之前在当耐特的DEMO里看到个打飞机的游戏,然后就把他的图片和音频扒了了下来。。。。自己凭着玩的心情重新写了一个。仅供娱乐哈。。。。。。我没有用框架,所有js都是自己写的。。。。。。所以就可以来当个简单的教程,对那些刚玩canvas的,或许能有些帮助,楼主玩canvas也不是很久,技术不是很好,请见谅哈。
闲话不多说,先上DEMO撒:飞机游戏 楼主写这个人纯碎娱乐,没想着写成多正式的游戏哈。
步入主题啦:打飞机游戏文件有index.html入口文件,allSprite.js精灵的逻辑处理文件,loading.js加载处理文件以及data.js(初始化的一些数据)。
  首先,正常的游戏基本上都需要一个loading,loading页面就是用来预加载数据的,包括精灵表图片,音频等,因为这是个小游戏,要加载的就只有一些音频和图片。里面的加载代码主要就下面这些,其他是制作loading动画的,那个比较简单,就不贴了,如果有兴趣的直接在DEMO里看控制台就行了:
- loadImg:function(datas){
 - var _this = this;
 - var dataIndex = 0;
 - li();
 - function li(){
 - if(datas[dataIndex].indexOf("mp3")>=0){
 - var audio = document.createElement("audio");
 - document.body.appendChild(audio);
 - audio.preload = "auto";
 - audio.src = datas[dataIndex];
 - audio.oncanplaythrough = function(){
 - this.oncanplaythrough = null;
 - dataIndex++;
 - if(dataIndex===datas.length){
 - _this.percent = 100;
 - }else {
 - _this.percent = parseInt(dataIndex/datas.length*100);
 - li.call(_this);
 - }
 - }
 - }else {
 - preLoadImg(datas[dataIndex] , function(){
 - dataIndex++;
 - if(dataIndex===datas.length){
 - _this.percent = 100;
 - } else {
 - _this.percent = parseInt(dataIndex/datas.length*100);
 - li.call(_this);
 - }
 - })
 - }
 - }
 - },
 - //再贴出preLoadImg的方法
 - function preLoadImg(src , callback){
 - var img = new Image();
 - img.src = src;
 - if(img.complete){
 - callback.call(img);
 - }else {
 - img.onload = function(){
 - callback.call(img);
 - }
 - }
 - }
 
我先在data.js里面用一个数组保存文件的链接,然后判断这些链接是图片还是音频,如果是图片就用preLoadImg加载,预加载图片的代码很简单,就是new一个图片对象,然后把链接赋给它,加载完后再回调。音频的加载则是通过生成一个HTML5的audio dom对象,把链接赋给它,audio有一个事件“canplaythrough”,浏览器预计能够在不停下来进行缓冲的情况下持续播放指定的音频/视频时,会发生 canplaythrough 事件,也就是说当canplaythrough被调用时,音频就已经被加载的差不多了,可以进行下一个音频的加载了。就这样当把所有东西都加载完后,再进行回调,开始游戏。
  游戏开始了,一个游戏,会需要很多的对象,所以我就统一写成了一个精灵对象,不同对象之间的每一帧的运动情况直接用behavior来分别编写就行了。
- W.Sprite = function(name , painter , behaviors , args){
 - if(name !== undefined) this.name = name;
 - if(painter !== undefined) this.painter = painter;
 - this.top = 0;
 - this.left = 0;
 - this.width = 0;
 - this.height = 0;
 - this.velocityX = 3;
 - this.velocityY = 2;
 - this.visible = true;
 - this.animating = false;
 - this.behaviors = behaviors;
 - this.rotateAngle = 0;
 - this.blood = 50;
 - this.fullBlood = 50;
 - if(name==="plan"){
 - this.rotateSpeed = 0.05;
 - this.rotateLeft = false;
 - this.rotateRight = false;
 - this.fire = false;
 - this.firePerFrame = 10;
 - this.fireLevel = 1;
 - }else if(name==="star"){
 - this.width = Math.random()*2;
 - this.speed = 1*this.width/2;
 - this.lightLength = 5;
 - this.cacheCanvas = document.createElement("canvas");
 - thisthis.cacheCtx = this.cacheCanvas.getContext('2d');
 - thisthis.cacheCanvas.width = this.width+this.lightLength*2;
