src/px/warp3d.c

/* Copyright (c) 1997 Regents of the University of California */

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

/*
 * 3D warping routines.
 */

#include <stdio.h>
#include <math.h>
#include "fvect.h"
#include "warp3d.h"

#define MIND    1e-5            /* minimum distance between input points */

typedef struct {
        GNDX    n;              /* index must be first */
        W3VEC   v;
} KEYDP;                /* key/data allocation pair */

#define fgetvec(p,v)    (fgetval(p,'f',v) > 0 && fgetval(p,'f',v+1) > 0 \
                                && fgetval(p,'f',v+2) > 0)

#define AHUNK   24              /* number of points to allocate at a time */

#ifndef malloc
extern char     *malloc(), *realloc();
#endif
extern void     free();


double
wpdist2(p1, p2)                 /* compute square of distance between points */
register W3VEC  p1, p2;
{
        double  d, d2;

        d = p1[0] - p2[0]; d2  = d*d;
        d = p1[1] - p2[1]; d2 += d*d;
        d = p1[2] - p2[2]; d2 += d*d;
        return(d2);
}


int
warp3d(po, pi, wp)              /* warp 3D point according to the given map */
W3VEC   po, pi;
register WARP3D *wp;
{
        int     rval = W3OK;
        GNDX    gi;
        W3VEC   gd, ov;

        if (wp->grid.gn[0] == 0 && (rval = new3dgrid(wp)) != W3OK)
                return(rval);
        rval |= gridpoint(gi, gd, pi, &wp->grid);
        if (wp->grid.flags & W3EXACT)
                rval |= warp3dex(ov, pi, wp);
        else if (wp->grid.flags & W3FAST)
                rval |= get3dgpt(ov, gi, wp);
        else
                rval |= get3dgin(ov, gi, gd, wp);
        po[0] = pi[0] + ov[0];
        po[1] = pi[1] + ov[1];
        po[2] = pi[2] + ov[2];
        return(rval);
}


int
gridpoint(ndx, rem, ipt, gp)    /* compute grid position for ipt */
GNDX    ndx;
W3VEC   rem, ipt;
register struct grid3d  *gp;
{
        int     rval = W3OK;
        register int    i;

        for (i = 0; i < 3; i++) {
                rem[i] = (ipt[i] - gp->gmin[i])/gp->gstep[i];
                if (rem[i] < 0.) {
                        ndx[i] = 0;
                        rval = W3GAMUT;
                } else if ((int)rem[i] >= gp->gn[i]) {
                        ndx[i] = gp->gn[i] - 1;
                        rval = W3GAMUT;
                } else
                        ndx[i] = (int)rem[i];
                rem[i] -= (double)ndx[i];
        }
        return(rval);
}


int
get3dgpt(ov, ndx, wp)           /* get value for voxel */
W3VEC   ov;
GNDX    ndx;
register WARP3D *wp;
{
        W3VEC   gpt;
        register LUENT  *le;
        KEYDP   *kd;
        int     rval = W3OK;
        register int    i;

        le = lu_find(&wp->grid.gtab, ndx);
        if (le == NULL)
                return(W3ERROR);
        if (le->data == NULL) {
                if (le->key != NULL)
                        kd = (KEYDP *)le->key;
                else if ((kd = (KEYDP *)malloc(sizeof(KEYDP))) == NULL)
                        return(W3ERROR);
                for (i = 0; i < 3; i++) {
                        kd->n[i] = ndx[i];
                        gpt[i] = wp->grid.gmin[i] + ndx[i]*wp->grid.gstep[i];
                        if (wp->grid.flags & W3FAST)    /* on centers */
                                gpt[i] += .5*wp->grid.gstep[i];
                }
                rval = warp3dex(kd->v, gpt, wp);
                le->key = (char *)kd->n;
                le->data = (char *)kd->v;
        }
        W3VCPY(ov, (float *)le->data);
        return(rval);
}


