Performance Quiz #11: Ten Questions on Value-Based Programming : Solution

Rico Mariani's Performance Tidbits : Performance Quiz #11: Ten Questions on Value-Based Programming

Fri, 08 Sep 2006 01:03:57 GMT

PingBack from http://blogs.msdn.com/ricom/archive/2006/08/31/733887.aspx

re: Performance Quiz #11: Ten Questions on Value-Based Programming : Solution

Pop Catalin Sever — Fri, 08 Sep 2006 02:22:26 GMT

"Question #10: How many rules did I break? :)

I lost count. I think three big ones but more than once each I suppose."

I think this is reqirement number one to be a great performance (games) programer : 'Break the rules but get that damn performance sky high!'.

Those rules were made for the others, you can't have the same set of rules for two things that start with diferent premises. Performance programming never has the same set of guidelines with generic programming, atleast to my knowlege, and I guess never will.

Thank you for the great articles so far, keep up the good work!

re: Performance Quiz #11: Ten Questions on Value-Based Programming : Solution

Pop Catalin Sever — Fri, 08 Sep 2006 05:34:31 GMT

"Question #5: Quad has no methods. Why?"

At least one method could be useful! A method wich changes the order of the corners either to retriangulate the quad or to flip the quad's triangles! Using a method on the quad rather than an method someplace else that recives a quad as a parameter will I think will have better perf because the method on the quad recives a managed pointer as a paramether raher than the structure's copy, so probably there is a reason to have methods on quad.

Structs versus classes in .NET

Erwyn van der Meer — Fri, 08 Sep 2006 11:24:14 GMT

Microsoft's Rico Mariani has two very interesting posts that shed some light on when to prefer structs

re: Performance Quiz #11: Ten Questions on Value-Based Programming : Solution

Serge — Fri, 08 Sep 2006 17:48:13 GMT

I still can't understand - why structs coudln't be inherited in C#? was it done for performance reasons or by some other limit in CLR?

re: Performance Quiz #11: Ten Questions on Value-Based Programming : Solution

Thomas — Sun, 10 Sep 2006 09:55:30 GMT

Structs do not contain any sort of vtable and such, hence you can't do inheritance. If they did they would be classes.

re: Performance Quiz #11: Ten Questions on Value-Based Programming : Solution

ricom — Tue, 12 Sep 2006 00:29:19 GMT

Of course that really only prevents virtual functions.

I'd really be worried more about what the subtype behavior would be like. Is it really safe to always pass a Child types where Base is expected? What if Child used some of the gaps previously present in Base?

I think this could be made to work, C++ does it after all, but then C++ has much more rigid rules about sharing types across assemblies and versioning them.

I'd have to think about it.

Get quizzed by Rico!

Scott Holden's Blog — Tue, 12 Sep 2006 05:04:41 GMT

Rico has been posting performance quizzes for a couple of years now. These are always interesting and...

Catching up...

ctodx — Thu, 14 Sep 2006 23:15:44 GMT

I'm sure that it's the same for you: you go away on vacation, have a great time, come back and your email...

re: Performance Quiz #11: Ten Questions on Value-Based Programming : Solution

Kris — Fri, 15 Sep 2006 21:03:56 GMT

Only the ignorant think any of those types should be classes. They can go use Java3D if that's what they want. lol.

Just do us all a favor and pass the large structures by "ref" where appropriate.

This is how we *should* transform Vectors:

public static void Vector3.Transform(ref Vector3 v, ref Matrix m);

PLEASE DO NOT PASS A HUGE MATRIX BY VALUE TO A TRANSFORM FUNCTION! (Like the current XNA Api)

Properties vs public fields redux...

Eric Gunnerson's C# Compendium — Thu, 01 Feb 2007 20:53:14 GMT

My blog reader burped recently, and gave forth a post (and reply ) than Rico wrote last September, but