src/px/warp3d.c

#ifndef lint
static const char       RCSid[] = "$Id: warp3d.c,v 3.9 2010/09/03 21:18:15 greg Exp $";
#endif
/*
 * 3D warping routines.
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

#include "rterror.h"
#include "rtio.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 */


double wpdist2(W3VEC p1, W3VEC p2);
static int gridpoint(GNDX ndx, W3VEC rem, W3VEC ipt, struct grid3d *gp);
static int get3dgpt(W3VEC ov, GNDX ndx, WARP3D *wp);
static int get3dgin(W3VEC ov, GNDX ndx, W3VEC rem, WARP3D *wp);
static void l3interp(W3VEC vo, W3VEC *cl, W3VEC dv, int n);
static int warp3dex(W3VEC ov, W3VEC pi, WARP3D *wp);
static lut_hashf_t gridhash;
static int new3dgrid(WARP3D *wp);
static void done3dgrid(struct grid3d *gp);


double
wpdist2(                        /* compute square of distance between points */
        register W3VEC  p1,
        register W3VEC  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(         /* warp 3D point according to the given map */
        W3VEC   po,
        W3VEC   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);
}


static int
gridpoint(      /* compute grid position for ipt */
        GNDX    ndx,
        W3VEC   rem,
        W3VEC   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);
}


static int
get3dgpt(               /* 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);
}


static int
get3dgin(       /* interpolate from warp grid */
        W3VEC   ov,
        GNDX    ndx,
        W3VEC   rem,
        WARP3D  *wp
)
{
        W3VEC   cv[8];
        GNDX    gi;
        int     rval = W3OK;
        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);
}


static void
l3interp(               /* trilinear interpolation (recursive) */
        W3VEC   vo,
        W3VEC   *cl,
        W3VEC   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];
}


static int
warp3dex(               /* compute warp using 1/r^2 weighted avg. */
        W3VEC   ov,
        W3VEC   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(                 /* 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(                        /* 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);
}


extern int
set3dwfl(               /* 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(                /* add 3D point pair to warp structure */
        register WARP3D *wp,
        W3VEC   pti,
        W3VEC   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((void *)wp->ip,
                                        (wp->npts+AHUNK)*sizeof(W3VEC));
                        if (na == NULL) return(0);
                        wp->ip = na;
                        na = (W3VEC *)realloc((void *)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);
}


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


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


static int
new3dgrid(                      /* 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;
                wp->grid.gstep[0] = gmax[0] - wp->grid.gmin[0];
                wp->grid.gstep[1] = gmax[1] - wp->grid.gmin[1];
                wp->grid.gstep[2] = gmax[2] - wp->grid.gmin[2];
                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);
}


