/*main部分代碼，定義了delta，在gameloop()中有如下代碼*/delta += Math.PI * deltaTime * 0.0003;/*?？糠执a*/??? for(var i = 0; i < this.num; i++)?? ?{?? ??? ?ctx2.beginPath();?? ??? ?ctx2.moveTo(this.x[i],canHeight);?? ??? ?//ctx2.lineTo(this.x[i], canHeight-this.len[i]);?? ??? ?var deltaX = Math.sin(delta);//[-1,1]?? ??? ?//console.log("dust delta:"+delta);?? ??? ?this.headX[i] = this.x[i] + deltaX * this.amp[i];?? ??? ?ctx2.quadraticCurveTo(this.x[i], canHeight - this.len[i] / 3, this.headX[i], canHeight - this.len[i]);?? ??? ?//console.log("x1: " + this.x[i] + " y1: " + (canHeight - this.len[i] / 2) + " x2: " + (this.x[i] + deltaX) + " y2: " + (canHeight - this.len[i]));?? ??? ??? ??? ?ctx2.stroke();?? ?}/*漂浮物部分代碼*/??? var deltaX = Math.cos(delta);//[-1,1]?? ?//console.log("dust delta:"+delta);?? ?for(var i = 0; i < this.num; i++)?? ?{?? ??? ?this.x[i] += deltaX * this.amp[i];?? ??? ?var id = this.dustCount[i];?? ??? ?ctx1.drawImage(this.img[id], this.x[i], this.y[i]);?? ??? ?//console.log("img: "+ this.dustCount[i]);?? ?}