src/hd/rhpict2.c

/* Copyright (c) 1999 Silicon Graphics, Inc. */

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

/*
 * Rendering routines for rhpict.
 */

#include "holo.h"
#include "view.h"
#include "random.h"

#ifndef DEPS
#define DEPS            0.02    /* depth epsilon */
#endif
#ifndef PEPS
#define PEPS            0.04    /* pixel value epsilon */
#endif
#ifndef MAXRAD
#define MAXRAD          64      /* maximum kernel radius */
#endif
#ifndef NNEIGH
#define NNEIGH          5       /* find this many neighbors */
#endif

#define NINF            16382

#define MAXRAD2         (MAXRAD*MAXRAD+1)

#define G0NORM          0.286   /* ground zero normalization (1/x integral) */

#ifndef FL4OP
#define FL4OP(f,i,op)   ((f)[(i)>>5] op (1L<<((i)&0x1f)))
#define CHK4(f,i)       FL4OP(f,i,&)
#define SET4(f,i)       FL4OP(f,i,|=)
#define CLR4(f,i)       FL4OP(f,i,&=~)
#define TGL4(f,i)       FL4OP(f,i,^=)
#define FL4NELS(n)      (((n)+0x1f)>>5)
#define CLR4ALL(f,n)    bzero((char *)(f),FL4NELS(n)*sizeof(int4))
#endif

static int4     *pixFlags;      /* pixel occupancy flags */
static float    pixWeight[MAXRAD2];     /* pixel weighting function */
static short    isqrttab[MAXRAD2];      /* integer square root table */

#define isqrt(i2)       (isqrttab[i2])

extern VIEW     myview;         /* current output view */
extern COLOR    *mypixel;       /* pixels being rendered */
extern float    *myweight;      /* weights (used to compute final pixels) */
extern float    *mydepth;       /* depth values (visibility culling) */
extern int      hres, vres;     /* current horizontal and vertical res. */


pixBeam(bp, hb)                 /* render a particular beam */
BEAM    *bp;
register HDBEAMI        *hb;
{
        GCOORD  gc[2];
        register RAYVAL *rv;
        FVECT   rorg, rdir, wp, ip;
        double  d, prox;
        COLOR   col;
        int     n;
        register int4   p;

        if (!hdbcoord(gc, hb->h, hb->b))
                error(CONSISTENCY, "bad beam in render_beam");
        for (n = bp->nrm, rv = hdbray(bp); n--; rv++) {
                                                /* reproject each sample */
                hdray(rorg, rdir, hb->h, gc, rv->r);
                if (rv->d < DCINF) {
                        d = hddepth(hb->h, rv->d);
                        VSUM(wp, rorg, rdir, d);
                        VSUB(ip, wp, myview.vp);
                        d = DOT(ip,rdir);
                        prox = d*d/DOT(ip,ip);  /* cos(diff_angle)^32 */
                        prox *= prox; prox *= prox; prox *= prox; prox *= prox;
                } else {
                        if (myview.type == VT_PAR || myview.vaft > FTINY)
                                continue;               /* inf. off view */
                        VSUM(wp, myview.vp, rdir, FHUGE);
                        prox = 1.;
                }
                viewloc(ip, &myview, wp);       /* frustum clipping */
                if (ip[2] < 0.)
                        continue;
                if (ip[0] < 0. || ip[0] >= 1.)
                        continue;
                if (ip[1] < 0. || ip[1] >= 1.)
                        continue;
                if (myview.vaft > FTINY && ip[2] > myview.vaft - myview.vfore)
                        continue;               /* not exact for VT_PER */
                p = (int)(ip[1]*vres)*hres + (int)(ip[0]*hres);
                if (mydepth[p] > FTINY) {       /* check depth */
                        if (ip[2] > mydepth[p]*(1.+DEPS))
                                continue;
                        if (ip[2] < mydepth[p]*(1.-DEPS)) {
                                setcolor(mypixel[p], 0., 0., 0.);
                                myweight[p] = 0.;
                        }
                }
                colr_color(col, rv->v);
                scalecolor(col, prox);
                addcolor(mypixel[p], col);
                myweight[p] += prox;
                mydepth[p] = ip[2];
        }
}


