WP7：将加速度计和指南针数据转换为模拟运动 API

Question

我正在为 Windows Phone 7.1 (Mango) 编写一个小型示例应用程序，并希望使用组合运动 API 来显示设备的运动。我需要编写模拟类，以便在使用不支持设备所有传感器的模拟器时能够测试我的应用程序。

我已经编写了一个简单的模拟类来模拟指南针（它只是模拟旋转设备）和模拟器中实际可用的加速度计。

现在我必须为 Motion API 编写一个新的模拟对象，但我希望我可以使用指南针和加速度计的值来计算用于 Motion 对象的值。不幸的是，我没有找到已经执行此操作的简单转换示例。

有人知道执行此转换的代码示例吗？尽管这很复杂，但如果已经有解决方案，我不想自己做这件事。

Answer 1

现在 Windows Phone 8 已经发布，而且我还没有手机可以测试，我又遇到了同样的问题。

非常类似于 WP7 Mock Microsoft.Devices.Sensors 的答案.使用模拟器时的指南针，我创建了与 Motion 具有相同方法的包装类API。当实际的 Motion API 支持时，就会使用它。否则，在调试模式下，将返回改变横滚、俯仰和偏航的模拟数据。

---

MotionWrapper

    /// <summary>
    /// Provides Windows Phone applications information about the device’s orientation and motion.
    /// </summary>
    public class MotionWrapper //: SensorBase<MotionReading> // No public constructors, nice one.
    {
        private Motion motion;

        public event EventHandler<SensorReadingEventArgs<MockMotionReading>> CurrentValueChanged;

        #region Properties
        /// <summary>
        /// Gets or sets the preferred time between Microsoft.Devices.Sensors.SensorBase<TSensorReading>.CurrentValueChanged events.
        /// </summary>
        public virtual TimeSpan TimeBetweenUpdates
        {
            get
            {
                return motion.TimeBetweenUpdates;
            }
            set
            {
                motion.TimeBetweenUpdates = value;
            }
        }

        /// <summary>
        /// Gets or sets whether the device on which the application is running supports the sensors required by the Microsoft.Devices.Sensors.Motion class.
        /// </summary>
        public static bool IsSupported
        {
            get
            {
#if(DEBUG)
                return true;
#else
                return Motion.IsSupported;
#endif

            }
        }
        #endregion

        #region Constructors
        protected MotionWrapper()
        {
        }

        protected MotionWrapper(Motion motion)
        {
            this.motion = motion;
            this.motion.CurrentValueChanged += motion_CurrentValueChanged;
        }
        #endregion

        /// <summary>
        /// Get an instance of the MotionWrappper that supports the Motion API
        /// </summary>
        /// <returns></returns>
        public static MotionWrapper Instance()
        {
#if(DEBUG)
            if (!Motion.IsSupported)
            {
                return new MockMotionWrapper();
            }
#endif
            return new MotionWrapper(new Motion());
        }

        /// <summary>
        /// The value from the underlying Motion API has changed. Relay it on within a MockMotionReading.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void motion_CurrentValueChanged(object sender, SensorReadingEventArgs<MotionReading> e)
        {
            var f = new SensorReadingEventArgs<MockMotionReading>();
            f.SensorReading = new MockMotionReading(e.SensorReading);
   RaiseValueChangedEvent(sender, f);
        }

        protected void RaiseValueChangedEvent(object sender, SensorReadingEventArgs<MockMotionReading> e)
        {
            if (CurrentValueChanged != null)
            {
                CurrentValueChanged(this, e);
            }
        }

        /// <summary>
        /// Starts acquisition of data from the sensor.
        /// </summary>
        public virtual void Start()
        {
            motion.Start();
        }

        /// <summary>
        /// Stops acquisition of data from the sensor.
        /// </summary>
        public virtual void Stop()
        {
            motion.Stop();
        }
    }

---

MockMotionWrapper

    /// <summary>
    /// Provides Windows Phone applications mock information about the device’s orientation and motion.
    /// </summary>
    public class MockMotionWrapper : MotionWrapper
    {
        /// <summary>
        /// Use a timer to trigger simulated data updates.
        /// </summary>
        private DispatcherTimer timer;

        private MockMotionReading lastCompassReading = new MockMotionReading(true);

