addendum to previous commit; duh

simple optimization to filter
just basic algebra, but I should have noticed this sooner!
2016-05-31 22:15:46 -07:00 · 2016-05-31 18:52:33 -07:00 · 2016-04-22 12:12:50 -07:00 · 2016-04-19 16:34:20 -07:00 · 2015-11-21 20:25:35 +01:00 · 2015-11-21 20:22:00 +01:00
14 changed files with 2095 additions and 626 deletions
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1 @@
+node_modules
--- a/.travis.yml
+++ b/.travis.yml
@ -0,0 +1,3 @@
+language: node_js
+node_js:
+  - "0.12"
--- a/README.md
+++ b/README.md
@ -1,16 +1,40 @@
 # xm.js

+[![Build Status](https://travis-ci.org/a1k0n/jsxm.svg?branch=master)](https://travis-ci.org/a1k0n/jsxm)
+
 FastTracker 2 .XM player, written for fun.

-[Demo](http://www.a1k0n.net/code/jsxm/) [warning: plays sound immediately on
-load]
+[Demo](http://www.a1k0n.net/code/jsxm/)

-By default it plays "my dirty old kamel" by Alexander Bulér aka
-[Zalza](http://zalza.bandcamp.com/). I love this tune, and wrote this code just
-to play it. It can also load other .XMs by loading index.html?_tune-uri.xm_,
-though it either needs to be local to your domain or cross-origin resource
-sharing must be enabled for that to work.
+There is an XM player and a visualizer which are separate components. The
+player API looks like this:

-It is fairly feature-complete, but is missing a bunch of effects.
+ - `XMPlayer.init` -> starts up audio context; it's available as
+   `XMPlayer.audioctx`
+ - `XMPlayer.load(ArrayBuffer)` -> returns `true` if loaded, otherwise
+   barfs randomly
+ - `XMPlayer.play()` -> starts playing
+ - `XMPlayer.pause()` -> obvious
+ - `XMPlayer.stop()` -> obvious; call this before loading a new one
+
+Loading trackview.js is optional; without it, the player won't do any
+visualizations. Or, you can override the following to get callbacks:
+
+ - `XMView.pushEvent(e)` -> push an audio event onto the queue. Called
+   once per tick (about 50Hz, controlled by song). `e` contains fields:
+   - `t` - audio timestamp
+   - `vu` - Float32Array of RMS power (volume) for each channel
+   - `scopes` - [Float32Array] of oscilloscope data, one array per
+     channel; `XMView.scope_width` contains # of samples to produce here
+   - `songpos` - position in the song (# patterns played)
+   - `pat` - pattern number currently playing
+   - `row` - row within pattern
+ - `XMView.pause()` - pause visualization
+ - `XMView.stop()` - stop/reset visualization
+
+The code which defines what the buttons do and downloads songs and so
+forth is in `shell.js`.
+
+The player is fairly feature-complete, but is missing a bunch of effects.

 MIT license.
--- a/index.html
+++ b/index.html
@ -1,29 +1,82 @@
 <head>
  <title>js xm</title>
+  <script src="http://a1k0n-pub.s3-website-us-west-1.amazonaws.com/xm/xmlist.js"></script>
+  <script src="xmeffects.js"></script>
+  <script src="trackview.js"></script>
  <script src="xm.js"></script>
+  <script src="shell.js"></script>
+  <style>
+
+.centered {
+  display: block;
+  margin-left: auto;
+  margin-right: auto;
+}
+
+#filelist a { color: #fff; }
+
+.playercontainer {
+  background:#000;
+}
+
+.draghover {
+  background:#000;
+  opacity: 0.5;
+}
+
+.hscroll {
+  overflow: auto;
+  margin-bottom: 14px;
+}
+
+.hscroll::-webkit-scrollbar {
+    -webkit-appearance: none;
+}
+
+.hscroll::-webkit-scrollbar:horizontal {
+    height: 11px;
+}
+
+.hscroll::-webkit-scrollbar-thumb {
+    border-radius: 2px;
+    border: 1px solid #93C3E9; /* should match background, can't be transparent */
+    background-color: #A0D4FD;
+}
+
+.hscroll::-webkit-scrollbar-track {
+    background-color: #333;
+    border-radius: 8px;
+}
+
+  </style>
 </head>
 <body>
-  <div><canvas id='vu' width=224 height=64></canvas></div>
-  <div><canvas id='gfxpattern' width=640 height=200></canvas></div>
-<pre id='debug'>
-</pre>
-<pre id='pattern'>
-</pre>
+  <div id="playercontainer" class="playercontainer" ondrop="XMPlayer.handleDrop(event)"
+      ondragover="XMPlayer.allowDrop(event)" ondragleave="XMPlayer.allowDrop(event)">
+    <div><canvas class="centered" id='title' width="640" height="22"></canvas></div>
+    <div class="hscroll">
+      <div><canvas class="centered" id='vu' width="224" height="64"></canvas></div>
+      <div><canvas class="centered" id='gfxpattern' width="640" height="504"></canvas></div>
+    </div>
+    <div id='instruments'></div>
+    <div>
+      <p style="text-align: center">
+        <button id="playpause" disabled="true" style="width: 100px; background: #ccc;">Play</button>
+        <button id="loadbutton" style="width: 100px; background: #ccc">Load</button>
+      </p>
+    </div>
+    <div style="display: none" id='filelist'></div>
+  </div>
+
 <pre>
 code: <a href="http://github.com/a1k0n/jsxm/">github.com/a1k0n/jsxm</a>
 todo:
- - file picker, upload more xms to a host we can access cross-origin
- - make display even more faithfully FT2-like
- - render instrument list
- - oscilloscopes
- - fix bugs!
-   - envelope loops - are they right or not now?
- - multi-sample instruments
- - missing XM effects (in rough order of priority):
-   - Rxy - retrigger
-   - E3x, E4x, E5x, E6x, E7x, E9x, EDx, EEx
+ - missing XM effects:
+   - E3x, E6x, E7x, E9x, EDx, EEx
   - 7xy - tremolo
-   - Gxx, Hxy, Kxx, Lxx, Pxy, Txy
+   - Kxx, Lxx, Pxy, Txy
+ - render pattern with the wider fonts for fewer channels
+ - fix occasional rendering/audio hiccups when switching songs
 </pre>
 </body>

--- a/kamel.xm
+++ b/kamel.xm
--- a/package.json
+++ b/package.json
@ -0,0 +1,23 @@
+{
+  "name": "jsxm",
+  "version": "1.0.0",
+  "description": "WebAudio FastTracker 2 .XM module player",
+  "keywords": "fasttracker xm webaudio",
+  "uri": "http://www.a1k0n.net/code/jsxm/",
+  "repository": "a1k0n/jsxm",
+  "author": "Andy Sloane <andy@a1k0n.net> (http://www.a1k0n.net/)",
+  "license": "MIT",
+  "contributors": [{
+    "name": "Johan Hillerström",
+    "email": "progr@mmer.nu"
+  }],
+  "main": "index.html",
+  "window": {
+    "frame": true,
+    "toolbar": false,
+    "position": "center",
+    "resizable": true
+  },
+  "scripts": { "test": "node test/all.js" },
+  "devDependencies": { "test": ">=0.0.5" }
+}
--- a/shell.js
+++ b/shell.js
@ -0,0 +1,111 @@
+(function (window, document) {
+if (!window.XMPlayer) {
+  window.XMPlayer = {};
+}
+var XMPlayer = window.XMPlayer;
+if (!window.XMView) {
+  window.XMView = {};
+}
+var XMView = window.XMView;
+
+function loadXMAndInit(xmdata) {
+  if (!XMPlayer.load(xmdata)) {
+    return;
+  }
+
+  XMView.init();
+
+  var playbutton = document.getElementById("playpause");
+  playbutton.innerHTML='Play';
+  playbutton.onclick = function() {
+    if (XMPlayer.playing) {
+      XMPlayer.pause();
+      playbutton.innerHTML='Play';
+    } else {
+      XMPlayer.play();
+      playbutton.innerHTML='Pause';
+    }
+  };
+  playbutton.disabled = false;
+
+  return XMPlayer.xm;
+}
+
+function downloadXM(uri) {
+  var xmReq = new XMLHttpRequest();
+  xmReq.open("GET", uri, true);
+  xmReq.responseType = "arraybuffer";
+  xmReq.onload = function (xmEvent) {
+    var arrayBuffer = xmReq.response;
+    if (arrayBuffer) {
+      loadXMAndInit(arrayBuffer);
+    } else {
+      console.log("unable to load", uri);
+    }
+  };
+  xmReq.send(null);
+}
+
+XMPlayer.allowDrop = function(ev) {
+  ev.stopPropagation();
+  ev.preventDefault();
+  var elem = document.getElementById("playercontainer");
+  elem.className = (ev.type == "dragover" ? "draghover" : "playercontainer");
+  return false;
+};
+
+XMPlayer.handleDrop = function(e) {
+  console.log(e);
+  e.preventDefault();
+  var elem = document.getElementById("playercontainer");
+  elem.className = "playercontainer";
+  var files = e.target.files || e.dataTransfer.files;
+  if (files.length < 1) return false;
+  var reader = new FileReader();
+  reader.onload = function(e) {
+    XMPlayer.stop();
+    loadXMAndInit(e.target.result);
+  };
+  reader.readAsArrayBuffer(files[0]);
+  return false;
+};
+
+function initFilelist() {
+  var el = document.getElementById('filelist');
+  xmuris.forEach(function(entry) {
+    var a = document.createElement('a');
+    a.text = entry[0];
+    a.href = '#'+entry[1];
+    a.onclick = function() {
+      el.style.display = "none";
+      XMPlayer.stop();
+      downloadXM(baseuri + entry[1]);
+    };
+    el.appendChild(a);
+    el.appendChild(document.createElement('br'));
+  });
+  var loadbutton = document.getElementById('loadbutton');
+  loadbutton.onclick = function() {
+    if (el.style.display == "none") {
+      el.style.display = "block";
+    } else {
+      el.style.display = "none";
+    }
+  };
+}
+
+window.onload = function() {
+  XMPlayer.init();
+  initFilelist();
+
+  var uri = location.hash.substr(1);
+  if (uri === "") {
+    uri = "kamel.xm";
+  }
+  if (!uri.startsWith("http")) {
+    uri = baseuri + uri;
+  }
+  downloadXM(uri);
+};
+
+})(window, document);
--- a/test/all.js
+++ b/test/all.js
@ -0,0 +1,130 @@
+window = {};
+
+require('../xm.js');
+require('../xmeffects.js');
+var XMPlayer = window.XMPlayer;
+
+testdata = require('./testdata.js');
+
+// test TODO:
+//  - audio output sample positions after ticks
+//  - unit test for envelopes
+//
+// using assert passed to the test function that just logs failures 
+exports['test XM startup'] = function(assert) {
+  testdata.resetXMData();
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, 'advance to initial song position');
+  assert.equal(XMPlayer.cur_pat, 0, 'advance to pattern 0');
+  assert.equal(XMPlayer.cur_tick, 0, 'advance to tick 0');
+  assert.equal(XMPlayer.cur_row, 0, 'advance to row 0');
+};
+
+exports['test non-existing song position'] = function(assert) {
+  testdata.resetXMData();
+  // 2 existing patterns, 1 non-existing
+  XMPlayer.xm.songpats = [0, 1, 2]
