Which statechanges are omptimized by driver?


Thats my first post on this board, so
dont take it too serios

Im writing my Renderer and
I dont know which statechanges i should manage my self.
void renderer::BindTexture(uint id)
if(id != bound_texture)
bound_texture = id;

Is this really neccessary, or does the driver
this kind of optimization for me?
Managing all the important states (textures,
vertexprograms, vbos) my self is … well, a bit work intesive
especially when you use textureunits and cubemaps which
require even more state changes.

I sort everything in my scene by texture, but every object calls
renderer->SetTexture(mytexture); in their Render() function.

So the state managing would only cut down the
amount of glDoSomeThing calls. Is this really worth the effort?

Sorry for my bad english

Args, damn typo.

There were a few interesting posts on this subject a while ago in the advanced forum. You better do a search for the long answer. The short one though is:
the driver doesn’t in general do checks to avoid state changes as this would be unnecessary overhead for apps which try to avoid state changes by sorting etc. . Anyway you can either make sure that the state you’re trying to set isn’t allready set or you can try to minimize state changes by sorting/grouping geometry according to the state they need. The latter should of course be better but also more complex.