int
kill_occl(h, v, nl, nd, n)              /* check for occlusion errors */
int     h, v;
register short  nl[NNEIGH][2];
int     nd[NNEIGH];
int     n;
{
        short   forequad[2][2];
        int     d;
        register int    i;
        register int4   p;

        if (n <= 0) {
#ifdef DEBUG
                error(WARNING, "neighborless sample in kill_occl");
#endif
                return(1);
        }
        p = v*hres + h;
        forequad[0][0] = forequad[0][1] = forequad[1][0] = forequad[1][1] = 0;
        for (i = n; i--; ) {
                d = isqrt(nd[i]);
                if (mydepth[nl[i][1]*hres+nl[i][0]]*(1.+DEPS*d) < mydepth[p])
                        forequad[nl[i][0]<h][nl[i][1]<v] = 1;
        }
        if (forequad[0][0]+forequad[0][1]+forequad[1][0]+forequad[1][1] > 2) {
                setcolor(mypixel[p], 0., 0., 0.);
                myweight[p] = 0.;       /* occupancy reset afterwards */
        }
        return(1);
}


int
smooth_samp(h, v, nl, nd, n)    /* grow sample point smoothly */
int     h, v;
register short  nl[NNEIGH][2];
int     nd[NNEIGH];
int     n;
{
        int     dis[NNEIGH], ndis;
        COLOR   mykern[MAXRAD2];
        int     maxr2;
        double  d;
        register int4   p;
        register int    r2;
        int     i, r, maxr, h2, v2;

        if (n <= 0)
                return(1);
        p = v*hres + h;                         /* build kernel values */
        maxr2 = nd[n-1];
        DCHECK(maxr2>=MAXRAD2, CONSISTENCY, "out of range neighbor");
        maxr = isqrt(maxr2);
        for (v2 = 1; v2 <= maxr; v2++)
                for (h2 = 0; h2 <= v2; h2++) {
                        r2 = h2*h2 + v2*v2;
                        if (r2 > maxr2) break;
                        copycolor(mykern[r2], mypixel[p]);
                        scalecolor(mykern[r2], pixWeight[r2]);
                }
        ndis = 0;                               /* find discontinuities */
        for (i = n; i--; ) {
                r = isqrt(nd[i]);
                d = mydepth[nl[i][1]*hres+nl[i][0]] / mydepth[p];
                d = d>=1. ? d-1. : 1.-d;
                if (d > r*DEPS || bigdiff(mypixel[p],
                                mypixel[nl[i][1]*hres+nl[i][0]], r*PEPS))
                        dis[ndis++] = i;
        }
                                                /* stamp out that kernel */
        for (v2 = v-maxr; v2 <= v+maxr; v2++) {
                if (v2 < 0) v2 = 0;
                else if (v2 >= vres) break;
                for (h2 = h-maxr; h2 <= h+maxr; h2++) {
                        if (h2 < 0) h2 = 0;
                        else if (h2 >= hres) break;
                        r2 = (h2-h)*(h2-h) + (v2-v)*(v2-v);
                        if (r2 > maxr2) continue;
                        if (CHK4(pixFlags, v2*hres+h2))
                                continue;       /* occupied */
                        for (i = ndis; i--; ) {
                                r = (h2-nl[dis[i]][0])*(h2-nl[dis[i]][0]) +
                                        (v2-nl[dis[i]][1])*(v2-nl[dis[i]][1]);
                                if (r < r2) break;
                        }
                        if (i >= 0) continue;   /* outside edge */
                        addcolor(mypixel[v2*hres+h2], mykern[r2]);
                        myweight[v2*hres+h2] += pixWeight[r2] * myweight[p];
                }
        }
        return(1);
}


int
random_samp(h, v, nl, nd, n, rf)        /* gather samples randomly */
int     h, v;
register short  nl[NNEIGH][2];
int     nd[NNEIGH];
int     n;
double  *rf;
{
        float   rnt[NNEIGH];
        double  rvar;
        register int4   p, pn;
        register int    ni;

