// javascript-astar
// http://github.com/bgrins/javascript-astar
// Freely distributable under the MIT License.
// Includes Binary Heap (with modifications) from Marijn Haverbeke.
// http://eloquentjavascript.net/appendix2.html
// Creates a Graph class used in the astar search algorithm.
function Graph(grid) {
var nodes = [];
var row, rowLength, len = grid.length;
for (y = 0; y <= 15; y++) {
row = grid[y];
nodes[y] = new Array(15);
for (x = 0; x <= 10; x++) {
nodes[x][y] = new GraphNode(x, y, row[x]);
}
}
this.input = grid;
this.nodes = nodes;
}
Graph.prototype.toString = function() {
var graphString = "\n";
var nodes = this.nodes;
var rowDebug, row, y, l;
// console.log("X Length: " + len);
for (var x = 0, len = nodes.length; x < len; x++) {
rowDebug = "";
row = nodes[x];
for (y = 0, l = row.length; y < l; y++) {
rowDebug += row[y].type + " ";
}
graphString = graphString + rowDebug + "\n";
}
return graphString;
};
function GraphNode(x,y,type) {
this.data = { };
this.x = x;
this.y = y;
this.pos = {
x: x,
y: y
};
this.type = type;
}
GraphNode.prototype.toString = function() {
return this.x + "," + this.y;
};
GraphNode.prototype.isWall = function() {
return this.type == GraphNodeType.WALL;
};
function BinaryHeap(scoreFunction){
this.content = [];
this.scoreFunction = scoreFunction;
}
BinaryHeap.prototype = {
push: function(element) {
// Add the new element to the end of the array.
this.content.push(element);
// Allow it to sink down.
this.sinkDown(this.content.length - 1);
},
pop: function() {
// Store the first element so we can return it later.
var result = this.content[0];
// Get the element at the end of the array.
var end = this.content.pop();
// If there are any elements left, put the end element at the
// start, and let it bubble up.
if (this.content.length > 0) {
this.content[0] = end;
this.bubbleUp(0);
}
return result;
},
remove: function(node) {
var i = this.content.indexOf(node);
// When it is found, the process seen in 'pop' is repeated
// to fill up the hole.
var end = this.content.pop();
if (i !== this.content.length - 1) {
this.content[i] = end;
if (this.scoreFunction(end) < this.scoreFunction(node)) {
this.sinkDown(i);
}
else {
this.bubbleUp(i);
}
}
},
size: function() {
return this.content.length;
},
rescoreElement: function(node) {
this.sinkDown(this.content.indexOf(node));
},
sinkDown: function(n) {
// Fetch the element that has to be sunk.
var element = this.content[n];
// When at 0, an element can not sink any further.
while (n > 0) {
// Compute the parent element's index, and fetch it.
var parentN = ((n + 1) >> 1) - 1,
parent = this.content[parentN];
// Swap the elements if the parent is greater.
if (this.scoreFunction(element) < this.scoreFunction(parent)) {
this.content[parentN] = element;
this.content[n] = parent;
// Update 'n' to continue at the new position.
n = parentN;
}
// Found a parent that is less, no need to sink any further.
else {
break;
}
}
},
bubbleUp: function(n) {
// Look up the target element and its score.
var length = this.content.length,
element = this.content[n],
elemScore = this.scoreFunction(element);
while(true) {
// Compute the indices of the child elements.
var child2N = (n + 1) << 1, child1N = child2N - 1;
// This is used to store the new position of the element,
// if any.
var swap = null;
// If the first child exists (is inside the array)...
if (child1N < length) {
// Look it up and compute its score.
var child1 = this.content[child1N],
child1Score = this.scoreFunction(child1);
// If the score is less than our element's, we need to swap.
if (child1Score < elemScore)
swap = child1N;
}
// Do the same checks for the other child.
if (child2N < length) {
var child2 = this.content[child2N],
child2Score = this.scoreFunction(child2);
if (child2Score < (swap === null ? elemScore : child1Score)) {
swap = child2N;
}
}
// If the element needs to be moved, swap it, and continue.
if (swap !== null) {
this.content[n] = this.content[swap];
this.content[swap] = element;
n = swap;
}
// Otherwise, we are done.
else {
break;
}
}
}
};