Retrieving Gyroscope Input (Windows Phone)

This topic demonstrates how to detect and use gyroscope input in an XNA Game Studio game on Windows Phone.

Each sensor may not be available on every device, specifically the gyroscope sensor is an optional component. Applications need a way to determine whether a particular sensor’s hardware is present on a device before using it. The IsSupported property on each sensor class is used to determine whether the sensor is available on the current hardware platform. This is a static property that can be queried without creating an instance of the respective sensor class.

Games have the option of polling for new data from the sensor using the familiar mechanism of using the Update and Draw methods. In the following code the latest reading from the gyroscope sensor is read in the Update method. This data is then used during the Draw method.

Note

Gyroscope input is only supported on Windows Phone. Other platforms have no access to this feature.

Adding Microsoft.Devices.Sensors to Your Application

Gyroscope input on Windows Phone OS 7.1 is not directly supported by XNA Game Studio 4.0 Refresh, but it is easy to add to an existing project. Gyroscope input is handled by the Microsoft.Devices.Sensors assembly, which must be referenced by your assembly before it can be used in your application.

To add Microsoft.Devices.Sensors to your game

1. In Solution Explorer, right-click your game project's References node, and then select Add Reference.
2. Select Microsoft.Devices.Sensors from the list, and then click OK.
3. Add using Microsoft.Devices.Sensors; to the top of any source file that will use the gyroscope classes and methods.

Use Gyroscope Data in Your Game

After adding a reference to Microsoft.Devices.Sensors you can use Gyroscope APIs.

To Get Gyroscope Values

1. Add a data member to your game to hold gyroscope data. Declaring an instance of Vector3) will hold the data returned from the gyroscope. The other members show here are used to draw the data later in the example.

   SpriteFont Font1;
   Vector2 FontPos;
   
   Vector3 gyroReading;
   

2. Get the latest gyroscope data within your game's Update method. Note the use of the IsSupported property to check if gyroscope data is available.

   if (Gyroscope.IsSupported)
   {
       //get current rotation rate, display happens in Draw()
       GyroscopeReading gr = new GyroscopeReading();
       gyroReading = gr.RotationRate;
   }
   

3. Do something with the gyroscope readings.

   Now you can use the gyroscope readings with your game's Draw method.

   if (Gyroscope.IsSupported)
   {
       //get current rotation rate, display happens in Draw()
       output += gyroReading.X.ToString("0.00") + " Y = "
       + gyroReading.Y.ToString("0.00") + " Z = "
       + gyroReading.Z.ToString("0.00");
   }
   
   // draw 
   spriteBatch.Begin();
   
   // Find the center of the string and draw
   Vector2 FontOrigin = Font1.MeasureString(output) / 2;
   spriteBatch.DrawString(Font1, output, FontPos, Color.LightGreen, 0, FontOrigin, 1.0f, SpriteEffects.None, 0.5f);
   spriteBatch.End();
   

See Also

Working with Touch Input (Windows Phone)
Retrieving Accelerometer Input (Windows Phone)
Input Overviews