+  // 1 channel, 1 row, 2 blank patterns
+  XMPlayer.xm.patterns = [
+    [[[-1, -1, -1, 0, 0]]],
+    [[[-1, -1, -1, 0, 0]]]
+  ];
+  XMPlayer.xm.tempo = 1;
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, 'advance to initial song position');
+  assert.equal(XMPlayer.cur_pat, 0, 'advance to pattern 0');
+  assert.equal(XMPlayer.cur_row, 0, 'advance to row 0');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 1, 'advance to song position 1');
+  assert.equal(XMPlayer.cur_pat, 1, 'advance to pattern 1');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, 'return to song position 0');
+  assert.equal(XMPlayer.cur_pat, 0, 'return to pattern 0');
+};
+
+exports['test non-existing first song position'] = function(assert) {
+  testdata.resetXMData();
+  // 2 existing patterns, 1 non-existing
+  XMPlayer.xm.songpats = [2, 0, 1]
+  // 1 channel, 1 row, 2 blank patterns
+  XMPlayer.xm.patterns = [
+    [[[-1, -1, -1, 0, 0]]],
+    [[[-1, -1, -1, 0, 0]]]
+  ];
+  XMPlayer.xm.tempo = 1;
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 1, 'advance to song position 1');
+  assert.equal(XMPlayer.cur_pat, 0, 'advance to pattern 0');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 2, 'advance to song position 2');
+  assert.equal(XMPlayer.cur_pat, 1, 'advance to pattern 1');
+};
+
+exports['test multiple non-existing song positions'] = function(assert) {
+  testdata.resetXMData();
+  // 2 existing patterns, 2 non-existing
+  XMPlayer.xm.songpats = [2, 0, 3, 1]
+  // 1 channel, 1 row, 2 blank patterns
+  XMPlayer.xm.patterns = [
+    [[[-1, -1, -1, 0, 0]]],
+    [[[-1, -1, -1, 0, 0]]]
+  ];
+  XMPlayer.xm.tempo = 1;
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 1, 'advance to song position 1');
+  assert.equal(XMPlayer.cur_pat, 0, 'advance to pattern 0');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 3, 'advance to song position 3');
+  assert.equal(XMPlayer.cur_pat, 1, 'advance to pattern 1');
+};
+
+exports['test non-existing song position with loop'] = function(assert) {
+  testdata.resetXMData();
+  // 2 existing patterns, 1 non-existing
+  XMPlayer.xm.songpats = [0, 1, 2]
+  // 1 channel, 1 row, 2 blank patterns
+  XMPlayer.xm.patterns = [
+    [[[-1, -1, -1, 0, 0]]],
+    [[[-1, -1, -1, 0, 0]]]
+  ];
+  XMPlayer.xm.song_looppos = 1;
+  XMPlayer.xm.tempo = 1;
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, 'advance to initial song position');
+  assert.equal(XMPlayer.cur_pat, 0, 'advance to pattern 0');
+  assert.equal(XMPlayer.cur_row, 0, 'advance to row 0');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 1, 'advance to song position 1');
+  assert.equal(XMPlayer.cur_pat, 1, 'advance to pattern 1');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 1, 'replay song position 1');
+  assert.equal(XMPlayer.cur_pat, 1, 'replay pattern 1');
+};
+
+exports['test non-existing song position with invalid loop'] = function(assert) {
+  testdata.resetXMData();
+  // 2 existing patterns, 1 non-existing
+  XMPlayer.xm.songpats = [0, 1, 2]
+  // 1 channel, 1 row, 2 blank patterns
+  XMPlayer.xm.patterns = [
+    [[[-1, -1, -1, 0, 0]]],
+    [[[-1, -1, -1, 0, 0]]]
+  ];
+  XMPlayer.xm.song_looppos = 4;
+  XMPlayer.xm.tempo = 1;
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, 'advance to initial song position');
+  assert.equal(XMPlayer.cur_pat, 0, 'advance to pattern 0');
+  assert.equal(XMPlayer.cur_row, 0, 'advance to row 0');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 1, 'advance to song position 1');
+  assert.equal(XMPlayer.cur_pat, 1, 'advance to pattern 1');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, 'return to song position 0');
+  assert.equal(XMPlayer.cur_pat, 0, 'return to pattern 0');
+};
+
+exports['test instruments'] = require('./instrument.js');
+exports['test effects'] = require('./effects.js');
+
+if (module == require.main) require('test').run(exports);
--- a/test/effects.js
+++ b/test/effects.js
@ -0,0 +1,506 @@
+var XMPlayer = window.XMPlayer;
+
+// tests TODO:
+//  - bxx: song jump
+//  - rxy: retrigger w/ volume changes
+// low priority TODO (trivial or already covered by other tests):
+//  - 5xy: porta+vol
+//  - 6xy: vibrato+vol
+//  - 8xx: panning
+//  - 9xx: sample offset
+
+exports['test 0xy arpeggio'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // [pat][row][channel]
+  xm.patterns[0][0][0] = [48, 1, -1, 0, 0x4f];  // C-4  1 -- 04f
+  XMPlayer.xm.tempo = 4;
+  XMPlayer.nextTick();
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.note, 48, 'note 0');
+  assert.equal(ch.period, 1152, 'row 0 tick 0 period 0');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 16*4, 'row 0 tick 1 period 4');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 16*15, 'row 0 tick 2 period f');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 16*0, 'row 0 tick 3 period 0');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 16*0, 'row 1 tick 0 period 0');
+};
+
+exports['test 1xx slide up'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // [pat][row][channel]
+  xm.patterns[0][0][0] = [48,  1, -1, 1, 0x01];  // C-4  1 -- 101
+  xm.patterns[0][1][0] = [-1, -1, -1, 1, 0x00];  // --- -- -- 100
+  XMPlayer.xm.tempo = 3;
+  XMPlayer.nextTick();
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.period, 1152, 'row 0 tick 0 period 0');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 1, 'row 0 tick 1 period -1');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 2, 'row 0 tick 2 period -2');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 2, 'row 1 tick 0 period -2');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 3, 'row 1 tick 1 period -3');
+};
+
+exports['test 2xx slide down'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // [pat][row][channel]
+  xm.patterns[0][0][0] = [48,  1, -1, 2, 0x01];  // C-4  1 -- 201
+  xm.patterns[0][1][0] = [-1, -1, -1, 2, 0x00];  // --- -- -- 200
+  XMPlayer.xm.tempo = 3;
+  XMPlayer.nextTick();
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.period, 1152, 'row 0 tick 0 period 0');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 + 1, 'row 0 tick 1 period +1');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 + 2, 'row 0 tick 2 period +2');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 + 2, 'row 1 tick 0 period +2');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 + 3, 'row 1 tick 1 period +3');
+};
+
+exports['test 3xx portamento'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // [pat][row][channel]
+  xm.patterns[0][0][0] = [48,  1, -1, 0, 0x00];  // C-4  1 -- 000
+  xm.patterns[0][1][0] = [49,  1, -1, 3, 0x09];  // C#4  1 -- 309
+  XMPlayer.xm.tempo = 3;
+  XMPlayer.nextTick();  // row 0 tick 0
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.period, 1152, 'row 0 tick 0 period 0');
+  XMPlayer.nextTick();  // row 0 tick 1
+  XMPlayer.nextTick();  // row 0 tick 2
+  XMPlayer.nextTick();  // row 1 tick 0
+  assert.equal(ch.period, 1152, 'row 1 tick 0 period 0');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 9, 'row 1 tick 1 period -9');
+  XMPlayer.nextTick();
+  assert.equal(ch.period, 1152 - 16, 'row 1 tick 2 period -16');
+};
+
+exports['test 4xy vibrato - sine'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // vibrato 4xy: speed x, depth y
+  // full cycle is 64/speed
+  xm.patterns[0] = [
+    [[48,  1, -1, 4, 0x81]],    // C-4  1 -- 481
+    [[-1, -1, -1, 4, 0x02]],    // --- -- -- 402
+    [[-1, -1, -1, 4, 0x10]],    // --- -- -- 410
+    [[-1, -1, -1, 4, 0x00]],    // --- -- -- 400
+    [[-1, -1, -1, 0, 0x00]],    // --- -- -- --- - no vibrato
+    [[-1, -1, -1, 4, 0x00]],    // --- -- -- 400 - resume vibrato @ pos 0
+    [[-1, -1, 0xb2, 0, 0x00]],  // --- -- V2 --- - volume effect vibrato
+  ];
+  // I should really be testing ch.doff directly
+  XMPlayer.xm.tempo = 3;
+  var ch = xm.channelinfo[0];
+  XMPlayer.nextTick();  // row 0 tick 0
+  var p0 = ch.doff;
+  assert.equal(ch.periodoffset, 0, 'row 0 tick 0 periodoffset=0');
+  XMPlayer.nextTick();  // row 0 tick 1
+  // compute logical period p from actual play frequency
+  var p = 16*12 * Math.log(p0 / ch.doff) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 0 tick 1 period +0');
+  XMPlayer.nextTick();  // row 0 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "1.414", 'row 0 tick 2 period +1.414');
+  XMPlayer.nextTick();  // row 1 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "4.000", 'row 1 tick 0 period +4.000');
+  XMPlayer.nextTick();  // row 1 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "4.000", 'row 1 tick 1 period +4.000');
+  XMPlayer.nextTick();  // row 1 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "2.828", 'row 1 tick 2 period 2.828');
+  XMPlayer.nextTick();  // row 2 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 2 tick 0 period +0');
+  XMPlayer.nextTick();  // row 2 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 2 tick 1 period +0');
+  XMPlayer.nextTick();  // row 2 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-0.392", 'row 2 tick 2 period -0.392');
+  XMPlayer.nextTick();  // row 3 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-0.780", 'row 3 tick 0 period -0.780');
+  XMPlayer.nextTick();  // row 3 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-0.780", 'row 3 tick 1 period -0.780');
+  XMPlayer.nextTick();  // row 3 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.161", 'row 3 tick 2 period -1.161');
+  XMPlayer.nextTick();  // row 4 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 4 tick 0 period 0 - no vibrato');
+  XMPlayer.nextTick();  // row 4 tick 1
+  XMPlayer.nextTick();  // row 4 tick 2
+  // I actually don't know whether vibrato is supposed to reset when the effect
+  // goes away or whether it should resume. Resuming is simpler to implement so
+  // that's what I'm assuming here...
