Game Development and XNA

2009-08-07T18:59:00.003-04:30

I'm back

I've been off for some time, I has been working on both the university and this great game we are creating at gasp, check out the trailer:

I will be working on the console a little these days, fixing bugs like garbage generation and optimizing it in general, also I'll improve the python interpreter and add some scripts to do useful stuff.

JG

2009-05-20T15:00:00.002-04:30

The new stuff didn't come so soon, did it?
I'm sorry but I just haven't got the time to finish tweaking some minor details. I'll finish this release and upload as soon as I have some free time. The work and the university have been very time consuming these days.

JG.

2009-03-20T18:15:00.003-04:30

New stuff coming very soon.

Integrated python interpreter, thanks to Samuel Christie
Some useful scripts to trace variables
Mouse controller sliders to tweak your variables on runtime
Logging
A lot more

Stay tuned.

JG

2009-03-10T11:55:00.007-04:30

Debug Console - Second Release

Hello, I fixed a lot of issues I had with the console I didn't know about.

I'm now using the same effect (an instance of XNA's BasicEffect) for every component.
Lines are now traceable. That is, each line you draw have a name, then when you draw a line with the same name, the previous line gets moved.
Some of you might had problems with the ShowLine and ShowMark methods, fixed.
I have created a new command parser in order to add scalability. You can now for example use Game1.console.Execute("trace Player1.position", position); and would be the same as using Game1.console.Show("Player1.position", position);. This is because later I will add the feature to trace values in runtime, something that will decrease debugging time for your games.

Things I need to fix:

console.DrawBox
console.Log
Test it on the XBOX

The code is now commited. and here's the .dll library

JG

2009-03-09T12:13:00.007-04:30

LINQ Benchmark fixed.
I posted about the benchmark in the Creators Club forums and they explained me why these results were incorrect. I measured it wrong.
The thing is that on the LINQ test I wasn't actually running the query. To run it, I must at least iterate over the result, this is because the defered execution of the IEnumerable implementation, and the return yield it runs.

So I rewrote it, and the results came out more predictable, here you have them.

I also increased the valueCount to a hundred million values. And there you have it, even though LINQ version is more elegant, it took almost twice the time, so for time critical operation I would prefer avoiding it.

JG

2009-03-05T12:58:00.005-04:30

LINQ Benchmark

For those of you that doesn't know LINQ yet, it's a new technology from c# 3.0 that lets you run queries independently from your database, even on c# objects (like arrays, List, LinkedList, etc) with a SQL-like statement .

Yesterday I was wondering how fast LINQ could run some queries compared to more traditional methods. I'm not talking about LINQ to SQL on an external database, but running a query on some IEnumerable object instead. So I created a small benchmark. I'm not sure if it is correct because there is some stuff that I might be timing erroneously, so please tell me if I should be considering things like JIT time, GC, or any other housekeeping.

Anyway, on a very simple test the results came out unexpectedly.

Here's the method I wrote:


static void Main(string[] args)
   {
       int valueCount = 1000000;
       Random random = new Random();
       float[] values = new float[valueCount];
  
       Stopwatch timer;
       // Initialize the values
       for (int i = 0; i < valueCount; i++)
       {
           values[i] = random.Next(valueCount);
       }
       GC.Collect();

  
       // LINQ
       Console.WriteLine("Try with the LINQ query");
       timer = Stopwatch.StartNew();
       IEnumerable<float> extracted1 = from v in values where v < 500000 select v;
       timer.Stop();
       Console.WriteLine(timer.Elapsed.TotalSeconds);
       Console.ReadLine();

       // Regular for
       Console.WriteLine("Try with the 'for' iteration");
       List<float> extracted2 = new List<float>();
       timer = Stopwatch.StartNew();
       float var;
       for (int i = 0; i < valueCount; i++)
       {
           var = values[i];
           if (var < 500000)
               extracted2.Add(var);
       }
       timer.Stop();
       Console.WriteLine(timer.Elapsed.TotalSeconds);
       Console.WriteLine(String.Format("Counts: {0}, {1}", extracted1.Count(), extracted2.Count()));
       Console.ReadLine();
   }

It creates an array of random values ranging from 0 up to 1 million. Then both tests try to extract 500000 numbers from the values given the simple rule (x < 500000). So here are the results:

This is one of the results I got. LINQ was 50 times faster??? Am I measuring this wrong?

