海葵不是从无到有逐渐变大而是突然出现向左移动？怎么回事？
fruitObj.prototype.draw=function(){
for(var i=0;i<this.num;i++){
//draw
//find an ang ,graw,fly up
if(this.l[i]<=14){
this.l[i]+=0.01*deltaTime;
}
else{
this.y[i]-=0.07*deltaTime;
}
ctx2.drawImage(this.orange,this.x[i]-this.l[i]*0.5,this.y[i]-this.l[i]*0.5),this.l[i],this.l[i];
}
}
