At this point, the difference value found in the above step could be used to modify the shadow because you now have a way of knowing how far each point being shaded is from the light relative to the distance from the light to the startShadow locator.

• 在这点上，发现在上一步的差异值能用于修改阴影，因为你现在有一个已知的方法，从光源处的每个被着色点相对于从光源到开始阴影定位器的距离有多远。