1. XNA Game Studio 2.0
Game Programming Made Easy(ier)
Reuben Ahmed
[February 12, 2008]

2. About Me
• 7 years of .NET/C#
• Minimal game programming
experience
• Avid video game player
– *Not reflected in my XBOX Live gamer score
• rahmed@bennettadelson.com

3. WARNING
• Disclaimer: Code shown during
this presentation is not meant to
be the “right” or “best” way of
creating a game.
• Purpose: Give you a basic
toolset to start off with XNA.

4. Agenda
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment (!)
• Distribution model
• Q & A

5. What is XNA?
• X-Platform Next Generation Architecture
• C# Game Framework
– Windows/XBOX 360
– Reduced learning curve
– Compiles to .NET Compact Framework
– Available, Approachable, and nearly Free
• Sony Playstation 3 Dev. Kit = ~$10,500
• XNA is free on Windows.
• $49/4 months or $99/year on XBOX 360.

6. System Requirements
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

7. System Requirements
• Visual C# 2005 Express Edition, Standard Edition,
Professional Edition , Team Edition for Software
Architects, Team Edition for Software Developers, Team
Edition for Software Testers, Team Edition for Database
Professionals , Team Suite
• No Visual Studio 2008 support currently!
• DirectX 9.0c, Pixel Shader 1.1+
XNA Studio 2.0 and C# Express URL:
• http://creators.xna.com/Education/newtoxna.aspx

8. Out of the box architecture
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

9. Out of the box architecture
• Graphics Device Manager
– Automatically sets up interaction with your
graphics card
• Optimized Game Loop
– Update, Draw methods
• Content Pipeline
– Game Assets (Graphics, Audio, etc.)
• DEMO: Our First XNA Game!
– Change background color

10. Graphics/Textures
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

11. Graphics/Textures – Drawing
1) Add Asset to your project
– Drag and drop graphic
2) Load Graphic into variable
– Texture2D class
– Content Pipeline method
• Content.Load <Texture2D> (“AssetName”);
3) Draw it
– SpriteBatch class
• SpriteBatch.Draw (Texture2D, Position, Color);

12. • DEMO: Adding a spaceship graphic!
• DEMO: Tint graphic with Draw
parameter.
Graphics/Textures - Demo

13. • Vector2 class
– Holds X and Y position
– Can represent Position, Acceleration, Velocity
Graphics – 2D Coordinates

14. • GraphicsDevice.Viewport
– Window size properties
• DEMO: Centering graphic with Vector2!
• Tip: Texture is drawn with upper left as
starting point…
GraphicsGraphics – Window Size

15. • DEMO: Scale image with Rectangles.
• Tip: Draw order matters!
GraphicsGraphics – Scale

16. Input
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

17. • Keyboard
– Static class
• Current state of keyboard
• Which keys are pressed
• Keys
– Enumerator
– Represents almost any key!
• DEMO: Read input to exit game.
Input – Read Keys

18. • Vector2
– (X,Y) can also represent velocity
• Vectors can be added/subtracted…
• Vector of (0,0) position + Vector of (5, 2)
velocity = new position of (5, 2).
Input – Vector2 Velocity

19. • DEMO: Move ship to right.
• DEMO: Use Keyboard to move ship
left/right.
Input – Vector2 Velocity

20. Collision Detection
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

21. • My ship is going off the screen!
• First level of collision detection:
– Window boundaries
– MathHelper class to the rescue…
• Clamp() method.
• DEMO: MathHelper.Clamp() to
boundaries.
Collision Detection

22. • Let’s add an “enemy”…remember:
– Texture2D
– Vector2 (position)
– Vector2 (velocity)
– MathHelper.Clamp (Window Boundaries)
• DEMO: Add a non-hostile Alien that
eerily resembles a Space Invader™!
Collision Detection

23. • Can we shoot a bullet?
– Bullet spawns from spaceship position.
– Moves vertically up (negative Y direction)
• DEMO: Kill it, KILL IT!
Collision Detection

24. • My bullets are too weak!
– Rectangles encompass every Texture.
– Rectangle.Intersects will help!
• DEMO: Encompass the alien and bullet
in rectangles, and figure out if they
collided…
Collision Detection

25. • 2D Per-Pixel Collision
– More expensive, but accurate
• Color Key Collision
– Detects collision based on color map!
Collision Detection, etc.

26. Text Writing
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

27. Text Writing
• SpriteFont asset
• SpriteBatch.DrawString()
• DEMO: Keep a bullet hit count label…

28. Audio
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

29. Audio
• Microsoft Cross Platform Audio Creation
Tool
– Creates a .XAP “Game Asset”
– .WAV files
• Classes
– audioEngine = new AudioEngine ("ContentAudioPROJECTNAME.xgs");
– waveBank = new WaveBank (audioEngine, "ContentAudioWave Bank.xwb");
– soundBank = new SoundBank (audioEngine, "ContentAudioSound Bank.xsb");
– soundBank.PlayCue (“CUENAME");
• DEMO: Background music. Loop it.

30. • Change volume level
• 3D Spatial audio!
Audio, etc.

31. XBOX 360 Deployment
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

32. XBOX 360 Deployment
• This costs money!
• Download XNA Creator’s License ($49 or
$99) from the Games Blade.
• Download/Launch XNA Game Studio
Connect (Free) from the Games Blade.
• Generate a key that your PC can use to
connect to your XBOX360…this only has
to be done once.

33. XBOX 360 Deployment

34. XBOX 360 Deployment
• Launch XGS Device Center on your PC.

35. • Your console is now connected!
XBOX 360 Deployment

36. • Either an XBOX 360 Project Type, OR a
Windows XNA Project Type can be
deployed!
• DEMO: Demonstrate “Copy Windows
Project to XBOX360 Project”
• Projects stay in sync.
• DEMO: Add GamePad input handling.
Add rumble!
XBOX 360 Deployment

37. • DEMO: …Deploy this thing.
– Incremental deployment support!
– No wireless deployment.
– Your game is now available on the Games
Blade!
• DEMO: Debugging on XBOX 360…
XBOX 360 Deployment

38. Distribution Model
• What is XNA?
• System Requirements
• Out of the box functionality
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A

39. Distribution Model

40. • XBL currently a managed portfolio
• Game Developer’s Conference 2008
– Microsoft prepared to announce XBL
Community Blade for XNA.
Distribution Model

41. Tip of the iceberg…
• Plethora of XNA Tutorials/Starter Kits
• Network Architecture
– Client/Server, Peer to Peer, Prediction Code
– XBOX Live Profile information
• Artificial Intelligence
– State Management samples
• Speech Recognition/Synthesis
– System.Speech .NET 3.0

42. Tip of the iceberg…
• XNA Racing Game: YouTube
• 1 week of code (professional game
development company)
• Jitted on the fly, 1080p, 30 FPS, running
on C# (Managed code!), with 2X Anti
aliasing!
• Graphics power is equated to a $350 PC
video card. Anti aliasing…one line of
code via XNA.

43. References
• MSDN XNA Game Studio 2.0
– Overview of framework
• http://creators.xna.com/
– Active community site
• http://www.xnadevelopment.com/
– Beginner tutorials
• http://www.phstudios.com/
– Introadvanced tutorials

44. Q & A
• What is XNA?
• System Requirements
• Out of the box architecture
• Graphics/Textures
• Input
• Collision Detection
• Text Writing
• Audio
• XBOX 360 Deployment
• Distribution model
• Q & A