rt->buf,
306	gregl	2.8	3sizeof(float)(rt->nrays+1),
307	greg	1.2	6sizeof(float)(rt->nrays+1)) <
308	gregl	2.8	3sizeof(float)(rt->nrays+1) )
309	greg	1.2	error(SYSTEM, "error reading from rtrace process");
310			i = rt->nrays;
311			while (i--) {
312			rt->dest[i][0] += rt->buf[3*i];
313			rt->dest[i][1] += rt->buf[3*i+1];
314			rt->dest[i][2] += rt->buf[3*i+2];
315			}
316			rt->nrays = 0;
317	greg	1.4	}
318
319
320			mkaxes(u, v, n) /* compute u and v to go with n */
321			FVECT u, v, n;
322			{
323			register int i;
324
325			v[0] = v[1] = v[2] = 0.0;
326			for (i = 0; i < 3; i++)
327			if (n[i] < 0.6 && n[i] > -0.6)
328			break;
329			v[i] = 1.0;
330			fcross(u, v, n);
331			normalize(u);
332			fcross(v, n, u);
333			}
334
335
336			rounddir(dv, alt, azi) /* compute uniform spherical direction */
337			register FVECT dv;
338			double alt, azi;
339			{
340			double d1, d2;
341
342			dv[2] = 1. - 2.*alt;
343			d1 = sqrt(1. - dv[2]*dv[2]);
344			d2 = 2.PI azi;
345			dv[0] = d1*cos(d2);
346			dv[1] = d1*sin(d2);
347			}
348
349
350			flatdir(dv, alt, azi) /* compute uniform hemispherical direction */
351			register FVECT dv;
352			double alt, azi;
353			{
354			double d1, d2;
355
356			d1 = sqrt(alt);
357			d2 = 2.PI azi;
358			dv[0] = d1*cos(d2);
359			dv[1] = d1*sin(d2);
360	greg	1.6	dv[2] = sqrt(1. - alt);
361	greg	1.1	}