LeapCSharpExample

This repo is an illustration of how I integrated the LeapMotion using C# on Windows using UltraLeap's v4 / v5 64bit drivers. It is the underpinning for the basic motion aspects of my personal project MidiPaw (https://www.midipaw.com) which is currently not open sourced.

A number of folks have inquired re how I got started integrating with Leap, and perhaps with additional creative endeavours the LeapMotion universe of fun things to do will grow.

Everything needed is free

• VisualStudio Community Edition
• Leap Motion SDK (to get drivers and LeapC.dll)

The interface code in the LeapMotion folder is provided by Ultraleap under Apache License 2.0 (http://www.apache.org/licenses/LICENSE-2.0). The other source code supplied by me is offered without restriction or requirement. You can use a copy of it or modify it for whatever purpose you wish, and it is provided as-is without warranty of any kind.

Overview of Folders/Classes/Files

• Controllers

  • This folder contains two classes to demonstrate Leap integration:
    • The base class Controller which is a generalized controller class that fires events based on changes in underlying state of the controller (i.e. movement happening, or in the case of other kinds of controllers, buttons pressing or pressure changing, etc)
    • The class ConrollerLeap which is an extension of the Controller class to provide the Controller services on a Leap Motion

• Helpers

  • These are a couple of simple classes to help the controller classes handle the motion-driven data being provided by the Leap Motion.

• LeapMotion

  • This collection of classes is derived from the C# Unity implementation that was originally provided with the Unity Modules 4.8 by Ultraleap. They have kindly confirmed that these are released under an open agreement and it is fine to use them in this way and share them publicly.

• LeapC.dll

  • This project includes the 64-bit LeapMotion v5.2 LeapC.dll. It is set to copy to the output directory (right click, properties to see this). If you are running the v4 Leap drivers, replace this with the 64-bit v4 LeapC.dll that you get from the Leap Motion SDK.
    • Alternatively, if you have the LeapC.dll that you wish to use sitting in a directory that Windows will use when searching for DLLs, you can omit the explicit LeapC.dll from this project and just let Windows find it at runtime fro m your registry or path.

• MainWindow.xaml.cs

  • This is the source behind the single window, showing the usage of Leap information for control (in this case just updating a text value)

ControllerLeap Usage

As shown in the very basic example of MainWindow.xaml.cs, the ControllerLeap class operates by just instantiating an instance (which automatically tries to connect) and then subscribe to the MotionEvent stream (and unsubscribe as the window is destroyed)

    public MainWindow()
    {
        InitializeComponent();

        clMyLeap = new ControllerLeap();

        clMyLeap.MotionEvent += HandleMotionEvent;
    }

    ~MainWindow()
    {
        if (clMyLeap != null)
            clMyLeap.MotionEvent -= HandleMotionEvent;
    }

From there, ControllerLeap will fire motion events to the handler that you've provided. It has a signature like this:

    void HandleMotionEvent(object sender, Controller.MotionEventArgs e)

Inside the handler, you receive a MotionEventArgs which contains only a MotionState member. The MotionState contains:

• An array of floats fValue[], one per type of defined Motion
• A boolean bLeft indicating if it is the left hand (this code currently tracks only one hand at a time)
• A float fFrameRate giving the current number of event calls per second

The indicies for the Motion values that can appear in a MotionState are (from Controller.cs):

    {
        mLeftRight,             // Left/Right position
        mUpDown,                // Up/Down position
        mForwardBack,           // Near/Far position
        mTiltForwardBack,       // Wiimote or pen
        mTiltLeftRight,         // Wiimote or pen
        mTwistLeftRight,        // Rotation of the hand, like airplane YAW
        mTurnLeftRight,         // Rotation of the hand, like airplane YAW
        mPressure,              // Pen
        mGrab,                  // Fist Motion
        mPinch,                 // Thumb and second finger pinch
        mDistance,              // Like two hand distance apart on a leap motion
        mSpread,                // Degree of spread-out fingers
        mSpeed,                 // Overall velocoity in any direction.
        mSpeedLeftRight,        // Absolute speed 0-1
        mSpeedUpDown,           // Absolute speed 0-1
        mSpeedForwardBack,      // Absolute speed 0-1
        mVelLeftRight,          // Directional speed 0-1, 0.5 is still
        mVelUpDown,             // Directional speed 0-1, 0.5 is still
        mVelForwardBack,        // Directional speed 0-1, 0.5 is still
    }

Not all of these Motions are supported/implemented by ControllerLeap. The implemented list can be seen in ControllerLeap.cs:

       mMoves = new Move[] { new Move { mMotion = Motions.mLeftRight, sDesc = "Move Left/Right", sImagePath = "",
                                        sHint = "Hand moving left and right" },
                            new Move { mMotion = Motions.mUpDown, sDesc = "Move Up/Down", sImagePath = "",
                                        sHint = "Hand moving up and down" },
                            new Move { mMotion = Motions.mForwardBack, sDesc = "Move Fore/Back", sImagePath = "",
                                        sHint = "Hand moving forward and back" },
                            new Move { mMotion = Motions.mTwistLeftRight, sDesc = "Twist Left/Right", sImagePath = "",
                                        sHint = "Tilting hand left and right" },
                            new Move { mMotion = Motions.mTiltForwardBack, sDesc = "Tilt Up/Down", sImagePath = "",
                                        sHint = "Tilting hand up (back) or down (forward)" },
                            new Move { mMotion = Motions.mTurnLeftRight, sDesc = "Turn Left/Right", sImagePath = "",
                                        sHint = "Turning or rotating hand left and right (yaw)" },
                            new Move { mMotion = Motions.mGrab , sDesc = "Open/Grab", sImagePath = "",
                                        sHint = "Opening left hand or grabbing, making a fist" },
                            new Move { mMotion = Motions.mPinch , sDesc = "Pinch", sImagePath = "",
                                        sHint = "Pinching with thumb and pointer finger" },
                            new Move { mMotion = Motions.mSpread , sDesc = "Spread", sImagePath = "",
                                        sHint = "Fingers spread or close together" },
                            new Move { mMotion = Motions.mSpeed , sDesc = "Speed", sImagePath = "",
                                        sHint = "Hand speed in any direction" },
                            new Move { mMotion = Motions.mSpeedLeftRight , sDesc = "Speed Left/Right", sImagePath = "",
                                        sHint = "Hand speed moving left or right" },
                            new Move { mMotion = Motions.mSpeedUpDown , sDesc = "Speed Up/Down", sImagePath = "",
                                        sHint = "Hand speed moving up or down" },
                            new Move { mMotion = Motions.mSpeedForwardBack , sDesc = "Speed Fore/Back", sImagePath = "",
                                        sHint = "Hand speed moving forward and back" },
                            new Move { mMotion = Motions.mVelLeftRight , sDesc = "Velocity Left/Right", sImagePath = "",
                                        sHint = "Hand velocity moving left or right, centered when still" },
                            new Move { mMotion = Motions.mVelUpDown , sDesc = "Velocity Up/Down", sImagePath = "",
                                        sHint = "Hand velocity moving up or down, centered when still" },
                            new Move { mMotion = Motions.mVelForwardBack , sDesc = "Velocity Fore/Back", sImagePath = "",
                                        sHint = "Hand velocity moving forward and back, centered when still" }

Good Luck!

I hope this helps gets a fun project or two started. Unfortunately I can't provide any direct support but hopefully you'll find it easy enough to get going!

• Steve