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Comparing ray/src/common/interp2d.c (file contents):
Revision 2.3 by greg, Mon Feb 11 20:01:15 2013 UTC vs.
Revision 2.4 by greg, Mon Feb 11 22:56:22 2013 UTC

#	Line 9 | Line 9 | static const char RCSid[] = "$Id$";
9
10		#include "copyright.h"
11
12	<	/*************************************************************
12	>	/***************************************************************
13		* This is a general method for 2-D interpolation similar to
14		* radial basis functions but allowing for a good deal of local
15		* anisotropy in the point distribution.  Each sample point
16		* is examined to determine the closest neighboring samples in
17		* each of NI2DIR surrounding directions.  To speed this
18	<	* calculation, we sort the data into 3 half-planes and
19	<	* perform simple tests to see which neighbor is closest in
20	<	* a each direction.  Once we have our approximate neighborhood
18	>	* calculation, we sort the data into half-planes and apply
19	>	* simple tests to see which neighbor is closest in each
20	>	* direction.  Once we have our approximate neighborhood
21		* for a sample, we can use it in a modified Gaussian weighting
22	<	* scheme with anisotropic surround.  Harmonic weighting is added
22	>	* with allowing local anisotropy.  Harmonic weighting is added
23		* to reduce the influence of distant neighbors.  This yields a
24		* smooth interpolation regardless of how the sample points are
25	<	* initiallydistributed.  Evaluation is accelerated by use of a
26	<	* fast approximation to the atan2(y,x) function.
27	<	**************************************************************/
25	>	* initially distributed.  Evaluation is accelerated by use of
26	>	* a fast approximation to the atan2(y,x) function.
27	>	****************************************************************/
28
29		#include <stdio.h>
30		#include <stdlib.h>
31		#include "rtmath.h"
32		#include "interp2d.h"
33
34	<	#define DECODE_RAD(ip,er)       ((ip)->rmin*(1. + .5*(er)))
35	<	#define ENCODE_RAD(ip,r)        ((int)(2.*(r)/(ip)->rmin) - 2)
34	>	#define DECODE_DIA(ip,ed)       ((ip)->dmin*(1. + .5*(ed)))
35	>	#define ENCODE_DIA(ip,d)        ((int)(2.*(d)/(ip)->dmin) - 2)
36
37		/* Sample order (private) */
38		typedef struct {
#	Line 54 | Line 54 | interp2_alloc(int nsamps)
54		return(NULL);
55
56		nip->ns = nsamps;
57	<	nip->rmin = .5;         /* default radius minimum */
57	>	nip->dmin = 1;          /* default minimum diameter */
58		nip->smf = NI2DSMF;     /* default smoothing factor */
59	<	nip->ra = NULL;
59	>	nip->da = NULL;
60		/* caller must assign spt[] array */
61		return(nip);
62		}
#	Line 73 | Line 73 | interp2_realloc(INTERP2 *ip, int nsamps)
73		}
74		if (nsamps == ip->ns);
75		return(ip);
76	<	if (ip->ra != NULL) {   /* will need to recompute distribution */
77	<	free(ip->ra);
78	<	ip->ra = NULL;
76	>	if (ip->da != NULL) {   /* will need to recompute distribution */
77	>	free(ip->da);
78	>	ip->da = NULL;
79		}
80		ip = (INTERP2 *)realloc(ip, sizeof(INTERP2)+sizeof(float)*2*(nsamps-1));
81		if (ip == NULL)
#	Line 113 | Line 113 | sort_samples(SAMPORD *sord, const INTERP2 *ip, double
113		qsort(sord, ip->ns, sizeof(SAMPORD), &cmp_spos);
114		}
115
116	<	/* private routine to encode radius with range checks */
116	>	/* private routine to encode sample diameter with range checks */
117		static int
118	<	encode_radius(const INTERP2 *ip, double r)
118	>	encode_diameter(const INTERP2 *ip, double d)
119		{
120	<	const int       er = ENCODE_RAD(ip, r);
120	>	const int       ed = ENCODE_DIA(ip, d);
121
122	<	if (er <= 0)
