Working on pathfinding
This commit is contained in:
555
moonlight/js/easystar-0.1.8.js
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555
moonlight/js/easystar-0.1.8.js
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//For require.js
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if (typeof define === "function" && define.amd) {
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define("easystar", [], function() {
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return EasyStar;
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});
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}
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//For browserify and node.js
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if (typeof module !== 'undefined' && module.exports) {
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module.exports = EasyStar;
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}
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//NameSpace
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var EasyStar = EasyStar || {};
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/**
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* A simple Node that represents a single tile on the grid.
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* @param {Object} parent The parent node.
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* @param {Number} x The x position on the grid.
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* @param {Number} y The y position on the grid.
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* @param {Number} costSoFar How far this node is in moves*cost from the start.
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* @param {Number} simpleDistanceToTarget Manhatten distance to the end point.
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**/
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EasyStar.Node = function(parent, x, y, costSoFar, simpleDistanceToTarget) {
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this.parent = parent;
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this.x = x;
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this.y = y;
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this.costSoFar = costSoFar;
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this.simpleDistanceToTarget = simpleDistanceToTarget;
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/**
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* @return {Number} Best guess distance of a cost using this node.
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**/
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this.bestGuessDistance = function() {
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return this.costSoFar + this.simpleDistanceToTarget;
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}
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};
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//Constants
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EasyStar.Node.OPEN_LIST = 0;
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EasyStar.Node.CLOSED_LIST = 1;
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/**
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* This is an improved Priority Queue data type implementation that can be used to sort any object type.
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* It uses a technique called a binary heap.
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*
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* For more on binary heaps see: http://en.wikipedia.org/wiki/Binary_heap
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*
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* @param {String} criteria The criteria by which to sort the objects.
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* This should be a property of the objects you're sorting.
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*
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* @param {Number} heapType either PriorityQueue.MAX_HEAP or PriorityQueue.MIN_HEAP.
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**/
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EasyStar.PriorityQueue = function(criteria,heapType) {
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this.length = 0; //The current length of heap.
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var queue = [];
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var isMax = false;
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//Constructor
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if (heapType==EasyStar.PriorityQueue.MAX_HEAP) {
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isMax = true;
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} else if (heapType==EasyStar.PriorityQueue.MIN_HEAP) {
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isMax = false;
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} else {
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throw heapType + " not supported.";
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}
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/**
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* Inserts the value into the heap and sorts it.
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*
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* @param value The object to insert into the heap.
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**/
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this.insert = function(value) {
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if (!value.hasOwnProperty(criteria)) {
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throw "Cannot insert " + value + " because it does not have a property by the name of " + criteria + ".";
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}
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queue.push(value);
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this.length++;
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bubbleUp(this.length-1);
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}
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/**
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* Peeks at the highest priority element.
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*
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* @return the highest priority element
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**/
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this.getHighestPriorityElement = function() {
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return queue[0];
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}
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/**
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* Removes and returns the highest priority element from the queue.
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*
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* @return the highest priority element
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**/
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this.shiftHighestPriorityElement = function() {
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if (this.length === 0) {
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throw ("There are no more elements in your priority queue.");
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} else if (this.length === 1) {
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var onlyValue = queue[0];
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queue = [];
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this.length = 0;
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return onlyValue;
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}
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var oldRoot = queue[0];
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var newRoot = queue.pop();
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this.length--;
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queue[0] = newRoot;
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swapUntilQueueIsCorrect(0);
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return oldRoot;
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}
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var bubbleUp = function(index) {
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if (index===0) {
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return;
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}
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var parent = getParentOf(index);
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if (evaluate(index,parent)) {
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swap(index,parent);
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bubbleUp(parent);
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} else {
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return;
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}
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}
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var swapUntilQueueIsCorrect = function(value) {
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var left = getLeftOf(value);
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var right = getRightOf(value);
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if (evaluate(left,value)) {
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swap(value,left);
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swapUntilQueueIsCorrect(left);
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} else if (evaluate(right,value)) {
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swap(value,right);
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swapUntilQueueIsCorrect(right);
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} else if (value==0) {
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return;
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} else {
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swapUntilQueueIsCorrect(0);
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}
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}
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var swap = function(self,target) {
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var placeHolder = queue[self];
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queue[self] = queue[target];
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queue[target] = placeHolder;
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}
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var evaluate = function(self,target) {
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if (queue[target]===undefined||queue[self]===undefined) {
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return false;
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}
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var selfValue;
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var targetValue;
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//Check if the criteria should be the result of a function call.