2009-02-21T03:00:00.002-04:30

Hey ya, next week I have planned to add the Log method, so you can keep a historical log of the runtime. Plus, i'll fix some minor bugs.
Another thing I should begin to care is "threadsafeness", because sometimes calling methods from different threads can cause consistency problems.

JG

2009-02-20T17:22:00.002-04:30

Not much people have downloaded the console, so I decided I'll post the things you'll get by using it. Probably some of you are wondering, why use this crappy component if I have my old school .NET's Console.WriteLine(debugThis) that hasn't ever let me down?. I'll explain the neat features:

The main feature is the Show method. It receives two parameters: a string identifying what you are showing, and a value. For example: Console.Show("Player1.Position", pos); you can write this call inside the Update of your main character and a new variable will be added to the Console's TreeView, and everytime this gets called the value in the TreeView gets updated. Let me show you a screenshot.

So, as you can see you will get live coverage of some variables of interest, and they will stay right there, visible everytime you need them. Another thing to note is that the console creates a hierarchy of values, if you need some other variables from Player1 you will get them grouped under the same node so you can quickly check the state of some component of your game. I'm planning to use the reflection API to add variables from the console itself, for example you could write "Game.Player1.Position" at runtime and you will see the value being added and updated every frame, I'm not sure if the .NET reflection API is available on the XBOX.

2009-02-18T00:49:00.009-04:30

Update: rewritten to be more clear.
I forgot to mention how to use the console. Here's what I do to add it to a new project:

Add the DebugConsole.dll as a reference to your project.
Create a new public class file, call it GameInfo.cs
Make your new GameInfo class implement the DebugConsole.IContainGameInfo interface. (i.e change the line "public class GameInfo" for "public class GameInfo : DebugConsole.IContainGameInfo"
Add the 4 public properties mentioned later to your GameInfo class
Create a static instance of the DebugConsole somewhere you can reach easily, something like Game1.Console (just add a DebugConsole variable in your Game1.cs file)
Construct the console with a new GameInfo instance (i.e add new DebugConsole.DebugConsole(new GameInfo());to your initialize method)
Add the console as a GameComponent (Game1.Components.Add(Game1.Console);)
That's it. Start using the console (i.e Game1.Console.Show("My var", myLocalVar);)

This are the properties you need to add to GameInfo, just copy and paste and replace the comments:

public Game Game { get { /* return your Game class here */ } }
public Matrix WorldMatrix { get { return Matrix.Identity; } }
public Matrix ViewMatrix { get { /* return your view matrix here */ } }
public Matrix ProjectionMatrix { get { /* return your projection matrix here */ }

If you have a 2D project, you can return Matrix.Identity in the View and Projection properties, but you won't be able to use marks.

I will upload an example project soon.

JG

2009-02-17T22:29:00.005-04:30

Let me introduce you to the Debug Console for XNA. It is designed to be an handy set of runtime tools you can use to debug your game. Right now it does not have too many features but it does have some that you may like.

Current Features

Show. Live! watch of variables.
Alert. A text that pops out to indicate when an event happens.
ShowMark. Put some marks on the 3D space.
ShowLine. Draw lines on the space.
ShowBox. Draw a box on the space (this is not currently in the DebugConsole, but in a matters of days will be).

Planned:

ShowSphere. self explained.
Improve performance by making smarter use of the video card calls.
Improve the way matrices are passed to the console, to make it more flexible and comfortable.