static void
done3dgrid(                     /* 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:	3.10
Committed:	Fri Feb 18 00:40:25 2011 UTC (13 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad5R2, rad4R2P2, rad5R0, rad5R1, rad4R2, rad4R1, rad4R2P1
Changes since 3.9:	+2 -2 lines
Log Message:	Major code reorg, moving mgflib to common and introducing BSDF material
#	User	Rev	Content
1	greg	3.1	#ifndef lint
2	greg	3.10	static const char RCSid[] = "$Id: warp3d.c,v 3.9 2010/09/03 21:18:15 greg Exp $";
3	greg	3.1	#endif
4			/*
5			* 3D warping routines.
6			*/
7
8			#include <stdio.h>
9	greg	3.5	#include <stdlib.h>
10	greg	3.1	#include <math.h>
11	schorsch	3.7
12			#include "rterror.h"
13			#include "rtio.h"
14	greg	3.1	#include "fvect.h"
15			#include "warp3d.h"
16
17			#define MIND 1e-5 /* minimum distance between input points */
18
19			typedef struct {
20			GNDX n; /* index must be first */
21	greg	3.2	W3VEC v;
22	greg	3.1	} KEYDP; /* key/data allocation pair */
23
24	greg	3.2	#define fgetvec(p,v) (fgetval(p,'f',v) > 0 && fgetval(p,'f',v+1) > 0 \
25			&& fgetval(p,'f',v+2) > 0)
26	greg	3.1
27	greg	3.2	#define AHUNK 24 /* number of points to allocate at a time */
28	greg	3.1
29
30	schorsch	3.7	double wpdist2(W3VEC p1, W3VEC p2);
31			static int gridpoint(GNDX ndx, W3VEC rem, W3VEC ipt, struct grid3d *gp);
32			static int get3dgpt(W3VEC ov, GNDX ndx, WARP3D *wp);
33			static int get3dgin(W3VEC ov, GNDX ndx, W3VEC rem, WARP3D *wp);
34			static void l3interp(W3VEC vo, W3VEC *cl, W3VEC dv, int n);
35			static int warp3dex(W3VEC ov, W3VEC pi, WARP3D *wp);
36			static lut_hashf_t gridhash;
37			static int new3dgrid(WARP3D *wp);
38			static void done3dgrid(struct grid3d *gp);
39
40
41	greg	3.1	double
42	schorsch	3.7	wpdist2( /* compute square of distance between points */
43			register W3VEC p1,
44			register W3VEC p2
45			)
46	greg	3.1	{
47			double d, d2;
48
49			d = p1[0] - p2[0]; d2 = d*d;
50			d = p1[1] - p2[1]; d2 += d*d;
51			d = p1[2] - p2[2]; d2 += d*d;
52			return(d2);
53			}
54
55
56			int
57	schorsch	3.7	warp3d( /* warp 3D point according to the given map */
58			W3VEC po,
59			W3VEC pi,
60			register WARP3D *wp
61			)
62	greg	3.1	{
63			int rval = W3OK;
64			GNDX gi;
65	greg	3.2	W3VEC gd, ov;
66	greg	3.1
67	greg	3.2	if (wp->grid.gn[0] == 0 && (rval = new3dgrid(wp)) != W3OK)
68	greg	3.1	return(rval);
69			rval \|= gridpoint(gi, gd, pi, &wp->grid);
70	greg	3.2	if (wp->grid.flags & W3EXACT)
71			rval \|= warp3dex(ov, pi, wp);
72			else if (wp->grid.flags & W3FAST)
73			rval \|= get3dgpt(ov, gi, wp);
74			else
75			rval \|= get3dgin(ov, gi, gd, wp);
76			po[0] = pi[0] + ov[0];
77			po[1] = pi[1] + ov[1];
78			po[2] = pi[2] + ov[2];
79	greg	3.1	return(rval);
80			}
81
82
83	schorsch	3.7	static int
84			gridpoint( /* compute grid position for ipt */
85			GNDX ndx,
86			W3VEC rem,
87			W3VEC ipt,
88			register struct grid3d *gp
89			)
90	greg	3.1	{
91			int rval = W3OK;
92			register int i;
93
94			for (i = 0; i < 3; i++) {
95			rem[i] = (ipt[i] - gp->gmin[i])/gp->gstep[i];