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if (typeof queue[self][criteria] === 'function') {
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selfValue = queue[self][criteria]();
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targetValue = queue[target][criteria]();
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} else {
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selfValue = queue[self][criteria];
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targetValue = queue[target][criteria];
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}
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if (isMax) {
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if (selfValue > targetValue) {
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return true;
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} else {
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return false;
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}
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} else {
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if (selfValue < targetValue) {
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return true;
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} else {
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return false;
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}
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}
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}
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var getParentOf = function(index) {
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return Math.floor(index/2)-1;
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}
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var getLeftOf = function(index) {
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return index*2 + 1;
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}
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var getRightOf = function(index) {
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return index*2 + 2;
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}
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};
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//Constants
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EasyStar.PriorityQueue.MAX_HEAP = 0;
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EasyStar.PriorityQueue.MIN_HEAP = 1;
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/**
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* Represents a single instance of EasyStar.
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* A path that is in the queue to eventually be found.
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*/
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EasyStar.instance = function() {
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this.isDoneCalculating = true;
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this.pointsToAvoid = {};
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this.startX;
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this.callback;
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this.startY;
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this.endX;
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this.endY;
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this.nodeHash = {};
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this.openList;
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};
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/**
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* EasyStar.js
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* github.com/prettymuchbryce/EasyStarJS
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* Licensed under the MIT license.
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*
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* Implementation By Bryce Neal (@prettymuchbryce)
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**/
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EasyStar.js = function() {
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var STRAIGHT_COST = 10;
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var DIAGONAL_COST = 14;
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var pointsToAvoid = {};
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var collisionGrid;
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var costMap = {};
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var iterationsSoFar;
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var instances = [];
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var iterationsPerCalculation = Number.MAX_VALUE;
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var acceptableTiles;
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var diagonalsEnabled = false;
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/**
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* Sets the collision grid that EasyStar uses.
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*
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* @param {Array|Number} tiles An array of numbers that represent
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* which tiles in your grid should be considered
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* acceptable, or "walkable".
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**/
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this.setAcceptableTiles = function(tiles) {
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if (tiles instanceof Array) {
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//Array
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acceptableTiles = tiles;
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} else if (!isNaN(parseFloat(tiles)) && isFinite(tiles)) {
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//Number
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acceptableTiles = [tiles];
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}
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};
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/**
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* Enable diagonal pathfinding.
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*/
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this.enableDiagonals = function() {
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diagonalsEnabled = true;
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}
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/**
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* Disable diagonal pathfinding.
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*/
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this.disableDiagonals = function() {
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diagonalsEnabled = false;
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}
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/**
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* Sets the collision grid that EasyStar uses.
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*
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* @param {Array} grid The collision grid that this EasyStar instance will read from.
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* This should be a 2D Array of Numbers.
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**/
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this.setGrid = function(grid) {
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collisionGrid = grid;
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//Setup cost map
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for (var y = 0; y < collisionGrid.length; y++) {
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for (var x = 0; x < collisionGrid[0].length; x++) {
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if (!costMap[collisionGrid[y][x]]) {
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costMap[collisionGrid[y][x]] = 1
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}
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}
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}
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};
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/**
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* Sets the tile cost for a particular tile type.
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*
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* @param {Number} The tile type to set the cost for.
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* @param {Number} The multiplicative cost associated with the given tile.
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**/
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this.setTileCost = function(tileType, cost) {
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costMap[tileType] = cost;
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};
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/**
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* Sets the number of search iterations per calculation.
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* A lower number provides a slower result, but more practical if you
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* have a large tile-map and don't want to block your thread while
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* finding a path.
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*
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* @param {Number} iterations The number of searches to prefrom per calculate() call.
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**/
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this.setIterationsPerCalculation = function(iterations) {
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iterationsPerCalculation = iterations;
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};
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/**
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* Avoid a particular point on the grid,
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* regardless of whether or not it is an acceptable tile.
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*
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* @param {Number} x The x value of the point to avoid.
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* @param {Number} y The y value of the point to avoid.
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**/
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this.avoidAdditionalPoint = function(x, y) {
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pointsToAvoid[x + "_" + y] = 1;
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};
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/**
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* Stop avoiding a particular point on the grid.
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*
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* @param {Number} x The x value of the point to stop avoiding.
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* @param {Number} y The y value of the point to stop avoiding.
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**/
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this.stopAvoidingAdditionalPoint = function(x, y) {
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delete pointsToAvoid[x + "_" + y];
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};
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/**
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* Stop avoiding all additional points on the grid.
