help to enhance "real 3d"?

by scarab on 02/26/2007 17:30, 24 messages, last message: 03/02/2007 20:11, 3404 views, last view: 05/05/2024 04:11

sorry for my bad english.

i have LCD shutter glasses(http://en.wikipedia.org/wiki/LCD_shutter_glasses) on an nvida graphiccard to play Sauerbraten in "real 3d" and i looks good but it can look a lot better if there is no ghost-effect (ore ghosting). i have take a 3d screenshot (.jps) renamed it in .jpg and opened it in the Gimp (http://en.wikipedia.org/wiki/GIMP) to create an anti-ghost-effect. Saved in .jps i saw nearly no ghost-effect.

i have take the picture for the left eye and subtract 20% of the picture for the right eye. I cant explain it so good. maybe you can understand it if you see that: http://www.scarab.kilu2.de/sb.png

maybe someone can programm a shader or something like that to remove ghosting in realtime?
if there is someone who can speak german i can explain it better in german.

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#5: ..

by Der/Nalia on 02/27/2007 13:43

I think nVidia has some drivers that will help with this. Checkout their site

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#6: ..

by scarab on 02/27/2007 15:52

maybe you should watch the wikipedia article to understand it: Another possible effect is "ghosting". Since the opaque phase of the LC still permits a small amount of light to transmit, some users experience secondary "ghost" images from the alternate channel. This effect can be exacerbated by persistence effects in the phosphors of the CRT, causing images to "bleed" over into the other channel.

--> the effect concerns not only the weapon!

--> I have the nvidia 3d stereo driver but its not only a driver for LCD shutter glasses. its a driver for all 3d-monitors/glasses. The problem is only by such 3d shutterglasses. (If you have a monitor that supports 100Hz refreshrate or more you can such such e very cheap LCD shutter glass. http://www.razor3d.de/en/3d_pc.asp)

--> In German:

beitrag aus nem forum den ich geschrieben hab:

1.was ist ghosting?
ghosting (auch crosstalk genannt) ist wenn ein auge eine art geisterbild
von dem warnimmt was eigentlich das andere auge sehen sollte.

2.wie entsteht ghosting?
- in erster linie durch die nachleuchtzeit des monitors.wenn das bild für ein auge gezeigt
wird leuchten die pixel von dem vorherigen bild für das andere auge nach.
- möglicherweise auch dadurch das die LCD's etwas zu früh oder zuspät schließen/Öffnen.

3.was kann man dagegen machen?

-bisher hat man fast nichts gegen ghosting unternehmen können außer einen monitor mit
P43-phosphor zu kaufen(die sehr selten sind).

- meine idee ist es das ghosting mit Pixel-Shadern heraus zu rechnen.

- dazu muss nur das aktuelle bild um ca. 90-95% verdunkelt werden und wenn das nächste
bild fertig is wird das verdunkelte bild von dem aktuellen bild abgezogen(vor dem abziehen
muss das aktuelle bild natürlich wieder verdunkelt werden und abgespeichert werden).

- jetzt stellt sich nur noch die frage ob hellere pixel länger nachleuchten oder stärker
nachleuchten oder eine kombination von beidem. die fertige rechnung könnte so aussehen:
(helligkeitsbereich z.B. 0-100 0=schwarz 100=weiß)
gezeigtes_pixel=neues_pixel-(altes_pixel -30 x0,2)

-kompatibilität: da grafikkarten schon seit ein paar jahren über leistungsfähige
Pixel-Shader verfügen müsste es auf den meisten rechnern funktionieren.

[...]

13 tage später:

Ich weiß zwar immer noch nich genau wie ghosting entsteht, aber ich hab's heute geschafft
es zu 95% aus .jps screenshots zu entfernen.

die beste qualität erziehlt man durch eine kombination aus 2 verschiedenen "verfahren":

1.das linke bild um 80-85% verdunkel und vom rechten bild abziehen(und umgekehrt).
Vorteile: -kein farbverlust
-bild wird nur minimal dunkler
Nachteil: -das aktuelle pixel muss eine bestimmte mindesthelligkeit
haben damit es funktioniert( ungefähr 10-15 wenn 0=schwarz und 100=weiß)

2.das linke bild wird invertiert um 85-95% verdunkelt und zum rechten bild addiert(und umgekehrt).
Vorteil: -funktioniert auch bei extrem dunklen bildern
Nachteil: -bild wird stark aufgehellt (um so stärker der AntiGhosting-effekt um so heller)
-farben werden blasser (um so stärker der AntiGhosting-effekt um so blasser)

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#7: ..

by scarab on 02/27/2007 15:59

this could help you to understand who it works:

None of these glasses produces an image. They are used to watch a standard monitor. They block the light from the right eye while the monitor shows an image for the left eye and vice versa. The monitor has to show separate images for the left and right eye at a high rate (usually between 80 and 160 Hz). This technique is called "time sequential stereo".

LC-Shutterglasses are often refered to as LCD-glasses, even by myself. That's not quite correct. LCD means Liquid Crystal Display, but there is no display here, just a shutter (light blocker) for each eye.

