Why do textures look crap? (.. and in GTL)

[pentoman]

Does anyone else notice a slight purple tinge to textures on some PC games? I will post some screenshots to show what I mean. I have a X800 GTO Radeon

I notice it because I am now using a big 26" LCD screen to play games and it really stands out. I notice it most on track textures in GTL, I have tried changing mipmap quality, Anisotropic Filtering, Anti Aliasing in the radeon settings but to no avail. I also tried the all the LOD quality/circuit detail level settings in GTL but it won't go away.

It's pretty bad here on Magny Cours Club:


Different view:


The afflictions I'm talking about if you can't see them:


It's pretty bad here too:


Less bad with the sun shining on it, but still noticeable:


And not there at all on the Castle Combe add-on track?:


I wouldn't normally complain but, since getting an xbox 360, the graphics are so good I'm noticing these little things now..

Russell

[xiphias]

Well, I think it's either the shader level under setup, or the colour profile of your screen?

[Jungles]

Lossy compression sometimes causes artifacts like that. Some procedurally-created textures, especially those involving "noise", can contain a lot of purplish blotches/speckles as well.

Another reason could be a common lighting artifact in some graphics renderers. Specular highlights and refractions can cause bluish, pinkish, or purplish colours.

Nearly impossible to know the exact cause without delving further into the textures themselves, the workings of the 3D graphics rendering engines involved, and your hardware and software configuation.

Edited by Jungles on Sunday 20th August 15:12

[_dobbo_]

It's hardly noticable at all on my screen - a Dell 20" TFT. I think I can only just see it where you have circled, and not at all on any of the other images.

[FourWheelDrift]

You won't notice it at all if you use cockpit view

[diver944]

I can't see any puplish at all, looks fine to me????

TBH I'm really not bothered what it looks like, its the drivability that counts in a sim. As long as I can see car shapes and they seem to move smoothly (and get out of my way) then I'm a happy bunny

[mackie1]

I can't see it in those grabs but I know what you are talking about, I've experienced it before. I play on an X800-XL connected to a Hyundai L90D+ 19in LCD and it looks perfick.

[pentoman]

diver944 said:

I can't see any puplish at all, looks fine to me????

TBH I'm really not bothered what it looks like, its the drivability that counts in a sim. As long as I can see car shapes and they seem to move smoothly (and get out of my way) then I'm a happy bunny

Fair enough, agreed the driveability is awesome, and I even thought the graphics were awesome on GTL, but when you're sat less than a metre from a 26" screen you notice this stuff pretty badly and it does rather taint the graphics side of things for me!

[UK952]

Ill swap your 26" screen for my 19" problem solved
Tony

[_dobbo_]

I'd wager it's because your 26" LCD is a TV rather than a PC monitor and that the internals are of lower quality. Perfectly adequate for TV use but not for close up PC work.

My 32" plasma looks crap up close with the laptop driving it compared to a proper PC monitor

[dilbert]

I don't know for sure. I'd hazard the following guess.

When the image is generated, textures are generally stretched to fill areas from a sample. This is usually done by convolution. Often, there is a mechanisim for doing gamma correction, throughout the pixel data path. You may not have a direct mechanisim to control it. The trouble with gamma correction is that if you add it in before and remove it after convolution, there is a loss of precision in the pixel data during convolution.

I'm guessing that this is where your "Chromatic Aberration" is coming from.

Edited by dilbert on Monday 21st August 13:01

[pentoman]

_dobbo_ said:

I'd wager it's because your 26" LCD is a TV rather than a PC monitor and that the internals are of lower quality. Perfectly adequate for TV use but not for close up PC work.

My 32" plasma looks crap up close with the laptop driving it compared to a proper PC monitor

There's one fatal flaw in that though.. you can see it in the screenshots! On any monitor! So it can't be the screen!

"Chromatic Abberation" seems likely.

It's just an annoying thing I notice, a bit like that purple edging you get with poor(er) quality camera lenses.

[_dobbo_]

pentoman said:

There's one fatal flaw in that though.. you can see it in the screenshots! On any monitor! So it can't be the screen!

Not quite correct. I can only just see it on on one monitor I use - and not at all on another three different ones, including a laptop. I only know it's there becuase you circled it and there is no way I would ever have noticed it otherwise.

Also at least one other person here has said they can't see it. So it obviously doesn't show at all on some monitors, and only a tiny a bit on others.

So I stand by my earlier comment, if it's bothering you on your LCD it's likely because it's not up to the quality of dedicated computer monitors.

Edited by _dobbo_ on Thursday 24th August 15:29

[FourWheelDrift]

pentoman said:

There's one fatal flaw in that though.. you can see it in the screenshots! On any monitor! So it can't be the screen!

Isn't that because you have captured the image as it appears on your monitor, the same way it would look if it was a black & white screenshot. If you look at the same track/texture on another monitor it'd probably be different and you could probably post a screenshot showing it.

I can only see it in the screenshots when it's circled, but it does look as though it's repeated to me, if it is a texture problem instead of a monitor problem isn't it just because of the texture map used, the colours being on the original photo/converted photo to dds graphic?

[dilbert]

_dobbo_ said:

pentoman said:

There's one fatal flaw in that though.. you can see it in the screenshots! On any monitor! So it can't be the screen!

Not quite correct. I can only just see it on on one monitor I use - and not at all on another three different ones, including a laptop. I only know it's there becuase you circled it and there is no way I would ever have noticed it otherwise.

Also at least one other person here has said they can't see it. So it obviously doesn't show at all on some monitors, and only a tiny a bit on others.

