 the sphere render after the cube
		scene.add(sphere);

		// create occlusion query set
		const querySet = new t3d.QuerySet(t3d.QUERYSET_TYPE.OCCLUSION, 1);

		const renderOption = {
			beforeRender: renderable => {
				if (renderable.object.userData.isSphere) {
					renderer.beginOcclusionQuery(0);
				}
			},
			afterRender: renderable => {
				if (renderable.object.userData.isSphere) {
					renderer.endOcclusionQuery();
				}
			}
		};

		const dstBuffer = new Array(1);
		let reading = false;

		const ti