        if (n <= 0)
                return(1);
        p = v*hres + h;
        if (*rf <= FTINY)               /* straight Voronoi regions */
                ni = 0;
        else {                          /* weighted choice */
                DCHECK(nd[n-1]>=MAXRAD2, CONSISTENCY, "out of range neighbor");
                rnt[0] = pixWeight[nd[0]];
                for (ni = 1; ni < n; ni++)
                        rnt[ni] = rnt[ni-1] + pixWeight[nd[ni]];
                rvar = rnt[n-1]*pow(frandom(), 1. / *rf);
                for (ni = 0; rvar > rnt[ni]+FTINY; ni++)
                        ;
        }
        pn = nl[ni][1]*hres + nl[ni][0];
        addcolor(mypixel[p], mypixel[pn]);
        myweight[p] += myweight[pn];
        return(1);
}


pixFinish(ransamp)              /* done with beams -- compute pixel values */
double  ransamp;
{
        if (pixWeight[0] <= FTINY)
                init_wfunc();           /* initialize weighting function */
        reset_flags();                  /* set occupancy flags */
        meet_neighbors(1,kill_occl,NULL); /* identify occlusion errors */
        reset_flags();                  /* reset occupancy flags */
        if (ransamp >= 0.)              /* spread samples over image */
                meet_neighbors(0,random_samp,&ransamp);
        else
                meet_neighbors(1,smooth_samp,NULL);
        free((char *)pixFlags);         /* free pixel flags */
        pixFlags = NULL;
}


reset_flags()                   /* allocate/set/reset occupancy flags */
{
        register int4   p;

        if (pixFlags == NULL) {
                pixFlags = (int4 *)calloc(FL4NELS(hres*vres), sizeof(int4));
                CHECK(pixFlags==NULL, SYSTEM, "out of memory in reset_flags");
        } else
                CLR4ALL(pixFlags, hres*vres);
        for (p = hres*vres; p--; )
                if (myweight[p] > FTINY)
                        SET4(pixFlags, p);
}


init_wfunc()                    /* initialize weighting function */
{
        register int    r2;
        register double d;

        for (r2 = MAXRAD2; --r2; ) {
                d = sqrt((double)r2);
                pixWeight[r2] = G0NORM/d;
                isqrttab[r2] = d + 0.99;
        }
        pixWeight[0] = 1.;
        isqrttab[0] = 0;
}


int
findneigh(nl, nd, h, v, rnl)    /* find NNEIGH neighbors for pixel */
short   nl[NNEIGH][2];
int     nd[NNEIGH];
int     h, v;
register short  (*rnl)[NNEIGH];
{
        int     nn = 0;
        int     d, n, hoff;
        register int    h2, n2;

        nd[NNEIGH-1] = MAXRAD2;
        for (hoff = 0; hoff < hres; hoff = (hoff<=0) - hoff) {
                h2 = h + hoff;
                if (h2 < 0 | h2 >= hres)
                        continue;
                if ((h2-h)*(h2-h) >= nd[NNEIGH-1])
                        break;
                for (n = 0; n < NNEIGH && rnl[h2][n] < NINF; n++) {
                        d = (h2-h)*(h2-h) + (v-rnl[h2][n])*(v-rnl[h2][n]);
                        if (d == 0 | d >= nd[NNEIGH-1])
                                continue;
                        if (nn < NNEIGH)        /* insert neighbor */
                                nn++;
                        for (n2 = nn; n2--; )   {
                                if (!n2 || d >= nd[n2-1]) {
                                        nd[n2] = d;
                                        nl[n2][0] = h2;
                                        nl[n2][1] = rnl[h2][n];
                                        break;
                                }
                                nd[n2] = nd[n2-1];
                                nl[n2][0] = nl[n2-1][0];
                                nl[n2][1] = nl[n2-1][1];
                        }
                }
        }
        return(nn);
}