+  XMPlayer.nextTick();  // row 5 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.531", 'row 5 tick 0 period -1.531 - vibrato resume');
+  XMPlayer.nextTick();  // row 5 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.531", 'row 5 tick 1 period -1.531');
+  XMPlayer.nextTick();  // row 5 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.886", 'row 5 tick 2 period -1.886');
+  XMPlayer.nextTick();  // row 6 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.111", 'row 6 tick 0 period -1.111');
+};
+
+exports['test 4xy vibrato - saw'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // vibrato 4xy: speed x, depth y
+  // full cycle is 64/speed
+  xm.patterns[0] = [
+    [[48,  1, -1, 14, 0x41]],  // C-4  1 -- E41 - 1 = saw (ramp-down)
+    [[-1, -1, -1,  4, 0x81]],  // --- -- -- 481
+    [[-1, -1, -1,  4, 0x00]],  // --- -- -- 400
+    [[-1, -1, -1,  0, 0x00]],  // --- -- -- --- - no vibrato
+    [[-1, -1, -1,  4, 0x00]],  // --- -- -- 400 - resume vibrato @ pos 0
+  ];
+  XMPlayer.xm.tempo = 4;
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.vibratotype, 0, 'initial vibratotype 0');
+  XMPlayer.nextTick();  // row 0 tick 0
+  var p0 = ch.doff;
+  assert.equal(ch.vibratotype, 1, 'row 0 tick 0 vibratotype=1');
+  XMPlayer.nextTick();  // row 0 tick 1
+  XMPlayer.nextTick();  // row 0 tick 2
+  XMPlayer.nextTick();  // row 0 tick 3
+  XMPlayer.nextTick();  // row 1 tick 0
+  assert.equal(ch.periodoffset, 0, 'row 1 tick 0 periodoffset=0');
+  XMPlayer.nextTick();  // row 1 tick 1
+  // compute logical period p from actual play frequency
+  var p = 16*12 * Math.log(p0 / ch.doff) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 1 tick 1 period +0');
+  XMPlayer.nextTick();  // row 1 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.500", 'row 1 tick 2 period +0.500');
+  XMPlayer.nextTick();  // row 1 tick 3
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "1.000", 'row 1 tick 3 period +1.000');
+  XMPlayer.nextTick();  // row 2 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "1.500", 'row 2 tick 0 period +1.500');
+  XMPlayer.nextTick();  // row 2 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "1.500", 'row 2 tick 1 period +1.500');
+  XMPlayer.nextTick();  // row 2 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-2.000", 'row 2 tick 2 period -2.000');
+  XMPlayer.nextTick();  // row 2 tick 3
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.500", 'row 2 tick 3 period -1.500');
+  XMPlayer.nextTick();  // row 3 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 3 tick 0 period 0 - no vibrato');
+  XMPlayer.nextTick();  // row 3 tick 1
+  XMPlayer.nextTick();  // row 3 tick 2
+  XMPlayer.nextTick();  // row 3 tick 3
+  XMPlayer.nextTick();  // row 4 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.000", 'row 4 tick 0 period -1.000 - vibrato resume');
+  XMPlayer.nextTick();  // row 4 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-1.000", 'row 4 tick 1 period -1.000');
+  XMPlayer.nextTick();  // row 4 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-0.500", 'row 4 tick 2 period -0.500');
+  XMPlayer.nextTick();  // row 4 tick 3
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 4 tick 3 period +0');
+};
+
+exports['test 4xy vibrato - square'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // vibrato 4xy: speed x, depth y
+  // full cycle is 64/speed
+  xm.patterns[0] = [
+    [[48,  1, -1, 14, 0x42]],  // C-4  1 -- E42 - 2 = square
+    [[-1, -1, -1,  4, 0x81]],  // --- -- -- 481
+    [[-1, -1, -1,  4, 0x02]],  // --- -- -- 402
+    [[-1, -1, -1,  4, 0x10]],  // --- -- -- 410
+    [[-1, -1, -1,  4, 0x03]],  // --- -- -- 403
+    [[-1, -1, -1,  0, 0x00]],  // --- -- -- --- - no vibrato
+    [[-1, -1, -1,  4, 0x00]],  // --- -- -- 400 - resume vibrato @ pos 0
+  ];
+  XMPlayer.xm.tempo = 3;
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.vibratotype, 0, 'initial vibratotype 0');
+  XMPlayer.nextTick();  // row 0 tick 0
+  var p0 = ch.doff;
+  assert.equal(ch.vibratotype, 2, 'row 0 tick 0 vibratotype=2');
+  XMPlayer.nextTick();  // row 0 tick 1
+  XMPlayer.nextTick();  // row 0 tick 2
+  XMPlayer.nextTick();  // row 1 tick 0
+  assert.equal(ch.periodoffset, 2, 'row 1 tick 0 periodoffset=2');
+  XMPlayer.nextTick();  // row 1 tick 1
+  // compute logical period p from actual play frequency
+  var p = 16*12 * Math.log(p0 / ch.doff) / Math.log(2);
+  assert.equal(p.toFixed(3), "2.000", 'row 1 tick 1 period +2.000');
+  XMPlayer.nextTick();  // row 1 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "2.000", 'row 1 tick 2 period +2.000');
+  XMPlayer.nextTick();  // row 2 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "4.000", 'row 2 tick 0 period +4.000');
+  XMPlayer.nextTick();  // row 2 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "4.000", 'row 2 tick 1 period +4.000');
+  XMPlayer.nextTick();  // row 2 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "4.000", 'row 2 tick 2 period +4.000');
+  XMPlayer.nextTick();  // row 3 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-4.000", 'row 3 tick 0 period -4.000');
+  XMPlayer.nextTick();  // row 3 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-4.000", 'row 3 tick 1 period -4.000');
+  XMPlayer.nextTick();  // row 3 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-4.000", 'row 3 tick 2 period -4.000');
+  XMPlayer.nextTick();  // row 4 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-6.000", 'row 4 tick 0 period -6.000');
+  XMPlayer.nextTick();  // row 4 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-6.000", 'row 4 tick 1 period -6.000');
+  XMPlayer.nextTick();  // row 4 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-6.000", 'row 4 tick 2 period -6.000');
+  XMPlayer.nextTick();  // row 4 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "0.000", 'row 4 tick 0 period 0 - no vibrato');
+  XMPlayer.nextTick();  // row 4 tick 1
+  XMPlayer.nextTick();  // row 4 tick 2
+  XMPlayer.nextTick();  // row 5 tick 0
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-6.000", 'row 5 tick 0 period -6.000 - vibrato resume');
+  XMPlayer.nextTick();  // row 5 tick 1
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-6.000", 'row 5 tick 1 period -6.000');
+  XMPlayer.nextTick();  // row 5 tick 2
+  p = -16*12 * Math.log(ch.doff / p0) / Math.log(2);
+  assert.equal(p.toFixed(3), "-6.000", 'row 5 tick 2 period -6.000');
+};
+
+exports['test Axy volume slide'] = function(assert) {
+  var xm = testdata.resetXMData();
+  XMPlayer.xm.tempo = 6;
+
+  xm.patterns[0] = [
+    [[48,  1, -1, 10, 0x0f]],  // C-4  1 -- A0f (slide down)
+    [[-1, -1, -1, 10, 0x90]],  // --- -- -- A90 (slide up)
+    [[-1, -1, -1, 10, 0x00]],  // --- -- -- A00 (continue same)
+    [[-1, -1, 0x30, 10, 0x11]],  // --- -- 20 A11 (invalid, do nothing)
+  ];
+  var ch = xm.channelinfo[0];
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 64, 'row 0 tick 0 vol 64');
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 49, 'row 0 tick 1 vol 49');
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 34, 'row 0 tick 2 vol 34');
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 19, 'row 0 tick 3 vol 19');
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 4, 'row 0 tick 4 vol 4');
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 0, 'row 0 tick 5 vol 0');
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 0, 'row 1 tick 0 vol 0');
+  XMPlayer.nextTick();
+  assert.equal(ch.vol, 9, 'row 1 tick 1 vol 9');
+  XMPlayer.nextTick();  // row 1 tick 2
+  XMPlayer.nextTick();  // tick 3
+  XMPlayer.nextTick();  // tick 4
+  XMPlayer.nextTick();  // tick 5
+  assert.equal(ch.vol, 45, 'row 1 tick 5 vol 45');
+  XMPlayer.nextTick();  // row 2 tick 0
+  assert.equal(ch.vol, 45, 'row 2 tick 0 vol 45');
+  XMPlayer.nextTick();  // row 2 tick 1
+  assert.equal(ch.vol, 54, 'row 2 tick 1 vol 54');
+  XMPlayer.nextTick();  // tick 2
