That's a thing I was dreaming for years : Linking a physical, real-world object to an opensim object. You move the object in opensim, the real object moves. You move the real object, the object in opensim moves. All in real-time.
Here is a short demo video, in mov and mp4 (H.264) format. If your web browser can't handle either, download the .mp4 version and open it with VLC. I don't Youtube, sorry. http://www.pescadoo.net/tmp/fun_with_udp.mov (1Mb) http://www.pescadoo.net/tmp/fun_with_udp.mp4 (1.9Mb) Right is the familiar Imprudence window. The object with eight yellow bars is a multi-slider, similar to a mixing desk. Each bar can be clicked and dragged to the desired value. Left is a less-familiar window with another application running. The app is Cycling74' Max/MSP, although that could any app that can animate objects (graphical or physical) and read/write network sockets. In this video, i first move the slider in opensim and you see the sliders in the external app moving. Then I move the sliders in the external app, and the sliders in opensim move. No delay. Real-time. But there is more fun. The external app is linked to a physical "control surface", with motorized sliders. Unfortunately I can't show it in the video, missing a camcorder. I use a Behringer BCF2000. See it here: http://www.behringer.com/EN/images/lightboxphotos/BCF2000_P0246_Left_XL.jpg It is attached to my desktop machine (not the simulator host) via USB/MIDI. You could as well control lights with DMX, motors with Arduino, a robotic device, or conversely move an opensim object with a dataglove, or anything you may imagine. How does it work? The opensim object contains two C# script, one for sending and one for receiving UDP messages using System.Net.Sockets (two scripts are needed because the receiver runs a forever loop and events can't interrupt). The simulator host and my desktop machine (both on same LAN) communicate through UDP messages. I omit the prim handling script for brevity. It is pure LSL and there is nothing new here. It reads and writes couples of (track_number, value) via link messages to the C# sender and receiver. Since i am a beginner in C#, there is much room for improvement. I was not able to declare a 'use' clause, so I had to fully qualify each instance and method, making the code quite ugly. UDP Sender script ----------------- //c# public static void SendUDPPacket (string hostNameOrAddress, int destinationPort, string data) { // Resolve the host name to an IP Address System.Net.IPAddress[] ipAddresses = System.Net.Dns.GetHostAddresses(hostNameOrAddress); // Use the first IP Address in the list System.Net.IPAddress destination = ipAddresses[0]; System.Net.IPEndPoint endPoint = new System.Net.IPEndPoint(destination, destinationPort); byte[] buffer = System.Text.Encoding.ASCII.GetBytes(data); // Send the packet System.Net.Sockets.Socket socket = new System.Net.Sockets.Socket (System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Dgram, System.Net.Sockets.ProtocolType.Udp); socket.SendTo(buffer, endPoint); socket.Close(); } int SLIDER_IN = 101; // Link Messages input int SLIDER_OUT = 102; // Link Messages output string remoteAddr = "192.168.0.21"; int remotePort = 51000; // Receiving a link message from the sliders public void default_event_link_message ( LSL_Types.LSLInteger sender_num, LSL_Types.LSLInteger num, LSL_Types.LSLString str, // Channel number LSL_Types.LSLString id) { // Channel value // Send the message over UDP if (num == SLIDER_OUT) SendUDPPacket (remoteAddr, remotePort, str+" "+id); } UDP Receiver script ------------------- //c# public static System.Net.Sockets.Socket BindUDPSocket (int listenPort) { // Local endpoint System.Net.IPEndPoint endPoint = new System.Net.IPEndPoint(System.Net.IPAddress.Any, listenPort); // Create socket System.Net.Sockets.Socket socket = new System.Net.Sockets.Socket (System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Dgram, System.Net.Sockets.ProtocolType.Udp); // Bind socket socket.Bind(endPoint); return socket; } int listenPort = 50000; int SLIDER_IN = 101; // Link Messages input int SLIDER_OUT = 102; // Link Messages output public void default_event_state_entry() { System.Net.Sockets.Socket socket = BindUDPSocket (listenPort); byte[] buffer = new byte[1024]; // Receiving a message from UDP (loop forever) while (true) { socket.Receive(buffer); string msg = System.Text.ASCIIEncoding.ASCII.GetString(buffer); // 1st word is Channel number // 2nd word is Channel value string[] parse = msg.Split(' '); // Send the message using LinkMessage llMessageLinked (LINK_THIS, SLIDER_IN, parse[0], parse[1]); System.Array.Clear (buffer, 0, 1024); } } Thanks to Nick Olsen for C# code http://nickstips.wordpress.com/2010/09/03/c-creating-and-sending-udp-packets/ _______________________________________________ Opensim-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/opensim-users