        #region Properties
        /// <summary>
        /// Gets or sets the preferred time between Microsoft.Devices.Sensors.SensorBase<TSensorReading>.CurrentValueChanged events.
        /// </summary>
        public override TimeSpan TimeBetweenUpdates
        {
            get
            {
                return timer.Interval;
            }
            set
            {
                timer.Interval = value;
            }
        }
        #endregion

        #region Constructors
        public MockMotionWrapper()
        {
            timer = new DispatcherTimer();
            timer.Interval = TimeSpan.FromMilliseconds(30);
            timer.Tick += new EventHandler(timer_Tick);
        }
        #endregion

        void timer_Tick(object sender, EventArgs e)
        {
            var reading = new Microsoft.Devices.Sensors.SensorReadingEventArgs<MockMotionReading>();
            lastCompassReading = new MockMotionReading(lastCompassReading);
            reading.SensorReading = lastCompassReading;

            //if (lastCompassReading.HeadingAccuracy > 20)
            //{
            //    RaiseValueChangedEvent(this, new CalibrationEventArgs());
            //}

            RaiseValueChangedEvent(this, reading);
        }

        /// <summary>
        /// Starts acquisition of data from the sensor.
        /// </summary>
        public override void Start()
        {
            timer.Start();
        }

        /// <summary>
        /// Stops acquisition of data from the sensor.
        /// </summary>
        public override void Stop()
        {
            timer.Stop();
        }

    }

---

MockMotionReading

//Microsoft.Devices.Sensors.MotionReading
/// <summary>
/// Contains information about the orientation and movement of the device.
/// </summary>
public struct MockMotionReading : Microsoft.Devices.Sensors.ISensorReading
{
    public static bool RequiresCalibration = false;

    #region Properties
    /// <summary>
    /// Gets the attitude (yaw, pitch, and roll) of the device, in radians.
    /// </summary>
    public MockAttitudeReading Attitude { get; internal set; }

    /// <summary>
    ///  Gets the linear acceleration of the device, in gravitational units.
    /// </summary>
    public Vector3 DeviceAcceleration { get; internal set; }

    /// <summary>
    /// Gets the rotational velocity of the device, in radians per second.
    /// </summary>
    public Vector3 DeviceRotationRate { get; internal set; }

    /// <summary>
    /// Gets the gravity vector associated with the Microsoft.Devices.Sensors.MotionReading.
    /// </summary>
    public Vector3 Gravity { get; internal set; }

    /// <summary>
    /// Gets a timestamp indicating the time at which the accelerometer reading was
    ///     taken. This can be used to correlate readings across sensors and provide
    ///     additional input to algorithms that process raw sensor data.
    /// </summary>
    public DateTimeOffset Timestamp { get; internal set; }
    #endregion

    #region Constructors

    /// <summary>
    /// Initialize an instance from an actual MotionReading
    /// </summary>
    /// <param name="cr"></param>
    public MockMotionReading(MotionReading cr)
        : this()
    {
        this.Attitude = new MockAttitudeReading(cr.Attitude);
        this.DeviceAcceleration = cr.DeviceAcceleration;
        this.DeviceRotationRate = cr.DeviceRotationRate;
        this.Gravity = cr.Gravity;
        this.Timestamp = cr.Timestamp;
    }

    /// <summary>
    /// Create an instance initialized with testing data
    /// </summary>
    /// <param name="test"></param>
    public MockMotionReading(bool test) 
        : this()
    {
        float pitch = 0.01f;
        float roll = 0.02f;
        float yaw = 0.03f;

        this.Attitude = new MockAttitudeReading()
        {
            Pitch = pitch,
            Roll = roll,
            Yaw = yaw,
            RotationMatrix = Matrix.CreateFromYawPitchRoll(yaw, pitch, roll),  
            Quaternion = Quaternion.CreateFromYawPitchRoll(yaw, pitch, roll), 

            Timestamp = DateTimeOffset.Now
        };

        // TODO: pull data from the Accelerometer
        this.Gravity = new Vector3(0, 0, 1f);
    }

    /// <summary>
    /// Create a new mock instance based on the previous mock instance
    /// </summary>
    /// <param name="lastCompassReading"></param>
    public MockMotionReading(MockMotionReading lastCompassReading)
        : this()
    {
        // Adjust the pitch, roll, and yaw as required.