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**/
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this.stopAvoidingAllAdditionalPoints = function() {
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pointsToAvoid = {};
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};
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/**
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* Find a path.
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*
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* @param {Number} startX The X position of the starting point.
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* @param {Number} startY The Y position of the starting point.
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* @param {Number} endX The X position of the ending point.
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* @param {Number} endY The Y position of the ending point.
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* @param {Function} callback A function that is called when your path
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* is found, or no path is found.
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*
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**/
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this.findPath = function(startX, startY ,endX, endY, callback) {
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//No acceptable tiles were set
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if (acceptableTiles === undefined) {
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throw "You can't set a path without first calling setAcceptableTiles() on EasyStar.";
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}
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//No grid was set
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if (collisionGrid === undefined) {
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throw "You can't set a path without first calling setGrid() on EasyStar.";
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}
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//Start or endpoint outside of scope.
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if (startX < 0 || startY < 0 || endX < 0 || endX < 0 ||
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startX > collisionGrid[0].length-1 || startY > collisionGrid.length-1 ||
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endX > collisionGrid[0].length-1 || endY > collisionGrid.length-1) {
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throw "Your start or end point is outside the scope of your grid.";
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}
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//Start and end are the same tile.
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if (startX===endX && startY===endY) {
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callback([]);
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}
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//End point is not an acceptable tile.
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var endTile = collisionGrid[endY][endX];
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var isAcceptable = false;
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for (var i = 0; i < acceptableTiles.length; i++) {
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if (endTile === acceptableTiles[i]) {
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isAcceptable = true;
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break;
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}
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}
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if (isAcceptable === false) {
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callback(null);
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return;
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}
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//Create the instance
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var instance = new EasyStar.instance();
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instance.openList = new EasyStar.PriorityQueue("bestGuessDistance",EasyStar.PriorityQueue.MIN_HEAP);
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instance.isDoneCalculating = false;
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instance.nodeHash = {};
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instance.startX = startX;
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instance.startY = startY;
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instance.endX = endX;
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instance.endY = endY;
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instance.callback = callback;
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instance.openList.insert(coordinateToNode(instance, instance.startX,
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instance.startY, null, STRAIGHT_COST));
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instances.push(instance);
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};
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/**
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* This method steps through the A* Algorithm in an attempt to
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* find your path(s). It will search 4 tiles for every calculation.
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* You can change the number of calculations done in a call by using
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* easystar.setIteratonsPerCalculation().
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**/
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this.calculate = function() {
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if (instances.length === 0 || collisionGrid === undefined || acceptableTiles === undefined) {
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return;
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}
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for (iterationsSoFar = 0; iterationsSoFar < iterationsPerCalculation; iterationsSoFar++) {
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if (instances.length === 0) {
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return;
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}
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//Couldn't find a path.
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if (instances[0].openList.length===0) {
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instances[0].callback(null);
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instances.shift();
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continue;
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}
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var searchNode = instances[0].openList.shiftHighestPriorityElement();
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searchNode.list = EasyStar.Node.CLOSED_LIST;
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if (searchNode.y > 0) {
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checkAdjacentNode(instances[0], searchNode, 0, -1, STRAIGHT_COST *
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costMap[collisionGrid[searchNode.y-1][searchNode.x]]);
