code: function (renderer, scene, sceneCamera, notUpdateScene) {
          if (!sceneCamera) {
              sceneCamera = scene.getMainCamera();
          }
          this.trigger('beforerender', this, renderer, scene, sceneCamera);
          this._renderShadowPass(renderer, scene, sceneCamera, notUpdateScene);
          this.trigger('afterrender', this, renderer, scene, sceneCamera);
      }
docs: Render scene to shadow textures
  @param  {clay.Renderer} renderer
  @param  {clay.Scene} scene
  @param  {clay.Camera} sceneCamera
  @param  {boolean} [notUpdateScene=false]
  @memberOf clay.prePass.ShadowMap.prototype