 - thisthis.cacheCanvas.height = this.width+this.lightLength*2;
 - this.painter.cache(this);
 - }else if(name==="badPlan"){
 - this.badKind = 1;
 - this.speed = 2;
 - this.rotateAngle = Math.PI;
 - }else if(name==="missle"){
 - this.width = missleWidth;
 - }else if(name==="boom"){
 - this.width = boomWidth;
 - }else if(name==="food"){
 - this.width = 40;
 - this.speed = 3;
 - this.kind = "LevelUP"
 - }
 - this.toLeft = false;
 - this.toTop = false;
 - this.toRight = false;
 - this.toBottom = false;
 - this.outArcRadius = Math.sqrt((this.width/2*this.width/2)*2);
 - if(args){
 - for(var arg in args){
 - this[arg] = args[arg];
 - }
 - }
 - }
 - Sprite.prototype = {
 - constructor:Sprite,
 - paint:function(){
 - if(this.name==="badPlan"){this.update();}
 - if(this.painter !== undefined && this.visible){
 - if(this.name!=="badPlan") {
 - this.update();
 - }
 - if(this.name==="plan"||this.name==="missle"||this.name==="badPlan"){
 - ctx.save();
 - ctx.translate(this.left , this.top);
 - ctx.rotate(this.rotateAngle);
 - this.painter.paint(this);
 - ctx.restore();
 - }else {
 - this.painter.paint(this);
 - }
 - }
 - },
 - update:function(time){
 - if(this.behaviors){
 - for(var i=0;i<this.behaviors.length;i++){
 - this.behaviors[i].execute(this,time);
 - }
 - }
 - }
 - }
 
写出精灵类后,就可以通过编写每个的painter以及behavior来生成不同的对象了。接下来就是写painter了,painter分成两种,一种是普通的painter,一种就是精灵表painter,因为像爆炸动画,飞机开枪动画,都不是一张图片就能搞定的,所以就需要用到精灵表了:
而绘制这些就要为他们定制一个精灵表绘制器,下面这个是最简单的精灵表绘制器,针对游戏的复杂性可以相对的修改精灵表写法,直到合适,不过原理都大同小异,就是小修小改而已:
XML/HTML Code复制内容到剪贴板- var SpriteSheetPainter = function(cells){
 - this.cells = cells || [];
 - this.cellIndex = 0;
 - }
 - SpriteSheetPainter.prototype = {
 - advance:function(){
 - if(this.cellIndex === this.cells.length-1){
 - this.cellIndex = 0;
 - }
 - else this.cellIndex++;
 - },
 - paint:function(sprite){
 - var cell = this.cells[this.cellIndex];
 - context.drawImage(spritesheet , cell.x , cell.y , cell.w , cell.h , sprite.left , sprite.top , cell.w , cell.h);
 - }
 - }
 
而普通的绘制器就更简单了,直接写一个painter,把要画的什么东西都写进去就行了。
有了精灵类和精灵表绘制器后,我们就可以把星星,飞机,子弹,爆炸对象都写出来了:下面是整个allSprite.js的代码:
- (function(W){
 - "use strict"
 - var planWidth = 24,
 - planHeight = 24,
 - missleWidth = 70,
 - missleHeight = 70,
 - boomWidth = 60;
 - //精灵类
 - W.Sprite = function(name , painter , behaviors , args){
 - if(name !== undefined) this.name = name;
 - if(painter !== undefined) this.painter = painter;
 - this.top = 0;
 - this.left = 0;
 - this.width = 0;
 - this.height = 0;
 - this.velocityX = 3;
 - this.velocityY = 2;
 - this.visible = true;
 - this.animating = false;
 - this.behaviors = behaviors;
 - this.rotateAngle = 0;
 - this.blood = 50;
 - this.fullBlood = 50;
 - if(name==="plan"){
