Pixel shader vs. vertex shader?

[Guest]

What should I be using? I have a GeForce3. I noticed if I have both turned on, the planets tend to have an unnatural look.. kind of a white-washed look to them. If I turn off vertex shaders, then the colors look better. I also noticed turning off pixel shaders when looking at Mars gets rid of bump mapping it appears.. the shadows look better with pixel shaders on.

Looking at earth, if pixel shaders and vertex shaders are on, it has a specular hilight making it look like a plastic ball.. i'm not really sure if earth has that kind of "shine" to it Turning off vertex shaders (but leaving pixel shaders on) again gives it a more natural look...

Does anyone know which configuration yields the most realistic appearance?

[Rassilon]

kind of a white-washed look to them. If I turn off vertex shaders, then the colors look better

Make sure your desktop is in 1024x768x32bit at minimum...

[MDesigner]

Hi, I was Guest previously :)

OK my desktop is already at 1280x960. So.. what about my questions on pixel shaders & vertex shaders?

[t00fri]

Hi, I was Guest previously :)

OK my desktop is already at 1280x960. So.. what about my questions on pixel shaders & vertex shaders?

I am surprised that you do not find the combination of pixel and vertex shaders nice. Have a look at my latest images in Bruckner's galery, e.g. Central America. Most people find it quite good.

I do the hires bumpmapping by means of GIMP in the texture file.

You may also adjust the specular reflections in solarsys.ssc to your taste by playing with the settings for

Specular Power
and specular color.

Bye Fridger

[Miserableman]

I find there is no difference in visual quality between no shader/pixel shader/vertex shader on my GeForce2, except I lose a good 10 frames a second with them both on.

So I turn them both off :O)

[t00fri]

I find there is no difference in visual quality between no shader/pixel shader/vertex shader on my GeForce2, except I lose a good 10 frames a second with them both on.

So I turn them both off :O)

Probably you are also a Windows user (since you did not tell your OS;-))? The reason why this matters is that in the Linux version of Celestia-1.2.4 and smaller, many keys do /not/ work, including CTRL P (pixel shader on|off) and CTRL V (vertex shader on|off). In the CVS version, I have fixed all keys to work properly.

With me it does make a BIG difference whether the P&V shaders are on or off...

Bye Fridger

[chris]

I find there is no difference in visual quality between no shader/pixel shader/vertex shader on my GeForce2, except I lose a good 10 frames a second with them both on.

So I turn them both off :O)

It depends on what object you're looking at . . .

In the default Celestia 1.2.4 package, only Mars, Mercury, Earth, the Moon, and Pluto have pixel and vertex shader effects visible on a Geforce2. All the major planets and moons with atmospheres have a haze effect applied, but this is only visible on a GF3+ because of a bug with software vertex program emulation that appears in some earlier versions of nVidia's OpenGL drivers.

--Chris

[Matt McIrvin]

The real Earth has shiny oceans, but not shiny continents. With some graphics cards, Celestia can mimic this with an ocean gloss map.

[JLP]

Too bad that Radeon 8500 isn't supported

[Mikeydude750]

Too bad that Radeon 8500 isn't supported

Ah yes, but that is another reason why NVidia's cards are a lot better. They are more powerful, and support more effects. Not that the Radeon 8500 is bad, mind you, but I would rather have a GF4 TI 4600 in my computer. Too bad my computer doesn't have an AGP port(thanks to the punks who invented Direct AGP), so I have to use a decent PCI card.
Even if I had an AGP port open, I still couldn't use the newest cards. My computer would still suck.

Trust me, my next computer WILL have a 4600 in it, even if I have to pay 2.5 G's for it.

[Miserableman]

I find there is no difference in visual quality between no shader/pixel shader/vertex shader on my GeForce2, except I lose a good 10 frames a second with them both on.

So I turn them both off :O)

Probably you are also a Windows user (since you did not tell your OS;-))? The reason why this matters is that in the Linux version of Celestia-1.2.4 and smaller, many keys do /not/ work, including CTRL P (pixel shader on|off) and CTRL V (vertex shader on|off). In the CVS version, I have fixed all keys to work properly.

With me it does make a BIG difference whether the P&V shaders are on or off...

Bye Fridger

I am a Windows user.

Perhaps I didn't make myself clear - when I enable pixel shading, Earth seems to darken slightly around the edges. When I then enable vertex shading, a specular (right word to use?) gloss is applied to the sphere. Both effects work, but neither actually increase the visual quality, and vertex shading takes a good chunk out of my cards performance.

Incidentally vertex shading doesn't work unless pixel shading is enabled - I assume this is correct, no?

[JLP]

Ah yes, but that is another reason why NVidia's cards are a lot better. They are more powerful, and support more effects. Not that the Radeon 8500 is bad, mind you, but I would rather have a GF4 TI 4600 in my computer. Too bad my computer doesn't have an AGP port(thanks to the punks who invented Direct AGP), so I have to use a decent PCI card.
Even if I had an AGP port open, I still couldn't use the newest cards. My computer would still suck.

Trust me, my next computer WILL have a 4600 in it, even if I have to pay 2.5 G's for it.

Actually Radeon 8500 supports more features then nVidias latest cards do. And if you read carefuly I said that Celestia doesn't support Radeon and not that Radeon doesn't support pixel and vertex shaders.which are much better and reacher implemented on Radeon 8500. And I considered buying GF4. But when I saw piss poor 2D picture quality on all samples I tried I decided for Radeon 8500. I mosly work in 2D so picture quality is very important to me and nVidia still is not an option here.