        // -90 to 90 deg
        float pitchDegrees = MathHelper.ToDegrees(lastCompassReading.Attitude.Pitch) - 0.5f;
        //pitchDegrees = ((pitchDegrees + 90) % 180) - 90;

        // -90 to 90 deg
        float rollDegrees = MathHelper.ToDegrees(lastCompassReading.Attitude.Roll);
        //rollDegrees = ((rollDegrees + 90) % 180) - 90;

        // 0 to 360 deg
        float yawDegrees = MathHelper.ToDegrees(lastCompassReading.Attitude.Yaw) + 0.5f;
        //yawDegrees = yawDegrees % 360;

        float pitch = MathHelper.ToRadians(pitchDegrees);
        float roll = MathHelper.ToRadians(rollDegrees);
        float yaw = MathHelper.ToRadians(yawDegrees);

        this.Attitude = new MockAttitudeReading()
        {
            Pitch = pitch,
            Roll = roll,
            Yaw = yaw,
            RotationMatrix = Matrix.CreateFromYawPitchRoll(yaw, pitch, roll),
            Quaternion = Quaternion.CreateFromYawPitchRoll(yaw, pitch, roll),

            Timestamp = DateTimeOffset.Now
        };

        this.DeviceAcceleration = lastCompassReading.DeviceAcceleration;
        this.DeviceRotationRate = lastCompassReading.DeviceRotationRate;
        this.Gravity = lastCompassReading.Gravity;
        Timestamp = DateTime.Now;

    }
    #endregion



}

---

MockAttitudeReading

public struct MockAttitudeReading : ISensorReading
{
    public MockAttitudeReading(AttitudeReading attitudeReading) : this()
    {
        Pitch = attitudeReading.Pitch;
        Quaternion = attitudeReading.Quaternion;
        Roll = attitudeReading.Roll;
        RotationMatrix = attitudeReading.RotationMatrix;
        Timestamp = attitudeReading.Timestamp;
        Yaw = attitudeReading.Yaw;
    }

    /// <summary>
    /// Gets the pitch of the attitude reading in radians.
    /// </summary>
    public float Pitch { get; set; }

    /// <summary>
    /// Gets the quaternion representation of the attitude reading.
    /// </summary>
    public Quaternion Quaternion { get; set; }

    /// <summary>
    /// Gets the roll of the attitude reading in radians.
    /// </summary>
    public float Roll { get; set; }

    /// <summary>
    /// Gets the matrix representation of the attitude reading.
    /// </summary>
    public Matrix RotationMatrix { get; set; }

    /// <summary>
    /// Gets a timestamp indicating the time at which the accelerometer reading was
    ///     taken. This can be used to correlate readings across sensors and provide
    ///     additional input to algorithms that process raw sensor data.
    /// </summary>
    public DateTimeOffset Timestamp { get; set; }

    /// <summary>
    /// Gets the yaw of the attitude reading in radians.
    /// </summary>
    public float Yaw { get; set; }
}

Answer 2

进行 Mockup 工作的一个良好起点是查看 Motion API 及其内部工作原理以及 API 核心使用哪些参数：

http://msdn.microsoft.com/en-us/library/hh202984%28VS.92%29.aspx

在继续之前，请记住 Motion API 是复杂的数学运算模型结合了不同手机传感器的输入。您可以找到许多不同的模型来通过组合加速度、位置和旋转来计算运动。您可以在本文中找到一个很好的描述：

http://www.instructables.com/id/Accelerometer-Gyro-Tutorial/

所以实际上，你必须使用上面文章中所示的方程和函数，然后计算价值观靠你自己。

这一切都不是简单的事情，但以这种方式是可能的。

我希望我能够帮助您:)，如果您已经做到了，请让社区知道。我认为 Codeplex 项目可以为 Windows Phone Motion API 编写一种模拟实用程序。