 - this.rotateSpeed = 0.05;
 - this.rotateLeft = false;
 - this.rotateRight = false;
 - this.fire = false;
 - this.firePerFrame = 10;
 - this.fireLevel = 1;
 - }else if(name==="star"){
 - this.width = Math.random()*2;
 - this.speed = 1*this.width/2;
 - this.lightLength = 5;
 - this.cacheCanvas = document.createElement("canvas");
 - this.cacheCtx = this.cacheCanvas.getContext('2d');
 - this.cacheCanvas.width = this.width+this.lightLength*2;
 - this.cacheCanvas.height = this.width+this.lightLength*2;
 - this.painter.cache(this);
 - }else if(name==="badPlan"){
 - this.badKind = 1;
 - this.speed = 2;
 - this.rotateAngle = Math.PI;
 - }else if(name==="missle"){
 - this.width = missleWidth;
 - }else if(name==="boom"){
 - this.width = boomWidth;
 - }else if(name==="food"){
 - this.width = 40;
 - this.speed = 3;
 - this.kind = "LevelUP"
 - }
 - this.toLeft = false;
 - this.toTop = false;
 - this.toRight = false;
 - this.toBottom = false;
 - this.outArcRadius = Math.sqrt((this.width/2*this.width/2)*2);
 - if(args){
 - for(var arg in args){
 - this[arg] = args[arg];
 - }
 - }
 - }
 - Sprite.prototype = {
 - constructor:Sprite,
 - paint:function(){
 - if(this.name==="badPlan"){this.update();}
 - if(this.painter !== undefined && this.visible){
 - if(this.name!=="badPlan") {
 - this.update();
 - }
 - if(this.name==="plan"||this.name==="missle"||this.name==="badPlan"){
 - ctx.save();
 - ctx.translate(this.left , this.top);
 - ctx.rotate(this.rotateAngle);
 - this.painter.paint(this);
 - ctx.restore();
 - }else {
 - this.painter.paint(this);
 - }
 - }
 - },
 - update:function(time){
 - if(this.behaviors){
 - for(var i=0;i<this.behaviors.length;i++){
 - this.behaviors[i].execute(this,time);
 - }
 - }
 - }
 - }
 - // 精灵表绘制器
 - W.SpriteSheetPainter = function(cells , isloop , endCallback , spritesheet){
 - this.cells = cells || [];
 - this.cellIndex = 0;
 - this.dateCount = null;
 - this.isloop = isloop;
 - this.endCallback = endCallback;
 - this.spritesheet = spritesheet;
 - }
 - SpriteSheetPainter.prototype = {
 - advance:function(){
 - this.cellIndex = this.isloop?(this.cellIndex===this.cells.length-1?0:this.cellIndex+1):(this.cellIndex+1);
 - },
 - paint:function(sprite){
 - if(this.dateCount===null){
 - this.dateCount = new Date();
 - }else {
 - var newd = new Date();
 - var tc = newd-this.dateCount;
 - if(tc>40){
 - this.advance();
 - this.dateCount = newd;
 - }
 - }
 - if(this.cellIndex<this.cells.length || this.isloop){
 - var cell = this.cells[this.cellIndex];
 - ctx.drawImage(this.spritesheet , cell.x , cell.y , cell.w , cell.h , sprite.left-sprite.width/2 , sprite.top-sprite.width/2 , cell.w , cell.h);
 - } else if(this.endCallback){
 - this.endCallback.call(sprite);
