Backlog - MIDI Audio Reactive Lab

Code

body { margin: 0; font-family: "Trebuchet MS", "Segoe UI", sans-serif; background: #080712; color: #f2f6ff; }
.topbar { padding: 0.75rem 1rem; display: flex; justify-content: space-between; align-items: center; }
.topbar a { color: #8ee7ff; text-decoration: none; }
button { border: 1px solid rgba(255,255,255,0.25); background: rgba(255,255,255,0.08); color: #f2f6ff; border-radius: 999px; padding: 0.35rem 0.7rem; }
main { width: min(980px, 92%); margin: 0 auto; }
.kicker { color: #8ee7ff; text-transform: uppercase; letter-spacing: 0.1em; }
.bars { margin-top: 1rem; border: 1px solid #2f2e4e; border-radius: 12px; min-height: 220px; display: grid; grid-template-columns: repeat(24, minmax(0, 1fr)); gap: 0.35rem; align-items: end; padding: 0.8rem; }
.bar { border-radius: 6px; background: linear-gradient(180deg, #ffa36d, #8070ff); }

if (!window.MotionPreference) {
  const __mql = window.matchMedia("(prefers-reduced-motion: reduce)");
  const __listeners = new Set();

  const MotionPreference = {
    prefersReducedMotion() {
      return __mql.matches;
    },
    setOverride(value) {
      const reduced = Boolean(value);
      document.documentElement.classList.toggle("reduced-motion", reduced);
      window.dispatchEvent(new CustomEvent("motion-preference", { detail: { reduced } }));
      for (const listener of __listeners) {
        try {
          listener({ reduced, override: reduced, systemReduced: __mql.matches });
        } catch {}
      }
    },
    onChange(listener) {
      __listeners.add(listener);
      try {
        listener({
          reduced: __mql.matches,
          override: null,
          systemReduced: __mql.matches,
        });
      } catch {}
      return () => __listeners.delete(listener);
    },
    getState() {
      return { reduced: __mql.matches, override: null, systemReduced: __mql.matches };
    },
  };

  window.MotionPreference = MotionPreference;
}

async function initSoundReactiveHooks() {
  return {
    supported: false,
    reason: "shared module unavailable in imported version",
    getLevel() {
      return 0;
    },
    destroy() {},
  };
}

const audioBtn = document.getElementById("audioBtn");
const statusEl = document.getElementById("status");
const bars = document.getElementById("bars");
let sound;
let raf = 0;

const nodes = Array.from({ length: 24 }, () => {
  const el = document.createElement("span");
  el.className = "bar";
  el.style.height = "20%";
  bars.appendChild(el);
  return el;
});

async function enableMidi() {
  if (!navigator.requestMIDIAccess) {
    return "MIDI unavailable in this browser.";
  }

  try {
    const access = await navigator.requestMIDIAccess();
    let hit = false;
    access.inputs.forEach((input) => {
      input.onmidimessage = (event) => {
        hit = true;
        const velocity = event.data[2] || 0;
        const normalized = velocity / 127;
        nodes.forEach((el, i) => {
          const wave = Math.sin((performance.now() * 0.002) + i) * 0.3 + 0.7;
          el.style.height = `${Math.max(10, (normalized * wave) * 100)}%`;
        });
      };
    });
    return hit ? "MIDI input attached." : "MIDI ready. Send notes from a controller.";
  } catch (_error) {
    return "MIDI permission rejected.";
  }
}

function animateAudio() {
  if (sound && sound.supported) {
    const level = sound.getLevel();
    nodes.forEach((el, i) => {
      const wave = Math.sin((performance.now() * 0.003) + i * 0.4) * 0.25 + 0.75;
      el.style.height = `${Math.max(10, level * wave * 100)}%`;
    });
  }
  raf = requestAnimationFrame(animateAudio);
}

audioBtn.addEventListener("click", async () => {
  sound = await initSoundReactiveHooks();
  const midiMessage = await enableMidi();
  if (sound.supported) {
    statusEl.textContent = `Audio reactive active. ${midiMessage}`;
    cancelAnimationFrame(raf);
    raf = requestAnimationFrame(animateAudio);
  } else {
    statusEl.textContent = `Audio unavailable (${sound.reason}). ${midiMessage}`;
  }
});

window.addEventListener("beforeunload", () => {
  cancelAnimationFrame(raf);
  if (sound && sound.destroy) sound.destroy();
});

<!doctype html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>MIDI / Audio Reactive Lab</title>
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <header class="topbar">
      <a href="../">Back to demos</a>
      <button id="audioBtn">Enable Audio Reactive</button>
    </header>

    <main>
      <p class="kicker">Backlog 28</p>
      <h1>MIDI / Audio Reactive Layers</h1>
      <p id="status">MIDI + audio listeners are idle.</p>
      <div class="bars" id="bars"></div>
    </main>

    <script src="script.js"></script>
  </body>
</html>

Backlog - MIDI Audio Reactive Lab

MIDI plus microphone-reactive visual bars experiment.

Source

Repository: libs-gen
Original demo id: 28-midi-audio-reactive-lab

Notes

MIDI plus microphone-reactive visual bars experiment.