Z buffer still 32 bits?

[harl]

Why the colour depth is incresing
to 128 bit (32 per chanel) ande the Z buffer
doesn't increase

I thing the increase in the colour doesn't
impact in the final qualty nor the Z-Buffer

But why DX increase the Colour and not the Z

[StealthHawk]

Originally posted by harl
Why the colour depth is incresing
to 128 bit (32 per chanel) ande the Z buffer
doesn't increase

I thing the increase in the colour doesn't
impact in the final qualty nor the Z-Buffer

But why DX increase the Colour and not the Z

The color depth is not increasing. That is internal precision that is 128bit.

[Uttar]

The 32-bit Z buffer is really 24-bit Z and 8-bit stencil.

What you've got to realize is that color got *FOUR* components and Z got *ONE* component.
So when you say 128-bit, it's really 128/4 - that's 32-bit precision.

That means that the R300 with 24-bit per-component precision got as much precision in color as in Z. The NV30 got potentially more precision in color, but it's engineered with FX12 in mind, so most of the time it got two times LESS precision.

There are a few other elements to consider, such as the precision not being shared equally. But if you really wanted more info on that, I'm sure Google could help.

In summary, Z precision is very far from being lackluster compared to color precision. While an increase in precision might happen in the future, it is not currently of any practical use. In fact, it might never be of any practical use.

As Stealth said, the color precision increase ( or to be more precise, the fragment precision increase, because it CAN affect Z ) is fundamentally different, since it's only internal. In the case of the Z value, there's no reason to only do only an internal increase.
Not like there'd be many reasons to do a real increase, anyway.


Uttar

[harl]

I knonw that Z & colour are diferent things
but I think thata a Z precision Incresa could
be more helpfull.

what about W-Buffer it is suposed to resolve
artifacts in some objets. why dont to use
32 or 64 wbuffer

[Nutty]

why? because theres no point.

A properly managed 24bit Z buffer has all the precision you need for current and future games.

Of course some ppl dont know how to setup Z buffers correctly, resulting in Z artifacts.