 - this.cellIndex = 0;
 - }
 - }
 - }
 - //特制飞机精灵表绘制器
 - W.controllSpriteSheetPainter = function(cells , spritesheet){
 - this.cells = cells || [];
 - this.cellIndex = 0;
 - this.dateCount = null;
 - this.isActive = false;
 - this.derection = true;
 - this.spritesheet = spritesheet;
 - }
 - controllSpriteSheetPainter.prototype = {
 - advance:function(){
 - if(this.isActive){
 - this.cellIndex++;
 - if(this.cellIndex === this.cells.length){
 - this.cellIndex = 0;
 - this.isActive = false;
 - }
 - }
 - },
 - paint:function(sprite){
 - if(this.dateCount===null){
 - this.dateCount = new Date();
 - }else {
 - var newd = new Date();
 - var tc = newd-this.dateCount;
 - if(tc>sprite.firePerFrame){
 - this.advance();
 - this.dateCount = newd;
 - }
 - }
 - var cell = this.cells[this.cellIndex];
 - ctx.drawImage(this.spritesheet , cell.x , cell.y , cell.w , cell.h , -planWidth/2 , -planHeight/2 , cell.w , cell.h);
 - }
 - }
 - W.planBehavior = [
 - {execute:function(sprite,time){
 - if(sprite.toTop){
 - sprite.top = sprite.top<planHeight/2? sprite.top : sprite.top-sprite.velocityY;
 - }
 - if(sprite.toLeft){
 - sprite.left = sprite.left<planWidth/2? sprite.left : sprite.left-sprite.velocityX;
 - }
 - if(sprite.toRight){
 - sprite.left = sprite.left>canvas.width-planWidth/2? sprite.left : sprite.left+sprite.velocityX;
 - }
 - if(sprite.toBottom){
 - sprite.top = sprite.top>canvas.height-planHeight/2? sprite.top : sprite.top+sprite.velocityY;
 - }
 - if(sprite.rotateLeft){
 - sprite.rotateAngle -= sprite.rotateSpeed;
 - }
 - if(sprite.rotateRight){
 - sprite.rotateAngle += sprite.rotateSpeed;
 - }
 - if(sprite.fire&&!sprite.painter.isActive){
 - sprite.painter.isActive = true;
 - this.shot(sprite);
 - }
 - },
 - shot:function(sprite){
 - this.addMissle(sprite , sprite.rotateAngle);
 - var missleAngle = 0.1
 - for(var i=1;i<sprite.fireLevel;i++){
 - this.addMissle(sprite , sprite.rotateAngle-i*missleAngle);
 - this.addMissle(sprite , sprite.rotateAngle+i*missleAngle);
 - }
 - var audio = document.getElementsByTagName("audio");
 - for(var i=0;i<audio.length;i++){
 - console.log(audio[i].paused)
 - if(audio[i].src.indexOf("shot")>=0&&audio[i].paused){
 - audio[i].play();
 - break;
 - }
 - }
 - },
 - addMissle:function(sprite , angle){
 - for(var j=0;j<missles.length;j++){
 - if(!missles[j].visible){
 - missles[j].left = sprite.left;
 - missles[j].top = sprite.top;
 - missles[j].rotateAngle = angle;
 - var missleSpeed = 20;
 - missles[j].velocityX = missleSpeed*Math.sin(-missles[j].rotateAngle);
 - missles[j].velocityY = missleSpeed*Math.cos(-missles[j].rotateAngle);
 - missles[j].visible = true;
 - break;
 - }
 - }
 - }
 - }
 - ]
 - W.starBehavior = [