int
get3dgin(ov, ndx, rem, wp)      /* interpolate from warp grid */
W3VEC   ov, rem;
GNDX    ndx;
WARP3D  *wp;
{
        W3VEC   cv[8];
        GNDX    gi;
        int     rval = 0;
        register int    i;
                                        /* get corner values */
        for (i = 0; i < 8; i++) {
                gi[0] = ndx[0] + (i & 1);
                gi[1] = ndx[1] + (i>>1 & 1);
                gi[2] = ndx[2] + (i>>2);
                rval |= get3dgpt(cv[i], gi, wp);
        }
        if (rval & W3ERROR)
                return(rval);
        l3interp(ov, cv, rem, 3);       /* perform trilinear interpolation */
        return(rval);
}


l3interp(vo, cl, dv, n)         /* trilinear interpolation (recursive) */
W3VEC   vo, *cl, dv;
int     n;
{
        W3VEC   v0, v1;
        register int    i;

        if (--n) {
                l3interp(v0, cl, dv, n);
                l3interp(v1, cl+(1<<n), dv, n);
        } else {
                W3VCPY(v0, cl[0]);
                W3VCPY(v1, cl[1]);
        }
        for (i = 0; i < 3; i++)
                vo[i] = (1.-dv[n])*v0[i] + dv[n]*v1[i];
}


int
warp3dex(ov, pi, wp)            /* compute warp using 1/r^2 weighted avg. */
W3VEC   ov, pi;
register WARP3D *wp;
{
        double  d2, w, wsum;
        W3VEC   vt;
        register int    i;

        vt[0] = vt[1] = vt[2] = 0.;
        wsum = 0.;
        for (i = wp->npts; i--; ) {
                d2 = wpdist2(pi, wp->ip[i]);
                if (d2 <= MIND*MIND) w = 1./(MIND*MIND);
                else w = 1./d2;
                vt[0] += w*wp->ov[i][0];
                vt[1] += w*wp->ov[i][1];
                vt[2] += w*wp->ov[i][2];
                wsum += w;
        }
        if (wsum > 0.) {
                ov[0] = vt[0]/wsum;
                ov[1] = vt[1]/wsum;
                ov[2] = vt[2]/wsum;
        }
        return(W3OK);
}


WARP3D *
new3dw(flgs)                    /* allocate and initialize WARP3D struct */
int     flgs;
{
        register WARP3D  *wp;

        if ((flgs & (W3EXACT|W3FAST)) == (W3EXACT|W3FAST)) {
                eputs("new3dw: only one of W3EXACT or W3FAST\n");
                return(NULL);
        }
        if ((wp = (WARP3D *)malloc(sizeof(WARP3D))) == NULL) {
                eputs("new3dw: no memory\n");
                return(NULL);
        }
        wp->ip = wp->ov = NULL;
        wp->npts = 0;
        wp->grid.flags = flgs;
        wp->grid.gn[0] = wp->grid.gn[1] = wp->grid.gn[2] = 0;
        return(wp);
}


WARP3D *
load3dw(fn, wp)                 /* load 3D warp from file */
char    *fn;
WARP3D  *wp;
{
        FILE    *fp;
        W3VEC   inp, outp;

        if ((fp = fopen(fn, "r")) == NULL) {
                eputs(fn);
                eputs(": cannot open\n");
                return(NULL);
        }
        if (wp == NULL && (wp = new3dw(0)) == NULL)
                goto memerr;
        while (fgetvec(fp, inp) && fgetvec(fp, outp))
                if (!add3dpt(wp, inp, outp))
                        goto memerr;
        if (!feof(fp)) {
                wputs(fn);
                wputs(": non-number in 3D warp file\n");
        }
        goto cleanup;
memerr:
        eputs("load3dw: out of memory\n");
cleanup:
        fclose(fp);
        return(wp);
}


int
set3dwfl(wp, flgs)              /* reset warp flags */
register WARP3D *wp;
int     flgs;
{
        if (flgs == wp->grid.flags)
                return(0);
        if ((flgs & (W3EXACT|W3FAST)) == (W3EXACT|W3FAST)) {
                eputs("set3dwfl: only one of W3EXACT or W3FAST\n");
                return(-1);
        }
        wp->grid.flags = flgs;
        done3dgrid(&wp->grid);          /* old grid is invalid */
        return(0);
}