96			if (rem[i] < 0.) {
97			ndx[i] = 0;
98			rval = W3GAMUT;
99			} else if ((int)rem[i] >= gp->gn[i]) {
100			ndx[i] = gp->gn[i] - 1;
101			rval = W3GAMUT;
102			} else
103			ndx[i] = (int)rem[i];
104			rem[i] -= (double)ndx[i];
105			}
106			return(rval);
107			}
108
109
110	schorsch	3.7	static int
111			get3dgpt( /* get value for voxel */
112			W3VEC ov,
113			GNDX ndx,
114			register WARP3D *wp
115			)
116	greg	3.1	{
117			W3VEC gpt;
118			register LUENT *le;
119			KEYDP *kd;
120			int rval = W3OK;
121			register int i;
122
123	greg	3.2	le = lu_find(&wp->grid.gtab, ndx);
124	greg	3.1	if (le == NULL)
125			return(W3ERROR);
126			if (le->data == NULL) {
127			if (le->key != NULL)
128			kd = (KEYDP *)le->key;
129			else if ((kd = (KEYDP *)malloc(sizeof(KEYDP))) == NULL)
130			return(W3ERROR);
131			for (i = 0; i < 3; i++) {
132			kd->n[i] = ndx[i];
133			gpt[i] = wp->grid.gmin[i] + ndx[i]*wp->grid.gstep[i];
134			if (wp->grid.flags & W3FAST) /* on centers */
135			gpt[i] += .5*wp->grid.gstep[i];
136			}
137	greg	3.2	rval = warp3dex(kd->v, gpt, wp);
138	greg	3.1	le->key = (char *)kd->n;
139	greg	3.2	le->data = (char *)kd->v;
140	greg	3.1	}
141	greg	3.2	W3VCPY(ov, (float *)le->data);
142	greg	3.1	return(rval);
143			}
144
145
146	schorsch	3.7	static int
147			get3dgin( /* interpolate from warp grid */
148			W3VEC ov,
149			GNDX ndx,
150			W3VEC rem,
151			WARP3D *wp
152			)
153	greg	3.1	{
154			W3VEC cv[8];
155			GNDX gi;
156	greg	3.3	int rval = W3OK;
157	greg	3.1	register int i;
158			/* get corner values */
159			for (i = 0; i < 8; i++) {
160			gi[0] = ndx[0] + (i & 1);
161			gi[1] = ndx[1] + (i>>1 & 1);
162			gi[2] = ndx[2] + (i>>2);
163			rval \|= get3dgpt(cv[i], gi, wp);
164			}
165			if (rval & W3ERROR)
166			return(rval);
167	greg	3.2	l3interp(ov, cv, rem, 3); /* perform trilinear interpolation */
168	greg	3.1	return(rval);
169			}
170
171
172	schorsch	3.7	static void
173			l3interp( /* trilinear interpolation (recursive) */
174			W3VEC vo,
175			W3VEC *cl,
176			W3VEC dv,
177			int n
178			)
179	greg	3.1	{
180			W3VEC v0, v1;
181			register int i;
182
183			if (--n) {
184			l3interp(v0, cl, dv, n);
185			l3interp(v1, cl+(1<<n), dv, n);
186			} else {
187			W3VCPY(v0, cl[0]);
188			W3VCPY(v1, cl[1]);
189			}
190			for (i = 0; i < 3; i++)
191			vo[i] = (1.-dv[n])v0[i] + dv[n]v1[i];
192			}
193
194
195	schorsch	3.7	static int
196			warp3dex( /* compute warp using 1/r^2 weighted avg. */
197			W3VEC ov,
198			W3VEC pi,
199			register WARP3D *wp
200			)
201	greg	3.1	{
202			double d2, w, wsum;
203	greg	3.2	W3VEC vt;
204	greg	3.1	register int i;
205
206	greg	3.2	vt[0] = vt[1] = vt[2] = 0.;
207	greg	3.1	wsum = 0.;
208			for (i = wp->npts; i--; ) {
209			d2 = wpdist2(pi, wp->ip[i]);
210			if (d2 <= MINDMIND) w = 1./(MINDMIND);
211			else w = 1./d2;
212	greg	3.2	vt[0] += w*wp->ov[i][0];
213			vt[1] += w*wp->ov[i][1];
214			vt[2] += w*wp->ov[i][2];
215	greg	3.1	wsum += w;
216			}
217			if (wsum > 0.) {
218	greg	3.2	ov[0] = vt[0]/wsum;