meet_neighbors(occ, nf, dp)     /* run through samples and their neighbors */
int     occ;
int     (*nf)();
char    *dp;
{
        short   ln[NNEIGH][2];
        int     nd[NNEIGH];
        int     h, v, n, v2;
        register short  (*rnl)[NNEIGH];
                                        /* initialize bottom row list */
        rnl = (short (*)[NNEIGH])malloc(NNEIGH*sizeof(short)*hres);
        CHECK(rnl==NULL, SYSTEM, "out of memory in meet_neighbors");
        for (h = 0; h < hres; h++) {
                for (n = v = 0; v < vres; v++)
                        if (CHK4(pixFlags, v*hres+h)) {
                                rnl[h][n++] = v;
                                if (n >= NNEIGH)
                                        break;
                        }
                while (n < NNEIGH)
                        rnl[h][n++] = NINF;
        }
        v = 0;                          /* do each row */
        for ( ; ; ) {
                for (h = 0; h < hres; h++) {
                        if (!CHK4(pixFlags, v*hres+h) != !occ)
                                continue;       /* occupancy mismatch */
                                                /* find neighbors */
                        n = findneigh(ln, nd, h, v, rnl);
                                                /* call on neighbors */
                        (*nf)(h, v, ln, nd, n, dp);
                }
                if (++v >= vres)                /* reinitialize row list */
                        break;
                for (h = 0; h < hres; h++)
                        for (v2 = rnl[h][NNEIGH-1]+1; v2 < vres; v2++) {
                                if (v2 - v > v - rnl[h][0])
                                        break;          /* not close enough */
                                if (CHK4(pixFlags, v2*hres+h)) {
                                        for (n = 0; n < NNEIGH-1; n++)
                                                rnl[h][n] = rnl[h][n+1];
                                        rnl[h][NNEIGH-1] = v2;
                                }
                        }
        }
        free((char *)rnl);              /* free row list */
}
Revision:	3.9
Committed:	Wed Mar 10 16:15:19 1999 UTC (26 years, 8 months ago) by gwlarson
Content type:	text/plain
Branch:	MAIN
Changes since 3.8:	+52 -68 lines
Log Message:	reduced NNEIGH default from 7 to 5 changed random sampling function to use sampled Voronoi regions
#	User	Rev	Content
1	gwlarson	3.1	/* Copyright (c) 1999 Silicon Graphics, Inc. */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ SGI";
5			#endif
6
7			/*
8			* Rendering routines for rhpict.
9			*/
10
11			#include "holo.h"
12			#include "view.h"
13	gwlarson	3.6	#include "random.h"
14	gwlarson	3.1
15	gwlarson	3.2	#ifndef DEPS
16	gwlarson	3.3	#define DEPS 0.02 /* depth epsilon */
17	gwlarson	3.2	#endif
18	gwlarson	3.3	#ifndef PEPS
19			#define PEPS 0.04 /* pixel value epsilon */
