private JPSNode[] getJPSNeighbours(JPSNode current, List<IObstacle> obsList) {
double x = current.getX();
double y = current.getY();
LinkedList<JPSNode> nodes = new LinkedList<JPSNode>();
JPSNode parent = current.came_from;
if (parent != null) { // determines whether to prune neighbors
JPSNode norm = normalizeDirection(x, y, parent.getX(), parent.getY());
double dx = norm.getX() * coordinateScaling;
double dy = norm.getY() * coordinateScaling;
JPSNode temp = new JPSNode(current);
if (((int) dx & (int) dy) != 0) { // diagonal direction
// check straight directions in the direction of the diagonal move
if (walkable(temp.setPosition(x, y + dy))) nodes.add(new JPSNode(temp));
if (walkable(temp.setPosition(x + dx, y))) nodes.add(new JPSNode(temp));
if (walkable(temp.setPosition(x + dx, y + dy))) nodes.add(new JPSNode(temp));
// forced neighbor checks
if (!walkable(temp.setPosition(x - dx, y))) nodes.add(new JPSNode(temp.shift(0, dy)));
if (!walkable(temp.setPosition(x, y - dy))) nodes.add(new JPSNode(temp.shift(dx, 0)));
} else { // straight direction
if (walkable(temp.setPosition(x + dx, y + dy))) {
nodes.add(new JPSNode(temp));
// forced neighbor checks
if (!walkable(temp.setPosition(x + dy, y + dx)))
nodes.add(new JPSNode(temp.shift(dx, dy)));
if (!walkable(temp.setPosition(x - dy, y - dx)))
nodes.add(new JPSNode(temp.shift(dx, dy)));
}
}
} else {
// no parent, return all that aren't blocked
JPSNode[] ns =
new JPSNode[] {
new JPSNode(x, y - coordinateScaling),
new JPSNode(x + coordinateScaling, y - coordinateScaling),
new JPSNode(x + coordinateScaling, y),
new JPSNode(x + coordinateScaling, y + coordinateScaling),
new JPSNode(x, y + coordinateScaling),
new JPSNode(x - coordinateScaling, y + coordinateScaling),
new JPSNode(x - coordinateScaling, y),
new JPSNode(x - coordinateScaling, y - coordinateScaling)
};
for (int i = 0; i < ns.length; i++) {
if (walkable(ns[i])) nodes.add(ns[i]);
}
}
return nodes.toArray(new JPSNode[nodes.size()]);
}
private JPSNode jump(JPSNode node, JPSNode parent, JPSNode goal) {
double x = node.getX(), y = node.getY(), px = parent.getX(), py = parent.getY();
double dx = (x - px);
double dy = (y - py);
// Log.e("Coordinatescaling: " + coordinateScaling);
// Log.e("dy: " + dy + " dx: " + dx);
// Log.e("JUMP! node: " + node.toString() + " parent: " + parent.toString() + " dx: " + dx + "
// dy: " + dy);
if (!walkable(node)) // check blocked
return null;
if (node.equals(goal)) // reached goal
return new JPSNode(node);
// resolve forced neighbors
JPSNode temp = new JPSNode(node);
if (((int) dx & (int) dy) != 0) { // diagonal
if ((walkable(temp.setPosition(x - dx, y + dy)) && !walkable(temp.setPosition(x - dx, y)))
|| (walkable(temp.setPosition(x + dx, y - dy))
&& !walkable(temp.setPosition(x, y - dy)))) {
return new JPSNode(node);
}
// recurse
JPSNode h = jump(node.derive(dx, 0), node, goal);
if (h != null) return new JPSNode(node);
JPSNode v = jump(node.derive(0, dy), node, goal);
if (v != null) return new JPSNode(node);
} else if (dx == 0) { // vertical, dx = 0, dy = 1 or -1
if ((walkable(temp.setPosition(x + coordinateScaling, y + dy))
&& !walkable(temp.setPosition(x + coordinateScaling, y)))
|| (walkable(temp.setPosition(x - coordinateScaling, y + dy))
&& !walkable(temp.setPosition(x - coordinateScaling, y)))) {
return new JPSNode(node);
}
} else { // horizontal, dx = 1 or -1, dy = 0
if ((walkable(temp.setPosition(x + dx, y + coordinateScaling))
&& !walkable(temp.setPosition(x, y + coordinateScaling)))
|| (walkable(temp.setPosition(x + dx, y - coordinateScaling))
&& !walkable(temp.setPosition(x, y - coordinateScaling)))) {
return new JPSNode(node);
}
}
return jump(node.derive(dx, dy), node, goal);
}