+  XMPlayer.nextTick();  // tick 3
+  assert.equal(ch.vol, 64, 'row 2 tick 3 vol 64');
+  XMPlayer.nextTick();  // tick 4
+  XMPlayer.nextTick();  // tick 5
+  XMPlayer.nextTick();  // row 3 tick 0
+  assert.equal(ch.vol, 32, 'row 3 tick 0 vol 32');
+  XMPlayer.nextTick();  // tick 1
+  assert.equal(ch.vol, 32, 'row 3 tick 1 vol 32');
+  XMPlayer.nextTick();  // tick 2
+  assert.equal(ch.vol, 32, 'row 3 tick 2 vol 32');
+};
+
+exports['test Dxx pattern jump'] = function(assert) {
+  var xm = testdata.resetXMData();
+  xm.tempo = 2;
+  xm.patterns[0] = [
+    [[-1, -1, -1, 0x0, 0x00]],  // 00 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 01 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 02 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 03 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 04 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 05 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 06 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 07 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 08 --- -- -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 09 --- -- -- 000
+    [[49,  1, -1, 0x0, 0x00]],  // 0a C#4  1 -- 000
+    [[-1, -1, -1, 0x0, 0x00]],  // 0b --- -- -- 000
+  ];
+  // argument is BCD, so 0x10 actually means 10 (decimal)
+  xm.patterns[1] = [
+    [[-1, -1, -1, 0x0, 0x00]],  // --- -- -- 000
+    [[48,  1, -1, 0xd, 0x10]],  // C-4  1 -- D10
+    [[-1, -1, -1, 0x0, 0x00]],  // --- -- -- 000
+  ];
+  xm.songpats = [1, 0];
+  XMPlayer.nextTick();  // play first, empty row (pattern 1)
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.cur_songpos, 0, "songpos 0");
+  assert.equal(XMPlayer.cur_pat, 1, "pattern 1");
+  assert.equal(XMPlayer.cur_row, 0, "row 0");
+
+  XMPlayer.nextTick();  // play C-4  1 -- D01 in pattern 1
+  XMPlayer.nextTick();  // we will jump to pattern 0 row 1 after this
+
+  assert.equal(xm.channelinfo[0].period, 1152, "play C-4 on Dxx row");
+
+  XMPlayer.nextTick();  // play row 0x0a C#4  1 -- 000 in pattern 0
+
+  assert.equal(xm.channelinfo[0].period, 1136, "play C#4 on following row");
+  assert.equal(XMPlayer.cur_songpos, 1, "songpos 0");
+  assert.equal(XMPlayer.cur_pat, 0, "pattern 1");
+  assert.equal(XMPlayer.cur_row, 10, "row 10");
+};
+
+exports['test Gxx global volume'] = function(assert) {
+  var xm = testdata.resetXMData();
+  xm.patterns = [
+    [
+      [[48, 1, -1, 16, 0x40]], // C-4  1 -- G40
+      [[48, 1, -1, 16, 0x2B]], // C-4  1 -- G2B
+      // test out of bounds volume
+      [[48, 1, -1, 16, 0x80]]  // C-4  1 -- G80
+    ]
+  ];
+  XMPlayer.xm.tempo = 1;
+  XMPlayer.nextTick();
+  // volume gets multiplied by 2 to match
+  // the initial max global volume of 128
+  assert.equal(XMPlayer.xm.global_volume, 0x40*2, 'global volume set to 0x40');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.xm.global_volume, 0x2B*2, 'global volume set to 0x2B');
+  XMPlayer.nextTick();
+  assert.equal(XMPlayer.xm.global_volume, 0x40*2, 'global volume set to 0x40');
+};
+
+exports['test Hxy global volume slide'] = function(assert) {
+  var xm = testdata.resetXMData();
+  xm.tempo = 6;
+  xm.global_volume = 128;
+
+  xm.patterns[0] = [
+    [[48,  1, -1, 17, 0x0f]],  // C-4  1 -- H0f (slide down)
+    [[-1, -1, -1, 17, 0x90]],  // --- -- -- H90 (slide up)
+    [[-1, -1, -1, 17, 0x00]],  // --- -- -- H00 (continue same)
+    [[-1, -1, 0x30, 17, 0x11]],  // --- -- 30 H11 (invalid, do nothing)
+  ];
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 128, 'row 0 tick 0 vol 128');
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 98, 'row 0 tick 1 vol 98');
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 68, 'row 0 tick 2 vol 68');
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 38, 'row 0 tick 3 vol 38');
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 8, 'row 0 tick 4 vol 8');
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 0, 'row 0 tick 5 vol 0');
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 0, 'row 1 tick 0 vol 0');
+  XMPlayer.nextTick();
+  assert.equal(xm.global_volume, 18, 'row 1 tick 1 vol 18');
+  XMPlayer.nextTick();  // row 1 tick 2
+  XMPlayer.nextTick();  // tick 3
+  XMPlayer.nextTick();  // tick 4
+  XMPlayer.nextTick();  // tick 5
+  assert.equal(xm.global_volume, 90, 'row 1 tick 5 vol 90');
+  XMPlayer.nextTick();  // row 2 tick 0
+  assert.equal(xm.global_volume, 90, 'row 2 tick 0 vol 90');
+  XMPlayer.nextTick();  // row 2 tick 1
+  assert.equal(xm.global_volume, 108, 'row 2 tick 1 vol 108');
+  XMPlayer.nextTick();  // tick 2
+  XMPlayer.nextTick();  // tick 3
+  assert.equal(xm.global_volume, 128, 'row 2 tick 3 vol 128');
+  XMPlayer.nextTick();  // tick 4
+  XMPlayer.nextTick();  // tick 5
+  XMPlayer.nextTick();  // row 3 tick 0
+  assert.equal(xm.global_volume, 128, 'row 3 tick 0 vol 128');
+  XMPlayer.nextTick();  // tick 1
+  assert.equal(xm.global_volume, 128, 'row 3 tick 1 vol 128');
+  XMPlayer.nextTick();  // tick 2
+  assert.equal(xm.global_volume, 128, 'row 3 tick 2 vol 128');
+};
+
+exports['test E4x set vibrato waveform'] = function(assert) {
+  var xm = testdata.resetXMData();
+  xm.patterns = [
+    [
+      [[48, 1, -1,  0, 0x00]], // C-4  1 -- ---  (default waveform - sine)
+      [[48, 1, -1, 14, 0x41]], // C-4  1 -- E41  (saw, ramp-down)
+      [[48, 1, -1, 14, 0x42]], // C-4  1 -- E42  (square)
+      [[48, 1, -1, 14, 0x43]]  // C-4  1 -- E43  (random)
+    ]
+  ];
+  xm.tempo = 1;
+  var ch = xm.channelinfo[0];
+  XMPlayer.nextTick();
+  assert.equal(ch.vibratotype, 0, 'row 0 tick 0 vibratotype=0');
+  XMPlayer.nextTick();
+  assert.equal(ch.vibratotype, 1, 'row 1 tick 0 vibratotype=1');
+  XMPlayer.nextTick();
+  assert.equal(ch.vibratotype, 2, 'row 2 tick 0 vibratotype=2');
+  XMPlayer.nextTick();
+  assert.equal(ch.vibratotype, 3, 'row 3 tick 0 vibratotype=3');
+};
+
+exports['test E5x finetune override'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // set an initial finetune so we know we're overriding it...
+  xm.instruments[0].samples[0].fine = -4;
+  xm.patterns = [
+    [
+      [[48, 1, -1,  0, 0x00]], // C-4  1 -- 000  (sample finetune -4)
+      [[48, 1, -1, 14, 0x50]], // C-4  1 -- E50  (finetune -128)
+      [[48, 1, -1, 14, 0x5f]]  // C-4  1 -- E5f  (finetune +127)
+    ]
+  ];
+  xm.tempo = 1;
+  var ch = xm.channelinfo[0];
+  XMPlayer.nextTick();
+  var f0 = ch.doff;
+  XMPlayer.nextTick();
+  // compare frequency relative to original finetune -4 note
+  var f1 = 12 * 128 * Math.log(ch.doff / f0) / Math.log(2);
+  assert.equal(f1.toFixed(2), "-124.00", "E50 finetune -128");
+  XMPlayer.nextTick();
+  var f2 = 12 * 128 * Math.log(ch.doff / f0) / Math.log(2);
+  assert.equal(f2.toFixed(2), "131.00", "E5f finetune +127");
+};
--- a/test/instrument.js
+++ b/test/instrument.js
@ -0,0 +1,57 @@
+var XMPlayer = window.XMPlayer;
+
+// TODO:
+//  - test volume envelope (sustain, release)
+//  - test panning envelope
+
+exports['test note on'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // [pat][row][channel]
+  xm.patterns[0][0][0] = [48, 1, 0x10 + 0x33, 0, 0];  // C-4  1 33 000
+  XMPlayer.nextRow();
+  var ch = xm.channelinfo[0];
+  assert.equal(ch.note, 48, 'set note');
+  assert.equal(ch.period, 1152, 'channel period');
+  assert.equal(ch.vol, 0x33, 'channel volume');
+  assert.equal(ch.samp, xm.instruments[0].samples[0], 'set sample');
+  assert.equal(ch.off, 0, 'trigger offset');
+};
+
+exports['test instrument trigger'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // [pat][row][channel]
+  xm.patterns[0][0][0] = [48, 1, 0x10 + 0x33, 0, 0];  // C-4  1 33 000
+  xm.patterns[0][1][0] = [-1, 1, -1, 0, 0];  // ---  1 -- 000
+  var ch = xm.channelinfo[0];
+  XMPlayer.nextRow();
+  ch.pan = 1;  // forcibly override panning
+  ch.off = 100;  // and sample offset
+  assert.equal(XMPlayer.cur_row, 0, 'row 0');
+  XMPlayer.nextRow();
+  assert.equal(XMPlayer.cur_row, 1, 'row 1');