219			ov[1] = vt[1]/wsum;
220			ov[2] = vt[2]/wsum;
221	greg	3.1	}
222			return(W3OK);
223			}
224
225
226			WARP3D *
227	schorsch	3.7	new3dw( /* allocate and initialize WARP3D struct */
228			int flgs
229			)
230	greg	3.1	{
231			register WARP3D *wp;
232
233			if ((flgs & (W3EXACT\|W3FAST)) == (W3EXACT\|W3FAST)) {
234			eputs("new3dw: only one of W3EXACT or W3FAST\n");
235			return(NULL);
236			}
237			if ((wp = (WARP3D *)malloc(sizeof(WARP3D))) == NULL) {
238			eputs("new3dw: no memory\n");
239			return(NULL);
240			}
241	greg	3.2	wp->ip = wp->ov = NULL;
242	greg	3.1	wp->npts = 0;
243			wp->grid.flags = flgs;
244			wp->grid.gn[0] = wp->grid.gn[1] = wp->grid.gn[2] = 0;
245			return(wp);
246			}
247
248
249			WARP3D *
250	schorsch	3.7	load3dw( /* load 3D warp from file */
251			char *fn,
252			WARP3D *wp
253			)
254	greg	3.1	{
255			FILE *fp;
256			W3VEC inp, outp;
257
258			if ((fp = fopen(fn, "r")) == NULL) {
259			eputs(fn);
260			eputs(": cannot open\n");
261			return(NULL);
262			}
263	greg	3.2	if (wp == NULL && (wp = new3dw(0)) == NULL)
264	greg	3.1	goto memerr;
265			while (fgetvec(fp, inp) && fgetvec(fp, outp))
266			if (!add3dpt(wp, inp, outp))
267			goto memerr;
268			if (!feof(fp)) {
269			wputs(fn);
270			wputs(": non-number in 3D warp file\n");
271			}
272			goto cleanup;
273			memerr:
274			eputs("load3dw: out of memory\n");
275			cleanup:
276			fclose(fp);
277			return(wp);
278			}
279
280
281	schorsch	3.7	extern int
282			set3dwfl( /* reset warp flags */
283			register WARP3D *wp,
284			int flgs
285			)
286	greg	3.2	{
287			if (flgs == wp->grid.flags)
288			return(0);
289			if ((flgs & (W3EXACT\|W3FAST)) == (W3EXACT\|W3FAST)) {
290			eputs("set3dwfl: only one of W3EXACT or W3FAST\n");
291			return(-1);
292			}
293			wp->grid.flags = flgs;
294			done3dgrid(&wp->grid); /* old grid is invalid */
295			return(0);
296			}
297
298
299			int
300	schorsch	3.7	add3dpt( /* add 3D point pair to warp structure */
301			register WARP3D *wp,
302			W3VEC pti,
303			W3VEC pto
304			)
305	greg	3.1	{
306			double d2;
307			register W3VEC *na;
308			register int i;
309
310			if (wp->npts == 0) { /* initialize */
311			wp->ip = (W3VEC )malloc(AHUNKsizeof(W3VEC));
312			if (wp->ip == NULL) return(0);
313	greg	3.2	wp->ov = (W3VEC )malloc(AHUNKsizeof(W3VEC));
314			if (wp->ov == NULL) return(0);
315	greg	3.1	wp->d2min = 1e10;
316			wp->d2max = 0.;
317			W3VCPY(wp->llim, pti);
318			W3VCPY(wp->ulim, pti);
319			} else {
320			if (wp->npts % AHUNK == 0) { /* allocate another hunk */
321	greg	3.6	na = (W3VEC )realloc((void )wp->ip,
322	greg	3.1	(wp->npts+AHUNK)*sizeof(W3VEC));
323			if (na == NULL) return(0);
324			wp->ip = na;
325	greg	3.6	na = (W3VEC )realloc((void )wp->ov,
326	greg	3.1	(wp->npts+AHUNK)*sizeof(W3VEC));
327			if (na == NULL) return(0);
328	greg	3.2	wp->ov = na;
329	greg	3.1	}
330			for (i = 0; i < 3; i++) /* check boundaries */
331			if (pti[i] < wp->llim[i])
332			wp->llim[i] = pti[i];
333			else if (pti[i] > wp->ulim[i])
334			wp->ulim[i] = pti[i];