 - {execute:function(sprite,time){
 - if(sprite.top > canvas.height){
 - sprite.left = Math.random()*canvas.width;
 - sprite.top = Math.random()*canvas.height - canvas.height;
 - }
 - sprite.top += sprite.speed;
 - }}
 - ]
 - W.starPainter = {
 - paint:function(sprite){
 - ctx.drawImage(sprite.cacheCanvas , sprite.left-sprite.width/2-sprite.lightLength , sprite.top-sprite.width/2-sprite.lightLength)
 - },
 - cache:function(sprite){
 - sprite.cacheCtx.save();
 - var opacity = 0.5,addopa = 1/sprite.lightLength;
 - sprite.cacheCtx.fillStyle = "rgba(255,255,255,0.8)";
 - sprite.cacheCtx.beginPath();
 - sprite.cacheCtx.arc(sprite.width/2+sprite.lightLength , sprite.width/2+sprite.lightLength , sprite.width/2 , 0 , 2*Math.PI);
 - sprite.cacheCtx.fill();
 - for(var i=1;i<=sprite.lightLength;i+=2){
 - opacity-=addopa;
 - sprite.cacheCtx.fillStyle = "rgba(255,255,255,"+opacity+")";
 - sprite.cacheCtx.beginPath();
 - sprite.cacheCtx.arc(sprite.width/2+sprite.lightLength , sprite.width/2+sprite.lightLength , sprite.width/2+i , 0 , 2*Math.PI);
 - sprite.cacheCtx.fill();
 - }
 - }
 - }
 - W.foodBehavior = [
 - {execute:function(sprite,time){
 - sprite.top += sprite.speed;
 - if(sprite.top > canvas.height+sprite.width){
 - sprite.visible = false;
 - }
 - }}
 - ]
 - W.foodPainter = {
 - paint:function(sprite){
 - ctx.fillStyle = "rgba("+parseInt(Math.random()*255)+","+parseInt(Math.random()*255)+","+parseInt(Math.random()*255)+",1)"
 - ctx.font="15px 微软雅黑"
 - ctx.textAlign = "center";
 - ctx.textBaseline = "middle";
 - ctx.fillText(sprite.kind , sprite.left , sprite.top);
 - }
 - }
 - W.missleBehavior = [{
 - execute:function(sprite,time){
 - sprite.left -= sprite.velocityX;
 - sprite.top -= sprite.velocityY;
 - if(sprite.left<-missleWidth/2||sprite.top<-missleHeight/2||sprite.left>canvas.width+missleWidth/2||sprite.top<-missleHeight/2){
 - sprite.visible = false;
 - }
 - }
 - }];
 - W.misslePainter = {
 - paint:function(sprite){
 - var img = new Image();
 - img.src="../planGame/image/plasma.png"
 - ctx.drawImage(img , -missleWidth/2+1 , -missleHeight/2+1 , missleWidth , missleHeight);
 - }
 - }
 - W.badPlanBehavior = [{
 - execute:function(sprite,time){
 - if(sprite.top > canvas.height || !sprite.visible){
 - var random = Math.random();
 - if(point>=200&&point<400){
 - sprite.fullBlood = 150;
 - if(random<0.1){
 - sprite.badKind = 2;
 - sprite.fullBlood = 250;
 - }
 - }else if(point>=400&&point<600){
 - sprite.fullBlood = 250;
 - if(random<0.2){
 - sprite.badKind = 2;
 - sprite.fullBlood = 400;
 - }
 - if(random<0.1){
 - sprite.badKind = 3;
 - sprite.fullBlood = 600;
 - }
 - }else if(point>=600){
 - sprite.fullBlood = 500;
 - if(random<0.4){
 - sprite.badKind = 2;
