Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: aldo_14 on September 20, 2002, 04:53:47 pm
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right...I've decided that part of my problems with clipping in games may very well be down to my archaic GFX card (GeForce 2 MX 100/200, 32Mb)...so I'm wondering if anyone else has encountered this in, well any games.... mainly if the owners of older Nvidia (or other) cards have noticed clipping in newer games and FS.. (i.e. the guns on the Herc Mk.I).
for me, the worst problem is Op:Flashpoint & I-War 2, which suffer horribly on occassion (especially Op:F), and this annoys the hell out of me. also, it makes clip-testing FS ships much harder.
Hence the poll.
Also, can anyone recommend a good sub £150 graphics card (remeber I'm in the UK)? I'm hoping to get a new, better one around Christmas time... mainly as I'll have a few paycheques in the bank, and also cos my bruv moves out in december - taking the PS2 with him.
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When you say clipping, do you mean zbuffer problems?
Clipping is the splitting of a polygon usually because it is off the edge of the screen. Z or W buffering (same thing really) is the system that determines which polygons are infront of each other, and what order they are rendered in.
If this goes wrong then polygons which you shouldnt be able to see because its behind something can flicker in and out of view.
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I have a 8MB onboard...:nod: and its works pretty well even though the box is only 4 years old...:rolleyes:
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GF3 cards are on sasle for only about 80 dollars in some places.
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Cheap as...:nod: I would get one but I ain't got no AGP slot only PCI:eek2:
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I used to get some strange clipping and textures effects quite often on some older cards (TNT in particular) when running certain games on Direct3D mode but have not noticed it for years now.
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hmmm, I don't seem to have clipping problems at all on my GeForce 2 GTS. (I'll find out more details on these "clipping" things though, I may be wrong on my asessment)
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No noticable clipping problems for my GF4 Ti 4600, and thats with the latest FS2 and nVidia Detonator drivers for 98...
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Are you running Win98 Thunder...I assumed if you had a GF4 Ti4600 (Also assuming a 'state of the art' computer system) you might be running WinNT4.0 or is it because of the File System..
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Originally posted by RandomTiger
When you say clipping, do you mean zbuffer problems?
Clipping is the splitting of a polygon usually because it is off the edge of the screen. Z or W buffering (same thing really) is the system that determines which polygons are infront of each other, and what order they are rendered in.
If this goes wrong then polygons which you shouldnt be able to see because its behind something can flicker in and out of view.
I believe so, yeah. Occlusion problems where the card renders occluded polygons 'simultaneously', so they are visible at the same time as they're being occluded (from what I remember). I did think that it could be the z-buffer, but I'm not totally sure, because I don't have anything else to compare it with.
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Originally posted by Max
Are you running Win98 Thunder...I assumed if you had a GF4 Ti4600 (Also assuming a 'state of the art' computer system) you might be running WinNT4.0 or is it because of the File System..
Yep, Windows 98... I want to move to XP Pro but afformentioned price problems plus the fact I'd have to get it legit would be a hassle.
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Originally posted by RandomTiger
...Z or W buffering (same thing really) is the system that determines which polygons are infront of each other, and what order they are rendered in.
This is a bit wrongly said. Z-buffer has no effect on the rendering order of primitives. Nor it works on per-polygon-level like you suggest, rather on per-pixel-level.
If this goes wrong then polygons which you shouldnt be able to see because its behind something can flicker in and out of view. [/B]
If complete polygons flicker in and out of view, it's very rarely about Z-buffer. Usually it's about drawing some things in wrong order when Z-buffering is not enabled.
If parts of polygons ( by "parts" I mean horizontal lines or blocks ) show on top of other polygons, it's called Z-buffer clipping or tearing, and this is the effect seen in for example Freespace. It's caused by too low precision of the Z-buffer. The idea of Z-buffer is to store the z-values of pixels drawn on screen on a buffer. If a pixel is about to be drawn over another pixel that has a Z-value closer to the screen, the drawing of the pixel gets aborted. But very often there are cases where the Z-values of the pixels are so close to each other that the numeric precision of the Z-buffer can't tell which is closer to the screen. And that's when pixels that shouldn't get drawn get drawn over other pixels.
