The document discusses using XNA for game development on Windows Phone. It covers topics like using 2D and 3D graphics, handling input from touches, sensors and orientation changes, integrating networking, ads and Xbox Live functionality, and optimizing performance. Code examples are provided for common tasks like drawing sprites, handling input and animating objects. Future directions for XNA on other platforms like Silverlight and Windows 8 are also mentioned.

2. Real life
Johan Lindfors

4. windows phone for games
• impressive performance
• sensors and touch
• potentially xbox-live
• ads and trials

5. kinectimals

6. harvest

7. implode

8. doodle fit

9. ilomilo

10. other favorites

11. xna in 1 minute
• a comprehensive framework for games
• integrated management of content
• games with 2d and ”sprites”
• games with 3d and ”meshes”
• shared features for pc, wp, xbox

12. initialize update render

13. managing content
• content pipeline
• import common files
• leverage compile time
• optimized binary format
• extensible

14. first some 2d
• x and y (and z)
• spriteBatch
• sprites/sprite sheets
• blending

15. and then some 3d
• x, y and z
• camera is described with matrices
• view
• projection
• world matrix transforms objects relatively
• movement (translation)
• rotation
• size (scale)

16. demo

17. effects - shaders
• configurable
• basic
• skinned
• environmentMap
• dualTexture
• alphaTest

18. demo

19. ”hardware scaler”
• 800x480 = 384 000 pixels
• 600x360 = 216 000 pixels (56%)
• 400x240 = 96 000 pixels (25%)
graphics.PreferredBackBufferHeight = 800;
graphics.PreferredBackBufferWidth = 480;

20. performance tips
• manage the stack and heap
• reference types live on the _______!
• value types live on the _______!
• pass large structures by reference
Matrix a, b, c;
c = Matrix.Multiply(a, b); // copies 192 bytes!
Matrix.Multiply(ref a, ref b, out c);
• don’t foreach or linq (know code cost)

21. performance tips
• gc is ”simpler” than on pc
• allocate objects early, reuse
• GC.Collect() can be your friend!
• after load, while paused
• cpu or gpu based?
• you can go up to 60 fps (60 hz)

22. demo

23. sound and music
• soundEffect
• load as content
• wp handles 64 simultaneously
• possible to change
• pitch
• volume
• 3d location

24. orientation
graphics.SupportedOrientations =
DisplayOrientation.Portrait |
DisplayOrientation.LandscapeLeft |
DisplayOrientation.LandscapeRight;
• default is ”LandscapeLeft”

25. orientation
Window.OrientationChanged += (s, e) =>
{
switch (Window.CurrentOrientation)
{
case DisplayOrientation.Portrait:
graphics.PreferredBackBufferHeight = 800;
graphics.PreferredBackBufferWidth = 480;
break;
default:
graphics.PreferredBackBufferHeight = 480;
graphics.PreferredBackBufferWidth = 800;
break;
}
graphics.ApplyChanges();
};

26. accelerometer
using Microsoft.Devices.Sensors;
• measures acceleration in X, Y and Z
• values returned between -1 and +1
• event based
• read values in event, store for usage

27. start accelerometer
Accelerometer accel;
private void startAccelerometer() {
accel = new Accelerometer();
accel.ReadingChanged += new
EventHandler
<AccelerometerReadingEventArgs>
(accel_ReadingChanged);
accel.Start();
}

28. read the accelerometer
Vector3 accelReading;
void accel_ReadingChanged(object sender,
AccelerometerReadingEventArgs e)
{
lock (this)
{
accelReading.X = (float)e.X;
accelReading.Y = (float)e.Y;
accelReading.Z = (float)e.Z;
}
}

29. touch
• windows phone handles 4 touch points
• all points have unique id
• pressed | moved | released
TouchCollection touches;
protected override void Update(GameTime gt)
{
touches = TouchPanel.GetState();
...
}

30. gestures
• wp can also handle gestures
• tap | drag | hold | flick | pinch ...
TouchPanel.EnabledGestures =
GestureType.Flick;
while (TouchPanel.IsGestureAvailable) {
GestureSample g = TouchPanel.ReadGesture();
if (g.GestureType == GestureType.Flick)
{ ... }
}

31. network
• http, rest, xml, sockets...
void wc_OpenReadCompleted(object sender,
OpenReadCompletedEventArgs e) {
if (e.Error == null)
{
mapImage = Texture2D.FromStream(
graphics.GraphicsDevice,
e.Result);
}
}

32. xbox live
• avatars and “trials” available for all
• developers with agreements
• profile
• invites
• achievements
• leaderboard
• gamerServices
• contact: wpgames@microsoft.com

33. trial mode
#if DEBUG
Guide.SimulateTrialMode = true;
#endif
bool isTrial = Guide.IsTrialMode;
...
Guide.ShowMarketplace(PlayerIndex.One);
• call to IsTrialMode takes 60 ms, cache!
• be creative in feature set
• trial or free light?

34. ads
• instead of user paying for app
• not for swedish apps yet*
using Microsoft.Advertising.Mobile.Xna;
...
AdManager adManager;
Ad bannerAd;
*not from Microsoft that is, there are options

35. marketplace
• local structure
• test kit in VS2010
• updates
• auto-publish

36. protect yourself
• ready for obfuscation?
public void d(bp.b A_0)
{
this.l = A_0;
this.i = new List<string>();
this.i.Add(am.a().e("SK_NO"));
this.i.Add(am.a().e("SK_YES"));
this.g = bo.a;
SignedInGamer.SignedIn += new
EventHandler<SignedInEventArgs>(this.d);
}

38. news in mango
• silverlight + xna
• fast application switching
• profiling
• combined api for movement

39. demo

40. tripeaks solitaire
• fabrication games
• true 3D
• all code in objective-c

41. -(BOOL) animate
{
if([self animation] == nil)
{
[self draw];
return NO;
}
else
{
BOOL animationDone = [[self animation] animate];
[self draw];
if (animationDone)
{
x += [[self animation] currentX];
y += [[self animation] currentY];
z += [[self animation] currentZ];
rotation += [[self animation] currentRotation];
[animations removeObjectAtIndex:0];
}
return animationDone;
}
}

42. public bool Animate()
{
if (this.Animation == null)
{
this.Draw();
return false;
}
else
{
bool animationDone = this.Animation.Animate();
this.Draw();
if (animationDone)
{
x += this.Animation.CurrentX;
y += this.Animation.CurrentY;
z += this.Animation.CurrentZ;
rotation += this.Animation.CurrentRotation;
animations.RemoveAt(0);
}
return animationDone;
}
}

43. public bool Animate(GraphicsDevice graphics, BasicEffect effect)
{
if (this.Animation == null)
{
this.Draw(graphics, effect);
return false;
}
else
{
bool animationDone = this.Animation.Animate();
this.Draw(graphics, effect);
if (animationDone)
{
x += this.Animation.CurrentX;
y += this.Animation.CurrentY;
z += this.Animation.CurrentZ;
rotation += this.Animation.CurrentRotation;
animations.RemoveAt(0);
}
return animationDone;
}
}

44. demo

45. future of xna?
• silverlight 5.0
• subset of XNA
• focused on business apps
• windows 8
• leverages directx 11
• likely to attract commercial studios

46. johan.lindfors@coderox.se

47. resources
• create.msdn.com
• jodegreef.wordpress.com - angry pigs
• www.xnaresources.com
• http://msdn.microsoft.com/en-
us/library/bb417503(XNAGameStudio.41).aspx
• programmeramera.se
• www.coderox.se