Init
This commit is contained in:
commit
de18c904c4
471
a-star.js
Normal file
471
a-star.js
Normal file
@ -0,0 +1,471 @@
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class Position
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{
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constructor(x, y)
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{
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this.x = x;
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this.y = y;
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}
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getDistance(position, test)
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{
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return Math.sqrt(Math.pow(position.x - this.x, 2) + Math.pow(position.y - this.y, 2));
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}
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}
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class Node
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{
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constructor(x, y)
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{
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this.position = new Position(x, y);
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this.g_cost = null;
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this.h_cost = null;
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this.f_cost = null;
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this.previous = null;
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this.isTraversable = true;
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}
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}
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class Map
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{
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constructor(width, height)
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{
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this.width = width;
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this.height = height;
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this.nodes = [];
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this.startNode = null;
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this.targetNode = null;
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this._initialize();
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}
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_initialize()
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{
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for (let y = 0; y < this.height; y++) {
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let nodes = [];
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for (let x = 0; x < this.width; x++) {
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nodes.push(new Node(x, y));
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}
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this.nodes.push(nodes);
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}
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}
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getNodeAt(x, y)
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{
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return this.nodes[y][x];
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}
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getNeighbours(node, allowDiagonals = false)
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{
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let positions = [
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new Position(node.position.x - 1, node.position.y),
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new Position(node.position.x + 1, node.position.y),
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new Position(node.position.x, node.position.y - 1),
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new Position(node.position.x, node.position.y + 1),
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];
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if (allowDiagonals) {
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positions = positions.concat(
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[
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new Position(node.position.x - 1, node.position.y - 1),
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new Position(node.position.x + 1, node.position.y - 1),
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new Position(node.position.x - 1, node.position.y + 1),
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new Position(node.position.x + 1, node.position.y + 1),
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]
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);
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}
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const neighbours = [];
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for (const position of positions) {
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if (position.x < 0 || position.x >= this.width || position.y < 0 || position.y >= this.height) {
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continue;
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}
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neighbours.push(this.getNodeAt(position.x, position.y));
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}
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return neighbours;
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}
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draw(canvas, unitWidth, unitHeight) {
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canvas.width = this.width * unitWidth;
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canvas.height = this.height * unitHeight;
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const context = canvas.getContext('2d');
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for (let y = 0; y < this.height; y++) {
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for (let x = 0; x < this.width; x++) {
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this.drawNode(x, y, this.getNodeAt(x, y).isTraversable ? COLOR_GROUND : COLOR_WALL, canvas);
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}
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}
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}
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drawNode(x, y, color, canvas)
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{
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const context = canvas.getContext('2d');
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const unitWidth = canvas.width / this.width;
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const unitHeight = canvas.height / this.height;
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context.fillStyle = color;
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context.fillRect(x * unitWidth, y * unitHeight, unitWidth, unitHeight);
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}
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static loadFromLayout(layout)
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{
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const width = layout[0].length;
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const height = layout.length;
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const map = new Map(width, height);
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for (let y = 0; y < height; y++) {
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for (let x = 0; x < width; x++) {
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switch (layout[y].substr(x, 1)) {
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case '#':
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map.getNodeAt(x, y).isTraversable = false;
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break;
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case ' ':
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map.getNodeAt(x, y).isTraversable = true;
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break;
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case 'S':
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map.startNode = map.getNodeAt(x, y);
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map.startNode.isTraversable = true;
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break;
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case 'T':
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map.targetNode = map.getNodeAt(x, y);
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map.targetNode.isTraversable = true;
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break;
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}
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}
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}
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return map;
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}
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}
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class Pathfinder
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{
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constructor(map)
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{
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this.map = map;
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this.open = [];
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this.closed = [];
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this.paths = {};
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}
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calculatePath(positionStart, positionTarget)
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{
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this.open.push(this.map.getNodeAt(positionStart.x, positionStart.y));
