如何让 ShadowCamera 在 three.js r73 中可见?

How to make ShadowCamera visible in three.js r73?

Light.shadowCameraVisible = true;

给予警告

THREE.Light: .shadowCameraVisible has been removed. Use new THREE.CameraHelper( light.shadow ) instead.

添加

Scene.add(new THREE.CameraHelper(Light.shadow ));

报错

Uncaught TypeError: this.camera.updateProjectionMatrix is not a function (three.js :35002)

CameraHelper 构造函数接受一个 Camera 对象:

var light = new THREE.SpotLight( 0xFFAA55 );
light.castShadow = true;

var helper = new THREE.CameraHelper( light.shadow.camera );
scene.add( helper );

Three.js r107

示例:http://jsfiddle.net/kvnc1g4y/