laod sample

1 files changed, 112 insertions, 0 deletions

diff --git a/client/lib/sampler.js b/client/lib/sampler.js
new file mode 100644
index 0000000..08f253d
--- /dev/null
+++ b/client/lib/sampler.js
@@ -0,0 +1,112 @@
+/**
+ * Sampler
+ * @module lib/sampler.js;
+ */
+
+import Tone from "tone";
+
+let output;
+let ready;
+let current = "";
+let samples = {};
+
+const player_count = 12;
+
+export function load(out, readyCallback) {
+  output = out;
+  ready = readyCallback;
+  document.body.addEventListener("dragover", dragOver);
+  document.body.addEventListener("drop", drop);
+}
+
+/**
+ * Drag and drop
+ */
+export function dragOver(event) {
+  event.preventDefault();
+}
+export function drop(event) {
+  event.preventDefault();
+  const files = event.dataTransfer.items
+    ? [...event.dataTransfer.items]
+        .filter((item) => item.kind === "file")
+        .map((item) => item.getAsFile())
+    : [...event.dataTransfer.files];
+
+  const file = files[0];
+  const reader = new FileReader();
+
+  reader.addEventListener(
+    "load",
+    () => loadSampleFromFile(file, reader.result),
+    false,
+  );
+
+  if (file) {
+    reader.readAsDataURL(file);
+  }
+}
+
+export function loadSampleFromFile(file, url) {
+  const { name } = file;
+  current = name;
+
+  const sample = (samples[name] = samples[name] || {});
+  sample.root = 440;
+  sample.players = [];
+  sample.index = -1;
+  for (let i = 0; i < player_count; i++) {
+    let player = new Tone.Player({
+      url,
+      retrigger: true,
+      playbackRate: 1,
+    });
+    player.name = name;
+    player.connect(output);
+    sample.players.push(player);
+  }
+  console.log("+ Sampler:", name, `(${sample.players.length} voices)`);
+  ready();
+}
+
+/**
+ * Player
+ */
+let last = 440;
+
+function play(freq) {
+  last = freq;
+  const sample = samples[current];
+  sample.index = (sample.index + 1) % sample.players.length;
+  const player = sample.players[sample.index];
+  player.playbackRate = freq / sample.root;
+  player.start();
+}
+
+function pause() {
+  // no-op
+}
+
+export default { load, play, pause };
+
+// for help tuning
+function keydown(e) {
+  // console.log(e.keyCode)
+  if (e.metaKey && last && current) {
+    const sample = samples[current];
+    const step = e.shiftKey ? (e.ctrlKey ? 0.1 : 1) : 10;
+    switch (e.keyCode) {
+      case 38: // up
+        e.preventDefault();
+        sample.root -= step;
+        play(last);
+        break;
+      case 40: // down
+        e.preventDefault();
+        sample.root += step;
+        play(last);
+        break;
+    }
+  }
+}
+window.addEventListener("keydown", keydown, true);