diff --git a/index.html b/index.html
index 3e1123e..60eb037 100644
--- a/index.html
+++ b/index.html
@@ -1,132 +1,13 @@
js xm
-
+
todo:
- - load xm using XHR
+ - load instruments
+ - load samples
+ - open audio and start generating
diff --git a/xm.js b/xm.js
new file mode 100644
index 0000000..48fe5eb
--- /dev/null
+++ b/xm.js
@@ -0,0 +1,242 @@
+var _note_names = ["C-", "C#", "D-", "D#", "E-", "F-", "F#", "G-", "G#", "A-", "A#", "B-"];
+function prettify_note(note) {
+ if (note <= 0) return "---";
+ if (note == 97) return "^^^";
+ note += 11;
+ return _note_names[note%12] + ~~(note/12);
+}
+
+function prettify_number(num) {
+ if (num == -1) return "--";
+ if (num < 10) return "0" + num;
+ return num;
+}
+
+function prettify_effect(t, p) {
+ if (t == -1) t = "-"; else t = t.toString(16);
+ if (p == -1) p = "--";
+ else if (p < 16) p = '0' + p.toString(16);
+ else p = p.toString(16);
+ return "" + t + p
+}
+
+function prettify_notedata(note, inst, vol, efftype, effparam) {
+ return (prettify_note(note) + " " + prettify_number(inst) + " "
+ + prettify_number(vol) + " "
+ + prettify_effect(efftype, effparam));
+}
+
+function getstring(dv, offset, len) {
+ var str = []
+ for (var i = offset; i < offset+len; i++) {
+ var c = dv.getUint8(i);
+ if (c == 0) break;
+ str.push(String.fromCharCode(c));
+ }
+ return str.join('');
+}
+
+channelinfo = []
+
+cur_songpos = -1, cur_pat = -1, cur_row = 64, cur_ticksamp = 0;
+function next_row(f_smp) {
+ if (cur_row >= 64) {
+ cur_row = 0;
+ cur_songpos++;
+ if (cur_songpos >= songpats.length)
+ cur_songpos = song_looppos;
+ cur_pat = songpats[cur_songpos];
+ }
+ var p = patterns[cur_pat];
+ var r = p[cur_row];
+ cur_row++;
+ for (var i = 0; i < cur_row.length; i++) {
+ // instrument trigger
+ if (r[i][1]) channelinfo[i].inst = r[i][1];
+ // note trigger
+ if (r[i][0]) {
+ if (r[i][0] == 97) {
+ // release note, FIXME once envelopes are implemented
+ } else {
+ // assume linear frequency table (flags header & 1 == 1)
+ var inst = channelinfo[i].inst;
+ var period = 7680 - r[i][0]*64 - instruments[inst].fine*0.5;
+ var freq = 8363 * ((4608 - period) / 768);
+ channelinfo[i].doff = freq / f_smp;
+ channelinfo[i].off = 0;
+ }
+ }
+ }
+}
+
+function next_tick(f_smp) {
+ // blah
+}
+
+function audio_cb(e) {
+ var f_smp = audioctx.sampleRate;
+ var buflen = e.outputBuffer.length;
+ var dataL = e.outputBuffer.getChannelData(0);
+ var dataR = e.outputBuffer.getChannelData(1);
+ var offset = 0;
+ var ticklen = f_smp * 2.5 / bpm;
+
+ while(buflen > 0) {
+ if (cur_ticksamp >= ticklen) {
+ next_tick(f_smp);
+ cur_ticksamp -= ticklen;
+ }
+ var tickduration = Math.min(buflen, ticklen - cur_ticksamp);
+ for (var i = 0; i < tickduration; i++) {
+ for (var j = 0; j < nchan; j++) {
+ }
+ }
+
+ cur_ticksamp += tickduration;
+ buflen -= tickduration;
+ }
+ console.log("buflen %d f_smp %d", buflen, f_smp);
+}
+
+function playXM(arrayBuf) {
+ var dv = new DataView(arrayBuf);
+ window.dv = dv;
+
+ var name = getstring(dv, 17, 20);
+ var hlen = dv.getUint32(0x3c, true) + 0x3c;
+ var songlen = dv.getUint16(0x40, true);
+ song_looppos = dv.getUint16(0x42, true);
+ nchan = dv.getUint16(0x44, true);
+ var npat = dv.getUint16(0x46, true);
+ var ninst = dv.getUint16(0x48, true);
+ var flags = dv.getUint16(0x4a, true);
+ tempo = dv.getUint16(0x4c, true);
+ bpm = dv.getUint16(0x4e, true);
+ for (var i = 0; i < nchan; i++) {
+ channelinfo.push({})
+ }
+ console.log("header len " + hlen);
+
+ console.log("songlen %d, %d channels, %d patterns, %d instruments", songlen, nchan, npat, ninst);
+ console.log("loop @%d", song_looppos);