20			#endif
21	gwlarson	3.2	#ifndef MAXRAD
22			#define MAXRAD 64 /* maximum kernel radius */
23			#endif
24			#ifndef NNEIGH
25	gwlarson	3.9	#define NNEIGH 5 /* find this many neighbors */
26	gwlarson	3.2	#endif
27
28			#define NINF 16382
29
30			#define MAXRAD2 (MAXRAD*MAXRAD+1)
31
32			#define G0NORM 0.286 /* ground zero normalization (1/x integral) */
33
34			#ifndef FL4OP
35			#define FL4OP(f,i,op) ((f)[(i)>>5] op (1L<<((i)&0x1f)))
36			#define CHK4(f,i) FL4OP(f,i,&)
37			#define SET4(f,i) FL4OP(f,i,\|=)
38			#define CLR4(f,i) FL4OP(f,i,&=~)
39			#define TGL4(f,i) FL4OP(f,i,^=)
40			#define FL4NELS(n) (((n)+0x1f)>>5)
41			#define CLR4ALL(f,n) bzero((char )(f),FL4NELS(n)sizeof(int4))
42			#endif
43
44			static int4 pixFlags; / pixel occupancy flags */
45			static float pixWeight[MAXRAD2]; /* pixel weighting function */
46	gwlarson	3.3	static short isqrttab[MAXRAD2]; /* integer square root table */
47	gwlarson	3.2
48	gwlarson	3.9	#define isqrt(i2) (isqrttab[i2])
49	gwlarson	3.3
50	gwlarson	3.1	extern VIEW myview; /* current output view */
51			extern COLOR mypixel; / pixels being rendered */
52			extern float myweight; / weights (used to compute final pixels) */
53	gwlarson	3.2	extern float mydepth; / depth values (visibility culling) */
54	gwlarson	3.1	extern int hres, vres; /* current horizontal and vertical res. */
55
56
57	gwlarson	3.2	pixBeam(bp, hb) /* render a particular beam */
58	gwlarson	3.1	BEAM *bp;
59			register HDBEAMI *hb;
60			{
61			GCOORD gc[2];
62			register RAYVAL *rv;
63			FVECT rorg, rdir, wp, ip;
64			double d, prox;
65			COLOR col;
66	gwlarson	3.2	int n;
67			register int4 p;
68	gwlarson	3.1
69			if (!hdbcoord(gc, hb->h, hb->b))
70			error(CONSISTENCY, "bad beam in render_beam");
71			for (n = bp->nrm, rv = hdbray(bp); n--; rv++) {
72			/* reproject each sample */
73			hdray(rorg, rdir, hb->h, gc, rv->r);
74			if (rv->d < DCINF) {
75			d = hddepth(hb->h, rv->d);
76			VSUM(wp, rorg, rdir, d);
77			VSUB(ip, wp, myview.vp);
78			d = DOT(ip,rdir);
79	gwlarson	3.2	prox = dd/DOT(ip,ip); / cos(diff_angle)^32 */
80			prox = prox; prox = prox; prox = prox; prox = prox;
81	gwlarson	3.1	} else {
82			if (myview.type == VT_PAR \|\| myview.vaft > FTINY)
83			continue; /* inf. off view */
84			VSUM(wp, myview.vp, rdir, FHUGE);
85	gwlarson	3.2	prox = 1.;
86	gwlarson	3.1	}
87			viewloc(ip, &myview, wp); /* frustum clipping */
88			if (ip[2] < 0.)
89			continue;
90			if (ip[0] < 0. \|\| ip[0] >= 1.)
91			continue;
92			if (ip[1] < 0. \|\| ip[1] >= 1.)
93			continue;
94			if (myview.vaft > FTINY && ip[2] > myview.vaft - myview.vfore)
95	gwlarson	3.2	continue; /* not exact for VT_PER */
96	gwlarson	3.1	p = (int)(ip[1]vres)hres + (int)(ip[0]*hres);
97	gwlarson	3.2	if (mydepth[p] > FTINY) { /* check depth */
98			if (ip[2] > mydepth[p]*(1.+DEPS))
99			continue;
100			if (ip[2] < mydepth[p]*(1.-DEPS)) {
101			setcolor(mypixel[p], 0., 0., 0.);