 - sprite.fullBlood = 700;
 - }
 - if(random<0.2){
 - sprite.badKind = 3;
 - sprite.fullBlood = 1000;
 - }
 - }
 - sprite.visible = true;
 - sprite.blood = sprite.fullBlood;
 - sprite.left = Math.random()*(canvas.width-2*planWidth)+planWidth;
 - sprite.top = Math.random()*canvas.height - canvas.height;
 - }
 - sprite.top += sprite.speed;
 - },
 - shot:function(sprite){
 - this.addMissle(sprite , sprite.rotateAngle);
 - var missleAngle = 0.1
 - for(var i=1;i<sprite.fireLevel;i++){
 - this.addMissle(sprite , sprite.rotateAngle-i*missleAngle);
 - this.addMissle(sprite , sprite.rotateAngle+i*missleAngle);
 - }
 - },
 - addMissle:function(sprite , angle){
 - for(var j=0;j<missles.length;j++){
 - if(!missles[j].visible){
 - missles[j].left = sprite.left;
 - missles[j].top = sprite.top;
 - missles[j].rotateAngle = angle;
 - var missleSpeed = 20;
 - missles[j].velocityX = missleSpeed*Math.sin(-missles[j].rotateAngle);
 - missles[j].velocityY = missleSpeed*Math.cos(-missles[j].rotateAngle);
 - missles[j].visible = true;
 - break;
 - }
 - }
 - }
 - }];
 - W.badPlanPainter = {
 - paint:function(sprite){
 - var img = new Image();
 - img.src="../planGame/image/ship.png"
 - switch(sprite.badKind){
 - case 1:ctx.drawImage(img , 96 , 0 , planWidth , planWidth , -planWidth/2 , -planHeight/2 , planWidth , planWidth);
 - break;
 - case 2:ctx.drawImage(img , 120 , 0 , planWidth , planWidth , -planWidth/2 , -planHeight/2 , planWidth , planWidth);
 - break;
 - case 3:ctx.drawImage(img , 144 , 0 , planWidth , planWidth , -planWidth/2 , -planHeight/2 , planWidth , planWidth);
 - break;
 - }
 - ctx.strokeStyle = "#FFF";
 - ctx.fillStyle = "#F00";
 - var bloodHeight = 1;
 - ctx.strokeRect(-planWidth/2-1 , planHeight+bloodHeight+3 , planWidth+2 , bloodHeight+2);
 - ctx.fillRect(planWidth/2-planWidth*sprite.blood/sprite.fullBlood , planHeight+bloodHeight+3 , planWidth*sprite.blood/sprite.fullBlood , bloodHeight);
 - }
 - }
 - W.planSize = function(){
 - return {
 - w:planWidth,
 - h:planHeight
 - }
 - }
 - })(window);
 
这些绘制方法之类的都相对比较简单。
主要说一下飞机的运动以及对象数量的控制,飞机怎么运动?毫无疑问,通过键盘控制它运动,可能很多人就会想到通过keydown这个方法按下的时候通过判断keyCode来让飞机持续运动。但是有个问题,keydown事件不支持多键按下,也就是说,当你按下X键时,keyCode是88,与此同时你按下方向键后,keyCode会瞬间变成37,也就是说,如果你单纯的想靠keydown来控制飞机运动,飞机就只能做一件事,要么只可以往某个方向移动,要么只会开枪。
所以,我们要通过keydown和keyup来实现飞机的运动,原理很容易理解:当我们按下往左的方向键时,我们给飞机一个往左的状态,也就是让飞机的toLeft属性为true,而在动画循环中,判断飞机的状态,如果toLeft为true则飞机的x值不停地减少,飞机也就会不停地往左移动,然后当我们抬起手指时触发keyup事件,我们就再keyup事件中解除飞机往左的状态。飞机也就停止往左移动了。其他状态也一样的原理,这样写的话,就能够让飞机多种状态于一生了。可以同时开枪同时到处跑了。
实现的代码如下:
XML/HTML Code复制内容到剪贴板- //keydown/keyup事件的绑定
 - window.onkeydown = function(event){
 - switch(event.keyCode){
 - case 88:myplan.fire = true;
 - break;
 - case 90:myplan.rotateLeft=true;
 - break;