122	>	if (ed <= 0)
123		return(0);
124	<	if (er >= 0xffff)
124	>	if (ed >= 0xffff)
125		return(0xffff);
126	<	return(er);
126	>	return(ed);
127		}
128
129		/* (Re)compute anisotropic basis function interpolant (normally automatic) */
#	Line 134 | Line 134 | interp2_analyze(INTERP2 *ip)
134		int     *rightrndx, *leftrndx, *endrndx;
135		int     bd;
136		/* sanity checks */
137	<	if (ip == NULL || (ip->ns <= 1) | (ip->rmin <= 0))
137	>	if (ip == NULL || (ip->ns <= 1) | (ip->dmin <= 0))
138		return(0);
139		/* need to allocate? */
140	<	if (ip->ra == NULL) {
141	<	ip->ra = (unsigned short (*)[NI2DIR])malloc(
140	>	if (ip->da == NULL) {
141	>	ip->da = (unsigned short (*)[NI2DIR])malloc(
142		sizeof(unsigned short)*NI2DIR*ip->ns);
143	<	if (ip->ra == NULL)
143	>	if (ip->da == NULL)
144		return(0);
145		}
146		/* get temporary arrays */
#	Line 186 | Line 186 | interp2_analyze(INTERP2 *ip)
186		const int       ii = sortord[i].si;
187		int             j;
188		/* preload with large radii */
189	<	ip->ra[ii][bd] = ip->ra[ii][bd+NI2DIR/2] = encode_radius(ip,
190	<	.25*(sortord[ip->ns-1].dm - sortord[0].dm));
189	>	ip->da[ii][bd] = ip->da[ii][bd+NI2DIR/2] = encode_diameter(ip,
190	>	.5*(sortord[ip->ns-1].dm - sortord[0].dm));
191		for (j = i; ++j < ip->ns; )     /* nearest above */
192		if (rightrndx[sortord[j].si] > rightrndx[ii] &&
193		leftrndx[sortord[j].si] < leftrndx[ii]) {
194	<	ip->ra[ii][bd] = encode_radius(ip,
195	<	.5*(sortord[j].dm - sortord[i].dm));
194	>	ip->da[ii][bd] = encode_diameter(ip,
195	>	sortord[j].dm - sortord[i].dm);
196		break;
197		}
198		for (j = i; j-- > 0; )          /* nearest below */
199		if (rightrndx[sortord[j].si] < rightrndx[ii] &&
200		leftrndx[sortord[j].si] > leftrndx[ii]) {
201	<	ip->ra[ii][bd+NI2DIR/2] = encode_radius(ip,
202	<	.5*(sortord[i].dm - sortord[j].dm));
201	>	ip->da[ii][bd+NI2DIR/2] = encode_diameter(ip,
202	>	sortord[i].dm - sortord[j].dm);
203		break;
204		}
205		}
#	Line 226 | Line 226 | get_wt(const INTERP2 *ip, const int i, double x, doubl
226		rd = dir * (NI2DIR/2./PI);
227		ri = (int)rd;
228		rd -= (double)ri;
229	<	rd = (1.-rd)*ip->ra[i][ri] + rd*ip->ra[i][(ri+1)%NI2DIR];
230	<	rd = ip->smf * DECODE_RAD(ip, rd);
229	>	rd = (1.-rd)*ip->da[i][ri] + rd*ip->da[i][(ri+1)%NI2DIR];
230	>	rd = ip->smf * DECODE_DIA(ip, rd);
231		d2 = x*x + y*y;
232		/* Gaussian times harmonic weighting */
233	<	return( exp(d2/(-2.*rd*rd)) * ip->rmin/(ip->rmin + sqrt(d2)) );
233	>	return( exp(d2/(-2.*rd*rd)) * ip->dmin/(ip->dmin + sqrt(d2)) );
234		}
235
236		/* Assign full set of normalized weights to interpolate the given position */
#	Line 243 | Line 243 | interp2_weights(float wtv[], INTERP2 *ip, double x, do
243		if ((wtv == NULL) | (ip == NULL))
244		return(0);
245		/* need to compute interpolant? */
246	<	if (ip->ra == NULL && !interp2_analyze(ip))
246	>	if (ip->da == NULL && !interp2_analyze(ip))
247		return(0);
248
249		wnorm = 0;                      /* compute raw weights */
#	Line 272 | Line 272 | interp2_topsamp(float wt[], int si[], const int n, INT
272		if ((n <= 0) | (wt == NULL) | (si == NULL) | (ip == NULL))
273		return(0);
274		/* need to compute interpolant? */
275	<	if (ip->ra == NULL && !interp2_analyze(ip))
275	>	if (ip->da == NULL && !interp2_analyze(ip))
276		return(0);
277		/* identify top n weights */
278		for (i = ip->ns; i--; ) {
#	Line 308 | Line 308 | interp2_free(INTERP2 *ip)
308		{
309		if (ip == NULL)
310		return;
311	<	if (ip->ra != NULL)
312	<	free(ip->ra);
311	>	if (ip->da != NULL)
312	>	free(ip->da);
313		free(ip);
314		}

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