Implemented gyroscope controls, no camera rotation and no filtering algorithm yet

src/guiengine/event_handler.cpp

@@ -202,7 +202,8 @@ bool EventHandler::OnEvent (const SEvent &event)
              event.EventType == EET_TOUCH_INPUT_EVENT ||
              event.EventType == EET_KEY_INPUT_EVENT   ||
              event.EventType == EET_JOYSTICK_INPUT_EVENT ||
-             event.EventType == EET_ACCELEROMETER_EVENT)
+             event.EventType == EET_ACCELEROMETER_EVENT ||
+             event.EventType == EET_GYROSCOPE_EVENT)
     {
         // Remember the mouse position
         if (event.EventType == EET_MOUSE_INPUT_EVENT &&

src/input/input_manager.cpp

@@ -937,6 +937,7 @@ bool InputManager::masterPlayerOnly() const
  */
 EventPropagation InputManager::input(const SEvent& event)
 {
+    const float ORIENTATION_MULTIPLIER = 10.0f;
     if (event.EventType == EET_JOYSTICK_INPUT_EVENT)
     {
         // Axes - FIXME, instead of checking all of them, ask the bindings
@@ -1238,7 +1239,29 @@ EventPropagation InputManager::input(const SEvent& event)
             
             float factor = UserConfigParams::m_multitouch_tilt_factor;
             factor = std::max(factor, 0.1f);
-            device->updateAxisX(float(event.AccelerometerEvent.Y) / factor);
+            if (UserConfigParams::m_multitouch_controls == MULTITOUCH_CONTROLS_GYROSCOPE)
+            {
+                device->updateOrientationFromAccelerometer(event.AccelerometerEvent.X, event.AccelerometerEvent.Y);
+                device->updateAxisX(device->getOrientation() * ORIENTATION_MULTIPLIER / factor);
+            }
+            else
+            {
+                device->updateAxisX(float(event.AccelerometerEvent.Y) / factor);
+            }
+        }
+    }
+    else if (event.EventType == EET_GYROSCOPE_EVENT)
+    {
+        MultitouchDevice* device = m_device_manager->getMultitouchDevice();
+
+        if (device && device->isGyroscopeActive())
+        {
+            m_device_manager->updateMultitouchDevice();
+
+            float factor = UserConfigParams::m_multitouch_tilt_factor;
+            factor = std::max(factor, 0.1f);
+            device->updateOrientationFromGyroscope(event.GyroscopeEvent.Z);
+            device->updateAxisX(device->getOrientation() * ORIENTATION_MULTIPLIER / factor);
         }
     }
 

src/input/multitouch_device.cpp

@@ -171,6 +171,9 @@ void MultitouchDevice::reset()
         event.x = 0;
         event.y = 0;
     }
+
+    m_orientation = 0.0f;
+    m_gyro_time = 0.0;
 } // reset
 
 // ----------------------------------------------------------------------------
@@ -212,6 +215,45 @@ bool MultitouchDevice::isAccelerometerActive()
     return false;
 }
 
+// ----------------------------------------------------------------------------
+/** Activates gyroscope
+ */
+void MultitouchDevice::activateGyroscope()
+{
+#ifdef ANDROID
+    if (!m_android_device->isGyroscopeActive())
+    {
+        m_android_device->activateGyroscope(1.0f / 60); // Assume 60 FPS, some phones can do 90 and 120 FPS but we won't handle them now
+    }
+#endif
+}
+
+// ----------------------------------------------------------------------------
+/** Deativates gyroscope
+ */
+void MultitouchDevice::deactivateGyroscope()
+{
+#ifdef ANDROID
+    if (m_android_device->isGyroscopeActive())
+    {
+        m_android_device->deactivateGyroscope();
+    }
+#endif
+}
+
+// ----------------------------------------------------------------------------
+/** Get gyroscope state
+ *  \return true if gyroscope is active
+ */
+bool MultitouchDevice::isGyroscopeActive()
+{
+#ifdef ANDROID
+    return m_android_device->isGyroscopeActive();
+#endif
+
+    return false;
+}
+
 // ----------------------------------------------------------------------------
 /** The function that is executed when touch event occurs. It updates the
  *  buttons state when it's needed.
@@ -382,6 +424,87 @@ void MultitouchDevice::updateAxisY(float value)
 
