Apr 13, 2010

Tessellation on XBox360

Today I found that XBox360 has tessellation feature.

I thought tessellation or geometry shader is supported from DirectX10 so that I was very excited by finding this. Tessellation is simply saying when I pass one triangle, I can use more than one triangles as the result. It is supposed to be fast and efficient due to hardware support.Actually I haven't been paying attention on geometry shader or tessellation, because I thought we cannot use it yet. I always skipped those parts when I read books. Now I need to track back and check what kind of techniques I can use with it.

It seems like PS3 doesn't have any similar functionality. Sony might think of SPU as the counter part.

Unfortunately the XBox360 SDK document doesn't explain about the tessellation at detail; for example performance or caveats. In addition, I haven't heard any XBox360 games have been using the tessellation feature before. It makes me wonder how useful it will be.


Jay said...

I am thinking that it is very useful to have vertex array accessing at vertex shader. It can allow us to generate normal values on the fly.
I am not sure whether the cost of normal reconstruction can beat the bandwidth cost for normal values.

RichG said...

Hi Jay,
Halo Wars used GPU tessellation to render vector field terrain. See:

HALO WARS : The Terrain Of Next Gen (GDC 2009)


Jay said...

Thanks RichG for the nice information.

It is very interesting that Halo Wars used it. Now I have reason to buy one. :D