gistfile1.js

// world is a 2d array of integers (eg world[10][15] = 0)
// pathStart and pathEnd are arrays like [5,10]
function findPath(world, pathStart, pathEnd)
{
  // shortcuts for speed
	var	abs = Math.abs;
	var	max = Math.max;
	var	pow = Math.pow;
	var	sqrt = Math.sqrt;

	// the world data are integers:
	// anything higher than this number is considered blocked
	// this is handy is you use numbered sprites, more than one
	// of which is walkable road, grass, mud, etc
	var maxWalkableTileNum = 0;

	// keep track of the world dimensions
	// Note that this A-star implementation expects the world array to be square: 
	// it must have equal height and width. If your game world is rectangular, 
	// just fill the array with dummy values to pad the empty space.
	var worldWidth = world[0].length;
	var worldHeight = world.length;
	var worldSize =	worldWidth * worldHeight;

	// which heuristic should we use?
	// default: no diagonals (Manhattan)
	var distanceFunction = ManhattanDistance;
	var findNeighbours = function(){}; // empty

	/*

	// alternate heuristics, depending on your game:

	// diagonals allowed but no sqeezing through cracks:
	var distanceFunction = DiagonalDistance;
	var findNeighbours = DiagonalNeighbours;

	// diagonals and squeezing through cracks allowed:
	var distanceFunction = DiagonalDistance;
	var findNeighbours = DiagonalNeighboursFree;

	// euclidean but no squeezing through cracks:
	var distanceFunction = EuclideanDistance;
	var findNeighbours = DiagonalNeighbours;

	// euclidean and squeezing through cracks allowed:
	var distanceFunction = EuclideanDistance;
	var findNeighbours = DiagonalNeighboursFree;

	*/