First, calculate the vector between the vertex in it's world position and the light position.

首先，计算顶点在世界位置及光源位置之间的矢量。

youdao

Those in the dark are in no position to light the way for others.; Persons in the dark cannot light the way for others.

以其昏昏， 使人昭昭是不行的。

《新英汉大辞典》

A directional light doesn't have a position, only a direction.

定向光没有位置，只有方向。

youdao

A red light means get into position. Yellow light means ready.

VOA: standard.2009.09.10

And if we do, in fact, hit it with light to get the electrons off, it will go back to the straight up in position, or if it gets knocked hard enough it does that, too.

而且如果我们这么做，事实上，用光轰击它以逐出电子，它就会在原位置沿直线返回，或者如果它被撞击的足够猛烈,也会出现上述现象。

麻省理工公开课 - 化学原理课程节选

"My position is to reconsider our current position in light of the most recent scientific data to ensure that the current position that Palau takes will not lead to the depletion and extinction of whales, " he said.

BBC: Palau pioneers 'shark sanctuary'

There is, of course, a natural tension between the need to control IT spending and maintaining a strong competitive position in light of new technologies.

WSJ: The Experts: What Is the No. 1 Technology Issue Facing Companies Today?

When the result is transformed back into its original condition, the only light remaining marks the position of the target, or things that looked similar to it, in the original image.

ECONOMIST: Optical recognition