Why is the normalized device coordinate system left?

Question

At first I wondered why the NDC is in the range of -1 to 1, and not from 0 to 1. I figured that perhaps the origin in the center is useful for something.

But why does he use the left coordinate system?

Could it be that the Z value is higher for objects further? That would be a good enough reason for me.

Answer 1

But why does he use the left coordinate system?

Add a "default" to this question. Because all that needed to be changed is glDepthRange(1.0f, 0.0f);and now you are right. And yes, this is the completely legal GL syntax; there has never been a limitation that the range near z is less than the far far.

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Answer 2

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Answer 3

Guess that the change in manual work belongs to how graphic cards interpret z values. Larger z → greater depth. An implied change of hand can be performed by a projection matrix at no additional cost. Then changing it will add an additional calculation step.