[wk_end]

Thanks - this is much clearer than the original article, which somehow never actually defines "reverse Z" before going on and on about it.

Why is it that most things you render are far away rather than close? I guess I'd expect the opposite, at least depending on what you're rendering. And I'd also assume you'd want better visual fidelity for closer things, so I find this a little counter-intuitive.

Are there certain cases where you'd want "regular Z" rather than "reverse Z"? Or cases where you'd want to limit your Z to [0, 0.5] instead of [0, 1]?

[Jasper_]

"Close" here means "millimeters away". The logarithmic nature of the depth buffer means that even your player character is considered far enough to be already at ~0.9 in a "regular Z" case (depending on where you put your near plane, of course). Go stare at a few depth buffers and you'll get a good taste of it.

[CamperBob2]

Why is it that most things you render are far away rather than close?

Because most things are far away rather than close...?

[wk_end]

I guess…but in terms of what you see on screen most of what you see is going to be dominated by closer things, is what I’m getting at. The world is very big but right now most of what I see is relatively speaking close to me. I don’t care much about the precise positions of stuff in China right now, but as for the stuff in my apartment in Canada it’s very important for my sense of reality that the positioning is quite exact - even though there’s a lot more stuff in China.

[cornstalks]

The reason for this is in the article:

> The reason for this bunching up of values near 1.0 is down to the non linear perspective divide.

The function in question is nonlinear. So using "normal" z, values in the range [0, 0.5] are going to be very, very close to the camera. The vast majority of things aren't going to be that close to the camera. Most typical distances are going to be in the [0.5, 1] range.

Hence, reversing that gives you more precision where it matters.

[recursivecaveat]

You still need precision even for things that are far away. You don't necessarily care that the building your character is looking at a mile away is exactly in the right spot, but imprecision causing Z-fighting will be very noticeable as the windows constantly flicker back and forth in front of the facade.

[xboxnolifes]

If you're standing outside holding a phone up to your face, you have 2 things close (hand/phone) and everything else (trees, buildings, cars, furniture, animals, etc) around you is not close.