int
add3dpt(wp, pti, pto)           /* add 3D point pair to warp structure */
register WARP3D *wp;
W3VEC   pti, pto;
{
        double  d2;
        register W3VEC  *na;
        register int    i;

        if (wp->npts == 0) {                    /* initialize */
                wp->ip = (W3VEC *)malloc(AHUNK*sizeof(W3VEC));
                if (wp->ip == NULL) return(0);
                wp->ov = (W3VEC *)malloc(AHUNK*sizeof(W3VEC));
                if (wp->ov == NULL) return(0);
                wp->d2min = 1e10;
                wp->d2max = 0.;
                W3VCPY(wp->llim, pti);
                W3VCPY(wp->ulim, pti);
        } else {
                if (wp->npts % AHUNK == 0) {    /* allocate another hunk */
                        na = (W3VEC *)realloc((char *)wp->ip,
                                        (wp->npts+AHUNK)*sizeof(W3VEC));
                        if (na == NULL) return(0);
                        wp->ip = na;
                        na = (W3VEC *)realloc((char *)wp->ov,
                                        (wp->npts+AHUNK)*sizeof(W3VEC));
                        if (na == NULL) return(0);
                        wp->ov = na;
                }
                for (i = 0; i < 3; i++)         /* check boundaries */
                        if (pti[i] < wp->llim[i])
                                wp->llim[i] = pti[i];
                        else if (pti[i] > wp->ulim[i])
                                wp->ulim[i] = pti[i];
                for (i = wp->npts; i--; ) {     /* check distances */
                        d2 = wpdist2(pti, wp->ip[i]);
                        if (d2 < MIND*MIND)     /* value is too close */
                                return(wp->npts);
                        if (d2 < wp->d2min)
                                wp->d2min = d2;
                        if (d2 > wp->d2max)
                                wp->d2max = d2;
                }
        }
        W3VCPY(wp->ip[wp->npts], pti);  /* add new point */
        wp->ov[wp->npts][0] = pto[0] - pti[0];
        wp->ov[wp->npts][1] = pto[1] - pti[1];
        wp->ov[wp->npts][2] = pto[2] - pti[2];
        done3dgrid(&wp->grid);          /* old grid is invalid */
        return(++wp->npts);
}


free3dw(wp)                     /* free WARP3D data */
register WARP3D *wp;
{
        done3dgrid(&wp->grid);
        free((char *)wp->ip);
        free((char *)wp->ov);
        free((char *)wp);
}


long
gridhash(gp)                    /* hash a grid point index */
GNDX    gp;
{
        return(((unsigned long)gp[0]<<GNBITS | gp[1])<<GNBITS | gp[2]);
}


int
new3dgrid(wp)                   /* initialize interpolating grid for warp */
register WARP3D *wp;
{
        W3VEC   gmax;
        double  gridstep, d;
        int     n;
        register int    i;
                                /* free old grid (if any) */
        done3dgrid(&wp->grid);
                                /* check parameters */
        if (wp->npts < 2)
                return(W3BADMAP);       /* undefined for less than 2 points */
        if (wp->d2max < MIND)
                return(W3BADMAP);       /* not enough disparity */
                                /* compute gamut */
        W3VCPY(wp->grid.gmin, wp->llim);
        W3VCPY(gmax, wp->ulim);
        gridstep = sqrt(wp->d2min);
        for (i = 0; i < 3; i++) {
                wp->grid.gmin[i] -= .501*gridstep;
                gmax[i] += .501*gridstep;
        }
        if (wp->grid.flags & W3EXACT) {
                wp->grid.gn[0] = wp->grid.gn[1] = wp->grid.gn[2] = 1;
                return(W3OK);           /* no interpolation, so no grid */
        }
                                /* create grid */
        for (i = 0; i < 3; i++) {
                d = gmax[i] - wp->grid.gmin[i];
                n = d/gridstep + .5;
                if (n >= MAXGN-1)
                        n = MAXGN-2;
                wp->grid.gstep[i] = d / n;
                wp->grid.gn[i] = n;
        }
                                /* initialize lookup table */
        wp->grid.gtab.hashf = gridhash;
        wp->grid.gtab.keycmp = NULL;
        wp->grid.gtab.freek = free;
        wp->grid.gtab.freed = NULL;
        return(lu_init(&wp->grid.gtab, 1024) ? W3OK : W3ERROR);
}


