Particle system example with TouchOSC control

examples/node/particle_touchosc.js

+#!/usr/bin/env node
+
+// Particle system example with Node and opc.js, controllable via OSC.
+// You can use this with TouchOSC, with the "Simple" touch layout.
+// Note that we don't push values *to* TouchOSC yet, so the initial state
+// of the controls may not match the state we keep here on the OSC server.
+//
+// Specify an LED layout file on the command line, or use the default (grid32x16z)
+
+var osc = require('node-osc');
+var oscServer = new osc.Server(8000, '0.0.0.0');
+
+var OPC = new require('./opc');
+var model = OPC.loadModel(process.argv[2] || '../layouts/grid32x16z.json');
+var client = new OPC('localhost', 7890);
+
+// State values; change over time
+var stateAngle1 = 0;
+var stateAngle2 = 0;
+
+// Parameters, set via OSC
+var hue = 0.3;
+var hueShift = 0.8;
+var saturation = 0.5;
+var brightness = 0.5;
+var falloff = 0.5;
+var rate1 = 0.1;
+var rate2 = 0.2;
+
+oscServer.on('message', function (msg, rinfo) {
+
+    // Show the message, for debugging
+    console.log(msg);
+
+    // First page, color
+    if (msg[0] == '/1/fader1') hue = msg[1];
+    if (msg[0] == '/1/fader2') hueShift = msg[1];
+    if (msg[0] == '/1/fader3') saturation = msg[1];
+    if (msg[0] == '/1/fader4') falloff = msg[1];
+    if (msg[0] == '/1/fader5') brightness = msg[1];
+
+    // XY pad, oscillator rates
+    if (msg[0] == '/3/xy') {
+        rate1 = msg[1];
+        rate2 = msg[2];
+    }
+});
+
+function draw() {
+
+    var numParticles = 200;
+    var particles = [];
+
+    var trail = 100.0;
+    var scaledRate1 = (rate1 - 0.5) * 0.5;
+    var scaledRate2 = (rate2 - 0.5) * 0.5;
+    stateAngle1 += scaledRate1;
+    stateAngle2 += scaledRate2;
+
+    for (var i = 0; i < numParticles; i++) {
+        var s = i / numParticles;
+
+        // Local state angles for this particle
+        var lsa1 = stateAngle1 + scaledRate1 * trail * s;
+        var lsa2 = stateAngle2 + scaledRate2 * trail * s;
+
+        // Compute position, this gives us the shape of our effect.
+        var radius = 0.1 + 2.0 * s;
+        var x = radius * Math.cos(lsa1);
+        var y = radius * Math.sin(lsa2);
+
+        particles[i] = {
+            point: [x, 0, y],
+            intensity: brightness * (1 - s),
+            falloff: falloff * 175,
+            color: OPC.hsv( hue + s * 2.0 * (hueShift - 0.5), saturation, 0.5)
+        };
+    }
+
+    client.mapParticles(particles, model);
+}
+
+setInterval(draw, 10);