No fixed function skinning?

Anything and everything that's related to OGRE or the wider graphics field that doesn't fit into the other forums.
Post Reply
Imperil

No fixed function skinning?

Post by Imperil »

I am not nit-picking or anything, I am just curious if there is a reason that Ogre decided to go the route of having no fixed function hardware skinning?

User avatar
tuan kuranes
OGRE Retired Moderator
OGRE Retired Moderator
Posts: 2653
Joined: Wed Sep 24, 2003 8:07 am
Location: Haute Garonne, France
x 4
Contact:

Post by tuan kuranes »

But there is fixed function hardware skinning.
or perhaps you're talking about something else than waht is shown in demo_skeletal_animation ?
(try replacing the robots by the ninja and you'get software skinning)

Imperil

Post by Imperil »

Is that not shader based hardware skinning?

I am meaning the fixed-function hardware skinning such as DirectX Indexed Skinning which is non-shader based.

EDIT: Yeah I just checked and that is shader-based skinning as the robot has a defined gpu program.

User avatar
:wumpus:
OGRE Retired Team Member
OGRE Retired Team Member
Posts: 3067
Joined: Tue Feb 10, 2004 12:53 pm
Location: The Netherlands
x 1

Post by :wumpus: »

We decided not to go with that as it there are no cards that can really benefit from it. I think the reason was: The cards actually supporting this fixed-function skinning properly, also do basic vertex shaders.

On earlier cards it was buggy or just very ill supported.

Imperil

Post by Imperil »

Ah ok great thanks for the info wumpus. I'm just poking around trying to find the best way to support a wide range of cards from the MX series up to the 6x00 series.

I hadn't used FFP skinning on an older card so I had no idea they were supported badly.

Thanks :)

User avatar
:wumpus:
OGRE Retired Team Member
OGRE Retired Team Member
Posts: 3067
Joined: Tue Feb 10, 2004 12:53 pm
Location: The Netherlands
x 1

Post by :wumpus: »

Yeah, the best way to support animation on the really old cards is to use a LOD bias to make the meshes lowpoly/lowvertex (you need to, anyway) and software skinning.

Imperil

Post by Imperil »

Along with getting the vertices and tri count down should I also aim for reducing as many bones as possible before software skinning? Or is this more based off the mesh data over the skeleton data?

User avatar
:wumpus:
OGRE Retired Team Member
OGRE Retired Team Member
Posts: 3067
Joined: Tue Feb 10, 2004 12:53 pm
Location: The Netherlands
x 1

Post by :wumpus: »

I don't think the number of bones really matters for software skinning (the animation work on the bones itself is done in both the software and hardware cases, anyway); the number of bone assignments/weights per vertex is to be minimized, though.

Imperil

Post by Imperil »

Great thanks a million for the information wumpus, it really helps :)

Post Reply