done3dgrid(gp)                  /* free interpolating grid for warp */
register struct grid3d  *gp;
{
        if (gp->gn[0] == 0)
                return;
        lu_done(&gp->gtab);
        gp->gn[0] = gp->gn[1] = gp->gn[2] = 0;
}
Revision:	3.2
Committed:	Wed Feb 5 15:59:07 1997 UTC (28 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 3.1:	+73 -54 lines
Log Message:	important bug fixes and improvements
#	User	Rev	Content
1	greg	3.1	/* Copyright (c) 1997 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* 3D warping routines.
9			*/
10
11			#include <stdio.h>
12			#include <math.h>
13			#include "fvect.h"
14			#include "warp3d.h"
15
16			#define MIND 1e-5 /* minimum distance between input points */
17
18			typedef struct {
19			GNDX n; /* index must be first */
20	greg	3.2	W3VEC v;
21	greg	3.1	} KEYDP; /* key/data allocation pair */
22
23	greg	3.2	#define fgetvec(p,v) (fgetval(p,'f',v) > 0 && fgetval(p,'f',v+1) > 0 \
24			&& fgetval(p,'f',v+2) > 0)
25	greg	3.1
26	greg	3.2	#define AHUNK 24 /* number of points to allocate at a time */
27	greg	3.1
28			#ifndef malloc
29			extern char malloc(), realloc();
30			#endif
31			extern void free();
32
33
34			double
35			wpdist2(p1, p2) /* compute square of distance between points */
36			register W3VEC p1, p2;
37			{
38			double d, d2;
39
40			d = p1[0] - p2[0]; d2 = d*d;
41			d = p1[1] - p2[1]; d2 += d*d;
42			d = p1[2] - p2[2]; d2 += d*d;
43			return(d2);
44			}
45
46
47			int
48			warp3d(po, pi, wp) /* warp 3D point according to the given map */
49			W3VEC po, pi;
50			register WARP3D *wp;
51			{
52			int rval = W3OK;
53			GNDX gi;
54	greg	3.2	W3VEC gd, ov;
55	greg	3.1
56	greg	3.2	if (wp->grid.gn[0] == 0 && (rval = new3dgrid(wp)) != W3OK)
57	greg	3.1	return(rval);
58			rval \|= gridpoint(gi, gd, pi, &wp->grid);
59	greg	3.2	if (wp->grid.flags & W3EXACT)
60			rval \|= warp3dex(ov, pi, wp);
61			else if (wp->grid.flags & W3FAST)
62			rval \|= get3dgpt(ov, gi, wp);
63			else
64			rval \|= get3dgin(ov, gi, gd, wp);
65			po[0] = pi[0] + ov[0];
66			po[1] = pi[1] + ov[1];
67			po[2] = pi[2] + ov[2];
68	greg	3.1	return(rval);
69			}
70
71
72			int
73			gridpoint(ndx, rem, ipt, gp) /* compute grid position for ipt */
74			GNDX ndx;
75			W3VEC rem, ipt;
76			register struct grid3d *gp;
77			{
78			int rval = W3OK;
79			register int i;
80
81			for (i = 0; i < 3; i++) {
82			rem[i] = (ipt[i] - gp->gmin[i])/gp->gstep[i];
83			if (rem[i] < 0.) {
84			ndx[i] = 0;
85			rval = W3GAMUT;
86			} else if ((int)rem[i] >= gp->gn[i]) {
87			ndx[i] = gp->gn[i] - 1;
88			rval = W3GAMUT;
89			} else
90			ndx[i] = (int)rem[i];
91			rem[i] -= (double)ndx[i];
92			}
93			return(rval);
94			}
95
96
97			int
