一个用于操控场景的实用类。
instancedMesh -- 实例化网格。
为给定的实例化网格的每个实例,创建一个包含新网格的新物体组(Object Group)。
mesh -- A mesh with multiple materials.
Converts the given multi-material mesh into an instance of [page:Group] holding for each material a separate mesh.
geometry -- 材料集的几何形状。
materials -- 为物体准备的材料。
创建一个新组,囊括了在材质中定义的每种材质的新网格。请注意,这和为一个网格定义多种材质的材质数组不同。
该方法对于同时需要材质和线框绘制的物体非常有用。
mesh -- InstancedMesh in which instances will be sorted.
compareFn -- Comparator function defining the sort order.
Sorts the instances within an [page:InstancedMesh], according to a user-defined callback. The callback will be provided with two arguments, indexA and indexB, and must return a numerical value. See [link:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#description Array.prototype.sort] for more information on sorting callbacks and their return values.
Because of the high performance cost, three.js does not sort [page:InstancedMesh] instances automatically. Manually sorting may be helpful to improve display of alpha blended materials (back to front), and to reduce overdraw in opaque materials (front to back).
[link:https://github.com/mrdoob/three.js/blob/master/examples/jsm/utils/SceneUtils.js examples/jsm/utils/SceneUtils.js]