Demos/jsxm
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IT WORKS!

Browse source 
fixed many, many bugs, implemented playing (should be relatively
efficient), volume envelopes (but not panning envelopes). found that
instruments start at 1, not 0, and note C-0 is 1, not 0... so it is now
in tune with FT2!

no effects are supported at all yet, and there's a bug where it stops
playing entirely for a while, but "my dirty old kamel" sounds
recognizable and in tune!
This commit is contained in:
Andy Sloane 2015-10-23 10:12:29 -07:00
commit fe99e1a3b2
1 changed files with 196 additions and 24 deletions
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220
xm.js
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@ -1,7 +1,7 @@
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 "^^^";
if (note < 0) return "---";
if (note == 96) return "^^^";
note += 11;
return _note_names[note%12] + ~~(note/12);
}
@ -36,9 +36,28 @@ function getstring(dv, offset, len) {
return str.join('');
}
channelinfo = []
var channelinfo = [];
var instruments = [];
var tempo = 4;
cur_songpos = -1, cur_pat = -1, cur_row = 64, cur_ticksamp = 0;
function GetEnvelope(env, ticks) {
// TODO: optimize, maybe
var y0;
for (var i = 0; i < env.length; i += 2) {
y0 = env[i+1];
if (ticks < env[i]) {
var x0 = env[i-2];
var y0 = env[i-1];
var dx = env[i] - x0;
var dy = env[i+1] - y0;
return y0 + (ticks - x0) * dy / dx;
}
}
return y0;
}
var cur_songpos = -1, cur_pat = -1, cur_row = 64, cur_ticksamp = 0;
var cur_tick = 6;
function next_row(f_smp) {
if (cur_row >= 64) {
cur_row = 0;
@ -50,27 +69,94 @@ function next_row(f_smp) {
var p = patterns[cur_pat];
var r = p[cur_row];
cur_row++;
for (var i = 0; i < cur_row.length; i++) {
pretty_row = [];
for (var i = 0; i < r.length; i++) {
pretty_row.push(prettify_notedata(r[i][0], r[i][1], r[i][2], r[i][3], r[i][4]));
// instrument trigger
if (r[i][1]) channelinfo[i].inst = r[i][1];
if (r[i][1] != -1) {
var inst = instruments[r[i][1] - 1];
if (inst !== undefined) {
channelinfo[i].inst = inst;
// retrigger?
channelinfo[i].off = 0;
channelinfo[i].release = 0;
channelinfo[i].envtick = 0;
// new instrument doesn ot reset volume!
} else {
// console.log("invalid inst", r[i][1], instruments.length);
}
}
// note trigger
if (r[i][0]) {
if (r[i][0] == 97) {
if (r[i][0] != -1) {
if (r[i][0] == 96) {
// release note, FIXME once envelopes are implemented
channelinfo[i].release = 1;
} else {
// assume linear frequency table (flags header & 1 == 1)
// is this true in kamel.xm?
var inst = channelinfo[i].inst;
var period = 7680 - r[i][0]*64 - instruments[inst].fine*0.5;
var freq = 8363 * ((4608 - period) / 768);
if (inst === undefined) {
continue;
}
// wtf is this?!
// var period = 7680 - r[i][0]*64 - inst.fine*0.5;
// var freq = 8363 * Math.pow(2, (4608 - period) / 768);
var note = r[i][0] + inst.note;
var freq = 8363 * Math.pow(2, note/12.0 + inst.fine/(12*128.0) - 4);
channelinfo[i].doff = freq / f_smp;
channelinfo[i].off = 0;
channelinfo[i].release = 0;
channelinfo[i].envtick = 0;
// console.log("channel", i, r[i][0], channelinfo[i]);
// if there's an instrument and a note, set the volume
if (r[i][0] != -1) {
channelinfo[i].volL = inst.vol;
channelinfo[i].volR = inst.vol;
}
}
}
if (r[i][2] != -1) {
// FIXME: panning
var v = r[i][2];
if (v < 0x10) {
console.log("channel", i, "invalid volume", v.toString(16));
} else if (v <= 0x50) {
channelinfo[i].volL = v - 0x10;
channelinfo[i].volR = v - 0x10;
} else {
console.log("channel", i, "volume effect", v.toString(16));
}
}
}
console.log(pretty_row.join(" "));
var debug = document.getElementById("debug");
debug.innerHTML = 'pat ' + cur_pat + ' row ' + (cur_row-1);
}
function next_tick(f_smp) {
// blah
cur_tick++;
if (cur_tick >= tempo) {
cur_tick = 0;
next_row(f_smp);
}
for (var j = 0; j < nchan; j++) {
var inst = channelinfo[j].inst;
if (inst === undefined) continue;
if (inst.env_vol !== undefined) {
channelinfo[j].env_vol = GetEnvelope(inst.env_vol, channelinfo[j].envtick);
if (inst.env_vol_type & 2) { // sustain loop?