98	greg	3.2	get3dgpt(ov, ndx, wp) /* get value for voxel */
99			W3VEC ov;
100	greg	3.1	GNDX ndx;
101			register WARP3D *wp;
102			{
103			W3VEC gpt;
104			register LUENT *le;
105			KEYDP *kd;
106			int rval = W3OK;
107			register int i;
108
109	greg	3.2	le = lu_find(&wp->grid.gtab, ndx);
110	greg	3.1	if (le == NULL)
111			return(W3ERROR);
112			if (le->data == NULL) {
113			if (le->key != NULL)
114			kd = (KEYDP *)le->key;
115			else if ((kd = (KEYDP *)malloc(sizeof(KEYDP))) == NULL)
116			return(W3ERROR);
117			for (i = 0; i < 3; i++) {
118			kd->n[i] = ndx[i];
119			gpt[i] = wp->grid.gmin[i] + ndx[i]*wp->grid.gstep[i];
120			if (wp->grid.flags & W3FAST) /* on centers */
121			gpt[i] += .5*wp->grid.gstep[i];
122			}
123	greg	3.2	rval = warp3dex(kd->v, gpt, wp);
124	greg	3.1	le->key = (char *)kd->n;
125	greg	3.2	le->data = (char *)kd->v;
126	greg	3.1	}
127	greg	3.2	W3VCPY(ov, (float *)le->data);
128	greg	3.1	return(rval);
129			}
130
131
132			int
133	greg	3.2	get3dgin(ov, ndx, rem, wp) /* interpolate from warp grid */
134			W3VEC ov, rem;
135	greg	3.1	GNDX ndx;
136			WARP3D *wp;
137			{
138			W3VEC cv[8];
139			GNDX gi;
140	greg	3.2	int rval = 0;
141	greg	3.1	register int i;
142			/* get corner values */
143			for (i = 0; i < 8; i++) {
144			gi[0] = ndx[0] + (i & 1);
145			gi[1] = ndx[1] + (i>>1 & 1);
146			gi[2] = ndx[2] + (i>>2);
147			rval \|= get3dgpt(cv[i], gi, wp);
148			}
149			if (rval & W3ERROR)
150			return(rval);
151	greg	3.2	l3interp(ov, cv, rem, 3); /* perform trilinear interpolation */
152	greg	3.1	return(rval);
153			}
154
155
156			l3interp(vo, cl, dv, n) /* trilinear interpolation (recursive) */
157			W3VEC vo, *cl, dv;
158			int n;
159			{
160			W3VEC v0, v1;
161			register int i;
162
163			if (--n) {
164			l3interp(v0, cl, dv, n);
165			l3interp(v1, cl+(1<<n), dv, n);
166			} else {
167			W3VCPY(v0, cl[0]);
168			W3VCPY(v1, cl[1]);
169			}
170			for (i = 0; i < 3; i++)
171			vo[i] = (1.-dv[n])v0[i] + dv[n]v1[i];
172			}
173
174
175			int
176	greg	3.2	warp3dex(ov, pi, wp) /* compute warp using 1/r^2 weighted avg. */
177			W3VEC ov, pi;
178	greg	3.1	register WARP3D *wp;
179			{
180			double d2, w, wsum;
181	greg	3.2	W3VEC vt;
182	greg	3.1	register int i;
183
184	greg	3.2	vt[0] = vt[1] = vt[2] = 0.;
185	greg	3.1	wsum = 0.;
186			for (i = wp->npts; i--; ) {
187			d2 = wpdist2(pi, wp->ip[i]);
188			if (d2 <= MINDMIND) w = 1./(MINDMIND);
189			else w = 1./d2;
190	greg	3.2	vt[0] += w*wp->ov[i][0];
191			vt[1] += w*wp->ov[i][1];
192			vt[2] += w*wp->ov[i][2];
193	greg	3.1	wsum += w;
194			}
195			if (wsum > 0.) {
196	greg	3.2	ov[0] = vt[0]/wsum;
197			ov[1] = vt[1]/wsum;
198			ov[2] = vt[2]/wsum;
199	greg	3.1	}
200			return(W3OK);
201			}
202
203
204			WARP3D *