+  assert.equal(ch.note, 48, 'note same after inst trigger');
+  assert.equal(ch.period, 1152, 'period same after inst trigger');
+  assert.equal(ch.vol, 64, 'vol reset after inst trigger');
+  assert.equal(ch.pan, 128, 'pan reset after inst trigger');
+  assert.equal(ch.samp, xm.instruments[0].samples[0], 'set sample');
+  assert.equal(ch.off, 0, 'set offset=0');
+};
+
+exports['test note trigger'] = function(assert) {
+  var xm = testdata.resetXMData();
+  // [pat][row][channel]
+  xm.patterns[0][0][0] = [48, 1, 0x10 + 0x33, 0, 0];  // C-4  1 33 000
+  xm.patterns[0][1][0] = [49, -1, -1, 0, 0];  // C#4 -- -- 000
+  var ch = xm.channelinfo[0];
+  XMPlayer.nextRow();
+  ch.pan = 1;  // forcibly override panning
+  ch.off = 100;  // and sample offset
+  ch.vibratopos = 1; // and vibrato position
+  XMPlayer.nextRow();
+  assert.equal(ch.note, 49, 'note updated after inst trigger');
+  assert.equal(ch.period, 1136, 'period updated after note trigger');
+  assert.equal(ch.vol, 0x33, 'vol not reset after note trigger');
+  assert.equal(ch.pan, 1, 'pan not reset after note trigger');
+  assert.equal(ch.off, 0, 'set offset=0');
+  assert.equal(ch.vibratopos, 0, 'set vibrato pos=0');
+};
--- a/test/testdata.js
+++ b/test/testdata.js
@ -0,0 +1,58 @@
+var XMPlayer = window.XMPlayer;
+
+// set up basic blank single-channel, single-pattern XM
+exports.resetXMData = function() {
+  var xm = {};
+  window.XMPlayer.xm = xm;
+  xm.channelinfo = [];
+  xm.songname = "test song";
+  xm.song_looppos = 0;
+  xm.nchan = 1;
+  xm.flags = 1;
+  xm.tempo = 3;
+  xm.bpm = 125;
+  xm.channelinfo.push({
+    number: 0,
+    filterstate: new Float32Array(3),
+    vol: 0,
+    pan: 128,
+    period: 1920 - 48*16,
+    vL: 0, vR: 0,
+    vLprev: 0, vRprev: 0,
+    mute: 0,
+    volE: 0, panE: 0,
+    retrig: 0,
+    vibratopos: 0,
+    vibratodepth: 1,
+    vibratospeed: 1,
+    vibratotype: 0,
+  });
+  xm.songpats = [0];
+  // 1 channel, 2 row blank pattern
+  xm.patterns = [
+    [
+      [[-1, -1, -1, 0, 0]],
+      [[-1, -1, -1, 0, 0]]
+    ]
+  ];
+  xm.instruments = [];
+  xm.instruments.push({
+    'name': "test instrument",
+    'number': 0,
+    'samples': [
+      { 'len': 256, 'loop': 0,
+        'looplen': 256, 'note': 0, 'fine': 0,
+        'pan': 128, 'type': 0, 'vol': 64,
+        'sampledata': new Float32Array(256)
+      }
+    ],
+    'samplemap': new Uint8Array(96),
+    'env_vol': new XMPlayer.Envelope([0, 64, 1, 0], 2, 0, 0, 0),
+    'env_pan': new XMPlayer.Envelope([0, 32], 0, 0, 0, 0)
+  });
+  // reset song position
+  XMPlayer.cur_songpos = -1;
+  XMPlayer.cur_pat = -1;
+  XMPlayer.cur_tick = 64;
+  return xm;
+};
--- a/trackview.js
+++ b/trackview.js
@ -0,0 +1,348 @@
+(function (window, document) {
+if (!window.XMPlayer) {
+  window.XMPlayer = {};
+}
+var player = window.XMPlayer;
+
+if (!window.XMView) {
+  window.XMView = {};
+}
+var view = window.XMView;
+
+var _pattern_cellwidth = 16 + 4 + 8 + 4 + 8 + 16 + 4;
+var _scope_width = _pattern_cellwidth - 1;
+var _pattern_border = 20;
+
+view.init = init;
+view.pushEvent = pushEvent;
+view.pause = pause;
+view.resume = resume;
+view.stop = stop;
+view.scope_width = _scope_width;
+
+// Load font (ripped from FastTracker 2)
+var fontimg = new window.Image();
+fontimg.src = "ft2font.png";
+
+var _fontmap_notes = [8*5, 8*22, 8*28];
+var pat_canvas_patnum;
+
+var audio_events;
+var paused_events;
+var shown_row;
+
+// canvas to render patterns onto
+var pat_canvas = document.createElement('canvas');
+
+// pixel widths of each character in the proportional font
+var _fontwidths = [
+  4, 7, 3, 6, 6, 6, 6, 5, 4, 5, 5, 5, 5, 5, 7, 7,
+  5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 6, 7, 7, 7, 7, 7,
+  4, 2, 5, 7, 7, 7, 7, 3, 4, 4, 6, 6, 3, 6, 2, 7,
+  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 2, 3, 6, 6, 6, 7,
+  7, 7, 7, 7, 7, 7, 7, 7, 7, 2, 7, 7, 7, 8, 8, 7,
+  7, 7, 7, 7, 8, 7, 7, 8, 8, 8, 7, 4, 7, 4, 4, 5,
+  3, 6, 6, 6, 6, 6, 4, 6, 6, 2, 4, 6, 2, 8, 6, 6,
+  6, 6, 4, 6, 4, 6, 7, 8, 7, 6, 6, 4, 2, 4, 4, 4];
+
+var _bigfontwidths = [
+   4, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
+  15, 15, 15, 15, 15, 15, 15, 15, 13, 13, 13, 15, 15, 15, 15, 15,
+   4,  5, 12, 16, 15, 15, 16,  5,  8,  8, 13, 10,  6, 10,  5, 12,
+  15, 15, 15, 15, 15, 15, 15, 15, 15, 15,  5,  6, 12, 10, 12, 15,
+  14, 15, 15, 15, 15, 15, 15, 15, 15,  5, 13, 15, 14, 15, 15, 15,
+  15, 16, 15, 15, 15, 15, 15, 15, 15, 15, 16,  7, 12,  7, 13, 15,
+   5, 13, 13, 13, 13, 13, 11, 13, 13,  5,  9, 13,  5, 16, 13, 13,
+  13, 13, 12, 13, 11, 13, 13, 16, 15, 13, 15,  9,  2,  9, 15, 15];
+
+// draw FT2 proportional font text to a drawing context
+// returns width rendered
+function drawText(text, dx, dy, ctx) {
+  var dx0 = dx;
+  for (var i = 0; i < text.length; i++) {
+    var n = text.charCodeAt(i);
+    var sx = (n&63)*8;
+    var sy = (n>>6)*10 + 56;
+    var width = _fontwidths[n];
+    ctx.drawImage(fontimg, sx, sy, width, 10, dx, dy, width, 10);
+    dx += width + 1;
+  }
+  return dx - dx0;
+}
+
+function getTextSize(text, widthtable) {
+  var width = 0;
+  for (var i = 0; i < text.length; i++) {
+    var n = text.charCodeAt(i);
+    width += widthtable[n] + 1;
+  }
+  return width;
+}
+
+function drawBigText(text, dx, dy, ctx) {
+  var dx0 = dx;
+  for (var i = 0; i < text.length; i++) {
+    var n = text.charCodeAt(i);
+    var sx = (n&31)*16;
+    var sy = (n>>5)*20 + 96;
+    var width = _bigfontwidths[n];
+    ctx.drawImage(fontimg, sx, sy, width, 20, dx, dy, width, 20);
+    dx += width + 1;
+  }
+  return dx - dx0;
+}
+
+function RenderPattern(canv, pattern) {
+  // a pattern consists of NxM cells which look like
+  // N-O II VV EFF
+  var cellwidth = _pattern_cellwidth;
+  canv.width = pattern[0].length * cellwidth + _pattern_border;
+  canv.height = pattern.length * 8;
+  var ctx = canv.getContext('2d');
+  ctx.fillcolor='#000';
+  ctx.fillRect(0, 0, canv.width, canv.height);
+  for (var j = 0; j < pattern.length; j++) {
+    var row = pattern[j];
+    var dy = j * 8;
+    // render row number
+    ctx.drawImage(fontimg, 8*(j>>4), 0, 8, 8, 2, dy, 8, 8);
+    ctx.drawImage(fontimg, 8*(j&15), 0, 8, 8, 10, dy, 8, 8);
+
+    for (var i = 0; i < row.length; i++) {
+      var dx = i*cellwidth + 2 + _pattern_border;
+      var data = row[i];
+
+      // render note
+      var note = data[0];
+      if (note < 0) {
+        // no note = ...
+        ctx.drawImage(fontimg, 0, 8*5, 16, 8, dx, dy, 16, 8);
+      } else {
+        var octave = (note/12)|0;
+        var note_fontrow = _fontmap_notes[(octave/3)|0];
+        note = (note % (12*3))|0;
+        ctx.drawImage(fontimg, 16+16*note, note_fontrow, 16, 8, dx, dy, 16, 8);
+      }
+      dx += 20;
+
+      // render instrument
+      var inst = data[1];
+      if (inst != -1) {  // no instrument = render nothing
+        if (inst > 15) {
+          ctx.drawImage(fontimg, 8*(inst>>4), 4*8, 4, 8, dx, dy, 4, 8);
+        }
+        ctx.drawImage(fontimg, 8*(inst&15), 4*8, 4, 8, dx+4, dy, 4, 8);
+      }
+      dx += 12;
+
+      // render volume
+      var vol = data[2];
+      if (vol < 0x10) {
+        // no volume = ..
+        ctx.drawImage(fontimg, 312, 0, 8, 8, dx, dy, 8, 8);
+      } else {
+        ctx.drawImage(fontimg, 8*(vol>>4) + 56*8, 4*8, 8, 8, dx, dy, 8, 8);
+        ctx.drawImage(fontimg, 8*(vol&15), 4*8, 4, 8, dx+4, dy, 4, 8);
+      }
+      dx += 8;
+
+      // render effect
+      var eff = data[3];
+      var effdata = data[4];
+      if (eff !== 0 || effdata !== 0) {
+        // draw effect with tiny font (4px space + effect type 0..9a..z)
+        ctx.drawImage(fontimg, 8*eff + 16*8, 4*8, 8, 8, dx, dy, 8, 8);
+        dx += 8;
+        // (hexadecimal 4-width font)
+        ctx.drawImage(fontimg, 8*(effdata>>4), 4*8, 4, 8, dx, dy, 4, 8);
+        ctx.drawImage(fontimg, 8*(effdata&15), 4*8, 4, 8, dx+4, dy, 4, 8);
+      } else {
+        // no effect = ...