102			myweight[p] = 0.;
103			}
104			}
105	gwlarson	3.1	colr_color(col, rv->v);
106	gwlarson	3.2	scalecolor(col, prox);
107	gwlarson	3.1	addcolor(mypixel[p], col);
108	gwlarson	3.2	myweight[p] += prox;
109			mydepth[p] = ip[2];
110	gwlarson	3.1	}
111	gwlarson	3.2	}
112
113
114			int
115	gwlarson	3.9	kill_occl(h, v, nl, nd, n) /* check for occlusion errors */
116	gwlarson	3.2	int h, v;
117	gwlarson	3.3	register short nl[NNEIGH][2];
118	gwlarson	3.9	int nd[NNEIGH];
119	gwlarson	3.2	int n;
120			{
121			short forequad[2][2];
122			int d;
123	gwlarson	3.9	register int i;
124			register int4 p;
125	gwlarson	3.2
126	gwlarson	3.5	if (n <= 0) {
127			#ifdef DEBUG
128			error(WARNING, "neighborless sample in kill_occl");
129			#endif
130	gwlarson	3.2	return(1);
131	gwlarson	3.5	}
132	gwlarson	3.3	p = v*hres + h;
133	gwlarson	3.2	forequad[0][0] = forequad[0][1] = forequad[1][0] = forequad[1][1] = 0;
134			for (i = n; i--; ) {
135	gwlarson	3.9	d = isqrt(nd[i]);
136	gwlarson	3.3	if (mydepth[nl[i][1]hres+nl[i][0]](1.+DEPS*d) < mydepth[p])
137	gwlarson	3.2	forequad[nl[i][0]<h][nl[i][1]<v] = 1;
138			}
139	gwlarson	3.3	if (forequad[0][0]+forequad[0][1]+forequad[1][0]+forequad[1][1] > 2) {
140			setcolor(mypixel[p], 0., 0., 0.);
141			myweight[p] = 0.; /* occupancy reset afterwards */
142	gwlarson	3.2	}
143			return(1);
144			}
145
146
147			int
148	gwlarson	3.9	smooth_samp(h, v, nl, nd, n) /* grow sample point smoothly */
149	gwlarson	3.2	int h, v;
150			register short nl[NNEIGH][2];
151	gwlarson	3.9	int nd[NNEIGH];
152	gwlarson	3.2	int n;
153			{
154	gwlarson	3.3	int dis[NNEIGH], ndis;
155	gwlarson	3.2	COLOR mykern[MAXRAD2];
156	gwlarson	3.9	int maxr2;
157	gwlarson	3.5	double d;
158	gwlarson	3.9	register int4 p;
159			register int r2;
160	gwlarson	3.3	int i, r, maxr, h2, v2;
161	gwlarson	3.2
162			if (n <= 0)
163			return(1);
164			p = vhres + h; / build kernel values */
165	gwlarson	3.9	maxr2 = nd[n-1];
166	gwlarson	3.2	DCHECK(maxr2>=MAXRAD2, CONSISTENCY, "out of range neighbor");
167	gwlarson	3.3	maxr = isqrt(maxr2);
168			for (v2 = 1; v2 <= maxr; v2++)
169			for (h2 = 0; h2 <= v2; h2++) {
170			r2 = h2h2 + v2v2;
171			if (r2 > maxr2) break;
172			copycolor(mykern[r2], mypixel[p]);
173			scalecolor(mykern[r2], pixWeight[r2]);
174			}
175			ndis = 0; /* find discontinuities */
176			for (i = n; i--; ) {
177	gwlarson	3.9	r = isqrt(nd[i]);
178	gwlarson	3.3	d = mydepth[nl[i][1]*hres+nl[i][0]] / mydepth[p];
179			d = d>=1. ? d-1. : 1.-d;
180			if (d > r*DEPS \|\| bigdiff(mypixel[p],
181			mypixel[nl[i][1]hres+nl[i][0]], rPEPS))
182			dis[ndis++] = i;
183	gwlarson	3.2	}
184	gwlarson	3.3	/* stamp out that kernel */
185	gwlarson	3.2	for (v2 = v-maxr; v2 <= v+maxr; v2++) {
186	gwlarson	3.3	if (v2 < 0) v2 = 0;
187			else if (v2 >= vres) break;
188	gwlarson	3.2	for (h2 = h-maxr; h2 <= h+maxr; h2++) {
189	gwlarson	3.3	if (h2 < 0) h2 = 0;
190			else if (h2 >= hres) break;
