Image Quality of various old video cards (Quake 3 comparison)

[silikone]

About the awful looking texture compression on Geforce. Is this a fault of the real-time compression taking place, or do the GPUs have trouble rendering even off-line compressed DXT1?

[The Serpent Rider]

About the awful looking texture compression

Which?

[silikone]

Which?

Infamous horrible DXT1 compression on pre-Geforce 4 card

[Fusion]

I'm not sure how any of us put up with these comparison shots.

"look at this 640x480 screenshot of the *insert card* vs the *insert card* running at 1600x1200.

[leileilol]

especially this bullshit one!!! Stinks of 3dfx fan revisionist history.

[appiah4]

I'm not sure how any of us put up with these comparison shots.

"look at this 640x480 screenshot of the *insert card* vs the *insert card* running at 1600x1200.

What does resolution have to do with the horrible skybox banding?

[leileilol]

The fabled "perfect" Voodoo also has banded filtering, fwiw....

[kithylin]

The fabled "perfect" Voodoo also has banded filtering, fwiw....

I guess I'm blind then. The voodoo one in the screenshot above looks pretty smooth and nice in the sky box there, at least compared to the screenshot on the left to my eyes. I see nothing at all wrong with the voodoo in that screenshot.

[leileilol]

Yep. Let's look real close into a zoomed 32x32 32-bit texture (swizzled to rgba4444 don't tell anyone) for The Truth(tm)


(also full disclosure this engine is id tech3 and there's no overbrights enabled here therefore it's as accurate as accurate can be)

Therefore by fact i'm right and everyone using these cards are idoits for using low quality filter product!!!!!!!!!!

[kithylin]

Yep. Let's look real close into a zoomed 32x32 32-bit texture (swizzled to rgba4444 don't tell anyone) for The Truth(tm)


(also full disclosure this engine is id tech3 and there's no overbrights enabled here therefore it's as accurate as accurate can be)

v3filter.png

Therefore by fact i'm right and everyone using these cards are idoits for using low quality filter product!!!!!!!!!!

Except of course no one can see the actual sky texture zoomed in that far. So your point is academic at best. In normal game play you view it from a distance. Which is all that matters. From normal view distance the sky looks perfectly fine, over on the voodoo side at least, in the above screenshot. Sorry but no one cares how your sky textures look when you zoom in under a microscope. All anyone actually cares about is how it looks when actually playing the game.

[The Serpent Rider]

VSA100 have perfect linear filtering in 32-bit color. It's practically identical to a modern GPU.

Is this a fault of the real-time compression taking place

Yes.

[silikone]

According to the source code, Quake 3 uploads the textures to a format called GL_RGB4_S3TC, but all documentation available online points to GL_COMPRESSED_RGB_S3TC_DXT1_EXT being the standard. I wonder if this has any implications for the image quality when texture compression is not disabled (but why wouldn't you).

[Fusion]

I'm not sure how any of us put up with these comparison shots.

"look at this 640x480 screenshot of the *insert card* vs the *insert card* running at 1600x1200.

What does resolution have to do with the horrible skybox banding?

I was talking about reviewers back in the day, I should have clarified.

[spiroyster]

According to the source code, Quake 3 uploads the textures to a format called GL_RGB4_S3TC, but all documentation available online points to GL_COMPRESSED_RGB_S3TC_DXT1_EXT being the standard. I wonder if this has any implications for the image quality...

GL_RGB4_S3TC and GL_COMPRESSED_RGB_S3TC_DXT1_EXT are one and the same. The RGB4 doesn't mean RGB + Alpha. It means it's aligned 4 bytes, so its 32-bit RGB (there is a GL_RGBA4_S3TC enum too for RGBA). Since its 32-bit per pixel, the actual layout of the data that GL needs to know (not the format) is still GL_RGBA, GL_UNSIGNED_BYTE.

