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/* GTS - Library for the manipulation of triangulated surfaces
* Copyright (C) 1999 Stphane Popinet
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <stdlib.h>
#include "gts.h"
static int compare_x (const void * p1, const void * p2) {
GtsPoint
* pp1 = *((gpointer *) p1),
* pp2 = *((gpointer *) p2);
if (pp1->x > pp2->x)
return 1;
return -1;
}
static int compare_y (const void * p1, const void * p2) {
GtsPoint
* pp1 = *((gpointer *) p1),
* pp2 = *((gpointer *) p2);
if (pp1->y > pp2->y)
return 1;
return -1;
}
static int compare_z (const void * p1, const void * p2) {
GtsPoint
* pp1 = *((gpointer *) p1),
* pp2 = *((gpointer *) p2);
if (pp1->z > pp2->z)
return 1;
return -1;
}
/**
* gts_kdtree_new:
* @points: an array of #GtsPoint.
* @compare: always %NULL.
*
* Note that the order of the points in array @points is modified by this
* function.
*
* Returns: a new 3D tree for @points.
*/
GNode * gts_kdtree_new (GPtrArray * points,
int (*compare) (const void *, const void *))
{
guint middle;
GPtrArray array;
GNode * node;
GtsPoint * point;
g_return_val_if_fail (points != NULL, NULL);
g_return_val_if_fail (points->len > 0, NULL);
/* sort the points */
if (compare == compare_x) compare = compare_y;
else if (compare == compare_y) compare = compare_z;
else compare = compare_x;
qsort (points->pdata, points->len, sizeof (gpointer), compare);
middle = (points->len - 1)/2;
point = points->pdata[middle];
node = g_node_new (point);
if (points->len > 1) {
array.len = middle;
if (array.len > 0) {
array.pdata = points->pdata;
g_node_prepend (node, gts_kdtree_new (&array, compare));
}
else
g_node_prepend (node, g_node_new (NULL));
array.len = points->len - middle - 1;
if (array.len > 0) {
array.pdata = &(points->pdata[middle + 1]);
g_node_prepend (node, gts_kdtree_new (&array, compare));
}
else
g_node_prepend (node, g_node_new (NULL));
}
return node;
}
/**
* gts_kdtree_range:
* @tree: a 3D tree.
* @bbox: a #GtsBBox.
* @compare: always %NULL.
*
* Returns: a list of #GtsPoint belonging to @tree which are inside @bbox.
*/
GSList * gts_kdtree_range (GNode * tree_3d,
GtsBBox * bbox,
int (*compare) (const void *, const void *))
{
GSList * list = NULL;
GtsPoint * p;
gdouble left, right, v;
GNode * node;
g_return_val_if_fail (tree_3d != NULL, NULL);
g_return_val_if_fail (bbox != NULL, NULL);
p = tree_3d->data;
if (p == NULL)
return NULL;
if (gts_bbox_point_is_inside (bbox, p))
list = g_slist_prepend (list, p);
if (compare == compare_x) {
left = bbox->y1; right = bbox->y2; v = p->y;
compare = compare_y;
}
else if (compare == compare_y) {
left = bbox->z1; right = bbox->z2; v = p->z;
compare = compare_z;
}
else {
left = bbox->x1; right = bbox->x2; v = p->x;
compare = compare_x;
}
if ((node = tree_3d->children)) {
if (right >= v)
list = g_slist_concat (list, gts_kdtree_range (node, bbox, compare));
node = node->next;
if (left <= v)
list = g_slist_concat (list, gts_kdtree_range (node, bbox, compare));
}
return list;
}
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