AMD: R8xx Speculation

[Chris123234]

Awesome stuff.

http://img193.imageshack.us/my.php?image=00003h.png
http://img193.imageshack.us/my.php?image=00002i.png
http://img193.imageshack.us/my.php?image=00001z.png
http://img193.imageshack.us/my.php?image=00000w.png

I especially like these ones.

Can someone help me understand the benefit of this? Are these details added automatically somehow? And, if not, why not just model the two versions instead of applying this on top of the low poly one, which seems more difficult than just modeling a higher poly one?

 

[Silent_Buddha]

It's only showing a difference of what you might normally get with traditional poly budgets in a given scene for a given building versus what you could do when adding in tesselation.

Regards,
SB

 

[Chris123234]

But, aren't those now polys overbudget, then?

 

[compres]

Naturally the increase in detail makes the images better, but as Chris I guess I have to read more about tessellation. Can someone give a short summary of what is going on and the benefits? Thanks in advance.

 

[Voxilla]

Naturally the increase in detail makes the images better, but as Chris I guess I have to read more about tessellation. Can someone give a short summary of what is going on and the benefits? Thanks in advance.

Just finely tessellated splines, possibly with displacement mapping.
This can result in loads of tiny triangles, not sure if the new hardware is any better at processing loads of these tiny triangles.

Do the ATI shader units process more than one triangle at a time ?
If so how many ?
How do the pixel processors deal efficiently with those tiny triangles ?
As they need to render at least 4x4 pixels at a time, or something similar.

 

[hoom]

Does anyone know if the Dynamic LoD can auto-scale based on the frame-rate?

It would require a new benchmarking regime if every card would be able to play at 60fps just by scaling tessellation LoD

 

[rpg.314]

Yes tesselation can be scaled depending on the framerate. It is parameter under complete control of shader programmer.

 

[Voxilla]

Yes tesselation can be scaled depending on the framerate. It is parameter under complete control of shader programmer.

Look what I did 6 years ago: http://users.belgacom.net/xvox/
Hardware only displacement mapping, even with trilinear filtering of the displacement maps.

If you press the A key, the continuous level of detail tessellation will be adapted so that the animation runs at 60 Hz on any card !

In wireframe mode you can see the tessellation pattern, slightly nicer than what ATI does if I may say.

 

[rpg.314]

Impressive, except all this tesselation was doe on CPU right? But I prefer doing them on a GPU, and that's why I am excited at dx11 tessellation.

 

[Voxilla]

Impressive, except all this tesselation was doe on CPU right? But I prefer doing them on a GPU, and that's why I am excited at dx11 tessellation.

No, all tessellation is done on the GPU !
The CPU does very little work.

If you read the technical document you can find how it is done.
It is done with vertex morphing.
On my GTX280 I'm getting 400 million tessellated triangles a second.
Would be slightly impossible to do this with the CPU, especially as the mesh is not a triangle strip.

 

[fellix]

Kewl!
Adaptive performance LOD scaling -- The thing HW tessellation should be used for in future DX11 titles!

 

[Demirug]

I wonder if Dirt 2 will carry a redistributable Dx11 package?

There is no redistributable Dx11 package.

 

[Broken Hope]

There is no redistributable Dx11 package.

There sort of is one for Vista.

http://blogs.msdn.com/directx/archive/2009/09/10/windows-7-transition-pack-for-windows-vista.aspx

 

[Demirug]

There sort of is one for Vista.

http://blogs.msdn.com/directx/archive/2009/09/10/windows-7-transition-pack-for-windows-vista.aspx

I know. As we have a DX11 launch Title we were informed about this early. But this is not classical redistributable that you can put on a game disk. It’s more like a service pack.

 

[trinibwoy]

Hmm, that's a strange model to use for a tessellation demo. Giving bricks volume is fine but they already did that in Toyshop with POM. I expected them to use something with more fine detail, like a character or vehicle. I assume that's just one of several models in the demo?

 

[fellix]

This is just small part of the NDA-ed press material.

 

[Cypher]

Hmm, that's a strange model to use for a tessellation demo. Giving bricks volume is fine but they already did that in Toyshop with POM. I expected them to use something with more fine detail, like a character or vehicle. I assume that's just one of several models in the demo?

Actually, ATi showed a demo comparing the quality and performance of normal mapping v. POM, v. tessellation, and tessellation ended up being faster by a rather significant margin. Tessellation also looks better in the end as well, because you also have a different silhouette due to the tessellated surface; something you can't get with POM. Shadowing also ends up looking better, both in terms of receiving and casting because you end up dealing with actual triangles and not a funky raycast in a texture.

Look at these two, in particular:
http://img193.imageshack.us/img193/7131/00001z.png
http://img193.imageshack.us/img193/1281/00000w.png

I dare you to compare those two pictures and say "Enh, POM looks as good", because it simply doesn't.

 

[trinibwoy]

My comment was about the choice of model/effect used, not whether POM was better than tessellation.....

 

[Cypher]

Oh...well, it's not just bricks, you also have roofing tiles and such this time

 

[Voxilla]

Actually, ATi showed a demo comparing the quality and performance of normal mapping v. POM, v. tessellation, and tessellation ended up being faster by a rather significant margin. Tessellation also looks better in the end as well, because you also have a different silhouette due to the tessellated surface; something you can't get with POM. Shadowing also ends up looking better, both in terms of receiving and casting because you end up dealing with actual triangles and not a funky raycast in a texture.

I'm still wondering if they did anything new to boost the maximum triangle rate of small triangles. Tessellating to pixel sized triangles is fine, but if you can do only like 500 million triangles a second, you then also can do only about 500 million rendered pixels per second...
Shaders and backend must be running at less than 10% efficiency in that case.