- <!doctype html>
- <html>
- <head><title>snake</title>
- <script>
- function Snake(canvas){
- this.canvas = canvas;
- this.length = 0;
- this.direction = ‘down‘;
- this.body = [],
- this.head = function(){
- return this.length == 0 ? null : this.body[0];
- };
- this.isAlive = true;
- this.onDie = null;
- this.onEat = null;
- this.speed = 200;
- this.auto = null;
- this.turnLeft = function(){
- if(this.direction == ‘left‘ || this.direction == ‘right‘){
- return;
- }else{
- this.direction = ‘left‘;
- }
- };
- this.turnRight = function(){
- if(this.direction == ‘left‘ || this.direction == ‘right‘){
- return;
- }else{
- this.direction = ‘right‘;
- }
- };
- this.turnUp = function(){
- if(this.direction == ‘up‘ || this.direction == ‘down‘){
- return;
- }else{
- this.direction = ‘up‘;
- }
- };
- this.turnDown = function(){
- if(this.direction == ‘up‘ || this.direction == ‘down‘){
- return;
- }else{
- this.direction = ‘down‘;
- }
- };
- this.moveTo = function(x, y){
- this.canvas.clsCanvas(this);
- this.body.pop();
- this.length--;
- this.grow(x, y);
- this.canvas.drawSnake(this);
- };
- this.grow = function(bX, bY){
- var head = {
- x : bX,
- y : bY
- };
- this.body.unshift(head);
- this.length++;
- };
- this.stepWalk = function(){
- if(!this.isAlive){return;}
- if(!this.head()){
- throw new Error(‘this snake is not initialized‘);
- }
- var nextBlock, head = this.head();
- var nX = head.x, nY = head.y;
- switch(this.direction){
- case ‘down‘:
- nY = head.y + 1;
- break;
- case ‘up‘:
- nY = head.y - 1;
- break;
- case ‘left‘:
- nX = head.x - 1;
- break;
- case ‘right‘:
- nX = head.x + 1;
- break;
- }
- if(nX < 1 || nY < 1 || nX > canvas.width || nY > canvas.height || this.contains(nX, nY)){
- this.isAlive = false;
- if(this.onDie){this.onDie();}
- }else{
- nextBlock = this.canvas.getBlock(nX, nY);
- if(this.canvas.isFoodBlock(nextBlock)){
- nextBlock.setAttribute(‘food‘,‘‘); // the food has been eaten
- this.grow(nX, nY);
- if(this.onEat){this.onEat();}
- var t = this;
- setTimeout(function(){t.stepWalk();},80 );
- }else{
- this.moveTo(nX, nY);
- }
- }
- };
- this.autoWalk = function(){
- var snake = this;
- this.auto = setInterval(function(){
- if(snake.isAlive){
- snake.stepWalk();
- }else{
- clearInterval(snake.auto);
- }
- }, this.speed );
- };
- this.contains = function(x,y){
- var len = this.length, snakeBody = this.body, b;
- for(var i=0;i<len;i++){
- b = snakeBody[i];
- if(b.x == x && b.y == y){
- return true;
- }
- }
- return false;
- };
- this.init = function(length){
- if(length<this.canvas.height){
- for(var i=0; i<length;i++){
- this.grow(1, i+1);
- }
- };
- this.canvas.drawSnake(this);
- this.canvas.createFood();
- },
- this.pause = function(){
- if(this.auto){
- clearInterval(this.auto);
- this.auto = null;
- }
- };
- }
- function SnakeCanvas(div){
- this.target = div;
- this.createView();
- }
- SnakeCanvas.prototype = {
- width: 20,
- height: 16,
- currentSnake : null,
- createView : function(){
- var i = 0, span;
- addClass(this.target, ‘target‘);
- while(i < 320){
- span = document.createElement(‘span‘);
- span.id = ‘span_‘ + (++i);
- addClass(span, ‘blocks‘);
- this.target.appendChild( span );
- }
- },
- getBlock : function(x, y){
- return document.getElementById(‘span_‘ + (y ? ((y-1) * this.width + x) : (x+1)));
- },
- activateBlock : function(block){
- block.setAttribute(‘act‘, ‘true‘);
- addClass(block, ‘snake-body‘);
- },
- inActivateBlock: function(block){
- block.setAttribute(‘act‘, ‘‘);
- removeClass(block, ‘snake-body‘);
- },
- switchBlock: function(block){
- var active = block.getAttribute(‘act‘);
