平行光
创建一个演示场景：
class Main {
protected _egret3DCanvas: egret3d.Egret3DCanvas;
protected view1: egret3d.View3D;
protected cameraCtl: egret3d.LookAtController;
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, 100, -100), new egret3d.Vector3D(0, 0, 0));
this.view1.backColor = 0xff888888;
this._egret3DCanvas.addView3D(this.view1);
///创建相机控制器
this.cameraCtl = new egret3d.LookAtController(this.view1.camera3D, new egret3d.Object3D());
this.cameraCtl.distance = 150;
this.cameraCtl.rotationX = 60;
///启动3DCanvas，注册每帧更新事件
this._egret3DCanvas.start();
this._egret3DCanvas.addEventListener(egret3d.Event3D.ENTER_FRAME, this.update, this);
///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();
var cube = new egret3d.Mesh(geometery_Cube, mat_cube);
this.view1.addChild3D(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);
}
public update(e: egret3d.Event3D) {
///更新控制器
this.cameraCtl.update();
}
}
1）什么是方向光：
平行光又称为方向光（Directional Light），是一组没有衰减的平行的光线，类似太阳光的效果。
2）方向光的模型如图：
3) 给演示场景添加一个方向光：
在演示代码的构造函数尾部我们可以添加如下代码：
///创建一个灯光组，该灯光组将管理场景内的灯光资源
var lights: egret3d.LightGroup = new egret3d.LightGroup();
///创建一个方向光对象，其中参数(-0.5, -0.6, 0.2)为方向向量，为灯光方向，默认方向为0, 0, 1)。
var dirLight: egret3d.DirectLight = new egret3d.DirectLight(new egret3d.Vector3D(-0.5, -0.6, 0.2));
///灯光漫反射颜色是红色，默认为白色
dirLight.diffuse = 0xff0000;
///写入组
lights.addLight(dirLight);
///设置灯效组。
cube.material.lightGroup = lights;
plane.material.lightGroup = lights;
还可以修改灯光的背光颜色，如下所示：
///创建一个灯光组，该灯光组将管理场景内的灯光资源
var lights: egret3d.LightGroup = new egret3d.LightGroup();
///创建一个方向光对象，其中参数(-0.5, -0.6, 0.2)为方向向量，为灯光方向，默认方向为0, 0, 1)。
var dirLight: egret3d.DirectLight = new egret3d.DirectLight(new egret3d.Vector3D(-0.5, -0.6, 0.2));
///灯光漫反射颜色是红色，默认为白色
dirLight.diffuse = 0xff0000;
///灯光背光颜色是灰色，默认为黑色
dirLight.ambient = 0x505050;
///写入组
lights.addLight(dirLight);
///设置灯效组。
cube.material.lightGroup = lights;
plane.material.lightGroup = lights;
guofei
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