Only update shadow properties of lights that support shadows (#5748)

Author: mrxz

src/components/light.js

@@ -199,6 +199,9 @@ export var Component = registerComponent('light',{
 if(newLight){
 if(this.light){
 el.removeObject3D('light');
+if(el.getObject3D('cameraHelper')){
+el.removeObject3D('cameraHelper');
+}
 }
 
 this.light=newLight;
@@ -232,18 +235,20 @@ export var Component = registerComponent('light',{
 vardata=this.data;
 varlight=this.light;
 
-light.castShadow=data.castShadow;
+// Cast shadows if enabled and light type supports shadows.
+light.castShadow=data.castShadow&&light.shadow;
 
 // Shadow camera helper.
 varcameraHelper=el.getObject3D('cameraHelper');
-if(data.shadowCameraVisible&&!cameraHelper){
+varshadowCameraVisible=data.shadowCameraVisible&&light.shadow;
+if(shadowCameraVisible&&!cameraHelper){
 cameraHelper=newTHREE.CameraHelper(light.shadow.camera);
 el.setObject3D('cameraHelper',cameraHelper);
-}elseif(!data.shadowCameraVisible&&cameraHelper){
+}elseif(!shadowCameraVisible&&cameraHelper){
 el.removeObject3D('cameraHelper');
 }
 
-if(!data.castShadow){returnlight;}
+if(!light.castShadow){returnlight;}
 
 // Shadow appearance.
 light.shadow.bias=data.shadowBias;