Add effect control via artnet

MusicBeam/ArtNet.pde

@@ -0,0 +1,100 @@
+import java.net.DatagramSocket;
+import java.net.DatagramPacket;
+import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicInteger;
+
+// Art-Net (DMX over Ethernet) effect selection.
+// Reads a single DMX channel; its value selects the active effect by index
+// (0 = Blackout / no effect, 1..N = the other effects). Opt-in via the
+// "Art-Net (DMX)" toggle. Uses only the JDK, no extra libraries.
+
+static final byte[] ART_NET_ID    = "Art-Net\0".getBytes();
+static final int ART_NET_OP_DMX   = 0x5000; // ArtDMX opcode
+static final int ART_NET_DMX_DATA = 18;     // offset of the DMX data in an ArtDMX packet
+static final int ART_NET_PORT     = 6454;  // Art-Net standard UDP port
+static final int ART_NET_UNIVERSE = 0;     // 15-bit universe to listen on
+static final int ART_NET_CHANNEL  = 1;     // 1-indexed DMX channel = effect index
+
+ArtNet artNet;
+
+class ArtNet implements Runnable
+{
+  final AtomicInteger pending = new AtomicInteger(Integer.MIN_VALUE);
+  volatile boolean running = false;
+  int lastValue = -1;  // edge-trigger; only touched by the receive thread
+  DatagramSocket socket;
+
+  // Called from controlEvent() on the animation thread. Idempotent.
+  void setEnabled(boolean on)
+  {
+    if (on && !running) {
+      try {
+        socket = new DatagramSocket(ART_NET_PORT);
+        running = true;
+        lastValue = -1;  // re-arm so the current console value is applied
+        new Thread(this).start();
+        println("Art-Net listening on UDP " + ART_NET_PORT + ", universe " + ART_NET_UNIVERSE + ", channel " + ART_NET_CHANNEL);
+      }
+      catch (Exception e) {
+        println("Art-Net failed to start: " + e.getMessage());
+        running = false;
+        socket = null;
+      }
+    } else if (!on && running) {
+      running = false;
+      if (socket != null)
+        socket.close();
+      socket = null;
+    }
+  }
+
+  // Receive loop; runs on its own thread and never touches ControlP5.
+  void run()
+  {
+    byte[] buf = new byte[530];  // 18 byte header + up to 512 DMX channels
+    DatagramPacket pkt = new DatagramPacket(buf, buf.length);
+    while (running) {
+      try {
+        pkt.setLength(buf.length);  // receive() shrinks length; reset so large packets aren't truncated
+        socket.receive(pkt);
+        parse(pkt.getData(), pkt.getLength());
+      }
+      catch (Exception e) {
+        if (running)
+          println("Art-Net receive error: " + e.getMessage());
+      }
+    }
+  }
+
+  // Read the selected channel of an ArtDMX packet and hand its value to the
+  // animation thread. Anything else is ignored.
+  void parse(byte[] b, int len)
+  {
+    int i = ART_NET_DMX_DATA + ART_NET_CHANNEL - 1;
+    if (len > i
+      && Arrays.equals(b, 0, ART_NET_ID.length, ART_NET_ID, 0, ART_NET_ID.length)
+      && le16(b, 8) == ART_NET_OP_DMX
+      && (le16(b, 14) & 0x7fff) == ART_NET_UNIVERSE)
+    {
+      int value = b[i] & 0xff;
+      if (value != lastValue) {  // edge-trigger so the GUI stays usable between changes
+        lastValue = value;
+        pending.set(value);
+      }
+    }
+  }
+
+  // 16 bit little-endian read.
+  int le16(byte[] b, int i)
+  {
+    return (b[i] & 0xff) | ((b[i+1] & 0xff) << 8);
+  }
+
+  // Called once per frame from draw(); the only place ControlP5 is touched.
+  void update()
+  {
+    int v = pending.getAndSet(Integer.MIN_VALUE);
+    if (v >= 0 && v < effectArray.length)
+      effectArray[v].activate();
+  }
+}

MusicBeam/MusicBeam.pde

@@ -34,7 +34,7 @@ Effect[] effectArray;
 
 DropdownList displays;
 
-Toggle projectorToggle, randomToggle, blackoutOnSilenceToggle;
+Toggle projectorToggle, randomToggle, blackoutOnSilenceToggle, artNetToggle;
 Slider randomTimeSlider, beatDelaySlider, minLevelSlider;
 Button nextButton;
 RadioButton activeEffect, activeSetting;
@@ -93,6 +93,9 @@ void draw() {
       effectArray[int(activeSetting.getValue())].showControls();
   }
 