- if(active){
- this.inActivateBlock(block);
- }else{
- this.activateBlock(block);
- }
- },
- isFoodBlock: function(block){
- return !!(block.getAttribute(‘food‘));
- },
- createFood : function(){
- var posX = 0, posY = 0, done = false, block;
- while( !done){
- posX = Math.floor(Math.random() * (this.width + 1));
- posY = Math.floor(Math.random() * (this.height + 1));
- if(posX == 0){ posX = 1;} if(posY == 0){ posY = 1;}
- block = this.getBlock(posX, posY);
- if(!this.currentSnake || (!this.currentSnake.contains(posX, posY))){
- block.setAttribute(‘food‘, ‘true‘);
- this.switchBlock(block);
- done = true;
- }
- }
- },
- clsCanvas : function(snake){
- var snakeBlock, i = 0;
- if(snake){
- for(;i<snake.length;i++){
- snakeBlock = snake.body[i];
- this.inActivateBlock(this.getBlock(snakeBlock.x, snakeBlock.y));
- }
- }else{
- while(i< this.width * this.height){
- this.inActivateBlock(this.getBlock(i));
- }
- }
- },
- drawSnake : function(snake){
- var snakeBlock;
- for(var i=0;i<snake.length;i++){
- snakeBlock = snake.body[i];
- this.activateBlock(this.getBlock(snakeBlock.x, snakeBlock.y));
- }
- this.currentSnake = snake;
- }
- };
- //---------------------------//
- function trim(text){
- var rnotwhite = /\S/,
- // Used for trimming whitespace
- trimLeft = /^\s+/,
- trimRight = /\s+$/;
- // IE doesn‘t match non-breaking spaces with \s
- if ( rnotwhite.test( "\xA0" ) ) {
- trimLeft = /^[\s\xA0]+/;
- trimRight = /[\s\xA0]+$/;
- }
- return text.toString().replace( trimLeft, "" ).replace( trimRight, "" );
- }
- function addClass(elem, className){
- var setClass;
- if ( elem.nodeType === 1 ) {
- if ( !elem.className ) {
- elem.className = className;
- } else {
- setClass = " " + elem.className + " ";
- if ( !~setClass.indexOf( " " + className + " " ) ) {
- setClass += className + " ";
- }
- elem.className = trim(setClass);
- }
- }
- }
- function removeClass(elem, value){
- var className;
- if ( elem.nodeType === 1 && elem.className ) {
- if ( value ) {
- className = (" " + elem.className + " ").replace( /[\n\t\r]/g, " " );
- className = className.replace(" " + value + " ", " ");
- elem.className = trim( className );
- } else {
- elem.className = "";
- }
- }
- }
- function keyDown(e){
- if(!snake || !snake.isAlive) {
- return;
- }
- e=e||window.event;
- var keyCode = e.keyCode||e.which||e.charCode;
- switch(keyCode){
- case 37://左
- snake.turnLeft();
- break;
- case 38://上
- snake.turnUp();
- break;
- case 39://右
- snake.turnRight();
- break;
- case 40://下
- snake.turnDown();
- break;
- case 80://p 暂停or开始
- case 229:
- if(snake.auto){
- snake.pause();
- }else{
- snake.autoWalk();
- }
- break;
- }
- }
- if(document.attachEvent){
- document.attachEvent(‘onkeydown‘, keyDown);
- }else if(document.addEventListener){
- document.addEventListener(‘keydown‘, keyDown, false);
- }
- </script>
- <style>
- div{
- margin: 20px auto;
- }
- .target{
- display:block;
- width: 400px;
- height: 320px;
- border: 1px solid black;
- overflow: hidden;
- }
- .blocks{
- display:block;
- width: 18px;
- height: 18px;
- border: 1px dotted #ddd;
- float:left;
- }
- .snake-body{
- background-color: #111;
- border-style: solid;
- }
- </style>
- </head>
- <body>
- <h1>Snake</h1>
- <div id=‘t‘></div>
- <div>
- 操作提示:按上下左右键操作,按 P 键暂停或继续
- </div>
- <script>
- var canvas = new SnakeCanvas( document.getElementById(‘t‘) );
- var snake = new Snake( canvas );
- snake.onDie = function(){
- alert(‘game over‘);
- };
- snake.onEat = function(){
- snake.canvas.createFood();
- };
- snake.init(3);
- snake.autoWalk();
- // snake.pause();
- </script>
- </html>
时间: 2024-10-09 01:08:10