+        ctx.drawImage(fontimg, 0, 8*5, 16, 8, dx+2, dy, 16, 8);
+      }
+    }
+  }
+}
+
+function redrawScreen() {
+  var e;
+  var t = player.audioctx.currentTime;
+  while (audio_events.length > 0 && audio_events[0].t < t) {
+    e = audio_events.shift();
+  }
+  if (!e) {
+    if (player.playing) {
+      window.requestAnimationFrame(redrawScreen);
+    }
+    return;
+  }
+  var VU = e.vu;
+  var scopes = e.scopes;
+  var ctx;
+
+  if (e.scopes !== undefined) {
+    // update VU meters & oscilliscopes
+    var canvas = document.getElementById("vu");
+    ctx = canvas.getContext("2d");
+    ctx.fillStyle = '#000';
+    ctx.fillRect(0, 0, canvas.width, 64);
+    ctx.fillStyle = '#0f0';
+    ctx.strokeStyle = '#55acff';
+    for (var j = 0; j < player.xm.nchan; j++) {
+      var x = _pattern_border + j * _pattern_cellwidth;
+      // render channel number
+      drawText(''+j, x, 1, ctx);
+
+      // volume in dB as a green bar
+      var vu_y = -Math.log(VU[j])*10;
+      ctx.fillRect(x, vu_y, 2, 64-vu_y);
+
+      // oscilloscope
+      var scope = scopes[j];
+      if (scope) {
+        ctx.beginPath();
+        for (var k = 0; k < _scope_width; k++) {
+          ctx.lineTo(x + 1 + k, 32 - 16 * scope[k]);
+        }
+        ctx.stroke();
+      }
+    }
+  }
+
+  if (e.row != shown_row || e.pat != pat_canvas_patnum) {
+    if (e.pat != pat_canvas_patnum) {
+      var p = player.xm.patterns[e.pat];
+      if (p) {
+        RenderPattern(pat_canvas, player.xm.patterns[e.pat]);
+        pat_canvas_patnum = e.pat;
+      }
+    }
+
+    var gfx = document.getElementById("gfxpattern");
+    ctx = gfx.getContext('2d');
+    ctx.fillStyle = '#000';
+    ctx.fillRect(0, 0, gfx.width, gfx.height);
+    ctx.fillStyle = '#2a5684';
+    ctx.fillRect(0, gfx.height/2 - 4, gfx.width, 8);
+    ctx.globalCompositeOperation = 'lighten';
+    ctx.drawImage(pat_canvas, 0, gfx.height / 2 - 4 - 8*(e.row));
+    ctx.globalCompositeOperation = 'source-over';
+    shown_row = e.row;
+  }
+
+  if (player.playing) {
+    window.requestAnimationFrame(redrawScreen);
+  }
+}
+
+function init() {
+  var title = document.getElementById("title");
+  // make title element fit text exactly, then render it
+  title.width = getTextSize(player.xm.songname, _bigfontwidths);
+  var ctx = title.getContext('2d');
+  drawBigText(player.xm.songname, 0, 1, ctx);
+
+  var instrlist = document.getElementById("instruments");
+  // clear instrument list if not already clear
+  while (instrlist.childNodes.length) {
+    instrlist.removeChild(instrlist.childNodes[0]);
+  }
+  var instrcols = ((player.xm.instruments.length + 7) / 8) | 0;
+  for (var i = 0; i < instrcols; i++) {
+    var canvas = document.createElement('canvas');
+    ctx = canvas.getContext('2d');
+    var instrcolumnwidth = 8*22;
+    canvas.width = instrcolumnwidth;
+    canvas.height = 8 * 10;
+    ctx.fillStyle = '#000';
+    ctx.fillRect(0, 0, canvas.width, canvas.height);
+    var hasname = 0, hasdata = 0;
+    for (var j = 8*i; j < Math.min(8*i+8, player.xm.instruments.length); j++) {
+      var y = 10*(j - 8*i);
+      var n = (j+1).toString(16);
+      if (j < 15) n = '0' + n;
+      var data = player.xm.instruments[j].samples;
+      if (data) {
+        var len = data[0].len;
+        data = data[0].sampledata;
+        var scale = Math.ceil(len / instrcolumnwidth);
+        ctx.strokeStyle = '#55acff';
+        ctx.beginPath();
+        for (var k = 0; k < Math.min(len / scale, instrcolumnwidth - 20); k++) {
+          ctx.lineTo(k + 20, y + data[k*scale] * 4 + 4);
+        }
+        ctx.stroke();
+        hasdata++;
+      }
+      var name = player.xm.instruments[j].name;
+      ctx.globalCompositeOperation = 'lighten';
+      drawText(n, 1, y, ctx);
+      if (name !== '') {
+        drawText(player.xm.instruments[j].name, 20, y, ctx);
+        hasname++;
+      }
+      ctx.globalCompositeOperation = 'source-over';
+    }
+    if (hasname || hasdata) {
+      instrlist.appendChild(canvas);
+    }
+  }
+
+  document.getElementById('vu').width = _pattern_border +
+    _pattern_cellwidth * player.xm.nchan;
+  var gfxpattern = document.getElementById("gfxpattern");
+  gfxpattern.width = _pattern_cellwidth * player.xm.nchan + _pattern_border;
+
+  // generate a fake audio event to render the initial paused screen
+  var scopes = [];
+  for (i = 0; i < player.xm.nchan; i++) {
+    scopes.push(new Float32Array(_scope_width));
+  }
+
+  // reset display
+  shown_row = undefined;
+  pat_canvas_patnum = undefined;
+
+  audio_events = [];
+  paused_events = [];
+  audio_events.push({
+    t: 0, row: 0, pat: player.xm.songpats[0],
+    vu: new Float32Array(player.xm.nchan),
+    scopes: scopes
+  });
+  redrawScreen();
+}
+
+function pushEvent(e) {
+  audio_events.push(e);
+  if (audio_events.length == 1) {
+    requestAnimationFrame(redrawScreen);
+  }
+}
+
+function pause() {
+  // grab all the audio events
+  var t = player.audioctx.currentTime;
+  while (audio_events.length > 0) {
+    var e = audio_events.shift();
+    e.t -= t;
+    paused_events.push(e);
+  }
+}
+
+function resume() {
+  var t = player.audioctx.currentTime;
+  while (paused_events.length > 0) {
+    var e = paused_events.shift();
+    e.t += t;
+    audio_events.push(e);
+  }
+  requestAnimationFrame(redrawScreen);
+}
+
+function stop() {
+  audio_events = [];
+  paused_events = [];
+}
+
+})(window, document);
--- a/xm.js
+++ b/xm.js
--- a/xmeffects.js
+++ b/xmeffects.js
@ -0,0 +1,346 @@
+(function (window) {
+if (!window.XMPlayer) {
+  window.XMPlayer = {};
+}
+var player = window.XMPlayer;
+
+function eff_t1_0(ch) {  // arpeggio
+  if (ch.effectdata !== 0 && ch.inst !== undefined) {
+    var arpeggio = [0, ch.effectdata>>4, ch.effectdata&15];
+    var note = ch.note + arpeggio[player.cur_tick % 3];
+    ch.period = player.periodForNote(ch, note);
+  }
+}
+
+function eff_t0_1(ch, data) {  // pitch slide up
+  if (data !== 0) {
+    ch.slideupspeed = data;
+  }
+}
+
+function eff_t1_1(ch) {  // pitch slide up
+  if (ch.slideupspeed !== undefined) {
+    // is this limited? it appears not
+    ch.period -= ch.slideupspeed;
+  }
+}
+
+function eff_t0_2(ch, data) {  // pitch slide down
+  if (data !== 0) {
+    ch.slidedownspeed = data;
+  }
+}
+
+function eff_t1_2(ch) {  // pitch slide down
+  if (ch.slidedownspeed !== undefined) {
+    // 1728 is the period for C-1
+    ch.period = Math.min(1728, ch.period + ch.slidedownspeed);
+  }
+}
+
+function eff_t0_3(ch, data) {  // portamento
+  if (data !== 0) {
+    ch.portaspeed = data;
+  }
+}
+
+function eff_t1_3(ch) {  // portamento
+  if (ch.periodtarget !== undefined && ch.portaspeed !== undefined) {
+    if (ch.period > ch.periodtarget) {
+      ch.period = Math.max(ch.periodtarget, ch.period - ch.portaspeed);
+    } else {
+      ch.period = Math.min(ch.periodtarget, ch.period + ch.portaspeed);
+    }
+  }
+}
+
+function eff_t0_4(ch, data) {  // vibrato
+  if (data & 0x0f) {
+    ch.vibratodepth = (data & 0x0f) * 2;
+  }
+  if (data >> 4) {
+    ch.vibratospeed = data >> 4;
+  }
+  eff_t1_4(ch);
+}
+
+function eff_t1_4(ch) {  // vibrato
+  ch.periodoffset = getVibratoDelta(ch.vibratotype, ch.vibratopos) * ch.vibratodepth;
+  if (isNaN(ch.periodoffset)) {
+    console.log("vibrato periodoffset NaN?",
+        ch.vibratopos, ch.vibratospeed, ch.vibratodepth);
+    ch.periodoffset = 0;
+  }
+  // only updates on non-first ticks
+  if (player.cur_tick > 0) {
+    ch.vibratopos += ch.vibratospeed;
+    ch.vibratopos &= 63;
+  }
+}
+
+function getVibratoDelta(type, x) {
+  var delta = 0;
+  switch (type & 0x03) {
+    case 1: // sawtooth (ramp-down)
+      delta = ((1 + x * 2 / 64) % 2) - 1;
+      break;
+    case 2: // square
+    case 3: // random (in FT2 these two are the same)
+      delta = x < 32 ? 1 : -1;
+      break;
+    case 0:
+    default: // sine
+      delta = Math.sin(x * Math.PI / 32);
+      break;
+  }
+  return delta;
+}
+
+function eff_t1_5(ch) {  // portamento + volume slide
+  eff_t1_a(ch);
+  eff_t1_3(ch);
+}
+
+function eff_t1_6(ch) {  // vibrato + volume slide
+  eff_t1_a(ch);
+  eff_t1_4(ch);
+}
+
+function eff_t0_8(ch, data) {  // set panning
+  ch.pan = data;
+}
+
+function eff_t0_9(ch, data) {  // sample offset
+  ch.off = data * 256;
+}
+
+function eff_t0_a(ch, data) {  // volume slide
+  if (data) {
+    ch.volumeslide = -(data & 0x0f) + (data >> 4);
+  }
+}
+
+function eff_t1_a(ch) {  // volume slide
+  if (ch.volumeslide !== undefined) {
+    ch.vol = Math.max(0, Math.min(64, ch.vol + ch.volumeslide));
+  }
+}
+
+function eff_t0_b(ch, data) {  // song jump (untested)
+  if (data < player.xm.songpats.length) {
+    player.cur_songpos = data;
+    player.cur_pat = player.xm.songpats[player.cur_songpos];
+    player.cur_row = -1;
+  }
+}
+
+function eff_t0_c(ch, data) {  // set volume
+  ch.vol = Math.min(64, data);
+}
+
+function eff_t0_d(ch, data) {  // pattern jump
+  player.cur_songpos++;
+  if (player.cur_songpos >= player.xm.songpats.length)
+    player.cur_songpos = player.xm.song_looppos;
+  player.cur_pat = player.xm.songpats[player.cur_songpos];
+  player.cur_row = (data >> 4) * 10 + (data & 0x0f) - 1;
+}
+
+function eff_t0_e(ch, data) {  // extended effects!
