added compass example

Author: codeanticode

wallpapers/ex2_compass/ex2_compass.pde

@@ -0,0 +1,100 @@
+// Based on the compass example from Rolf van Gelder.
+// http://cagewebdev.com/index.php/android-processing-examples/
+
+import android.content.Context;
+import android.hardware.Sensor;
+import android.hardware.SensorManager;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+
+Context context;
+SensorManager manager;
+SensorListener listener;
+Sensor accelerometer;
+Sensor magnetometer;
+
+float easing = 0.05;
+
+float azimuth;
+float pitch;
+float roll;
+
+void setup() {
+  fullScreen(P2D);
+  orientation(PORTRAIT);
+}
+
+void draw() {
+  background(255);
+  
+  float cx = width * 0.5;
+  float cy = height * 0.4;
+  float radius = 0.8 * cx;
+  
+  translate(cx, cy);
+  
+  noFill();
+  stroke(0);
+  strokeWeight(2);
+  ellipse(0, 0, radius*2, radius*2);
+  line(0, -cy, 0, -radius);
+  
+  fill(192, 0, 0);
+  noStroke();    
+  rotate(-azimuth);
+  beginShape();
+  vertex(-30, 40);
+  vertex(0, 0);
+  vertex(30, 40);
+  vertex(0, -radius);
+  endShape();
+}
+
+public void onResume() {
+  super.onResume();  
+  
+  // This works for regular apps
+  //Context context = surface.getActivity();
+  
+  // This for fragments:
+  context = (Context) surface.getComponent();
+  
+  listener = new SensorListener();
+  manager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
+  accelerometer = manager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
+  magnetometer  = manager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
+
+  manager.registerListener(listener, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
+  manager.registerListener(listener, magnetometer, SensorManager.SENSOR_DELAY_NORMAL);
+}
+
+public void onPause() {
+  super.onPause();
+  if (manager != null) manager.unregisterListener(listener);
+}
+
+class SensorListener implements SensorEventListener {
+  float[] gravity = new float[3];
+  float[] geomagnetic = new float[3];
+  float[] I = new float[16];
+  float[] R = new float[16];
+  float orientation[] = new float[3]; 
+  
+  public void onSensorChanged(SensorEvent event) {
+    if (event.accuracy == SensorManager.SENSOR_STATUS_ACCURACY_LOW) return;
+    
+    if (event.sensor.getType() ==  Sensor.TYPE_MAGNETIC_FIELD) {
+      arrayCopy(event.values, geomagnetic);
+    }
+    if (event.sensor.getType() ==  Sensor.TYPE_ACCELEROMETER) {
+      arrayCopy(event.values, gravity);
+    }
+    if (SensorManager.getRotationMatrix(R, I, gravity, geomagnetic)) {
+      SensorManager.getOrientation(R, orientation);
+      azimuth += easing * (orientation[0] - azimuth);
+      pitch += easing * (orientation[1] - pitch);
+      roll += easing * (orientation[2] - roll);;
+    }    
+  }
+  public void onAccuracyChanged(Sensor sensor, int accuracy) { }
+}