programmable clipping
- Thread starter 2008 IQ is unacceptable
- Start date
The depth buffer isn't fixed between a range of values - it's set by the application (using the near and far z planes). However, with a 32-bit depth buffer, you only have ~4 billion different values, with an exponential falloff in precision the further away you get from the camera.
An application could arbitrarily say that it measured distances in lightyears, and set their far z plane 10^30 units away. Then the application would have a draw distance of 10^30 lightyears - but good luck representing day-to-day distances (metres) at any sort of precision with those settings.
The point is that actual numbers of distance don't matter - it's the ratios.
2008 IQ is unacceptable
Banned
Well, the depth buffer still needs a serious overhaul that isn't seen in dx10 games.
Thanks for all the kind replies=]
Thanks for all the kind replies=]
2008 IQ is unacceptable
Banned
Agreed.
That's exactly the problem I see with the z-buffer.
Doesn't matter how many bits of precision with the z-buffer, you still won't get good precision far away from the camera.
Sure the distance may be long as hell, but they don't appear long as hell due to the nature of the z-buffer.
Besides, how many games with the z-buffer give you good precision far above and far below? Practically none.
Bloodrayne 2 does but it had z-fighting errors so that's probably why you don't see many recent games that look like that.
With a float Z buffer shader precision is more of an issue than Z buffer precision.
Making claims about "the nature of the z-buffer" without even knowing what it's used for is not a good basis for discussion.
Nope. That's the first pic that showed up on a google image search on "Just Cause".
Just modifying the caps bit shouldn't be too hard I guess.
With a floating point z-buffer and a reversed projection matrix (far plane = 0, near = 1) you get a pretty even precision distribution across the whole range.
Oh Mighty Humus, be aware that I am currently in the process of assembling an international team of crimson skies fans we are going to fly to sweden kidnap you, tie you to a chair and poke you with a pointy stick untill you promise to fix the game.
here's the official explaination from nvidia it may help.
"The reason for the corruption is because the game doesn't check correctly for the support of Nonpower of two textures. The Forceware driver now have an unlimited support for Nonpow2 textures. That means we don't export the caps NONPOW2CONDITIONAL anymore. However the game misinterprets this as we don't support Pow2 and/or nonpow2 textures."
Do not take this lightly we do have a Rubber Chicken and are not afraid to use it...........
I have written a tool to change every single caps bit some time ago. Must be somewhere on my hard disk.
2008 IQ is unacceptable
Banned
2 questions:
what are all the differences between the w-buffer and an 32 bit fp inverted z-buffer?
I know one is that the w-buffer is more linear in distribution, but I don't know much more than that.
even though a 32 bit fp inverted z-buffer isn't a perfect replacement can it do everything a w-buffer can do and just as well?
I just wish they'd do away with the depth buffer altogether and just have have HW programmable clipping.
what are all the differences between the w-buffer and an 32 bit fp inverted z-buffer?
I know one is that the w-buffer is more linear in distribution, but I don't know much more than that.
even though a 32 bit fp inverted z-buffer isn't a perfect replacement can it do everything a w-buffer can do and just as well?
I just wish they'd do away with the depth buffer altogether and just have have HW programmable clipping.
I don't understand. How can you ask a question like this:
and make a statement like this
and make a statement like this
in the same post at a place like this with a straight face?
2008 IQ is unacceptable
Banned
Just ignore the 2nd quoted statement=]
Read this paper.
To summarize, fp32 complementary z buffer has enough precision that you start to become limited by your vertex data precision, so the depth buffer resolution is a total non-issue anymore.
fp32 depth buffers are required by DX10, so you can stop complaining about depth buffer precision on any modern hardware!
Both are linear, but in different ways. The W-buffer is linear in scene depth, but it's non-linear pixel-to-pixel in screen space. A Z-buffer is linear pixel-to-pixel in screen space, but non-linear in scene depth. Intuitively the W-buffer sounds like the better choice, unless you're the one designing the hardware. The linearity in screen-space of Z-buffer means you can create much simpler hardware for interpolating Z, it also means that the resulting Z values are highly compressible which makes techniques like Z-compression possible. The disadvantage is that precision is distributed in a non-linear fashion. However, if you're working with floating point numbers, which are non-linear in themselves, you can make the non-linearities sort of cancel each other out. That's what the inverted projection is all about. If you map the far plane to 0 and near to 1, you get a depth distribution that's not quite linear, but good enough, while maintaining the advantages of a Z-buffer.
Johnny_Physics
Newcomer
Ok, let's recap:
"Awesome! Great draw distance!"
"Boo! Z-buffer artifacts!"
Seems a bit weird to me, but let's try another set of pictures, I think I start to understand what you're trying to say.
Now IQ, which of these pictures would you say is more w-buffered?
This one:
Or this one:
"Awesome! Great draw distance!"
"Boo! Z-buffer artifacts!"
Seems a bit weird to me, but let's try another set of pictures, I think I start to understand what you're trying to say.
Now IQ, which of these pictures would you say is more w-buffered?
This one:
Or this one:
2008 IQ is unacceptable
Banned
That's JK 2 which uses the z-buffer due to the fact that opengl didn't use the w-buffer. Looks like it uses the w-buffer tho, but it don't.Ok, let's recap:
"Awesome! Great draw distance!"
"Boo! Z-buffer artifacts!"
Seems a bit weird to me, but let's try another set of pictures, I think I start to understand what you're trying to say.
Now IQ, which of these pictures would you say is more w-buffered?
This one:
Or this one:
2008 IQ is unacceptable
Banned
No it has a negative lod bias.
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