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if (instances[0].isDoneCalculating===true) {
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instances.shift();
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continue;
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}
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}
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if (searchNode.x < collisionGrid[0].length-1) {
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checkAdjacentNode(instances[0], searchNode, 1, 0, STRAIGHT_COST *
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costMap[collisionGrid[searchNode.y][searchNode.x+1]]);
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if (instances[0].isDoneCalculating===true) {
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instances.shift();
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continue;
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}
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}
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if (searchNode.y < collisionGrid.length-1) {
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checkAdjacentNode(instances[0], searchNode, 0, 1, STRAIGHT_COST *
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costMap[collisionGrid[searchNode.y+1][searchNode.x]]);
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if (instances[0].isDoneCalculating===true) {
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instances.shift();
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continue;
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}
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}
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if (searchNode.x > 0) {
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checkAdjacentNode(instances[0], searchNode, -1, 0, STRAIGHT_COST *
|
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costMap[collisionGrid[searchNode.y][searchNode.x-1]]);
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if (instances[0].isDoneCalculating===true) {
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instances.shift();
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continue;
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}
|
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}
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if (diagonalsEnabled) {
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if (searchNode.x > 0 && searchNode.y > 0) {
|
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checkAdjacentNode(instances[0], searchNode, -1, -1, DIAGONAL_COST *
|
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costMap[collisionGrid[searchNode.y-1][searchNode.x-1]]);
|
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if (instances[0].isDoneCalculating===true) {
|
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instances.shift();
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continue;
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}
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}
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if (searchNode.x < collisionGrid[0].length-1 && searchNode.y < collisionGrid.length-1) {
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checkAdjacentNode(instances[0], searchNode, 1, 1, DIAGONAL_COST *
|
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costMap[collisionGrid[searchNode.y+1][searchNode.x+1]]);
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if (instances[0].isDoneCalculating===true) {
|
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instances.shift();
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continue;
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||||
}
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||||
}
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if (searchNode.x < collisionGrid[0].length-1 && searchNode.y > 0) {
|
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checkAdjacentNode(instances[0], searchNode, 1, -1, DIAGONAL_COST *
|
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costMap[collisionGrid[searchNode.y-1][searchNode.x+1]]);
|
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if (instances[0].isDoneCalculating===true) {
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instances.shift();
|
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continue;
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||||
}
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}
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if (searchNode.x > 0 && searchNode.y < collisionGrid.length-1) {
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checkAdjacentNode(instances[0], searchNode, -1, 1, DIAGONAL_COST *
|
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costMap[collisionGrid[searchNode.y+1][searchNode.x-1]]);
|
||||
if (instances[0].isDoneCalculating===true) {
|
||||
instances.shift();
|
||||
continue;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
//Private methods follow
|
||||
|
||||
var checkAdjacentNode = function(instance, searchNode, x, y, cost) {
|
||||
var adjacentCoordinateX = searchNode.x+x;
|
||||
var adjacentCoordinateY = searchNode.y+y;
|
||||
|
||||
if (instance.endX === adjacentCoordinateX && instance.endY === adjacentCoordinateY) {
|
||||
instance.isDoneCalculating = true;
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||||
var path = [];
|
||||
var pathLen = 0;
|
||||
path[pathLen] = {x: adjacentCoordinateX, y: adjacentCoordinateY};
|
||||
pathLen++;
|
||||
path[pathLen] = {x: searchNode.x, y:searchNode.y};
|
||||
pathLen++;
|
||||
var parent = searchNode.parent;
|
||||
while (parent!=null) {
|
||||
path[pathLen] = {x: parent.x, y:parent.y};
|
||||
pathLen++;
|
||||
parent = parent.parent;
|
||||
}
|
||||
path.reverse();
|
||||
instance.callback(path);
|
||||
}
|
||||
|
||||
if (pointsToAvoid[adjacentCoordinateX + "_" + adjacentCoordinateY] === undefined) {
|
||||
for (var i = 0; i < acceptableTiles.length; i++) {
|
||||
if (collisionGrid[adjacentCoordinateY][adjacentCoordinateX] === acceptableTiles[i]) {
|
||||
|
||||
var node = coordinateToNode(instance, adjacentCoordinateX,
|
||||
adjacentCoordinateY, searchNode, cost);
|
||||
|
||||
if (node.list === undefined) {
|
||||
node.list = EasyStar.Node.OPEN_LIST;
|
||||
instance.openList.insert(node);
|
||||
} else if (node.list === EasyStar.Node.OPEN_LIST) {
|
||||
if (searchNode.costSoFar + cost < node.costSoFar) {
|
||||
node.costSoFar = searchNode.costSoFar + cost;
|
||||
node.parent = searchNode;
|
||||
}
|
||||
}
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
};
|
||||
|
||||
//Helpers
|
||||
|
||||
var coordinateToNode = function(instance, x, y, parent, cost) {
|
||||
if (instance.nodeHash[x + "_" + y]!==undefined) {
|
||||
return instance.nodeHash[x + "_" + y];
|
||||
}
|
||||
var simpleDistanceToTarget = getDistance(x, y, instance.endX, instance.endY);
|
||||
if (parent!==null) {
|
||||
var costSoFar = parent.costSoFar + cost;
|
||||
} else {
|
||||
costSoFar = simpleDistanceToTarget;
|
||||
}
|
||||
var node = new EasyStar.Node(parent,x,y,costSoFar,simpleDistanceToTarget);
|
||||
instance.nodeHash[x + "_" + y] = node;
|
||||
return node;
|
||||
};
|
||||
|
||||
var getDistance = function(x1,y1,x2,y2) {
|
||||
return Math.sqrt(Math.abs(x2-x1)*Math.abs(x2-x1) + Math.abs(y2-y1)*Math.abs(y2-y1)) * STRAIGHT_COST;
|
||||
};
|
||||
}
|
||||
Reference in New Issue
Block a user