README.md

帧事件

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• 演示准备

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创建一个演示场景：
class Main {

    protected _egret3DCanvas: egret3d.Egret3DCanvas;
    protected view1: egret3d.View3D;
    protected cube: egret3d.Mesh;

    public constructor() {

        ///创建3DCanvas
        this._egret3DCanvas = new egret3d.Egret3DCanvas();
        this._egret3DCanvas.x = 0;
        this._egret3DCanvas.y = 0;
        this._egret3DCanvas.width = window.innerWidth;
        this._egret3DCanvas.height = window.innerHeight;
        this._egret3DCanvas.start();
        ///创建View3D
        this.view1 = new egret3d.View3D(0, 0, window.innerWidth, window.innerHeight);
        this.view1.camera3D.lookAt(new egret3d.Vector3D(0, 1000, -1000), new egret3d.Vector3D(0, 0, 0));
        this.view1.backColor = 0xff888888;
        this._egret3DCanvas.addView3D(this.view1);
        ///启动3DCanvas
        this._egret3DCanvas.start();
        ///创建立方体，放置于场景内(0,0,0)位置
        var mat_cube: egret3d.TextureMaterial = new egret3d.TextureMaterial();
        var geometery_Cube: egret3d.CubeGeometry = new egret3d.CubeGeometry();
        this.cube = new egret3d.Mesh(geometery_Cube, mat_cube);
        this.view1.addChild3D(this.cube);
        ///创建面片，放置于场景内(0,0,0)位置
        var mat_Plane: egret3d.TextureMaterial = new egret3d.TextureMaterial();
        var geometery_Plane: egret3d.PlaneGeometry = new egret3d.PlaneGeometry();
        var plane = new egret3d.Mesh(geometery_Plane, mat_Plane);
        this.view1.addChild3D(plane);

    }

}      

1) 该事件的持有对象为egret3d.Egret3DCanvas对象，所以注册该事件应该如示例代码所示：
	this._egret3DCanvas.addEventListener(egret3d.Event3D.ENTER_FRAME, this.OnUpdate, this);
2）事件触发时，注册函数会传递一个类型为egret3d.Event3D的参数，其中egret3d.Event3D.delay为每帧间隔延时，egret3d.Event3D.time为当前时间戳；
3) 示例代码：
	通过每帧更新控制cube进行x轴水平运动。

			class Main {
			
			    protected _egret3DCanvas: egret3d.Egret3DCanvas;
			    protected view1: egret3d.View3D;
			    protected cube: egret3d.Mesh;
			
			    private cur_x: number;
			    private radio: number = 1;;
			
			    public constructor() {
			        ///创建3DCanvas
			        this._egret3DCanvas = new egret3d.Egret3DCanvas();
			        this._egret3DCanvas.x = 0;
			        this._egret3DCanvas.y = 0;
			        this._egret3DCanvas.width = window.innerWidth;
			        this._egret3DCanvas.height = window.innerHeight;
			        this._egret3DCanvas.start();
			        ///创建View3D
			        this.view1 = new egret3d.View3D(0, 0, window.innerWidth, window.innerHeight);
			        this.view1.camera3D.lookAt(new egret3d.Vector3D(0, 1000, -1000), new egret3d.Vector3D(0, 0, 0));
			        this.view1.backColor = 0xff888888;
			        this._egret3DCanvas.addView3D(this.view1);
			        ///启动3DCanvas，注册每帧更新事件
			        this._egret3DCanvas.start();
			        ///创建立方体，放置于场景内(0,0,0)位置
			        var mat_cube: egret3d.TextureMaterial = new egret3d.TextureMaterial();
			        var geometery_Cube: egret3d.CubeGeometry = new egret3d.CubeGeometry();
			        this.cube = new egret3d.Mesh(geometery_Cube, mat_cube);
			        this.view1.addChild3D(this.cube);
			        ///创建面片，放置于场景内(0,0,0)位置
			        var mat_Plane: egret3d.TextureMaterial = new egret3d.TextureMaterial();
			        var geometery_Plane: egret3d.PlaneGeometry = new egret3d.PlaneGeometry();
			        var plane = new egret3d.Mesh(geometery_Plane, mat_Plane);
			        this.view1.addChild3D(plane);
			        ///注册事件，持有对象为_egret3DCanvas，每帧触发该注册方法，需要依次写入事件标识符，注册方法和注册对象。
			        this._egret3DCanvas.addEventListener(egret3d.Event3D.ENTER_FRAME, this.OnUpdate, this);
			    }
			
			
			    ///注册后，该事件将每帧响应
			    public OnUpdate(e: egret3d.Event3D) {
			        var speed = 0.04;
			        ///我们这里简单的控制cube的x值来进行水平位移动画
			        ///限制x的运动范围为-200至200之间。
			        if (this.cube.x > 200) {
			            this.radio = -1;
			        } else if (this.cube.x < -200) {
			            this.radio = 1;
			        }
			        ///通过速度和每帧间隔时长计算位移，radio是位移方向系数。
			        this.cube.x += speed * e.delay * this.radio;
			    }
			}