The resolution and no. of colors are infinite, they just depend on your VGA and monitor. That's the reason why IMHO the shutterglasses technology can't be beaten by any other stereo technology within the next few years. And it's cheap too. Even Headtracking is possible, as StereoGraphics demonstrated. Well, it's different from the headtracking in VR-helmets. It's used to watch objects from different angles.

The most important column in the chart is "Controller". The Controller makes the difference. You may also build your own homebrew controller. Please consult the Controller Comparison Chart.

For issues concerning the physical appearance and comfort of different glasses please go to the X-RAY Lab.

The major drawback of Shutterglasses is cross-talk (ghosting). Another drawback is flicker, but this can be dealt with by using high refresh rates.

LCD Shutterglasses require a standard CRT (cathode-ray tube) monitor or CRT-projector. They're not compatible to LCD- screens or -projectors.

The wired Shutterglasses usually have a standard 3.5 mm stereo jack (like a walkman headphone) and should be interchangeable. The new VESA-connectors have different electrical specifications! Do not connect your "old" glasses to a VESA 3 connector directly or through a "dumb" adaptor. You'll need an intelligent adaptor. Consult the technology page for details.

Check out the Technology Page and the 3D-Boards Page!

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#8: ..

by Max of S2D [Fr] on 02/27/2007 19:23

If there is a ghost effect, that's because your weapon rotate a bit when you walk.

/maxroll 0

will stop this effect ;)

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#9: ..

by scarab on 02/27/2007 20:04

no, its no bug in the engine, it a problem of 3d shutter glasses. it in all games, not only in sauerbraten.
i talk about real 3d not about 3d viewing on a 2d monitor.

i just think that it would be cool to play without this effect and thats maybe not so hard to programm something to remove it.

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#10: Re: ..

by shadow,516 on 02/27/2007 20:26, refers to #9

This is something you need to bring up with nVidia.

We're not going to program a shader like this for such a niche market. The nVidia drivers should have ghost-correction built in.

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#11: ..

by scarab on 02/27/2007 21:11

is it difficult to programm such a shader? sauerbraten already use shaders.
if it works in a game i can post it in the nvidia-stereo-3d forum and nvidia maybe integrate it in his driver.

and maybe soon its not any longer a niche market.

if it work, sauerbraten would be the first game with a perfect locking real 3d engine and that with only 20€ hardware costs.

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#12: Re: ..

by Drakas on 02/27/2007 21:35, refers to #9

umm... if this is not a sauerbraten issue, why do you bring it up???

Ask aard or eihrul directly for suggestions. Putting it up in the forum won't help.

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#13: ..

by ethan592 on 02/27/2007 21:55

i imagine that this occurs because of how the weapon is displayed. the gun model is displayed relative to the camera. why not just do /hudgun 0 so you dont see it?

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#14: um

by Aardappel_ on 02/27/2007 22:07

this might be happening because the hudgun is not drawn in correct proportion withe the rest of the 3d world (it is slightly fake to stop the barrel poking into walls).

This can maybe fixed to some extend, but frankly we don't have time to support such specialized hardware setups right now. Like someone said, either put up with the ghosting or play with "hudgun 0".

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#15: Re: um

by shadow,516 on 02/28/2007 04:13, refers to #14

Maybe we could have the hudgun \"push back\" when you come close to a wall. It would be a pretty neat feature.

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#16: Re: um

by Pxtl on 02/28/2007 05:20, refers to #15

Apparently lots of games have this problem. Similarly, in many games all the HUD stuff is drawn at infinity... which is, depth-wise, further away than all the terrain it's being drawn over. So you've got something that appears to be in front of everything, but your depth-perception says is in behind.

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#17: ..

by SanHolo on 02/28/2007 08:40

Someone explains that gohsting is caused by the afterglow of the previous picture on the CRT monitor. I now ask myself why this is also visible on the screenshots...

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#18: Re: um

by Passa on 02/28/2007 13:21, refers to #15

Eew, Area 51 does that, gives me motion sickness..

FEAR does it a little too, but to a far less severe degree.

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#19: ..

by scarab on 02/28/2007 14:13

re:#17: that right. at the picture i have simlulate the ghosting because you cant make a screenshot of it.

i make a new graphic that shows all more clearly.

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#20: ..

by scarab on 02/28/2007 15:55

i have made a video (with my mobile phone): http://www.scarab.kilu2.de/3d-brille/28022007.3gp.WMV

and a graphic: http://www.scarab.kilu2.de/3d-brille/lcdsg.gif

on the video you dont see the ghosting very intense but at the light its realy intense.

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#21: ..

by cookies_suck_omg_who_the_hell_keeps_these_things on 03/02/2007 11:36

have you heard of youtube

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#22: ..

by scarab on 03/02/2007 13:10

what do you mean?

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#23: Re: ..

by Drakas on 03/02/2007 16:10, refers to #22

don't listen to him :)
the file runs fine.

i doubt that anyone will actually imlement what you'd like to see :(

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#24: ..

by scarab on 03/02/2007 20:11

:(

i have started a thread at the nvidia stereo forum. maybe someone there can help.

if someone is interested ore find this thread via google, here is the link:
http://forums.nvidia.com/index.php?showtopic=29375&st=0&p=166137&#entry166137

thank you for your attention.

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