191			r2 = (h2-h)(h2-h) + (v2-v)(v2-v);
192	gwlarson	3.2	if (r2 > maxr2) continue;
193			if (CHK4(pixFlags, v2*hres+h2))
194			continue; /* occupied */
195	gwlarson	3.3	for (i = ndis; i--; ) {
196			r = (h2-nl[dis[i]][0])*(h2-nl[dis[i]][0]) +
197			(v2-nl[dis[i]][1])*(v2-nl[dis[i]][1]);
198			if (r < r2) break;
199			}
200			if (i >= 0) continue; /* outside edge */
201	gwlarson	3.2	addcolor(mypixel[v2*hres+h2], mykern[r2]);
202	gwlarson	3.5	myweight[v2hres+h2] += pixWeight[r2] myweight[p];
203	gwlarson	3.2	}
204			}
205			return(1);
206			}
207
208
209	gwlarson	3.6	int
210	gwlarson	3.9	random_samp(h, v, nl, nd, n, rf) /* gather samples randomly */
211	gwlarson	3.6	int h, v;
212			register short nl[NNEIGH][2];
213	gwlarson	3.9	int nd[NNEIGH];
214	gwlarson	3.6	int n;
215	gwlarson	3.7	double *rf;
216	gwlarson	3.2	{
217	gwlarson	3.9	float rnt[NNEIGH];
218			double rvar;
219			register int4 p, pn;
220			register int ni;
221	gwlarson	3.6
222			if (n <= 0)
223			return(1);
224	gwlarson	3.9	p = v*hres + h;
225			if (rf <= FTINY) / straight Voronoi regions */
226			ni = 0;
227			else { /* weighted choice */
228			DCHECK(nd[n-1]>=MAXRAD2, CONSISTENCY, "out of range neighbor");
229			rnt[0] = pixWeight[nd[0]];
230			for (ni = 1; ni < n; ni++)
231			rnt[ni] = rnt[ni-1] + pixWeight[nd[ni]];
232			rvar = rnt[n-1]pow(frandom(), 1. / rf);
233			for (ni = 0; rvar > rnt[ni]+FTINY; ni++)
234			;
235	gwlarson	3.6	}
236	gwlarson	3.9	pn = nl[ni][1]*hres + nl[ni][0];
237			addcolor(mypixel[p], mypixel[pn]);
238			myweight[p] += myweight[pn];
239	gwlarson	3.6	return(1);
240			}
241
242
243			pixFinish(ransamp) /* done with beams -- compute pixel values */
244	gwlarson	3.7	double ransamp;
245	gwlarson	3.6	{
246	gwlarson	3.5	if (pixWeight[0] <= FTINY)
247			init_wfunc(); /* initialize weighting function */
248	gwlarson	3.2	reset_flags(); /* set occupancy flags */
249	gwlarson	3.9	meet_neighbors(1,kill_occl,NULL); /* identify occlusion errors */
250	gwlarson	3.2	reset_flags(); /* reset occupancy flags */
251	gwlarson	3.7	if (ransamp >= 0.) /* spread samples over image */
252	gwlarson	3.9	meet_neighbors(0,random_samp,&ransamp);
253	gwlarson	3.6	else
254	gwlarson	3.9	meet_neighbors(1,smooth_samp,NULL);
255	gwlarson	3.2	free((char )pixFlags); / free pixel flags */
256			pixFlags = NULL;
257			}
258
259
260			reset_flags() /* allocate/set/reset occupancy flags */
261			{
262	gwlarson	3.4	register int4 p;
263	gwlarson	3.2
264			if (pixFlags == NULL) {
265			pixFlags = (int4 )calloc(FL4NELS(hresvres), sizeof(int4));
266			CHECK(pixFlags==NULL, SYSTEM, "out of memory in reset_flags");
267			} else
268			CLR4ALL(pixFlags, hres*vres);
269			for (p = hres*vres; p--; )
270			if (myweight[p] > FTINY)
271			SET4(pixFlags, p);
272	gwlarson	3.4	}
273
274
275			init_wfunc() /* initialize weighting function */
276			{
277	gwlarson	3.9	register int r2;
278	gwlarson	3.4	register double d;