+  var eff = data >> 4;
+  data = data & 0x0f;
+  switch (eff) {
+    case 1:  // fine porta up
+      ch.period -= data;
+      break;
+    case 2:  // fine porta down
+      ch.period += data;
+      break;
+    case 4:  // set vibrato waveform
+      ch.vibratotype = data & 0x07;
+      break;
+    case 5:  // finetune
+      ch.fine = (data<<4) + data - 128;
+      break;
+    case 8:  // panning
+      ch.pan = data * 0x11;
+      break;
+    case 0x0a:  // fine vol slide up (with memory)
+      if (data === 0 && ch.finevolup !== undefined)
+        data = ch.finevolup;
+      ch.vol = Math.min(64, ch.vol + data);
+      ch.finevolup = data;
+      break;
+    case 0x0b:  // fine vol slide down
+      if (data === 0 && ch.finevoldown !== undefined)
+        data = ch.finevoldown;
+      ch.vol = Math.max(0, ch.vol - data);
+      ch.finevoldown = data;
+      break;
+    case 0x0c:  // note cut handled in eff_t1_e
+      break;
+    default:
+      console.log("unimplemented extended effect E", ch.effectdata.toString(16));
+      break;
+  }
+}
+
+function eff_t1_e(ch) {  // note cut
+  switch (ch.effectdata >> 4) {
+    case 0x0c:
+      if (player.cur_tick == (ch.effectdata & 0x0f)) {
+        ch.vol = 0;
+      }
+      break;
+  }
+}
+
+function eff_t0_f(ch, data) {  // set tempo
+  if (data === 0) {
+    console.log("tempo 0?");
+    return;
+  } else if (data < 0x20) {
+    player.xm.tempo = data;
+  } else {
+    player.xm.bpm = data;
+  }
+}
+
+function eff_t0_g(ch, data) {  // set global volume
+  if (data <= 0x40) {
+    // volume gets multiplied by 2 to match
+    // the initial max global volume of 128
+    player.xm.global_volume = Math.max(0, data * 2);
+  } else {
+    player.xm.global_volume = player.max_global_volume;
+  }
+}
+
+function eff_t0_h(ch, data) {  // global volume slide
+  if (data) {
+    // same as Axy but multiplied by 2
+    player.xm.global_volumeslide = (-(data & 0x0f) + (data >> 4)) * 2;
+  }
+}
+
+function eff_t1_h(ch) {  // global volume slide
+  if (player.xm.global_volumeslide !== undefined) {
+    player.xm.global_volume = Math.max(0, Math.min(player.max_global_volume,
+      player.xm.global_volume + player.xm.global_volumeslide));
+  }
+}
+
+function eff_t0_r(ch, data) {  // retrigger
+  if (data & 0x0f) ch.retrig = (ch.retrig & 0xf0) + (data & 0x0f);
+  if (data & 0xf0) ch.retrig = (ch.retrig & 0x0f) + (data & 0xf0);
+
+  // retrigger volume table
+  switch (ch.retrig >> 4) {
+    case 1: ch.vol -= 1; break;
+    case 2: ch.vol -= 2; break;
+    case 3: ch.vol -= 4; break;
+    case 4: ch.vol -= 8; break;
+    case 5: ch.vol -= 16; break;
+    case 6: ch.vol *= 2; ch.vol /= 3; break;
+    case 7: ch.vol /= 2; break;
+    case 9: ch.vol += 1; break;
+    case 0x0a: ch.vol += 2; break;
+    case 0x0b: ch.vol += 4; break;
+    case 0x0c: ch.vol += 8; break;
+    case 0x0d: ch.vol += 16; break;
+    case 0x0e: ch.vol *= 3; ch.vol /= 2; break;
+    case 0x0f: ch.vol *= 2; break;
+  }
+  ch.vol = Math.min(64, Math.max(0, ch.vol));
+}
+
+function eff_t1_r(ch) {
+  if (player.cur_tick % (ch.retrig & 0x0f) === 0) {
+    ch.off = 0;
+  }
+}
+
+function eff_unimplemented() {}
+function eff_unimplemented_t0(ch, data) {
+  console.log("unimplemented effect", player.prettify_effect(ch.effect, data));
+}
+
+player.effects_t0 = [  // effect functions on tick 0
+  eff_t1_0,  // 1, arpeggio is processed on all ticks
+  eff_t0_1,
+  eff_t0_2,
+  eff_t0_3,
+  eff_t0_4,  // 4
+  eff_t0_a,  // 5, same as A on first tick
+  eff_t0_a,  // 6, same as A on first tick
+  eff_unimplemented_t0,  // 7
+  eff_t0_8,  // 8
+  eff_t0_9,  // 9
+  eff_t0_a,  // a
+  eff_t0_b,  // b
+  eff_t0_c,  // c
+  eff_t0_d,  // d
+  eff_t0_e,  // e
+  eff_t0_f,  // f
+  eff_t0_g,  // g
+  eff_t0_h,  // h
+  eff_unimplemented_t0,  // i
+  eff_unimplemented_t0,  // j
+  eff_unimplemented_t0,  // k
+  eff_unimplemented_t0,  // l
+  eff_unimplemented_t0,  // m
+  eff_unimplemented_t0,  // n
+  eff_unimplemented_t0,  // o
+  eff_unimplemented_t0,  // p
+  eff_unimplemented_t0,  // q
+  eff_t0_r,  // r
+  eff_unimplemented_t0,  // s
+  eff_unimplemented_t0,  // t
+  eff_unimplemented_t0,  // u
+  eff_unimplemented_t0,  // v
+  eff_unimplemented_t0,  // w
+  eff_unimplemented_t0,  // x
+  eff_unimplemented_t0,  // y
+  eff_unimplemented_t0,  // z
+];
+
+player.effects_t1 = [  // effect functions on tick 1+
+  eff_t1_0,
+  eff_t1_1,
+  eff_t1_2,
+  eff_t1_3,
+  eff_t1_4,
+  eff_t1_5,  // 5
+  eff_t1_6,  // 6
+  eff_unimplemented,  // 7
+  null,   // 8
+  null,   // 9
+  eff_t1_a,  // a
+  null,   // b
+  null,   // c
+  null,   // d
+  eff_t1_e,  // e
+  null,   // f
+  null,  // g
+  eff_t1_h,  // h
+  eff_unimplemented,  // i
+  eff_unimplemented,  // j
+  eff_unimplemented,  // k
+  eff_unimplemented,  // l
+  eff_unimplemented,  // m
+  eff_unimplemented,  // n
+  eff_unimplemented,  // o
+  eff_unimplemented,  // p
+  eff_unimplemented,  // q
+  eff_t1_r,  // r
+  eff_unimplemented,  // s
+  eff_unimplemented,  // t
+  eff_unimplemented,  // u
+  eff_unimplemented,  // v
+  eff_unimplemented,  // w
+  eff_unimplemented,  // x
+  eff_unimplemented,  // y
+  eff_unimplemented   // z
+];
+
+})(window);
Author	SHA1	Message	Date
Andy Sloane	219479ecc6	addendum to previous commit; duh	2016-05-31 22:15:46 -07:00
Andy Sloane	f6113fc6c4	simple optimization to filter just basic algebra, but I should have noticed this sooner!	2016-05-31 18:52:33 -07:00
Andy Sloane	ea423577f0	[#4 ] Re-enable iOS hack Before it was running a 1Hz oscillator for 10ms which caused a huge DC offset when it was done.. Turns out it works if you just immediately stop and disconnect it, without causing DC offsets or other problems.	2016-04-22 12:12:50 -07:00
Andy Sloane	27d9435d83	[#24 ] Implement M0 volume effect (portamento) Written so Mx is equivalent to 3x0; I think if both are present, it might not do exactly what FT2 does.	2016-04-19 16:34:20 -07:00
Johan Hillerström	7153fa7f3c	Merge pull request #21 from hillerstorm/implement_E4x Implement E4x and address some vibrato issues	2015-11-21 20:25:35 +01:00
Johan Hillerström	e3d159e7ff	Add contributors to package.json	2015-11-21 20:22:00 +01:00
Johan Hillerström	1d8b91c8ea	Remove E4x from missing effects	2015-11-21 20:21:39 +01:00
Johan Hillerström	9b959532fb	Add tests for E4x, E41 and E42	2015-11-21 20:19:30 +01:00
Johan Hillerström	677c157c71	Fix failing vibrato test	2015-11-21 19:54:54 +01:00
Johan Hillerström	e39f601038	Double vibrato depth to act like FT2	2015-11-21 15:50:58 +01:00
Johan Hillerström	b81d675b66	Test for resetting vibrato pos on note retrigger	2015-11-21 15:50:48 +01:00
Johan Hillerström	413bc4b538	Retrigger waveforms 0-3	2015-11-21 15:50:35 +01:00
Johan Hillerström	5af28d860e	Update vibratopos according to the spec	2015-11-21 14:58:33 +01:00
Johan Hillerström	0e47b13d83	Implement all vibrato waveforms	2015-11-21 14:58:32 +01:00
Johan Hillerström	fb103e61bc	Read vibrato waveform type	2015-11-21 14:58:32 +01:00
Andy Sloane	65a2ea2863	[#5 ] implement volume effect vibrato	2015-11-20 17:43:48 -08:00
Andy Sloane	8b3f318f60	[#19 ] handle loops of length 0 also more robust way to find sample offsets to load in the file	2015-11-20 17:42:41 -08:00
Andy Sloane	2679587654	update screen if pattern changes without row changing this is solely for strobe - CELL II, pretty much...	2015-11-20 12:09:57 -08:00
Andy Sloane	34e975ef55	changed my mind: render 000 effect as ... also make the track view much taller in the standalone player	2015-11-19 20:47:28 -08:00
Andy Sloane	89e6b9c554	fix Dxx effect argument is BCD, so 0x10 actually means 10 decimal	2015-11-19 20:24:00 -08:00
Andy Sloane	bf138a245c	re-sort Dxx test	2015-11-16 19:21:51 -08:00
Andy Sloane	21e3f073d9	add test for Dxx effect	2015-11-16 19:20:29 -08:00
Andy Sloane	e347807abf	Change cur_row to actually mean current row It used to really mean "next row", and resulted in showing the wrong row in the pattern view (row -1 instead of the last row). Fixes #14.	2015-11-16 18:59:46 -08:00