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let count = 0;
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while (this.open.length > 0) {
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count++;
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if (count > 1000) {
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alert('Path could not be calculated!');
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return;
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}
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let current = this._getCheapestNode(this.open);
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this._removeNodeFromOpen(current);
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this.closed.push(current);
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if (current.position.x === positionTarget.x && current.position.y === positionTarget.y) {
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break;
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}
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for (const neighbour of this.map.getNeighbours(current)) {
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if (!neighbour.isTraversable || this.closed.indexOf(neighbour) > -1) {
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continue;
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}
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const is_inside_open = this.open.indexOf(neighbour) > -1;
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const g_cost = neighbour.position.getDistance(positionStart) * 10;
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const h_cost = neighbour.position.getDistance(positionTarget) * 10;
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const f_cost = g_cost + h_cost;
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if (!is_inside_open) {
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neighbour.g_cost = g_cost;
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neighbour.h_cost = h_cost;
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neighbour.f_cost = f_cost;
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neighbour.previous = current;
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}
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if (!is_inside_open || current.position.getDistance(neighbour.position) < neighbour.position.getDistance(neighbour.previous.position)) {
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neighbour.f_cost = f_cost;
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neighbour.previous = current;
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if (!is_inside_open) {
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this.open.push(neighbour);
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}
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}
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}
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}
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}
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getPath(positionStart, positionTarget)
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{
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this.map.startNode = this.map.getNodeAt(positionStart.x, positionStart.y);
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this.map.targetNode = this.map.getNodeAt(positionTarget.x, positionTarget.y);
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let path = [];
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if (!this.map.getNodeAt(positionTarget.x, positionTarget.y).isTraversable) {
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return path;
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}
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this.calculatePath(positionStart, positionTarget);
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let targetNode = null;
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for (const node of this.closed) {
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if (node.position.x == positionTarget.x && node.position.y == positionTarget.y) {
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targetNode = node;
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break;
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}
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}
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let node = targetNode;
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while (node !== null) {
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path = [node].concat(path);
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node = node.previous;
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}
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return path;
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}
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reset()
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{
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this.open = [];
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this.closed = [];
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for (const node of this.map.nodes) {
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node.g_cost = null;
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node.h_cost = null;
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node.f_cost = null;
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node.previous = null;
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}
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this.map.startNode = null;
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this.map.targetNode = null;
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}
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_getCheapestNode(nodes)
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{
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let cheapest = nodes[0];
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for (const node of nodes) {
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if (node.f_cost < cheapest.f_cost || (node.f_cost == cheapest.f_cost && node.h_cost < cheapest.h_cost)) {
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cheapest = node;
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}
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}
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return cheapest;
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}
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_removeNodeFromOpen(node)
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{
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const index = this.open.indexOf(node);
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if (index === -1) {
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return;
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}
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this.open = this.open.slice(0, index).concat(this.open.slice(index + 1));
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}
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}
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class Player
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{
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constructor(x, y)
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{
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this.x = x;
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this.y = y;
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this.speed = 0.5;
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this.color = '#ff0000';
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}
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draw(canvas, color = this.color)
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{
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const context = canvas.getContext('2d');
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const width = canvas.width / GRID_WIDTH;
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const height = canvas.height / GRID_HEIGHT;
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context.fillStyle = color;
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context.fillRect(this.x * GRID_WIDTH, this.y * GRID_HEIGHT, GRID_WIDTH, GRID_HEIGHT);
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}
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}
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function calculateRoute(start, target)
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{
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const map = Map.loadFromLayout(layout);
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const canvas = document.getElementById('canvas');
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if (!map.getNodeAt(target.x, target.y).isTraversable) {
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return [];
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}
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map.draw(canvas, GRID_WIDTH, GRID_HEIGHT);
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const pathfinder = new Pathfinder(map);
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const path = pathfinder.getPath(start, target);
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/*
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for (const node of path) {
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map.drawNode(node.position.x, node.position.y, '#ffff00', canvas);
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}
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*/
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return path;
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}
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function movePlayerTo(player, x, y, canvas)
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{