+  if (artNet != null)
+    artNet.update();
+
   if (randomToggle!=null)
     if (randomToggle.getState()&&randomTimer>=randomTimeSlider.getValue()*60)
     {
@@ -115,6 +118,8 @@ void controlEvent(ControlEvent event)
 {
   if (event.getName()=="next")
     nextRandom();
+  else if (event.getName()=="artNet" && artNet!=null)
+    artNet.setEnabled(artNetToggle.getState());
 }
 
 void drawBeatBoard()
@@ -222,6 +227,7 @@ void initControls()
   PApplet.runSketch(args, stage);
   stage.noLoop();
   initEffects();
+  artNet = new ArtNet();
   initSettings();
   stage.loop();
 }
@@ -237,9 +243,12 @@ void initRandomControls() {
   nextButton = cp5.addButton("next").setSize(350, 45).setPosition(415, 60);
   nextButton.getCaptionLabel().set("Next Effect").align(ControlP5.CENTER, ControlP5.CENTER);
 
-  blackoutOnSilenceToggle = cp5.addToggle("blackoutOnSilence").setSize(350, 45).setPosition(415, 110);
+  blackoutOnSilenceToggle = cp5.addToggle("blackoutOnSilence").setSize(172, 45).setPosition(415, 110);
   blackoutOnSilenceToggle.getCaptionLabel().set("Blackout on Silence").align(ControlP5.CENTER, ControlP5.CENTER);
 
+  artNetToggle = cp5.addToggle("artNet").setSize(172, 45).setPosition(593, 110);
+  artNetToggle.getCaptionLabel().set("Art-Net (DMX)").align(ControlP5.CENTER, ControlP5.CENTER);
+
   activeEffect = cp5.addRadioButton("activeEffects").setPosition(415, 170).setSize(250, 45).setItemsPerRow(1).setSpacingRow(5).setNoneSelectedAllowed(true);
   activeSetting = cp5.addRadioButton("activeSettings").setPosition(720, 170).setSize(45, 45).setItemsPerRow(1).setSpacingRow(5);
 }

README.md

@@ -12,6 +12,17 @@ MusicBeam is written in [Processing][Processing] a JAVA based language that is e
 The latest releases can be found at: [musicbeam.org](http://www.musicbeam.org)
 
 
+## Art-Net (DMX) Control
+
+The active effect can be selected over the network with Art-Net messages. The button **Art-Net (DMX)** starts a background thread that listens on UDP port 6454 for DMX frames and monitors channel 1 of universe 0. The channel value gets mapped to the available Effects. Channel value 0 maps to the Blackout effect.
+
+It can be tried out using [`examples/artnet_test.py`](examples/artnet_test.py):
+
+```console
+python3 examples/artnet_test.py 3     # select effect 3
+```
+
+
 ## Contributing
 
 MusicBeam is writing in Processing a Java sublanguage. It is extremely easy to write even without prior coding experience.

examples/artnet_test.py

@@ -0,0 +1,38 @@
+#!/usr/bin/env python3
+"""Test MusicBeam's Art-Net effect selection by sending ArtDMX frames.
+
+Enable the "Art-Net (DMX)" toggle in MusicBeam first, then:
+
+    python3 artnet_test.py 3               select effect 3
+    python3 artnet_test.py 0               blackout / no effect
+    python3 artnet_test.py demo            cycle through all effects, then blackout
+    python3 artnet_test.py 3 192.168.1.20  send to another machine
+"""
+import socket
+import sys
+import time
+
+EFFECT_COUNT = 11  # effect indices 0..10, 0 = Blackout
+
+
+def send(value, host):
+    packet = bytearray(b"Art-Net\x00")
+    packet += (0x5000).to_bytes(2, "little")  # OpCode: ArtDMX
+    packet += (14).to_bytes(2, "big")         # protocol version
+    packet += bytes([0, 0])                   # sequence, physical
+    packet += bytes([0, 0])                   # universe 0
+    packet += (1).to_bytes(2, "big")          # one DMX channel
+    packet += bytes([value])                  # channel 1 = effect index
+    socket.socket(socket.AF_INET, socket.SOCK_DGRAM).sendto(packet, (host, 6454))
+    print(f"sent effect index {value} to {host}")
+
+
+if len(sys.argv) < 2:
+    sys.exit(__doc__)
+host = sys.argv[2] if len(sys.argv) > 2 else "127.0.0.1"
+if sys.argv[1] == "demo":
+    for value in list(range(EFFECT_COUNT)) + [0]:
+        send(value, host)
+        time.sleep(2)
+else:
+    send(int(sys.argv[1]), host)