+ console.log("flags=%d tempo %d bpm %d", flags, tempo, bpm);
+
+ songpats = [];
+ for (var i = 0; i < songlen; i++) {
+ songpats.push(dv.getUint8(0x50 + i));
+ }
+ console.log("song patterns: ", songpats);
+
+ var idx = hlen;
+ patterns = [];
+ for (var i = 0; i < npat; i++) {
+ var pattern = []
+ var patheaderlen = dv.getUint32(idx, true);
+ var patrows = dv.getUint16(idx + 5, true);
+ var patsize = dv.getUint16(idx + 7, true);
+ console.log("pattern %d: %d bytes, %d rows", i, patsize, patrows);
+ idx += 9;
+ for (var j = 0; j < patrows; j++) {
+ row = [];
+ pretty_row = [];
+ for (var k = 0; k < nchan; k++) {
+ var byte0 = dv.getUint8(idx); idx++;
+ var note = -1, inst = -1, vol = -1, efftype = -1, effparam = -1;
+ if (byte0 & 0x80) {
+ if (byte0 & 0x01) {
+ note = dv.getUint8(idx); idx++;
+ }
+ if (byte0 & 0x02) {
+ inst = dv.getUint8(idx); idx++;
+ }
+ if (byte0 & 0x04) {
+ vol = dv.getUint8(idx); idx++;
+ }
+ if (byte0 & 0x08) {
+ efftype = dv.getUint8(idx); idx++;
+ }
+ if (byte0 & 0x10) {
+ effparam = dv.getUint8(idx); idx++;
+ }
+ } else {
+ note = byte0;
+ inst = dv.getUint8(idx); idx++;
+ vol = dv.getUint8(idx); idx++;
+ efftype = dv.getUint8(idx); idx++;
+ effparam = dv.getUint8(idx); idx++;
+ }
+ pretty_row.push(prettify_notedata(note, inst, vol, efftype, effparam));
+ row.push([note, inst, vol, efftype, effparam]);
+ }
+ if (i == 0)
+ console.log(pretty_row.join(" "));
+ pattern.push(row);
+ }
+ patterns.push(pattern);
+ }
+
+ instruments = []
+ // now load instruments
+ for (i = 0; i < ninst; i++) {
+ var hdrsiz = dv.getUint32(idx, true);
+ var instname = getstring(dv, idx+0x4, 22);
+ var nsamp = dv.getUint16(idx+0x1b, true);
+ if (nsamp > 0) {
+ // FIXME: ignoring keymaps for now and assuming 1 sample / instrument
+ // var keymap = getarray(dv, idx+0x21);
+ var samphdrsiz = dv.getUint32(idx+0x1d, true);
+ console.log("hdrsiz %d; instrument %d: '%s' %d samples, samphdrsiz %d",
+ hdrsiz, i, instname, nsamp, samphdrsiz);
+ idx += hdrsiz;
+ for (var j = 0; j < nsamp; j++) {
+ var samplen = dv.getUint32(idx, true);
+ var samploop = dv.getUint32(idx+4, true);
+ var samplooplen = dv.getUint32(idx+8, true);
+ var sampvol = dv.getUint8(idx+12);
+ var sampfinetune = dv.getInt8(idx+13);
+ var samptype = dv.getUint8(idx+14);
+ var samppan = dv.getUint8(idx+15);
+ var sampnote = dv.getUint8(idx+16);
+ var sampname = getstring(dv, idx+18, 22);
+ var sampleoffset = idx + samphdrsiz;
+ console.log("sample %d: len %d name '%s' loop %d/%d vol %d",
+ j, samplen, sampname, samploop, samplooplen, sampvol);
+ console.log(" type %d note %s finetune %d pan %d",
+ samptype, prettify_note(sampnote), sampfinetune, samppan);
+ idx += samplen + samphdrsiz;
+ }
+ instruments.push({
+ 'name': instname,
+ 'off': sampleoffset, 'len': samplen, 'loop': samploop,
+ 'looplen': samplooplen, 'note': sampnote, 'fine': sampfinetune,
+ 'pan': samppan})
+ } else {
+ instruments.push(null);
+ }
+ }
+
+ audioctx = new webkitAudioContext();
+ gainNode = audioctx.createGain();
+ gainNode.gain.value = 1.0; // master volume
+ jsNode = audioctx.createScriptProcessor(4096, 0, 2);
+ jsNode.onaudioprocess = audio_cb;
+ // jsNode.connect(gainNode);
+
+ var debug = document.getElementById("debug");
+ console.log("loaded \"" + name + "\"");
+ debug.innerHTML = name;
+
+ // start playing
+ gainNode.connect(audioctx.destination);
+}
+
+var xmReq = new XMLHttpRequest();
+xmReq.open("GET", "kamel.xm", true);
+xmReq.responseType = "arraybuffer";
+xmReq.onload = function (xmEvent) {
+ var arrayBuffer = xmReq.response;
+ if (arrayBuffer) {
+ playXM(arrayBuffer);
+ }
+}
+xmReq.send(null);