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const deltaX = x - player.x;
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const deltaY = y - player.y;
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player.draw(canvas, COLOR_GROUND);
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if (x !== player.x) {
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player.x += deltaX > 0 ? player.speed : -player.speed;
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if (deltaX < 0.1 && deltaX > -0.1) {
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player.x = x;
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}
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}
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if (y !== player.y) {
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player.y += deltaY > 0 ? player.speed : -player.speed;
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if (deltaY < 0.1 && deltaY > -0.1) {
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player.y = y;
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}
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}
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player.draw(canvas);
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}
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function movePlayerRoute(player, route, canvas)
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{
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let index = 1;
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const interval = setInterval(
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() => {
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movePlayerTo(player, route[index].position.x, route[index].position.y, canvas);
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if (route[index].position.x === player.x && route[index].position.y === player.y) {
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index++;
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}
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if (index === route.length) {
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clearInterval(interval);
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oldTarget = route[route.length - 1];
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isTargeting = false;
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}
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},
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20
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);
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}
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function update()
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{
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map.draw(canvas, GRID_WIDTH, GRID_HEIGHT);
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player.draw(canvas);
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}
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const layout = [
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' ##########################',
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' S # # # # #',
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' # ###### # # ####### # #',
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' # # # ##### #',
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' # #### # # ####### # #',
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' # # # # # ##### # #',
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' # # #### # # ### # # # #',
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' # # # # # # # # # #',
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' # ###### # ### # # # # # #',
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' # # # # # # #',
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'###################### # ##### #',
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'# # # # # # # ',
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'# # # # # ## # # # ##### # ',
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'# # # # # # # # # ',
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'# ##### ## ##### ##### # # ',
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'# # # # # # ',
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'##### ###### # ######### # ',
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'# # # ',
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'########################## '
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];
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const GRID_WIDTH = 40;
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const GRID_HEIGHT = GRID_WIDTH;
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const COLOR_WALL = '#aaaaaa';
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const COLOR_GROUND = '#005500';
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const map = Map.loadFromLayout(layout);
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const canvas = document.getElementById('canvas');
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let oldTarget = map.startNode.position;
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let isTargeting = false;
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const player = new Player(oldTarget.x, oldTarget.y);
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canvas.addEventListener(
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'click',
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(event) => {
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if (isTargeting) {
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return;
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}
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isTargeting = true;
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const rect = canvas.getBoundingClientRect();
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const x = parseInt((event.clientX - rect.x) / GRID_WIDTH);
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const y = parseInt((event.clientY - rect.y) / GRID_HEIGHT);
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if (player.x === x && player.y === y) {
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isTargeting = false;
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return;
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}
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const target = new Position(x, y);
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const route = calculateRoute(new Position(player.x, player.y), new Position(x, y));
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if (route.length > 1) {
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movePlayerRoute(player, route, canvas);
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} else {
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isTargeting = false;
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}
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}
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);
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const picker = document.getElementById('color-picker')
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picker.value = player.color;
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picker.addEventListener(
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'input',
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(event) => {
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player.color = event.target.value;
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update();
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}
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);
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update();
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33
index.html
Normal file
33
index.html
Normal file
@ -0,0 +1,33 @@
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<!DOCTYPE html>
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<html lang="de">
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<head>
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<style>
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html {
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height: 100%;
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}
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body {
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background-color: black;
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min-height: 100%;
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padding: 0;
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margin: 0;
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display: flex;
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flex-flow: column wrap;
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justify-content: center;
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align-items: center;
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}
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#color-picker {
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width: 100%;
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}
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</style>
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<script defer src="a-star.js"></script>
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</head>
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<body>
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<div id="app">
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<canvas id="canvas"></canvas>
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<div id="bar"><input id="color-picker" type="color"></div>
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</div>
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</body>
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</html>
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Loading…
Reference in New Issue
Block a user