Wow! Kyro's Z buffer accuracy rocks!

[AdamK47]

Previously, all of the other cards I own (which include a Radeon, GeForce 2, and Voodoo 5) would display 16-bit Z buffer inaccuracy renderings. All of the boards would exibit the problems in the same places in games. Some more severe than others. 32-bit color would clear it up, but with the sacrafice of performance. With my new Kyro, I can play those same games without those annoying 16-bit Z buffer errors. I included two screenshots bellow. I used the zoom in function in Quake 3 on map Q3DM9. The top one is the Kyro. The bottom one is the 3dfx Voodoo 5. It's true that the Voodoo 5 can produce near 32-bit color quality, but the 16-bit Z buffer is still rearing it's ugly head. You'll notice that the Kyro can render the entire frame on the stain glass window while the Voodoo 5 has a lot of clipping on the frame. The best way for you to see this is to actually play the game in 16-bit mode and view the same stained glass window.

16bit vs. 16-bit

And yes... I'm a video card freak for owning all four boards.

 

[AdamK47]

Oh sure, you moderators are getting really good laughs by moving my threads around. Grrrrrrrr!

 

[MGallik]

Hmmmm....

I'm not really sure I see it, but, I do notice the upper
image is blurred where as the lower is much sharper.

 

[AdamK47]

Thats because I had the LOD bias on the Voodoo 5 set to -1.00. If I had it set to the default 0 the textures would look sharper on the Kyro.

What I'm trying to point out is the texture rendering around distant objects is much better on the Kyro in 16-bit color than any of the other boards. Notice the frame around the stained glass. All the textures are there with the Kyro. Play Q3DM9 and zoom in on the stained glass window and your'll notice some textures being rendered incorrectly.

 

[BenSkywalker]

The Kyro always internally renders in 32bit, it just outputs 16bit color when 16bit color is selected(instead of 16bit Z and color).

 

[Deeko]

Hmmm I really don't see it....the bottom one actually looks better to me? I dunno maybe that's just the post filter in action, but I don't see what you're talking about...maybe I'm just dumb

 

[DaveB3D]

Basically this is because KYRO doesn't deal with Z data in the traditional sense. They can use 32-bit Z accuracy with no problem because they don't have to use the bandwidth, it is all internal on the chip.

 

[bluemax]

How does the Kyro stack up against the Voodoo5 when it comes to FSAA for both quality and speed?
BTW, what's a Kyro worth these days?

 

[BFG10K]

I seriously doubt anybody would notice that in normal gameplay. I'd much rather have that invisible problem than the lackluster fillrate that comes with the Kyro.

The bottom one is the 3dfx Voodoo 5. It's true that the Voodoo 5 can produce near 32-bit color quality, but the 16-bit Z buffer is still rearing it's ugly head.

Make sure you have disabled the "Depth Precision" setting under OpenGL because that might be adding additional artifacts.

 

[AdamK47]

<< Basically this is because KYRO doesn't deal with Z data in the traditional sense. They can use 32-bit Z accuracy with no problem because they don't have to use the bandwidth, it is all internal on the chip. >>


Thanks for the info Dave!



<< How does the Kyro stack up against the Voodoo5 when it comes to FSAA for both quality and speed? >>


The Kyro has pretty good FSAA for being supersampled. I'd say its supersampleing quality in 2x2 mode is the best out there. It does have a 2 sample method too, but thats either 1x2 or 2x1.



<< Make sure you have disabled the &quot;Depth Precision&quot; setting under OpenGL because that might be adding additional artifacts. >>


Never enabled it. I'm all for visual quality and that means disabling the many 3dfx's driver speed hacks.

 

[RoboTECH]

okay, I feel like a dumbass

<looks at ground and kicks a rock>

could you circle the z-buffer errors in the 5500 shot? I'm not seeing it.



****EDIT****

okay, I found an error on the stained glass frame.

at least I assume that the little line on the lower portion of the stained glass frame is what you're talking about?

<scratches head>

uh...how long did it take you to find that?

 

[Laz]

I must really be missing it, cause I see things missing in the top image. On the left side past the stained glass I only see half of the iron frame, I'm assuming this taken from a different angle and the window is reccessed (sory I don't play Quake).

 

[Ciber]

lol they both look the same to me

 

[lsd]

The bottom one looks a lot better than the top one. The image is much more sharper. IF you don't notice thats it's sharper i suggest you get some glasses

 

[AdamK47]

You Voodooers must have been playing in 16-bit your whole life. I've noticed crap popping up all over the place since I went from 32-bit on the nVidia boards to 16-bit on the Voodoo 5. That is not the only place that Z buffer errors accure. It's all over the place. You guys just don't notice them or just think it must be a problem with the game.

 

[Eug]

Well, I must say the bottom one looks better to me too.

But truth be told, I would be perfectly happy with either of those images, as long as it was lightening fast. After all, with Q3, speed is king.

 

[BFG10K]

Never enabled it. I'm all for visual quality and that means disabling the many 3dfx's driver speed hacks.

I'm sure you didn't enable it, but I believe it is turned on by default.

 

[sandorski]

Yea, I could see what Adam is talking about, but I must parrot the other comments: the bottom screenie looks better even with the missing parts. Of course it would be preferable to have all the goodness of the 2 screenies mixed into one.

 

[EvilDonnyboy]

i don't see the differences in z accuracy in the screen shots either.

maybe u should try some UT shots (if glide doens't bias things in z accuracy). i alwaz notice the flashing and tearing bullet/rocket marks with 16 bit z-buffer on my Matrox G400.

 

[shawn_16]

which kyro did you get?

 

[GraeValient]

What the hell is a Kryo

 

[vss1980]

Ok, the easiest Z error I could find in the pictures is as follows:

I am assuming the V5 is the bottom picture. Look at the stained glass. It has a sort of 2 stage concrete coloured surround. On the outer most surround, at the bottom, where the tip is, you might be able to notice that just above the tip, a Z-buffer error has occured and just above the tip a piece of the wall texture is displayed instead of the window texture/decal.
Also, the whole top-half of the outer surround is missing, which is quite a large error.

This is not a new problem, and in fact, in Half-Life happens very often on nVidia and 3Dfx cards. Also, on some maps that are large enough, due to the lack of depth offered by a 16-bit Z-buffer, some of the textures in the distance can just disappear.

Also, as Adam said, the LOD is adjusted on the V5 so it looks a little sharper, and in the games viewpoint, he is standing further back from the window on the V5 shot, so the mip-maps of textures look better.

By the way, I dont know why you 3Dfx boys are getting so happy about LOD bias control, S3 users have had that since the Savage 3D was around.

But sticking to the topic, Z errors are a pain and the only way around it is to use 32-bit, but even then, it could still happen - its just likely not to. My TNT2 exhibits the same behaviour.

 

[AdamK47]

I'm glad someone here can see it. Ever since I've been using the Voodoo 5 16-bit Z buffer errors have been jumping out at me all over the place. I would have never have noticed this had I not been playing in 32-bit color mode for a long time before hand.

 

[vss1980]

Dont worry Adam.

There are lots of other Z buffer errors that could be pointed out apart from them. Many people just simply don't notice (kinda like some cant notice the difference between a 96kbps MP3 and the CD track).

Other Z-buffer errors to look for are zig-zag edges to objects or how textures have been applied to an object. Sometimes the ends of objects have a zig-zag pattern to them - this is incorrect unless the object is meant to be like that.

 

[BFG10K]

I think most people did notice the errors but the point is that you only notice it when you are standing still and are zooming. I don't know too many people who play Quake 3 like that.