// if we're sustaining a note, leave env_vol alone
if (channelinfo[j].release == 0) {
if (channelinfo[j].envtick >= inst.env_vol[inst.env_vol_sustain*2]) {
continue;
}
}
}
channelinfo[j].envtick++;
} else {
channelinfo[j].env_vol = 64;
}
}
}
function audio_cb(e) {
@ -78,8 +164,10 @@ function audio_cb(e) {
var buflen = e.outputBuffer.length;
var dataL = e.outputBuffer.getChannelData(0);
var dataR = e.outputBuffer.getChannelData(1);
dataL.fill(0);
dataR.fill(0);
var offset = 0;
var ticklen = f_smp * 2.5 / bpm;
var ticklen = 0|(f_smp * 2.5 / bpm);
while(buflen > 0) {
if (cur_ticksamp >= ticklen) {
@ -87,15 +175,76 @@ function audio_cb(e) {
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++) {
for (var j = 0; j < nchan; j++) {
var inst = channelinfo[j].inst;
if (inst === undefined) continue;
var samp = inst.sampledata;
var sample_end = inst.len;
var looplen = 0;
var loop = false;
if (inst.type & 3) {
loop = true;
looplen = inst.looplen;
sample_end = looplen + inst.loop;
}
var samplen = inst.len;
var env_vol = channelinfo[j].env_vol / 64.0;
var volL = env_vol * channelinfo[j].volL / 64.0;
var volR = env_vol * channelinfo[j].volR / 64.0;
if (volL < 0) volL = 0;
if (volR < 0) volR = 0;
if (volR == 0 && volL == 0)
break;
var k = channelinfo[j].off;
var dk = channelinfo[j].doff;
// console.log(j, offset, channelinfo[j]);
for (var i = offset; i < offset+tickduration; i++) {
var si = samp[k|0]; // TODO: bilinear filtering
dataL[i] += volL * si;
dataR[i] += volR * si;
k += dk;
if (k >= sample_end) { // TODO: implement pingpong looping
if (loop) {
k -= looplen;
} else {
// kill sample
channelinfo[j].inst = undefined;
break;
}
}
}
channelinfo[j].off = k;
channelinfo[j].doff = dk;
}
offset += tickduration;
cur_ticksamp += tickduration;
buflen -= tickduration;
}
console.log("buflen %d f_smp %d", buflen, f_smp);
}
function ConvertSample(array, bits) {
var len = array.length;
var acc = 0;
if (bits == 0) { // 8 bit sample
var samp = new Float32Array(len);
for (var k = 0; k < len; k++) {
acc += array[k];
var b = acc&255;
if (b & 128) b = b-256;
samp[k] = (b - 128) / 128.0;
}
return samp;
} else {
len /= 2;
var samp = new Float32Array(len);
for (var k = 0; k < len; k++) {
acc += array[k*2] + (array[k*2 + 1] << 8);
var b = acc&65535;
if (b & 32768) b = b-65536;
samp[k] = b / 32768.0;
}
return samp;
}
}
function playXM(arrayBuf) {
@ -159,7 +308,9 @@ function playXM(arrayBuf) {
effparam = dv.getUint8(idx); idx++;
}
} else {
note = byte0;
// byte0 is note from 1..96 or 0 for nothing or 97 for release
// so we subtract 1 so that C-0 is stored as 0
note = byte0 - 1;
inst = dv.getUint8(idx); idx++;
vol = dv.getUint8(idx); idx++;
efftype = dv.getUint8(idx); idx++;
@ -175,12 +326,20 @@ function playXM(arrayBuf) {
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);
var env_nvol = dv.getUint8(idx+225);
var env_vol_type = dv.getUint8(idx+233);
var env_vol_sustain = dv.getUint8(idx+227);
var env_vol_loop_start = dv.getUint8(idx+228);
var env_vol_loop_end = dv.getUint8(idx+229);
env_vol = [];
for (var j = 0; j < env_nvol*2; j++) {
env_vol.push(dv.getUint16(idx+129+j*2, true));
}
if (nsamp > 0) {
// FIXME: ignoring keymaps for now and assuming 1 sample / instrument
// var keymap = getarray(dv, idx+0x21);
@ -203,24 +362,37 @@ function playXM(arrayBuf) {
j, samplen, sampname, samploop, samplooplen, sampvol);
console.log(" type %d note %s finetune %d pan %d",
samptype, prettify_note(sampnote), sampfinetune, samppan);
console.log(" vol env", env_vol, env_vol_sustain,
env_vol_loop_start, env_vol_loop_end, "type", env_vol_type);
idx += samplen + samphdrsiz;
}
instruments.push({
inst = {
'name': instname,
'off': sampleoffset, 'len': samplen, 'loop': samploop,
'len': samplen, 'loop': samploop,
'looplen': samplooplen, 'note': sampnote, 'fine': sampfinetune,
'pan': samppan})
'pan': samppan, 'type': samptype, 'vol': sampvol,
'fine': sampfinetune,
'sampledata': ConvertSample(new Uint8Array(arrayBuf, sampleoffset, samplen), samptype & 4),
};
if (env_vol_type) {
inst.env_vol = env_vol;
inst.env_vol_type = env_vol_type;
inst.env_vol_sustain = env_vol_sustain;
inst.env_vol_loop_start = env_vol_loop_start;
inst.env_vol_loop_end = env_vol_loop_end;
}
instruments.push(inst);
} else {
instruments.push(null);
}
}
audioctx = new webkitAudioContext();
audioctx = new AudioContext();
gainNode = audioctx.createGain();
gainNode.gain.value = 1.0; // master volume
gainNode.gain.value = 0.2; // master volume
jsNode = audioctx.createScriptProcessor(4096, 0, 2);
jsNode.onaudioprocess = audio_cb;
// jsNode.connect(gainNode);
jsNode.connect(gainNode);
var debug = document.getElementById("debug");
console.log("loaded \"" + name + "\"");