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Skonk
03-11-2008, 06:12 PM
Just wondering if many people are using XNA and if so, how are things going with it?

I'v been playing around with it for a while, i'l never be an expert programmer but i find it a lot of fun to tinker with :) Created a simple 2D side scrolling game and a few other bits n bobs. I find myself just coding sample apps to test a particular feature more than anything.

For anyone who doesn't know what XNA is, its a game development framework created by Microsoft which sits ontop of the .Net and .Net Compact frameworks allowing users to create games that run on PC, XBox 360 and once version 3 comes out the Zune media device too. If you want more info nip over to http://creators.xna.com .

Would be interesting to see how other Lightwave users are getting on with it anyway.

To try to keep myself interested I setup a blog so i could post my progress (which in the end i havn't really done) but I have knocked up a few tutorials which deal with some common things beginners often ask about (3D First Person Camera, Animated 2D Sprites, Simple Menu System) so if anyone was interested my site is http://www.xnafusion.com - the actual written tutorials are also on there as PDF's so they can be printed (I always prefere to print tutorials off and then following them from the hard copy. Removes the temptation to copy/paste).

Bit of shameless website pimping on my part sorry :)

Jim.

walfridson
03-12-2008, 03:13 AM
I've only published walkthrough stuff with it.

Tried this? http://www.codeplex.com/xnadevru/Wiki/View.aspx?title=Managed%20Bullet%20Physics%20Libra ry

Skonk
03-12-2008, 05:57 AM
Iv seen a few of the physics systems people have put out, some really good stuff :)

warmiak
03-14-2008, 12:47 AM
Yeah, I am creating my personal 3d engine for XNA (generally geared toward 360 ).

One has to be extremely carefully writing managed code for 360 - the usual way of coding things can quickly backfire given pretty crappy implementation of XNA on 360 in terms of performance ( at least compared with PC or with native C++)

But if a lot of stuff is moved into shaders ( particle, etc) one can do pretty decent things with it ...

Skonk
03-14-2008, 07:15 AM
From what i'v read, some people experience the opposite. I.E games run fast on the XBox and slow on PC. I think its down to how you code it.

Also to get the best out of the xbox you need to code your game to use multiple threads to take advantage of all the cores (ofcourse this will also help on the pc). But breaking it down into threads that run evenly on each core isn't an easy task.

RTSchramm
03-14-2008, 10:14 AM
From what I heard is that XNA is about 5% slower than if you used direct calls to the OS API's instead of using the pre-built XNA wrappers.

Rich

walfridson
03-14-2008, 01:39 PM
Very true, microsoft said so themself when I went to a XNA meeting.

Skonk
03-14-2008, 05:51 PM
Yeh, managed code in general will suffer a little performance overhead (the info i'd seen said around 1 or 2% but that may be old info). But the justification is that the actual development process is so much quicker that it makes up for a slight loss in performance.

In real terms the performance overhead translates to a couple of frames per second which isn't really that big of a deal in most cases.

Jim.

warmiak
03-15-2008, 01:30 PM
Yeh, managed code in general will suffer a little performance overhead (the info i'd seen said around 1 or 2% but that may be old info). But the justification is that the actual development process is so much quicker that it makes up for a slight loss in performance.

In real terms the performance overhead translates to a couple of frames per second which isn't really that big of a deal in most cases.

Jim.

Nope.

It does translate into a lot - and we are not talking here only about slower performance but inability to do a lot of things that are possible with C++.

It is no coincidence that virtually every commercial game is written in C++ - if you are in a competitive environment C# just won't do.

And on XboX 360 XNA is much slower than on windows - it is a known fact. Since we are talking about physics libraries, the C# wrapper around bullet library is running at 3-5 FPS on XBox 360 while on a comparable PC runs a lot faster.
Again, the reason is not just C# but an inferior XNA implementation on Xbox 360.