279
280	gwlarson	3.6	for (r2 = MAXRAD2; --r2; ) {
281			d = sqrt((double)r2);
282			pixWeight[r2] = G0NORM/d;
283			isqrttab[r2] = d + 0.99;
284			}
285	gwlarson	3.4	pixWeight[0] = 1.;
286			isqrttab[0] = 0;
287	gwlarson	3.2	}
288
289
290			int
291	gwlarson	3.9	findneigh(nl, nd, h, v, rnl) /* find NNEIGH neighbors for pixel */
292	gwlarson	3.2	short nl[NNEIGH][2];
293	gwlarson	3.9	int nd[NNEIGH];
294	gwlarson	3.2	int h, v;
295			register short (*rnl)[NNEIGH];
296			{
297			int nn = 0;
298	gwlarson	3.9	int d, n, hoff;
299	gwlarson	3.2	register int h2, n2;
300
301	gwlarson	3.3	nd[NNEIGH-1] = MAXRAD2;
302	gwlarson	3.9	for (hoff = 0; hoff < hres; hoff = (hoff<=0) - hoff) {
303	gwlarson	3.2	h2 = h + hoff;
304			if (h2 < 0 \| h2 >= hres)
305			continue;
306	gwlarson	3.3	if ((h2-h)*(h2-h) >= nd[NNEIGH-1])
307	gwlarson	3.2	break;
308			for (n = 0; n < NNEIGH && rnl[h2][n] < NINF; n++) {
309			d = (h2-h)(h2-h) + (v-rnl[h2][n])(v-rnl[h2][n]);
310	gwlarson	3.9	if (d == 0 \| d >= nd[NNEIGH-1])
311	gwlarson	3.2	continue;
312	gwlarson	3.3	if (nn < NNEIGH) /* insert neighbor */
313			nn++;
314			for (n2 = nn; n2--; ) {
315	gwlarson	3.2	if (!n2 \|\| d >= nd[n2-1]) {
316			nd[n2] = d;
317			nl[n2][0] = h2;
318			nl[n2][1] = rnl[h2][n];
319			break;
320			}
321			nd[n2] = nd[n2-1];
322			nl[n2][0] = nl[n2-1][0];
323			nl[n2][1] = nl[n2-1][1];
324			}
325			}
326			}
327			return(nn);
328			}
329
330
331	gwlarson	3.9	meet_neighbors(occ, nf, dp) /* run through samples and their neighbors */
332			int occ;
333	gwlarson	3.2	int (*nf)();
334	gwlarson	3.7	char *dp;
335	gwlarson	3.2	{
336			short ln[NNEIGH][2];
337	gwlarson	3.9	int nd[NNEIGH];
338	gwlarson	3.2	int h, v, n, v2;
339			register short (*rnl)[NNEIGH];
340			/* initialize bottom row list */
341			rnl = (short ()[NNEIGH])malloc(NNEIGHsizeof(short)*hres);
342			CHECK(rnl==NULL, SYSTEM, "out of memory in meet_neighbors");
343			for (h = 0; h < hres; h++) {
344			for (n = v = 0; v < vres; v++)
345			if (CHK4(pixFlags, v*hres+h)) {
346			rnl[h][n++] = v;
347			if (n >= NNEIGH)
348			break;
349			}
350			while (n < NNEIGH)
351			rnl[h][n++] = NINF;
352			}
353			v = 0; /* do each row */
354			for ( ; ; ) {
355			for (h = 0; h < hres; h++) {
356	gwlarson	3.9	if (!CHK4(pixFlags, v*hres+h) != !occ)
357			continue; /* occupancy mismatch */
358			/* find neighbors */
359			n = findneigh(ln, nd, h, v, rnl);
360			/* call on neighbors */
361			(*nf)(h, v, ln, nd, n, dp);
362	gwlarson	3.2	}
363			if (++v >= vres) /* reinitialize row list */
364			break;
365			for (h = 0; h < hres; h++)
366			for (v2 = rnl[h][NNEIGH-1]+1; v2 < vres; v2++) {
367			if (v2 - v > v - rnl[h][0])
368			break; /* not close enough */
369			if (CHK4(pixFlags, v2*hres+h)) {
370			for (n = 0; n < NNEIGH-1; n++)
371			rnl[h][n] = rnl[h][n+1];
372			rnl[h][NNEIGH-1] = v2;
373			}
374			}
375			}
376			free((char )rnl); / free row list */
377	gwlarson	3.1	}