So I stand by my earlier comment, if it's bothering you on your LCD it's likely because it's not up to the quality of dedicated computer monitors.

Edited by _dobbo_ on Thursday 24th August 15:29

It accept it may be the case that you can only just see it in a still image. Obviously the "feature" must be there because I can see it both when circled and not. It's in the data. The better your display, the more likely you are to see it.

More importantly though this is a still image. IIRC a "british standard" human has better edge perception for moving objects. This is mainly to do with contrast, but also to do with colour.

[pentoman]

FourWheelDrift said:

pentoman said:

There's one fatal flaw in that though.. you can see it in the screenshots! On any monitor! So it can't be the screen!

Isn't that because you have captured the image as it appears on your monitor, the same way it would look if it was a black & white screenshot. If you look at the same track/texture on another monitor it'd probably be different and you could probably post a screenshot showing it.

I can only see it in the screenshots when it's circled, but it does look as though it's repeated to me, if it is a texture problem instead of a monitor problem isn't it just because of the texture map used, the colours being on the original photo/converted photo to dds graphic?

Not sure what you're saying there.. the screenshot will be identical whatever your monitor, as it's taken out of the video buffer of the graphics card.

I am at work now, on a 17" DELL CRT. The effect is much less noticeable (the whole image is softer in fact) - so I totally see why everyone is having trouble seeing it, it seems like I'm going crazy!

But I assure you it's very noticeable on a big LCD. Mine's a brand new Samsung LE74 which is a good model, and I even especially bought a super-fancy-pants VGA cable for it.
Apart from this annoyance though, the image is amazing for playing GTL!

[_dobbo_]

dilbert said:

The better your display, the more likely you are to see it.

I believe the reverse is true. Both my 21" CRT at work and my 20" TFT at home were/are expensive bits of kit.

My 20" TFT at home, which is a "proper" monitor goes to substantially higher resolutions than any 26" LCD TV. I can see the purple bits but hardly at all. Certainly I've never noticed them when playing GTL at 1650x1080. Those samsung TVs can't get near that resolution.

Don't get me wrong I'm not saying LCD TVs are in any way bad, I'm just saying for PC use there is no way a TV will be remotely as good as a similarly priced or even a cheaper dedicated PC monitor.

[dilbert]

_dobbo_ said:

dilbert said:

The better your display, the more likely you are to see it.

I believe the reverse is true. Both my 21" CRT at work and my 20" TFT at home were/are expensive bits of kit.

My 20" TFT at home, which is a "proper" monitor goes to substantially higher resolutions than any 26" LCD TV. I can see the purple bits but hardly at all. Certainly I've never noticed them when playing GTL at 1650x1080. Those samsung TVs can't get near that resolution.

Don't get me wrong I'm not saying LCD TVs are in any way bad, I'm just saying for PC use there is no way a TV will be remotely as good as a similarly priced or even a cheaper dedicated PC monitor.

Without wishing to patronise, at the level you are talking it's entirely subjective.

To to be able to see this sort of defect one needs a greater video bandwidth. If the increased video bandwidth introduces noise and instability (which this artefact is not) then the improvement in performance has not introduced an improvement in quality.

A bigger video bandwidth is more difficult to achieve without introducing noise and instability, and with this in mind a greater video bandwidth is better.

To see more of the image is not always what you want, as in this case. Some systems introduce video filtering, which limits the bandwidth. These systems have a high bandwidth but recognise this does not necassarily lead to picture quality. The thing is if you have a good high bandwidth display, you can introduce a filter of your choice. If you don't have a good high bandwidth display, you cant turn it into one whatever you do.

So, what this means, is if your display shows, or can be made to show, these artefacts, then it has a better capability, than one which will not. The decision about wanting to see them is purely subjective.

This ideology is tied up with what I believe is the problem in the pixel path of this games console. During the design, they have concluded that problems may occur, so functionality has been introduced with the intention of correcting any faults. The trouble is that it has introduced problems of it's own which cannot now be removed with ease.

The same is true for a bigger display too. A bigger display is not necassarily better, unless resolution increases with the square of display size. If you have a bigger display, and the resolution does not correspondingly increase, then the pixels get bigger. Individually the pixels are easier to see. This makes aliasing perceptually worse, and the video bandwidth has to be reduced to make an allowance.

Less is more!

Edited by dilbert on Thursday 24th August 18:21

[pentoman]

_dobbo_ said:

dilbert said:

The better your display, the more likely you are to see it.

I believe the reverse is true. Both my 21" CRT at work and my 20" TFT at home were/are expensive bits of kit.

My 20" TFT at home, which is a "proper" monitor goes to substantially higher resolutions than any 26" LCD TV. I can see the purple bits but hardly at all. Certainly I've never noticed them when playing GTL at 1650x1080. Those samsung TVs can't get near that resolution.

I play in 1360x768, the TV's max resolution, which isn't too bad.

I was extremely super careful about buying this TV to use as a monitor (ask my girlfriend...!) because I am a hi-res lover, using 1600*1200 on my previous 19" CRT (even once using 1920x1xxx on it!).

However I have not regretted it. The lack of vertical resolution is the only irritation when you have lots of windows open, and you also tend to notice poor details/parts of the image very easily when you've got a 26" image 50cm in front of you at not a terribly high resolution.

Also I have it set to a fairly spangly image mode, with strong colours and contrast, which I'm sure amplifies a lot of things you might otherwise not notice.

I think those combine to say why it's so noticeable.

It's the same on xbox 360 - it looks fantastic from normal TV-sitting distance, but if you sit 50cm away like you do with a PC monitor, you start to notice things.