205			new3dw(flgs) /* allocate and initialize WARP3D struct */
206			int flgs;
207			{
208			register WARP3D *wp;
209
210			if ((flgs & (W3EXACT\|W3FAST)) == (W3EXACT\|W3FAST)) {
211			eputs("new3dw: only one of W3EXACT or W3FAST\n");
212			return(NULL);
213			}
214			if ((wp = (WARP3D *)malloc(sizeof(WARP3D))) == NULL) {
215			eputs("new3dw: no memory\n");
216			return(NULL);
217			}
218	greg	3.2	wp->ip = wp->ov = NULL;
219	greg	3.1	wp->npts = 0;
220			wp->grid.flags = flgs;
221			wp->grid.gn[0] = wp->grid.gn[1] = wp->grid.gn[2] = 0;
222			return(wp);
223			}
224
225
226			WARP3D *
227			load3dw(fn, wp) /* load 3D warp from file */
228			char *fn;
229			WARP3D *wp;
230			{
231			FILE *fp;
232			W3VEC inp, outp;
233
234			if ((fp = fopen(fn, "r")) == NULL) {
235			eputs(fn);
236			eputs(": cannot open\n");
237			return(NULL);
238			}
239	greg	3.2	if (wp == NULL && (wp = new3dw(0)) == NULL)
240	greg	3.1	goto memerr;
241			while (fgetvec(fp, inp) && fgetvec(fp, outp))
242			if (!add3dpt(wp, inp, outp))
243			goto memerr;
244			if (!feof(fp)) {
245			wputs(fn);
246			wputs(": non-number in 3D warp file\n");
247			}
248			goto cleanup;
249			memerr:
250			eputs("load3dw: out of memory\n");
251			cleanup:
252			fclose(fp);
253			return(wp);
254			}
255
256
257			int
258	greg	3.2	set3dwfl(wp, flgs) /* reset warp flags */
259			register WARP3D *wp;
260			int flgs;
261			{
262			if (flgs == wp->grid.flags)
263			return(0);
264			if ((flgs & (W3EXACT\|W3FAST)) == (W3EXACT\|W3FAST)) {
265			eputs("set3dwfl: only one of W3EXACT or W3FAST\n");
266			return(-1);
267			}
268			wp->grid.flags = flgs;
269			done3dgrid(&wp->grid); /* old grid is invalid */
270			return(0);
271			}
272
273
274			int
275	greg	3.1	add3dpt(wp, pti, pto) /* add 3D point pair to warp structure */
276			register WARP3D *wp;
277			W3VEC pti, pto;
278			{
279			double d2;
280			register W3VEC *na;
281			register int i;
282
283			if (wp->npts == 0) { /* initialize */
284			wp->ip = (W3VEC )malloc(AHUNKsizeof(W3VEC));
285			if (wp->ip == NULL) return(0);
286	greg	3.2	wp->ov = (W3VEC )malloc(AHUNKsizeof(W3VEC));
287			if (wp->ov == NULL) return(0);
288	greg	3.1	wp->d2min = 1e10;
289			wp->d2max = 0.;
290			W3VCPY(wp->llim, pti);
291			W3VCPY(wp->ulim, pti);
292			} else {
293			if (wp->npts % AHUNK == 0) { /* allocate another hunk */
294			na = (W3VEC )realloc((char )wp->ip,
295			(wp->npts+AHUNK)*sizeof(W3VEC));
296			if (na == NULL) return(0);
297			wp->ip = na;
298	greg	3.2	na = (W3VEC )realloc((char )wp->ov,
299	greg	3.1	(wp->npts+AHUNK)*sizeof(W3VEC));
300			if (na == NULL) return(0);
301	greg	3.2	wp->ov = na;
302	greg	3.1	}
303			for (i = 0; i < 3; i++) /* check boundaries */
304			if (pti[i] < wp->llim[i])