If you're interested you can download the source code.
I definitely want to get feedback from you, so leave a comment/bug report/feature request/anything else, whenever you want.

UPDATE: Instructions on next post.

Until next post,
JG

2009-02-09T11:20:00.000-04:30

Test.

Are you reading this?

2009-02-05T19:23:00.004-04:30

Hey there, I haven't posted anything about XNA tools yet, that's right, and I feel bad about it. I'm going to be posting sometime soon. In the meantime check out the game we made for the Global Game Jam, here in Caracas.

The Game Jam is a 48 hours event where you and your team create a small game. This year the first global Game Jam took place and 1600 participants around the globe worked to create more than 300 games.

You can check out the games made here at Universidad Simón Bolívar here.

Our game was Gnaka-Gnaka (pronunced in Spanish ñaka-ñaka) written on XNA by these 8 persons

Jose Alberto Gomez / Artist
Alex Perez / Sound Designer
Henry Quintero / Programmer
Alejandro Martinez / Graphics Programmer
Andres Barrera / Programmer
Luis Miguel Blanco / Programmer
Jose Dunia / Programmer
and me, also programming

We might be releasing it on the Xbox LIVE Community Games, in the meantime you can download it from the link above.
The game includes the Debug Console which I talked about before. You can use it if you like, later next week I'll be posting about it and offering a direct link to the code.

See ya then.

2008-11-02T15:37:00.002-04:30

Ok. First of all I'm sorry about this post because probably some of you are expecting a post about the XNA tools and stuff, But I just havn't got the time to post about them... I'm sure next week i'll have some time off and I promise I'll finally begin to post about them. This post is to give some congrats to my Team because we won 2nd place on the Dream Build Play 2008 Competition which I feel is quite a good achievement for our first game... Congratulations also to the other teams that made it to the end: Gambit from Singapore with "CarneyVale Showtime" (1st Place), Our team :) (2nd Place), Weapon of choice (3rd Place), and HuricaneX2 (with the 4th prize). The games just look fantastic... If you want more information check the Dream Build Play site (www.dreambuildplay.com)

2008-10-07T02:00:00.008-04:30

Andy Patrick has a very nice blog about a game he's making, and he has written some posts about the tools that everyone involved in game programming should know about, you should definitely check it out if you are an XNA game programmer. These tools include: the CLRProfiler, PIX, Reflector (great one if you want to learn how XNA works internally), and some others. Since he already wrote about those very useful tools, (I haven't had the time to check out all of them) I'm gonna be talking about some other tools we're going to be using and some tools we are developing, especially a drop-in XNA debugging console I created for the development of Battle Tennis. I will be also adding some features to the console and sharing it with you (game devs) so you can use it for your own projects (and I can have some more feedback :). I'm going to be posting the console itself soon so stay tuned... By the way leave a comment or something if you're reading this so I know there's at least someone "tuned" ;)

2008-10-01T02:12:00.005-04:30

Hello, this is my first post, I'm one of the members of the Battle Tennis team, which is a game we are making here in Venezuela. Check out the video of our entry to the DBP competition. Hope you like it.

&amp;amp;amp;amp;amp;amp;amp;lt;a href="http://video.msn.com/video.aspx?vid=7cacdd73-c857-4e70-812e-f9a2a76d829f" target="_new" title="Battle Tennis - Dream Build Play Trailer"&amp;amp;amp;amp;amp;amp;amp;gt;Video: Battle Tennis - Dream Build Play Trailer&amp;amp;amp;amp;amp;amp;amp;lt;/a&amp;amp;amp;amp;amp;amp;amp;gt;

This was made by a four people team:

Jose Alberto Gomez (Artist)
Alex Perez (Music artist)
Alejandro Martinez (Programmer)
and myself, also a programmer.

I will be posting about some of the tools that we made and used to get BT up and running, and game dev in general...