erosmarcon / astar-js

A* Pathfinder

What is

A javascript implementation of A* path-finding algorithm.

How to setup

<script src="js/AStar.js"></script>

How to use

Create a map passing width and height values (number of cells on each axis)

var graph = new AStarGraph(100, 100);

Define origin and destination coordinates, eg:

var origin      = {x:10, y:20};
var destination = {x:80, y:90};

By default every cell is walkable, to set it as an obstacle change the walkable property:

graph.getCellAt(x, y).walkable = false;

Call the solve function to find the path. You can force it to be orthogonal:

 var solution = graph.solve(origin, destination, orthogonal);

You get a result object with a description property, possible values are:

• AStarGraph.INVALID_DESTINATION
• AStarGraph.NO_PATH
• AStarGraph.TOO_LONG
• AStarGraph.SOLVED

If description is AStarGraph.SOLVED, result has a path property (an array of x and y coordinates):

switch (solution.description) {
    case AStarGraph.INVALID_DESTINATION:
        message = "Destination point is not walkable!"
        break;
    case AStarGraph.NO_PATH:
        message="No walkable path beetween points!"
        break;
    case AStarGraph.TOO_LONG:
        message = "Too many iterations!"
        break;
    case AStarGraph.UNSOLVED:
        message = "Unable to find path"
        break;
    case AStarGraph.SOLVED:
        message = "Path found!";
        if (solution.path != null) {
            message += "(" + solution.path.length + " steps)";
            view.showSolution(solution.path)
        }
        break;
}

Examples

• 2D Example - built with CreateJS
• 3D Example - built with ThreeJS (2D path-finding in a 3D Environment)

Next Steps

Add the third axis to support full 3D path-finding.