UnityGUI performance tweaks and tips?

My current project is making extensive use of UnityGUI and is taking a pretty huge performance hit (drops from 78 fps to 50 fps). So I thought I'd start a thread to solicit tips and tweaks to help speed up UnityGUI performance. So in the spirit of the holidays, I'll go first (I actually learned this from Daniel Brauer on the Alpha List):

Instead of writing a series of GUILayout instructions like this:

Code (csharp):

1. GUILayout.Box ("Title");
2. GUILayout.Button ("Button One");
3. GUILayout.Button ("Button Two");

You can import GUILayout from the UnityEngine and just call the instructions, like so:

Code (csharp):

1. import UnityEngine.GUILayout;
2.  
3. Box ("Title");
4. Button ("Button One");
5. Button ("Button Two");

Anyone else have some UnityGUI tweaks / tips to share?

 

That'll save typing, but won't have any noticeable effect on performance. Since the GUI stuff is done in code, I suppose the usual tips for optimizing code apply here as well (probably more so, since OnGUI functions run more often than Update).

--Eric

 

One thing that will probably help you get some frames is to not abuse of Matrix multiplications (although I think you will only really notice it after a lot of elements)

Instead of doing things like:

Code (csharp):

1. GUI.matrix *= Matrix4x4.TRS( new Vector3(30,30,0), ..., ... );
2. GUI.Box(new Rect(0,0,30,30),"Box");

try using something like:

Code (csharp):

1. GUI.Box(new Rect(30,30,30,30), "Box");

I haven't really tested the performance improvement from doing this, but with a lot (and I mean A LOT) of elements with matrix multiplications I did find it to push some frames (i.e. perhaps 5 to 10fps). Could have been just some lucky chance

Regards,
Afonso

 

This is probably obvious, but keep your calculations out of the OnGUI function.
Since OnGUI can be called multiple times per frame, anything that is not dependent on keeping time with the GUI shouldn't be there.
Basically Update() and OnGUI() are not interchangeable even though it may seem so.

I'm pretty sure GUI.Layout would be slightly slower than GUI since it has to calculate the layout in more detail, rather than just throwing everything in based on it's Rect parameter. Nicholas would be the one to ask though.