use 1 and Math.sqrt(2) for costStraight and costDiagonal, rather than allowing options to be passed in. Issue bgrins#12

Author: bgrins

astar.js

@@ -52,16 +52,14 @@ var astar = {
         options = options || {};
         var heuristic = options.heuristic || astar.manhattan;
         var diagonal = !!options.diagonal;
-        var costDiagonal = options.costDiagonal || 1;
-        var costStraight = options.costStraight || 1;
         var closest = options.closest || false;
 
         var openHeap = astar.heap();
 
         // set the start node to be the closest if required
         var closestNode = start;
 
-        start.h = heuristic(start.pos, end.pos, costStraight, costDiagonal);
+        start.h = heuristic(start.pos, end.pos);
 
         function pathTo(node){
             var curr = node;
@@ -110,7 +108,7 @@ var astar = {
                     // Found an optimal (so far) path to this node.  Take score for node to see how good it is.
                     neighbor.visited = true;
                     neighbor.parent = currentNode;
-                    neighbor.h = neighbor.h || heuristic(neighbor.pos, end.pos, costStraight, costDiagonal);
+                    neighbor.h = neighbor.h || heuristic(neighbor.pos, end.pos);
                     neighbor.g = gScore;
                     neighbor.f = neighbor.g + neighbor.h;
 
@@ -150,10 +148,12 @@ var astar = {
         var d2 = Math.abs (pos1.y - pos0.y);
         return d1 + d2;
     },
-    diagonal: function(pos0, pos1, D, D2) {
-      var d1 = Math.abs (pos1.x - pos0.x);
-      var d2 = Math.abs (pos1.y - pos0.y);
-      return (D * (d1 + d2)) + ((D2 - (2 * D)) * Math.min(d1, d2));
+    diagonal: function(pos0, pos1) {
+        var D = 1;
+        var D2 = Math.sqrt(2);
+        var d1 = Math.abs (pos1.x - pos0.x);
+        var d2 = Math.abs (pos1.y - pos0.y);
+        return (D * (d1 + d2)) + ((D2 - (2 * D)) * Math.min(d1, d2));
     },
     neighbors: function(grid, node, diagonals) {
         var ret = [];