spnav-csharp-wrapper/SpaceNav.cs

using System;
using System.Runtime.InteropServices;
using System.Threading;

namespace SpaceNavWrapper
{
	public class SpaceNavDriver : IDisposable
    {

		const string DLL_NAME = "spnavhdi";
        
        #region Constants
        private const int SPNAV_EVENT_MOTION = 1;
        private const int SPNAV_EVENT_BUTTON = 2;
        private const ushort SPNAV_VENDOR_ID = 0x046d;
        private const ushort SPNAV_PRODUCT_ID = 0x0c627;
        #endregion

		public event EventHandler<MotionEventArgs> Motion;
		public event EventHandler<EventArgs> Button;
        
		private Thread eventThread;
        private bool deviceReady;
        private double _sensitivity = 1.0;
        private int _threshold = 5;
		private bool isDisposed;

		#region Structures
		private struct SpNavEventMotion
        {
            public int type;
            public int x, y, z;
            public int rx, ry, rz;
            public uint period;
            public IntPtr data;
        }

        private struct SpNavEventButton
        {
            public int type;
            public int press;
            public int bnum;
        }

        [StructLayout(LayoutKind.Explicit)]
        private struct SpNavEvent
        {
            [FieldOffset(0)] public int type;
            [FieldOffset(0)] public SpNavEventMotion motion;
            [FieldOffset(0)] public SpNavEventButton button;
        }
        #endregion
        
        #region DLL Imports
        [DllImport(DLL_NAME)]
        private static extern int spnav_open(ushort vendor_id, ushort product_id);
        [DllImport(DLL_NAME)]
        private static extern int spnav_close();
        [DllImport(DLL_NAME)]
        private static extern int spnav_wait_event(ref SpNavEvent ev);
        [DllImport(DLL_NAME)]
        private static extern int spnav_wait_event_timeout(ref SpNavEvent ev, int timeout);
        [DllImport(DLL_NAME)]
        private static extern int spnav_sensitivity(double sens);
        [DllImport(DLL_NAME)]
        private static extern int spnav_deadzone(int threshold);
        #endregion
        
        public SpaceNavDriver()
        {
			eventThread = new Thread(HandleEvents)
			{
				IsBackground = true,
				Name = "3Dconnexion-Event-Dispatcher"
			};
			eventThread.Start();
        }
        
        public void InitDevice()
        {
			spnav_open(SPNAV_VENDOR_ID, SPNAV_PRODUCT_ID);
			spnav_deadzone(5);
			deviceReady = true;
        }

		private void HandleEvents(object obj)
		{        
            // Block while the device isn't ready
            while (!deviceReady) {}
            Console.WriteLine("Device ready !");
			while (!isDisposed)
            {
                SpNavEvent sev = new SpNavEvent();
				int ev_type = spnav_wait_event(ref sev);
				Console.WriteLine("Event type : {0}", sev.type);
                switch (ev_type)
                {
                    case SPNAV_EVENT_BUTTON:
						//return new SpaceNavButtonEvent(Convert.ToBoolean(sev.button.press), sev.button.bnum);
						Button(this, new EventArgs());
						break;
                    case SPNAV_EVENT_MOTION:
						var ev = sev.motion;
                        Motion(this, new MotionEventArgs(ev.x, ev.y, ev.z, ev.rx, ev.ry, ev.rz));
						break;
                }
            }
		}

		public double Sensitivity
		{
			get => _sensitivity;
			set
			{
				_sensitivity = value;
				spnav_sensitivity(value);
			}
		}

		public int Threshold
		{
			get => _threshold;
			set
			{
				_threshold = value;
				spnav_deadzone(value);
			}
		}
        
        public void Dispose()
        {
            if (!isDisposed)
            {
                CloseDevice();
                Button = null;
                Motion = null;
            }
            isDisposed = true;
        }

		private void CloseDevice()
		{
			// TODO : handle retcode and errors
			spnav_close();
		}
	}
}