[t00fri]

Actually Radeon 8500 supports more features then nVidias latest cards do. And if you read carefuly I said that Celestia doesn't support Radeon and not that Radeon doesn't support pixel and vertex shaders.which are much better and reacher implemented on Radeon 8500. And I considered buying GF4. But when I saw piss poor 2D picture quality on all samples I tried I decided for Radeon 8500. I mosly work in 2D so picture quality is very important to me and nVidia still is not an option here.

I agree. All our leading measuring reports over here agree that the 2D quality of the latest GeForce (3 + 4) cards has enormously deteriorated compared to GeForce 2 GTS (output filters!).

There is generically a strong decrease in performance at 1600x1200. I run my GeForce 2 GTS at 1600x1200 on a very good monitor and my 2D quality is superb!

Since my professional work is also mostly 2D, I have not yet dared to upgrade to GeForce 4...

Bye Fridger

[chris]

Actually Radeon 8500 supports more features then nVidias latest cards do. And if you read carefuly I said that Celestia doesn't support Radeon and not that Radeon doesn't support pixel and vertex shaders.which are much better and reacher implemented on Radeon 8500. And I considered buying GF4. But when I saw piss poor 2D picture quality on all samples I tried I decided for Radeon 8500. I mosly work in 2D so picture quality is very important to me and nVidia still is not an option here.

I haven't seen a difference in 2D quality between nVidia's and ATI's cards, but it does depend somewhat on the vendor making the card. Though I do work for nVidia, I still try to stay objective, and the Radeon 8500 does indeed have a more flexible pixel shader than the GF3/4. It's not supported in Celestia simply because I don't have an 8500 at home. That's not likely to change, thus I have zero interest in writing code to use ATI specific extensions. What I will do is use non vendor specific OpenGL extensions whenever they provide the functionality I need. ARB_vertex_program should be standardized soon, and I'll start using it provided that it gives me everything NV_vertex_program does. Together with the DOT3 texture extension, that should be enough to make bump mapping work nicely on the Radeon (strictly speaking, all I need is DOT3, but I'm lazy that way.) For non-standard stuff, I'll stick to nVidia extensions. Porting to another vendor's extensions just isn't how I want to spend my weekends

--Chris

[Mikeydude750]

Ah yes, but that is another reason why NVidia's cards are a lot better. They are more powerful, and support more effects. Not that the Radeon 8500 is bad, mind you, but I would rather have a GF4 TI 4600 in my computer. Too bad my computer doesn't have an AGP port(thanks to the punks who invented Direct AGP), so I have to use a decent PCI card.
Even if I had an AGP port open, I still couldn't use the newest cards. My computer would still suck.

Trust me, my next computer WILL have a 4600 in it, even if I have to pay 2.5 G's for it.

Actually Radeon 8500 supports more features then nVidias latest cards do. And if you read carefuly I said that Celestia doesn't support Radeon and not that Radeon doesn't support pixel and vertex shaders.which are much better and reacher implemented on Radeon 8500. And I considered buying GF4. But when I saw piss poor 2D picture quality on all samples I tried I decided for Radeon 8500. I mosly work in 2D so picture quality is very important to me and nVidia still is not an option here.

Well, I guess I was wrong on the 2D part. I just keep myself informed on the 3D parts of the cards. Sorry about that.

Looks like someone should add support for the Radeon here.

[Thilo]

Actually the C'T ( a german magazine) thoroughly tested GeForce4 cards, and came to the same conclusion.

The best card, that scored a "good" (in the school grade system) was the VisionTek Xtasy card, and that's the card that i have recently bought. The 2d quality is okay, and performance in Celestia is wonderful. (I'm working with Linux).

[t00fri]

Actually the C'T ( a german magazine) thoroughly tested GeForce4 cards, and came to the same conclusion.

The best card, that scored a "good" (in the school grade system) was the VisionTek Xtasy card, and that's the card that i have recently bought. The 2d quality is okay, and performance in Celestia is wonderful. (I'm working with Linux).

In fact among others I was implicitly referring to the C't test measurements. Normally their results are quite reliable...

Good to hear that your 2D quality is reasonable. Much usually depends also on the bandwidth of the connected monitor /and/ the quality of the cable, of course.

Bye Fridger

[boertje]

the question remains...
I also think that vertex shaders seem to have funny effects. Of course viewing the reflection of the sun on the oceans is pretty nice but mars only seems brighter and loosing bump mapping effects. Turning them off seems much better to me there. What are the vertex shaders actually working on at mars? atmosphere? On the other hand Pluto and Mercury again look more detailed (and gaining bump mapping effects). I'm a little confused and don't want to surf space with having two fingers on ctrl+v all the time ;)
btw I'm using a gf3

[Size_Mick]

I don't really expect an answer now that we're all the way to page 2, but does the Geforce2 series even support pixel shaders? Specifically, I have a Geforce2 MX and I thought it only supported vertex shaders, and I'm not even sure about that. Would it do anything for me to turn on pixel shaders? Franky I can't tell the difference with vertex shaders on.

PC is running Win2k and Detonator 28.32, and I run Celestia in 1024x768 32bpp in case that matters.

[t00fri]

I don't really expect an answer now that we're all the way to page 2, but does the Geforce2 series even support pixel shaders? Specifically, I have a Geforce2 MX and I thought it only supported vertex shaders, and I'm not even sure about that. Would it do anything for me to turn on pixel shaders? Franky I can't tell the difference with vertex shaders on.

PC is running Win2k and Detonator 28.32, and I run Celestia in 1024x768 32bpp in case that matters.

With my GeForce 2 GTS everything that is needed works.

Go to Mercury and press CTRL P you should see a difference.

In order to see the specular reflections of the sun in the oceans of the earth, you have to have both pixel and vertex shaders active /AND/ you need to use a texture with an alpha channel, in which the info on reflections are stored! This file can only be a *.png (or specially prepared *.dds) format, NOT a JPEG!

Bye Fridger