As mentioned above in the directional lights section, the rendering of shadows for directional lights is an approximation that allows us to use a single render to cover a largeish area with shadows.

• 你也可以使用着色语言作为技术的实现基础来处理阴影投射体和接收体的材质来实现更复杂的阴影算法，比如实现支持自投影的深度阴影贴图。