335			for (i = wp->npts; i--; ) { /* check distances */
336			d2 = wpdist2(pti, wp->ip[i]);
337			if (d2 < MINDMIND) / value is too close */
338			return(wp->npts);
339			if (d2 < wp->d2min)
340			wp->d2min = d2;
341			if (d2 > wp->d2max)
342			wp->d2max = d2;
343			}
344			}
345			W3VCPY(wp->ip[wp->npts], pti); /* add new point */
346	greg	3.2	wp->ov[wp->npts][0] = pto[0] - pti[0];
347			wp->ov[wp->npts][1] = pto[1] - pti[1];
348			wp->ov[wp->npts][2] = pto[2] - pti[2];
349	greg	3.1	done3dgrid(&wp->grid); /* old grid is invalid */
350			return(++wp->npts);
351			}
352
353
354	schorsch	3.7	extern void
355			free3dw( /* free WARP3D data */
356			register WARP3D *wp
357			)
358	greg	3.1	{
359			done3dgrid(&wp->grid);
360	greg	3.5	free((void *)wp->ip);
361			free((void *)wp->ov);
362			free((void *)wp);
363	greg	3.1	}
364
365
366	schorsch	3.7	static unsigned long
367			gridhash( /* hash a grid point index */
368	greg	3.10	const char *gp
369	schorsch	3.7	)
370	greg	3.1	{
371	greg	3.8	return(((unsigned long)((const unsigned char)gp)[0]<<GNBITS \| ((const unsigned char)gp)[1])<<GNBITS \| ((const unsigned char*)gp)[2]);
372	greg	3.1	}
373
374
375	schorsch	3.7	static int
376			new3dgrid( /* initialize interpolating grid for warp */
377			register WARP3D *wp
378			)
379	greg	3.1	{
380	greg	3.2	W3VEC gmax;
381	greg	3.1	double gridstep, d;
382	greg	3.2	int n;
383	greg	3.1	register int i;
384			/* free old grid (if any) */
385			done3dgrid(&wp->grid);
386			/* check parameters */
387			if (wp->npts < 2)
388			return(W3BADMAP); /* undefined for less than 2 points */
389			if (wp->d2max < MIND)
390			return(W3BADMAP); /* not enough disparity */
391			/* compute gamut */
392			W3VCPY(wp->grid.gmin, wp->llim);
393	greg	3.2	W3VCPY(gmax, wp->ulim);
394	greg	3.1	gridstep = sqrt(wp->d2min);
395			for (i = 0; i < 3; i++) {
396			wp->grid.gmin[i] -= .501*gridstep;
397	greg	3.2	gmax[i] += .501*gridstep;
398	greg	3.1	}
399			if (wp->grid.flags & W3EXACT) {
400			wp->grid.gn[0] = wp->grid.gn[1] = wp->grid.gn[2] = 1;
401	greg	3.3	wp->grid.gstep[0] = gmax[0] - wp->grid.gmin[0];
402			wp->grid.gstep[1] = gmax[1] - wp->grid.gmin[1];
403			wp->grid.gstep[2] = gmax[2] - wp->grid.gmin[2];
404	greg	3.1	return(W3OK); /* no interpolation, so no grid */
405			}
406			/* create grid */
407			for (i = 0; i < 3; i++) {
408	greg	3.2	d = gmax[i] - wp->grid.gmin[i];
409			n = d/gridstep + .5;
410			if (n >= MAXGN-1)
411			n = MAXGN-2;
412			wp->grid.gstep[i] = d / n;
413			wp->grid.gn[i] = n;
414	greg	3.1	}
415			/* initialize lookup table */
416			wp->grid.gtab.hashf = gridhash;
417			wp->grid.gtab.keycmp = NULL;
418			wp->grid.gtab.freek = free;
419			wp->grid.gtab.freed = NULL;
420			return(lu_init(&wp->grid.gtab, 1024) ? W3OK : W3ERROR);
421			}
422
423
424	schorsch	3.7	static void
425			done3dgrid( /* free interpolating grid for warp */
426			register struct grid3d *gp
427			)
428	greg	3.1	{
429			if (gp->gn[0] == 0)
430			return;
431			lu_done(&gp->gtab);
432			gp->gn[0] = gp->gn[1] = gp->gn[2] = 0;
433			}