camera.viewport.project(layaMonkey3D.transform.position, camera.projectionViewMatrix, _outPos);
//获取的2d坐标必须做兼容屏幕适配操作
layaMonkey2D.pos(_outPos.x / Laya.stage.clientScaleX, _outPos.y / Laya.stage.clientScaleY);
https://layaair.ldc.layabox.com/demo/?category=3d&group=camera&name=D3SpaceToD2Space