 // ----------------------------------------------------------------------------
 
+float MultitouchDevice::getOrientation()
+{
+    return m_orientation;
+}
+
+// ----------------------------------------------------------------------------
+
+void MultitouchDevice::updateOrientationFromAccelerometer(float x, float y)
+{
+    const float ACCEL_DISCARD_THRESHOLD = 4.0f;
+    const float ACCEL_MULTIPLIER = 0.05f; // Slowly adjust the angle over time, this prevents shaking
+    const float ACCEL_CHANGE_THRESHOLD = 0.01f; // ~0.5 degrees
+
+    if (fabsf(x) + fabsf(y) < ACCEL_DISCARD_THRESHOLD)
+    {
+        // The device is flat on the table, cannot reliably determine the orientation
+        return;
+    }
+
+    float angle = atan2f(y, x);
+    if (angle > (M_PI / 2.0))
+    {
+        angle = (M_PI / 2.0);
+    }
+    if (angle < -(M_PI / 2.0))
+    {
+        angle = -(M_PI / 2.0);
+    }
+
+    float delta = angle - m_orientation;
+    delta *= ACCEL_MULTIPLIER;
+    if (delta > ACCEL_CHANGE_THRESHOLD)
+    {
+        delta = ACCEL_CHANGE_THRESHOLD;
+    }
+    if (delta < -ACCEL_CHANGE_THRESHOLD)
+    {
+        delta = -ACCEL_CHANGE_THRESHOLD;
+    }
+
+    m_orientation += delta;
+
+    //Log::warn("Accel", "X %03.4f Y %03.4f angle %03.4f delta %03.4f orientation %03.4f", x, y, angle, delta, m_orientation);
+}
+
+// ----------------------------------------------------------------------------
+
+void MultitouchDevice::updateOrientationFromGyroscope(float z)
+{
+    const float GYRO_SPEED_THRESHOLD = 0.005f;
+
+    double now = StkTime::getRealTime();
+    float timedelta = now - m_gyro_time;
+    m_gyro_time = now;
+    if (timedelta > 0.5f)
+    {
+        timedelta = 0.1f;
+    }
+
+    float angular_speed = -z;
+
+    if (fabsf(angular_speed) < GYRO_SPEED_THRESHOLD)
+    {
+        angular_speed = 0.0f;
+    }
+
+    m_orientation += angular_speed * timedelta;
+    if (m_orientation > (M_PI / 2.0))
+    {
+        m_orientation = (M_PI / 2.0);
+    }
+    if (m_orientation < -(M_PI / 2.0))
+    {
+        m_orientation = -(M_PI / 2.0);
+    }
+
+    //Log::warn("Gyro", "Z %03.4f angular_speed %03.4f delta %03.4f orientation %03.4f", z, angular_speed, angular_speed * timedelta, m_orientation);
+}
+
+// ----------------------------------------------------------------------------
+
 /** Sends proper action for player controller depending on the button type
  *  and state.
  *  \param button The button that should be handled.

src/input/multitouch_device.hpp

@@ -87,6 +87,9 @@ private:
      *  at the edge of button */
     float m_deadzone_edge;
 
+    float m_orientation;
+    double m_gyro_time;
+
 #ifdef ANDROID
     /** Pointer to the Android irrlicht device */
     CIrrDeviceAndroid* m_android_device;
@@ -125,9 +128,16 @@ public:
     void activateAccelerometer();
     void deactivateAccelerometer();
     bool isAccelerometerActive();
-    
+
+    void activateGyroscope();
+    void deactivateGyroscope();
+    bool isGyroscopeActive();
+
     void updateAxisX(float value);
     void updateAxisY(float value);
+    float getOrientation();
+    void updateOrientationFromAccelerometer(float x, float y);
+    void updateOrientationFromGyroscope(float z);
     void updateDeviceState(unsigned int event_id);
     void updateController();
     void updateConfigParams();

src/states_screens/race_gui_multitouch.cpp

@@ -104,6 +104,11 @@ void RaceGUIMultitouch::close()
     {
         m_device->deactivateAccelerometer();
     }
+
+    if (m_device->isGyroscopeActive())
+    {
+        m_device->deactivateGyroscope();
+    }
 }   // close
 
 
@@ -120,6 +125,11 @@ void RaceGUIMultitouch::init()
     {
         m_device->activateAccelerometer();
     }
+    if (UserConfigParams::m_multitouch_controls == MULTITOUCH_CONTROLS_GYROSCOPE)
+    {
+        m_device->activateAccelerometer();
+        m_device->activateGyroscope();
+    }
 
     const float scale = UserConfigParams::m_multitouch_scale;
 
@@ -155,7 +165,7 @@ void RaceGUIMultitouch::init()
 
     m_height = (unsigned int)(2 * col_size + margin / 2);
     
-    if (m_device->isAccelerometerActive())
+    if (m_device->isAccelerometerActive() || m_device->isGyroscopeActive())
     {
         m_device->addButton(BUTTON_UP_DOWN,
                     int(steering_accel_x), int(steering_accel_y),