Z-buffer tearing problems shouldn't really exist in today's cards playing today's games. I wouldn't even say it's about the card itself, every new card has a 32-bit Z-buffer which has more than enough precision. It's either about the drivers or the application.
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Your right of course it being on a per pixel level but when its really bad it does look like whole polygons are invloved.
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Originally posted by Max
I have a 8MB onboard...:nod:
Same here. :no::sigh::doubt:
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Aldo, seeing as this thread has kind of gotten off topic, I will answer your question as directly as possible. Get a GeForce4 ti 4200. It should be available for less that 96 lbs.(sorry I don't have a symbol for them), that is less than $150 US.
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This is it;
(http://www.3dap.com/hlp/hosted/reciprocity/aldostuff/clip1.jpg)
(http://www.3dap.com/hlp/hosted/reciprocity/aldostuff/clip3.jpg)
(zoomed in with binoculars)
(http://www.3dap.com/hlp/hosted/reciprocity/aldostuff/clip2.jpg)
(normal range - still there, less visible)
From Op:Flashpoint, i also have some less severe problems with I-War 2.
I'm beginning to wonder if it is to do with the game engine...because it's far more apparent here than in other games (including newish ones like Max Payne and Startopia). It's still very annoying. the other, probably unconnected thing is that there are some strange artifacts occuring when rendering black smoke, explosions (any time of day) or (on the entire screen) in nightime - these resemble small blobs evenly spaced... I don;t have a technical term and can;t take a screenshot (they get omitted..maybe it's a disply thing, but I'd doubt it)...
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Originally posted by Eternal One
If complete polygons flicker in and out of view, it's very rarely about Z-buffer. Usually it's about drawing some things in wrong order when Z-buffering is not enabled.
Hmm...actually, it springs to mind now that there's a 'W-buffer' option in the graphics options section for op:f, which my card doesn't support. Not sure what W-buffer is though.
(Um, and I guess clipping is a bad term...AFAIK, 'clipping' is the process of subdividing partially occluded faces so only the non-occluded part is rendered)
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Aldo, that's very bad Z-buffer artifacts/tearing/clipping/whatever you got there. Are you sure you've got your card's driver options set out properly? Make sure you don't have your z-buffering restricted to 16-bit or similar. Also, GF2 family should support W-buffering, even my Radeon 7000 does. W-buffer is a more "accurate" Z-buffer, and it'd really help if you could turn it on.
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Originally posted by Eternal One
Aldo, that's very bad Z-buffer artifacts/tearing/clipping/whatever you got there. Are you sure you've got your card's driver options set out properly? Make sure you don't have your z-buffering restricted to 16-bit or similar. Also, GF2 family should support W-buffering, even my Radeon 7000 does. W-buffer is a more "accurate" Z-buffer, and it'd really help if you could turn it on.
I am wondering myself, if i've been an utter tit and screwed it up by switching it to 16 bit colour (I presume) mode... which apparently isn't the best choice.......I'm going to twiddle and see what works, but i'm intending on reformatting my HD and restting all my setting swhen I can get enough CD-Rs, anyways.
EDIT - I am a tit. It seems to work fine in 32 bit mode...i presume this is buffer size and not colour, then (did the Vodoo cards use a 16-bit z-buffer? Because they apparently don't support this). However, I cannot activate W-buffer - it won't let me select this option. I cna only presume this is because I somewhat idiotically bought the PC without checking the specs enough. (on the other hand, it was cheap, so ne'ermind - youg et what you pay for)
The one thing it doesn't explain, is why some of my models have less noticeable clipping on other PCs than on mine.
EDIT2 - BTw, big thanks Eternal One...if you hadn't mentioned 16-bit buffering, I'd probably never had cottoned on.
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Might also be drivers. I had trouble with Battlezone II until I realized that my drivers had a DirectX 5 compatability mode that I had checked and DirectX7 Battlezone II didn't like it much.
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I used to have a GF2 32meg. No clipping problems asa bad as you have.
Course now I have a GF4 64meg, and I'm a happy pilot :nod:
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clipping is due to a bad Z-buffer depth.
if your card only likes running a 32bit Z-buffer (like mine) then it wont like a game that assumes and 8bit Zbuffer, hence the strange clipping problems, distance fade hall-of-mirrors effect etc.
Its simply a case of lazy game design rather than a problem with the hardware.