...when texture compression is not disabled (but why wouldn't you)

It does have implications for the image quality, it's a lossy compression at the end of the day. S3TC is a compressed format that can be decompressed on the fly (since unlike png and jpg, which need to be decompressed in their entirety before upload), it is effectivly 'tiled' and so only small regions are required to be decompressed at run time and not the entire image. Faster and more effieicent, unless you have the VRAM and get adaquate FPS anyhows, in which case no point.

Solution: Don't turn it on in the first place.

[leileilol]

the deal with Q3 having it on is that it's default on to future proof for forthcoming S3 cards that "need" it. I don't think Carmack had the foresight on expecting Nvidia or anyone else to support this once thought exclusive S3 feature (FWIW, Q3 was all developed on primarily TNTs. Exploring the configs shipped with the game should reveal that)

as for much ado about texel filtering.... lol hold SiS's beer

This is what bad texture filtering truly looks like.

[spiroyster]

Since its 32-bit per pixel

I got this wrong, there are two 16-bit colours. And 32-bits of meta. So while the colour is 32-bits (2 x 16-bit colours combined in some fashion), 4x4 of pixels box is defined by 64-bits (so a bit like 4-bit per pixel, but not laid out that way as its not raw, its 'processed'). 'Ouch' on that compression, but 'cool' being able to decompress on a per-box basis at run-time.

the deal with Q3 having it on is that it's default on to future proof for forthcoming S3 cards that "need" it.

I'll revise that then...
Solution: Always turn it off.

[silikone]

Since its 32-bit per pixel

I got this wrong, there are two 16-bit colours. And 32-bits of meta. So while the colour is 32-bits (2 x 16-bit colours combined in some fashion), 4x4 of pixels box is defined by 64-bits (so a bit like 4-bit per pixel, but not laid out that way as its not raw, its 'processed'). 'Ouch' on that compression, but 'cool' being able to decompress on a per-box basis at run-time.

So what exactly is the difference between RGB4 and RGB in this context?

I'll revise that then...
Solution: Always turn it off.

I guess it could prove useful on a Savage 3D, which would defecate itself it were tasked to run full-res Quake 3 textures without compression.
It's interesting to see that Quake 3 explicitly turns on trilinear filtering when it detects a Savage. No other card received a default configuration "boon".

[spiroyster]

So what exactly is the difference between RGB4 and RGB in this context?

No idea. https://www.opengl.org/discussion_board ... 50464.html suggests mipmaps are affected by this token.

3. Changes to the level Parameter
Level takes negative numbers for GL_RGB_S3TC and GL_RGBA_S3TC formats only. Any other formats will generate an
error.

The negative number indicates the pixels contain 0 to abs(level) mipmaps.

Can't say I have much experience with this compression format tbh.

I guess it could prove useful on a Savage 3D, which would defecate itself it were tasked to run full-res Quake 3 textures without compression.
It's interesting to see that Quake 3 explicitly turns on trilinear filtering when it detects a Savage. No other card received a default configuration "boon".

Apparently the S3TC is best on Savage (surprisingly o.0). Others I guess just didn't get it right. It would be interesting to know if this is actually done in hardware on nVidia. This kind of thing can be done in software (by the driver), and given it is itself an optimisation, who knows where it is actually done because simply enabling it would raise your FPS. Fugly though.
[EDIT:] Thinking about it, I hope it's not done in software because I can't see how there would be much performance gain o.0

[leileilol]

No other card received a default configuration "boon".

Q3 will force bilinear on Voodoo hardware no matter what (As a workaround to early ICD bugs that didn't like trilinear filtered multitextured surfaces, even if you wanted to safely use trilinear in a vertex-lit only render path, q3 can't allow you to do it, you'll have to force it on via your glide settings panel instead)

[silikone]

No other card received a default configuration "boon".

Q3 will force bilinear on Voodoo hardware no matter what (As a workaround to early ICD bugs that didn't like trilinear filtered multitextured surfaces, even if you wanted to safely use trilinear in a vertex-lit only render path, q3 can't allow you to do it, you'll have to force it on via your glide settings panel instead)

I think that the most interesting forced downgrade is the utilization of an alternate material/shader when using a Rage Pro in the menu. The material's name itself also indicates this.