[]3D阴影无法渲染出来

//添加方向光
var directionLight = scene.addChild(new Laya.DirectionLight());
directionLight.color = new Laya.Vector3(0.6, 0.6, 0.6);
directionLight.direction = new Laya.Vector3(1, -1, 0);

directionLight.shadow = true;
directionLight.shadowDistance = 3;
directionLight.shadowResolution = 2048;
directionLight.shadowPSSMCount = 1;
directionLight.shawowPCFType = 3;
box.meshRender.receiveShadow = true;
sphere.meshRender.castShadow = true; box 和 sphere 都是 Sprite3D 的，贴了2D贴图，为啥出不来阴影