State sorting order

[Succinct]

What is the best order to sort state changes in for maximum performance? Is sorting by texture more important than sorting by state?

Is there a list anywhere of expensive changes vs. inexpensive changes?

I know that this question has been being posted/answered frequently lately, and I just wanted a reference for everyone to go to.

Thank you for your bandwidth.
-- Succinct



[This message has been edited by Succinct (edited 05-25-2001).]

[Tom Nuydens]

It all depends on your hardware, but generally, textures are by far the most expensive, probably followed by material and lighting changes.

- Tom

[Tim Stirling]

I was thinking of sorting by geometry type is well, I have a mixture of tris, quads, and polygons (>4 verts). The triangles and quads would be a lot faster with just the single call, in my test this would usualy double the frame rate. I have changing texture not too expensive but worth sorting, especialy if you have more textures than video memory.

[ET3D]

In the list of things to sort by, people often forget "distance from viewer", which is getting more useful, now that chips have special Z culling hardware (HyperZ,...).

[Tim Stirling]

I knew that as well but I don't think it will speed things up as much as sorting my geometry, but it is probably better than sorting out most state changes (most data will be in a `normal' state i.e opaque etc.) maybe not on non hyper z cards

[ET3D]

True about the geometry sorting. Although even without sorting, I got a 50% increase in frame rate just replacing the GL_POLYGON code that was used in the code before I received it with a test that starts and ends GL_TRIANGLES or GL_QUADS or GL_POLYGON as necessary.