Andy Sloane	215f72c19d	Fix samples for instruments with >1 sample The sample offset was incorrectly computed, and was including the sample headers for all samples after the first one into the first sample's data, causing various glitches at the beginning of the sample. Fixes #10.	2015-11-16 18:47:41 -08:00
Andy Sloane	bb5555f5a1	Merge pull request #13 from hillerstorm/implement_Hxy_effect Implement Hxy effect	2015-11-14 20:28:14 -08:00
Johan Hillerström	be1c0df30d	Remove Hxy from missing effects	2015-11-15 00:38:55 +01:00
Johan Hillerström	007f0db8f7	Add test case for Hxy	2015-11-15 00:37:46 +01:00
Johan Hillerström	0f3888cfff	Implement the Hxy effect	2015-11-15 00:37:35 +01:00
Andy Sloane	0e82964315	add license field to package.json I was certain I had already added it, but somehow it went missing.	2015-11-14 09:38:43 -08:00
Andy Sloane	c35bb07fac	fix some wrong comments here and there	2015-11-14 09:37:15 -08:00
Andy Sloane	05216f5ce0	implement E5x finetune override nf_chill.xm just needs EDx now	2015-11-14 09:29:08 -08:00
Andy Sloane	9a410aa535	Merge remote-tracking branch 'hillerstorm/implement_Gxx_effect'	2015-11-14 08:39:27 -08:00
Andy Sloane	0f86a8d2c5	Merge pull request #11 from hillerstorm/fix_out_of_range_pattern_error Fix non-existing pattern error	2015-11-14 08:35:04 -08:00
Andy Sloane	660729010b	jshint cleanup of xmeffects	2015-11-14 08:30:35 -08:00
Andy Sloane	267ecbeffb	test for effect Axy	2015-11-14 08:27:17 -08:00
Johan Hillerström	8fe05fb89d	Remove Gxx from missing effects	2015-11-14 13:07:51 +01:00
Johan Hillerström	88584b9cd0	Add test case for Gxx	2015-11-14 13:04:43 +01:00
Johan Hillerström	eff3fd1ed6	Implement the Gxx effect	2015-11-14 13:04:29 +01:00
Johan Hillerström	b04e6c00b0	Introduce a global volume variable	2015-11-14 13:04:16 +01:00
Johan Hillerström	fc6be2b246	Add tests for non-existing song positions	2015-11-14 12:35:28 +01:00
Johan Hillerström	1f2b0ba419	Add safeguards when setting cur_pat	2015-11-14 12:35:18 +01:00
Andy Sloane	570aa33a20	added test for vibrato... and fixed vibrato naturally when i actually tested it, it turned out to be subtly broken also reorg'd the tests a bit, sorry @hillerstorm.	2015-11-13 22:06:50 -08:00
Andy Sloane	be463856db	Add round 1 of tests	2015-11-12 10:57:02 -08:00
Andy Sloane	6a5fe5e024	Remove XM suffix from XMPlayer calls	2015-11-12 08:56:33 -08:00
Andy Sloane	ce5fd027a3	add build status and API docs to README	2015-11-11 22:49:40 -08:00
Andy Sloane	9bf35716f3	add travis testing	2015-11-11 22:32:56 -08:00
Andy Sloane	7ca90f9b98	really basic test runner npm test now does... something somewhat useful. now to write a bunch of tests.	2015-11-11 22:28:49 -08:00
Andy Sloane	8c37c8d96b	Separate html "shell" javascript; player now standalone Closes #3. The code which defines what the buttons do and downloads songs and so forth are now completely separated from the player, which has the following API: - `XMPlayer.initAudio` -> starts up audio context; it's available as `XMPlayer.audioctx` - `XMPlayer.loadXM(ArrayBuffer)` -> returns `true` if loaded, otherwise barfs randomly - `XMPlayer.playXM()` -> starts playing - `XMPlayer.pauseXM()` -> obvious - `XMPlayer.stopXM()` -> obvious; call this before loading a new one Loading trackview.js is now optional; without it, the player won't do any visualizations. Or, you can override the following to get callbacks: - `XMView.pushEvent(e)` -> push an audio event onto the queue. Called once per tick (about 50Hz, controlled by song). `e` contains fields: - `t` - audio timestamp - `vu` - Float32Array of RMS power (volume) for each channel - `scopes` - [Float32Array] of oscilloscope data, one array per channel; `XMView.scope_width` contains # of samples to produce here - `songpos` - position in the song (# patterns played) - `pat` - pattern number currently playing - `row` - row within pattern - `XMView.pause()` - pause visualization - `XMView.stop()` - stop/reset visualization	2015-11-11 21:19:41 -08:00
Andy Sloane	8e114a16da	Split viewer code into trackview.js Also disabled iOS hack, as it seems to be causing issues, and fixed a minor drag-n-drop bug (wouldn't load if track was already playing past length of newly loaded track). To play without a viewer, you still have to stub it out. Not sure the best way to handle that case yet.	2015-11-11 18:01:15 -08:00
Andy Sloane	4b6e75332e	Merge pull request #9 from hillerstorm/namespacing_and_global_leakage Namespacing and global leakage	2015-11-11 16:12:14 -08:00
Johan Hillerström	1667ab502b	Add window fallback	2015-11-12 01:09:20 +01:00
Johan Hillerström	664686f199	Add newlines	2015-11-12 01:05:59 +01:00
Johan Hillerström	7aa67803ed	Use postfix increment operator	2015-11-12 01:04:59 +01:00
Andy Sloane	e34970c05f	Merge pull request #8 from luckcolors/master Added nw.js package.json file for building desktop app.	2015-11-11 15:49:23 -08:00
Johan Hillerström	ea36dceb55	Wrap in IIFE and namespace any shared info	2015-11-12 00:08:32 +01:00
Johan Hillerström	a37555ed58	Reorder to load without any issues	2015-11-12 00:00:43 +01:00
luckcolors	14d88e9a10	Removed toolbar.	2015-11-11 22:49:25 +01:00
luckcolors	41e8713b74	First commit for desktop app Nw.js	2015-11-11 22:28:21 +01:00
Andy Sloane	2cf8840665	Contact with the real world Many, many fixes found after posting this on my website. - drag n drop supported - plays on OSX and iOS safari now - random other hiccups fixed there seems to be some remaining issues cleaning up when loading a new song.	2015-11-10 20:30:41 -08:00
Andy Sloane	5aa5c06ab0	update readme	2015-11-04 10:23:54 -08:00
Andy Sloane	541a9d721c	no longer storing xms in git	2015-11-04 10:21:27 -08:00
Andy Sloane	7d6481ad73	file picker!	2015-11-04 10:21:04 -08:00
Andy Sloane	a547732063	render a nice big title and center stuff	2015-11-04 07:19:44 -08:00
Andy Sloane	f092f847f7	instrument list rendering with FT2 font.	2015-11-04 06:22:49 -08:00
Andy Sloane	54809c2b81	bugfix for 9xx offset effect	2015-11-04 05:50:29 -08:00
Andy Sloane	b859f27109	disable looping if looplen = 0... so much pathological crap in XM files...	2015-11-03 18:16:00 -08:00
Andy Sloane	f95bd1e169	whoops, more refactoring bugs i should really write some tests.	2015-11-03 17:55:12 -08:00
Andy Sloane	3c0a865824	update the effects code after moving stuff into xm	2015-11-03 09:57:40 -08:00
Andy Sloane	fd52b21e3f	only instruments with samplemaps can play by refactoring the xm loader i inadvertently broke this	2015-11-03 09:50:19 -08:00
Andy Sloane	ea6edaf2e4	add play/pause function	2015-11-03 09:36:00 -08:00
Andy Sloane	5967da7353	only reset pan/vol on instrument, not note	2015-11-03 07:18:30 -08:00
Andy Sloane	07cd6e8111	another corner case, another broken .xm	2015-11-02 22:51:04 -08:00
Andy Sloane	06ad3ed8a5	fix instrument trigger glitch	2015-11-02 22:29:59 -08:00
Andy Sloane	27d0a0b1c3	render volume effect column with the icons	2015-11-02 16:51:02 -08:00
Andy Sloane	c4370f447c	implemented multiple samples / instrument	2015-11-02 13:46:23 -08:00
Andy Sloane	22dd555228	zoom scopes out 4x; looks way better	2015-11-02 13:46:22 -08:00
Andy Sloane	d68e8e8225	show all instrument names	2015-11-01 21:26:03 -08:00
Andy Sloane	114240ca9f	oscilloscopes. couldn't really think of a better way to do it, but it looks pretty awesome. you can really see the filter effect too.	2015-11-01 09:26:03 -08:00
Andy Sloane	3daeeee96b	implement retrigger, move effects into separate js	2015-11-01 07:42:52 -08:00
Andy Sloane	6dee1787f3	show the instruments	2015-10-31 11:39:49 -07:00
Andy Sloane	a3b94c51b9	oh man, DUH	2015-10-31 11:17:22 -07:00
Andy Sloane	49005f0ae0	so many weird uses of effects	2015-10-31 10:52:46 -07:00
Andy Sloane	5e141535ab	fix some filter weirdness	2015-10-31 09:33:59 -07:00
Andy Sloane	32b09bdf63	various envelope/effect fixes Dubmood's .xms seem to expose a lot of bugs...	2015-10-31 09:27:38 -07:00