// retourne le noeud voisin d'un noeud (algorithme générique)
private QuadTreeNodeInterface<E> sibling(
AbstractQuadTreeNode<E> node, int[] ancestortype, int[] reverter) {
int[] path = new int[treeRoot.maxNodeDepth + 1];
int pathlength = 0;
// recherche du plus proche ancetre commun
AbstractQuadTreeNode<E> ancestor = node;
while (true) {
if (ancestor.getPositionInParentNode() == ROOT) {
return null; // no common ancestor -> exit
}
path[pathlength] = ancestor.getPositionInParentNode();
pathlength++;
if (ancestor.getPositionInParentNode() == ancestortype[0]) {
ancestor = ancestor.getParent();
break;
}
if (ancestor.getPositionInParentNode() == ancestortype[1]) {
ancestor = ancestor.getParent();
break;
}
ancestor = ancestor.getParent();
}
// parcours de l'arbre en utilisant le chemin symetrique
AbstractQuadTreeNode<E> cursor = ancestor, next = null;
for (int i = pathlength - 1; i >= 0; i--) {
if (cursor.children == null) break;
next = cursor.children.get(reverter[path[i]]);
if (next == null) break;
cursor = next;
}
return cursor;
}