 - case 67:myplan.rotateRight=true;
 - break;
 - case 37:myplan.toLeft = true;
 - break;
 - case 38:myplan.toTop = true;
 - break;
 - case 39:myplan.toRight = true;
 - break;
 - case 40:myplan.toBottom = true;
 - break;
 - }
 - }
 - window.onkeyup = function(event){
 - switch(event.keyCode){
 - case 88:myplan.fire = false;
 - break;
 - case 90:myplan.rotateLeft=false;
 - break;
 - case 67:myplan.rotateRight=false;
 - break;
 - case 37:myplan.toLeft = false;
 - break;
 - case 38:myplan.toTop = false;
 - break;
 - case 39:myplan.toRight = false;
 - break;
 - case 40:myplan.toBottom = false;
 - break;
 - }
 - }
 - //飞机每一帧的状态更新处理代码
 - execute:function(sprite,time){
 - if(sprite.toTop){
 - spritesprite.top = sprite.top<planHeight/2? sprite.top : sprite.top-sprite.velocityY;
 - }
 - if(sprite.toLeft){
 - spritesprite.left = sprite.left<planWidth/2? sprite.left : sprite.left-sprite.velocityX;
 - }
 - if(sprite.toRight){
 - spritesprite.left = sprite.left>canvas.width-planWidth/2? sprite.left : sprite.left+sprite.velocityX;
 - }
 - if(sprite.toBottom){
 - spritesprite.top = sprite.top>canvas.height-planHeight/2? sprite.top : sprite.top+sprite.velocityY;
 - }
 - if(sprite.rotateLeft){
 - sprite.rotateAngle -= sprite.rotateSpeed;
 - }
 - if(sprite.rotateRight){
 - sprite.rotateAngle += sprite.rotateSpeed;
 - }
 - if(sprite.fire&&!sprite.painter.isActive){
 - sprite.painter.isActive = true;
 - this.shot(sprite);
 - }
 
就是如此简单。
然后说下对象控制,打飞机游戏,会发射大量子弹,产生大量对象,包括爆炸啊,飞机啊,子弹等,如果不停地进行对象的生成和销毁,会让浏览器的负荷变得很大,运行了一段时间后就会卡出翔了。所以,我们要用可以循环利用的对象来解决这个问题,不进行对象的销毁,对所有对象进行保存,循环利用。
我的做法就是,在游戏初始化的时候,直接生成一定数量的对象,存放在数组里面。当我们需要一个对象的时候,就从里面取,当用完后,再放回数组里面。数组里的所有对象都有一个属性,visible,代表对象当前是否可用。
举个例子,当我的飞机发射一发炮弹,我需要一发炮弹,所以我就到炮弹数组里遍历,如果遍历到的炮弹visible为true,也就说明该对象正在使用着,不能拿来用,所以继续遍历,直到遍历到visible为false的炮弹对象,说明这个对象暂时没人用。然后就可以拿过来重新设置属性,投入使用了。当炮弹击中敌人或者打出画布外的时候,把炮弹的visible设成false,又成了一个没人用的炮弹在数组里存放起来等待下一次调用。
所以,我们要预算算好页面大概要用到多少个对象,然后就预先准备好对象,这样,在游戏进行中,不会有对象进行生成和销毁,对游戏性能方面就有了提升了。
  最后再说下音频,游戏里面要用到多个同样的audio才能保证音效的不间断性:
复制代码
- var audio = document.getElementsByTagName("audio");
 - for(var i=0;i<audio.length;i++){
 - console.log(audio[i].paused)
 - if(audio[i].src.indexOf("boom")>=0&&audio[i].paused){
 - audio[i].play();
 - break;
 - }
 - }
 
好吧,基本上就这样了。技术或许还不够好,纯碎做个记录,如果代码有不当正处,欢迎指出,共同学习。
源码地址:https://github.com/whxaxes/canvas-test/tree/gh-pages/src/Game-demo/planGame
HTML5,Canvas
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稳了!魔兽国服回归的3条重磅消息!官宣时间再确认!
昨天有一位朋友在大神群里分享,自己亚服账号被封号之后居然弹出了国服的封号信息对话框。
这里面让他访问的是一个国服的战网网址,com.cn和后面的zh都非常明白地表明这就是国服战网。
而他在复制这个网址并且进行登录之后,确实是网易的网址,也就是我们熟悉的停服之后国服发布的暴雪游戏产品运营到期开放退款的说明。这是一件比较奇怪的事情,因为以前都没有出现这样的情况,现在突然提示跳转到国服战网的网址,是不是说明了简体中文客户端已经开始进行更新了呢?
                        



