CodeStock 2008 XNA

By CSharpner · August 9, 2008

• Use XNA to develop games for:
  • Windows
  • XBox 360
  • Zune (3.0 XNA SDK needed)
• 2D and 3D graphics supported.
• Works with any Visual Studio SKU (Update 2008-12-17: for XNA 2.0, but XNA 3.0 requires any Visual Studio 2008 SKU).
• http://creators.xna.com/resources/essentials.aspx
• XNA Game Studio 2.0 - Needed if you're not using Visual Studio 2008.
• Current version is 3.0 CTP (pre-beta). (Update 2008-12-17: 3.0 has been RTM for several months now)
  • Supports Visual Studio 2008.
  • www.microsoft.com/express/download
• Drivers for wired XBox controller (driver not needed if using Vista)
  • Download here.
  • Samples & Start kits:
    • http://creators.xna.com/education/starterkits/
• "Game Loop"
  • XNA games have a "game loop" that continuously runs. Each iteration calls your code for updating object positions and drawing.
  • LoadGraphicsContent()
    • load sound, images, from folder.
    • makes objects out of them.
  • Update()
    • Called by framework, you handle.
    • You check state, update, then call Draw()
  • Draw()
    • You read state and draw your scene for that time slice.
• 2D objects.
  • Sprite batch
    • Bundles up multiple sprites to send to the GPU for one quick render.
    • There's a start, a bundling, and an end.
  • Content Manager
  • Manages life of objects (sprites, sounds, images, etc...)
  • Game Time
    • Important concept. Provides timing information for:
      • how many milliseconds since last update, etc...
      • helps games run the same on different speed hardware.
  • Content Pipeline
    • Processes art assets at build time.
    • Creates names for assets to use in code.
    • Uses content subproject in your game.
  • Sprites
    • There's no "sprite" class, but there is a Texture2D class.
      • example: Ball.BallTexture = content.Load... (didn't have time to write down the whole line)
      • Update 2008-12-17: Ball.BallTexture = content.Load("Ball");
    • Shaders (.x files) - information to send to GPU.
      • HLSL (High Level Shader Language)... not available on Zune (Zune has no GPU).
        • GPU effects.
      • There's no intellisense for this.
    • Purple ($FF00FF) is transparent, unless your sprite files are in a format that supports transparency (alpha channels are supported!!!) (Update 2008-12-17: PNG and JPG images with transparancy work wonderfully! No need for purple.)
    • Background image (in 2D games) is considered a sprite.
    • Vector2 (point?)
    • Origin is 0,0
    • When a sprite is rotated, it's rotated around the origin.
    • When scaling a sprite, the origin doesn't scale with the image.
• GamePad object/class is the controller.
• Sounds
  • XACT is a tool in XNA 2.0 & 3.0. BTW, no XBox 360 support in XNA 3.0 (will be in final release... they just don't do it until final release because of complex restrictions/paperwork to get it certified). (Update 2008-12-17: 3.0 has been RTM for several months now. You can currently run your game on XBox 360 after a $99 fee.)
    • XACT is a GUI app.
    • Can create banks of sounds (.XSB files).
  • Zune doesn't support XACT, so use the Audio API.
• Development
  • You can step through your code, directly into the XBox 360.
  • XBox 360 uses a modified version of the compact framework.
  • To put your own games on your own XBox, you must subscribe to the $99/year ($50/3 months) service.
    • With this service, you can also publish your games for peer review and eventually sell them on XBox Live for REAL money. M$ keeps about 1/2. (Update 2008-12-17: You keep 70%!!!)
    • With $99 sub, you get TorqueX framework... normally $150 or so just by itself. Apparently you get lots of cool stuff for game dev with TorqueX.
• Zune
  • Screen res = 320x240
  • No shaders
  • No GPU
  • No XACT
  • WiFi support
  • No emulator available - must deploy to Zune during development
  • 16MB max for game.
  • no data transfer to PC (to prevent copying MP3s... stupid DRM crapola)
• XNA community games
  • Make an installer, then enter "rating" information, then publish.
  • Peers review your game, then pass (or fail) for whether it works, not whether they like it.
  • You get paid when people buy through XBox Live. You keep 70%.
  • Game size determines sell price (yah, I know... really poor formula... I can add 20MB of random data too!) (Update 2008-12-17: You set your price. If your game size is too big, there's a MINIMUM amount you're allowed to charge. You can charge more though.)
  • I need to find the creators club web site... sounds like cool stuff on there. (Update 2008-12-17: http://creators.xna.com)
    • There's a really nice racing demo game on there.
    • (Update 2008-12-17 http://creators.xna.com)
  • Starter kit content is all free to use in your own games.
    • Takes about 45 minutes to compile and deploy to XBox 360 on the first compile.
• Text in games
  • No font system... must make text sprites in content folder.
• Resources
  • http://msdn.microsoft.com/en-us/xna/default.aspx
  • xnadevelopment.com
  • ziggyware.com
  • creators.xna.com
  • thezbuffer.com
  • blogs.msdn.com/shawnhar
  • blogs.msdn.com/xna
  • ILoveVB.net/web/blogs/vbxma (if you really want to punish yourself). I wouldn't have posted this link, but it's Chris' own blog, so he deserves his link here.
  • twincitiesxnausersgroup.com
  • igda.org/wiki/index.php/igm (what's up with PHP on this site???)