1.什麼時候需要場景物件？
場景物件有區別於上一篇介紹的地圖對象，它們分別應用於不同類型的遊戲。先前的地圖物件應用於格子類的遊戲，例如推箱子，坦克大戰。而本節介紹的場景對象，則適用於擁有特定場景的遊戲，例如超級瑪麗，恐龍快打等。這類遊戲通常在2d場景內控制一個玩家對象，隨著玩家的移動，場景跟著移動。
2.場景範例：
效果：（左右鍵控制超級瑪莉的移動）
<body>
<div><canvas id="gameCanvas">请使用支持canvas的浏览器查看</canvas></div>
</body>
<script src="cnGame_v1.0.js"></script>
<script>
var Src="http://images.cnblogs.com/cnblogs_com/Cson/290336/o_player.png";
var background="background.png";
/* 初始化 */
cnGame.init('gameCanvas',{width:500,height:400});
var floorY=cnGame.height-40;
var gameObj=(function(){
/* 玩家对象 */
var player=function(options){
this.init(options);
this.speedX=0;
this.moveDir;
this.isJump=false;
}
cnGame.core.inherit(player,cnGame.Sprite);
player.prototype.initialize=function(){
this.addAnimation(new cnGame.SpriteSheet("playerRight",Src,{frameSize:[50,60],loop:true,width:150,height:60}));
this.addAnimation(new cnGame.SpriteSheet("playerLeft",Src,{frameSize:[50,60],loop:true,width:150,height:120,beginY:60}));
}
player.prototype.moveRight=function(){
if(cnGame.core.isUndefined(this.moveDir)||this.moveDir!="right"){
this.moveDir="right";
this.speedX<0&&(this.speedX=0);
this.setMovement({aX:10,maxSpeedX:15});
this.setCurrentAnimation("playerRight");
}
}
player.prototype.moveLeft=function(){
if(cnGame.core.isUndefined(this.moveDir)||this.moveDir!="left"){
this.moveDir="left";
this.speedX>0&&(this.speedX=0);
this.setMovement({aX:-10,maxSpeedX:15});
this.setCurrentAnimation("playerLeft");
}
}
player.prototype.stopMove=function(){
if(this.speedX<0){
this.setCurrentImage(Src,0,60);
}
else if(this.speedX>0){
this.setCurrentImage(Src);
}
this.moveDir=undefined;
this.resetMovement();
}
player.prototype.update=function(){
player.prototype.parent.prototype.update.call(this);//调用父类update
if(cnGame.input.isPressed("right")){
this.moveRight();
}
else if(cnGame.input.isPressed("left")){
this.moveLeft();
}
else{
this.stopMove();
}
}
return {
initialize:function(){
cnGame.input.preventDefault(["left","right","up","down"]);
this.player=new player({src:Src,width:50,height:60,x:0,y:floorY-60});
this.player.initialize();
this.background=new cnGame.View({src:background,player:this.player,imgWidth:2301});
this.background.centerPlayer(true);
this.background.insideView(this.player,"x");
},
update:function(){
this.player.update();
this.background.update([this.player]);
},
draw:function(){
this.background.draw();
this.player.draw();
}
};
})();
cnGame.loader.start([Src,background],gameObj);
</script>/**
*初始化
**/
init:function(options){
/**
*默认对象
**/
var defaultObj={
width:cg.width,
height:cg.height,
imgWidth:cg.width,
imgHeight:cg.height,
x:0,
y:0
}
options=options||{};
options=cg.core.extend(defaultObj,options);
this.player=options.player;
this.width=options.width;
this.height=options.height;
this.imgWidth=options.imgWidth;
this.imgHeight=options.imgHeight;
this.centerX=this.width/2;
this.src=options.src;
this.x=options.x;
this.y=options.y;
this.insideArr=[];
this.isLoop=false;;
this.isCenterPlayer=false;
this.onEnd=options.onEnd;
},/**
*背景移动时的更新
**/
update:function(spritelist){//传入所有sprite的数组
if(this.isCenterPlayer){
if(this.player.x>this.centerX){
if(this.x<this.imgWidth-this.width){
var marginX=this.player.x-this.centerX;
this.x+=marginX;
if(spritelist){
for(var i=0,len=spritelist.length;i<len;i++){
if(spritelist[i]==this.player){
spritelist[i].x=this.centerX;
}
else{
spritelist[i].x-=marginX;
}
}
}
}
else if(this.isLoop){
if(spritelist){
for(var i=0,len=spritelist.length;i<len;i++){
if(spritelist[i]!=this.player){
spritelist[i].move(this.imgWidth-this.width);
}
}
}
this.x=0;
}
else{
this.onEnd&&this.onEnd();
}
}
}
for(var i=0,len=this.insideArr.length;i<len;i++){
inside.call(this,this.insideArr[i]);
}
},/**
*
*场景
*
**/
cnGame.register("cnGame",function(cg){
/**
*使指定对象在可视区域view内
**/
var inside=function(sprite){
var dir=sprite.insideDir;
if(dir!="y"){
if(sprite.x<0){
sprite.x=0;
}
else if(sprite.x>this.width-sprite.width){
sprite.x=this.width-sprite.width;
}
}
if(dir!="x"){
if(sprite.y<0){
sprite.y=0;
}
else if(sprite.y>this.height-sprite.height){
sprite.y=this.height-sprite.height;
}
}
}
var view=function(options){
this.init(options);
}
view.prototype={
/**
*初始化
**/
init:function(options){
/**
*默认对象
**/
var defaultObj={
width:cg.width,
height:cg.height,
imgWidth:cg.width,
imgHeight:cg.height,
x:0,
y:0
}
options=options||{};
options=cg.core.extend(defaultObj,options);
this.player=options.player;
this.width=options.width;
this.height=options.height;
this.imgWidth=options.imgWidth;
this.imgHeight=options.imgHeight;
this.centerX=this.width/2;
this.src=options.src;
this.x=options.x;
this.y=options.y;
this.insideArr=[];
this.isLoop=false;;
this.isCenterPlayer=false;
this.onEnd=options.onEnd;
},
/**
*使player的位置保持在场景中点之前的移动背景
**/
centerPlayer:function(isLoop){
isLoop=isLoop||false;
this.isLoop=isLoop;
this.isCenterPlayer=true;
},
/**
*使对象的位置保持在场景内
**/
insideView:function(sprite,dir){//dir为限定哪个方向在view内，值为x或y，不传则两个方向皆限定
if(cg.core.isArray(sprite)){
for(var i=0,len=sprite.length;i登入後複製 以上是HTML5遊戲框架cnGameJS開發實錄-遊戲場景對象的詳細內容。更多資訊請關注PHP中文網其他相關文章！