305			wp->llim[i] = pti[i];
306			else if (pti[i] > wp->ulim[i])
307			wp->ulim[i] = pti[i];
308			for (i = wp->npts; i--; ) { /* check distances */
309			d2 = wpdist2(pti, wp->ip[i]);
310			if (d2 < MINDMIND) / value is too close */
311			return(wp->npts);
312			if (d2 < wp->d2min)
313			wp->d2min = d2;
314			if (d2 > wp->d2max)
315			wp->d2max = d2;
316			}
317			}
318			W3VCPY(wp->ip[wp->npts], pti); /* add new point */
319	greg	3.2	wp->ov[wp->npts][0] = pto[0] - pti[0];
320			wp->ov[wp->npts][1] = pto[1] - pti[1];
321			wp->ov[wp->npts][2] = pto[2] - pti[2];
322	greg	3.1	done3dgrid(&wp->grid); /* old grid is invalid */
323			return(++wp->npts);
324			}
325
326
327			free3dw(wp) /* free WARP3D data */
328			register WARP3D *wp;
329			{
330			done3dgrid(&wp->grid);
331			free((char *)wp->ip);
332	greg	3.2	free((char *)wp->ov);
333	greg	3.1	free((char *)wp);
334			}
335
336
337			long
338			gridhash(gp) /* hash a grid point index */
339			GNDX gp;
340			{
341			return(((unsigned long)gp[0]<<GNBITS \| gp[1])<<GNBITS \| gp[2]);
342			}
343
344
345			int
346	greg	3.2	new3dgrid(wp) /* initialize interpolating grid for warp */
347	greg	3.1	register WARP3D *wp;
348			{
349	greg	3.2	W3VEC gmax;
350	greg	3.1	double gridstep, d;
351	greg	3.2	int n;
352	greg	3.1	register int i;
353			/* free old grid (if any) */
354			done3dgrid(&wp->grid);
355			/* check parameters */
356			if (wp->npts < 2)
357			return(W3BADMAP); /* undefined for less than 2 points */
358			if (wp->d2max < MIND)
359			return(W3BADMAP); /* not enough disparity */
360			/* compute gamut */
361			W3VCPY(wp->grid.gmin, wp->llim);
362	greg	3.2	W3VCPY(gmax, wp->ulim);
363	greg	3.1	gridstep = sqrt(wp->d2min);
364			for (i = 0; i < 3; i++) {
365			wp->grid.gmin[i] -= .501*gridstep;
366	greg	3.2	gmax[i] += .501*gridstep;
367	greg	3.1	}
368			if (wp->grid.flags & W3EXACT) {
369			wp->grid.gn[0] = wp->grid.gn[1] = wp->grid.gn[2] = 1;
370			return(W3OK); /* no interpolation, so no grid */
371			}
372			/* create grid */
373			for (i = 0; i < 3; i++) {
374	greg	3.2	d = gmax[i] - wp->grid.gmin[i];
375			n = d/gridstep + .5;
376			if (n >= MAXGN-1)
377			n = MAXGN-2;
378			wp->grid.gstep[i] = d / n;
379			wp->grid.gn[i] = n;
380	greg	3.1	}
381			/* initialize lookup table */
382			wp->grid.gtab.hashf = gridhash;
383			wp->grid.gtab.keycmp = NULL;
384			wp->grid.gtab.freek = free;
385			wp->grid.gtab.freed = NULL;
386			return(lu_init(&wp->grid.gtab, 1024) ? W3OK : W3ERROR);
387			}
388
389
390			done3dgrid(gp) /* free interpolating grid for warp */
391			register struct grid3d *gp;
392			{
393			if (gp->gn[0] == 0)
394			return;
395			lu_done(&gp->gtab);
396			gp->gn[0] = gp->gn[1] = gp->gn[2] = 0;
397			}