jsxm/xm.js
Andy Sloane 5161e55669 added volume column effects, fixed panning
when there was no panning envelope, panning was totally wrong

panning is still sort of wrong, in that the RMS power of a channel is
not constant over pans...
2015-10-27 15:38:42 -07:00

758 lines
22 KiB
JavaScript

var _note_names = ["C-", "C#", "D-", "D#", "E-", "F-", "F#", "G-", "G#", "A-", "A#", "B-"];
var f_smp = 44100; // updated by play callback, default value here
audioContext = window.AudioContext || window.webkitAudioContext;
function prettify_note(note) {
if (note < 0) return "---";
if (note == 96) 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_volume(num) {
if (num < 0x10) return "--";
return num.toString(16);
}
function prettify_effect(t, p) {
t = t.toString(16);
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_volume(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('');
}
var channelinfo = [];
var instruments = [];
var tempo = 4;
// Return 2-pole Butterworth lowpass filter coefficients for
// center frequncy f_c (relative to sampling frequency)
function FilterCoeffs(f_c) {
// if (f_c > 0.5) { // we can't lowpass above the nyquist frequency...
// return [1, 0, 0];
// }
var wct = Math.sqrt(2) * Math.PI * f_c;
var e = Math.exp(-wct);
var c = e * Math.cos(wct);
var s = e * Math.sin(wct);
var gain = (1 - 2*c + c*c + s*s) / 2;
return [gain, 2*c, -c*c - s*s];
}
popfilter = FilterCoeffs(200.0 / 44100.0);
popfilter_alpha = 0.9837;
function UpdateChannelPeriod(ch, period) {
var freq = 8363 * Math.pow(2, (1152.0 - period) / 192.0);
ch.doff = freq / f_smp;
ch.filter = FilterCoeffs(ch.doff / 2);
}
function PeriodForNote(ch, note) {
return 1920 - note*16 - ch.inst.fine / 8.0;
}
function UpdateChannelNote(ch, note) {
ch.period = PeriodForNote(ch, note);
UpdateChannelPeriod(ch, ch.period);
}
var cur_songpos = -1, cur_pat = -1, cur_row = 64, cur_ticksamp = 0;
var cur_tick = 6;
var patdisplay = [];
function next_row() {
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++;
pretty_row = [];
for (var i = 0; i < r.length; i++) {
var ch = channelinfo[i];
ch.update = false;
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] != -1) {
var inst = instruments[r[i][1] - 1];
if (inst !== undefined) {
ch.inst = inst;
// retrigger unless overridden below
triggernote = true;
// new instrument doesn ot reset volume!
} else {
// console.log("invalid inst", r[i][1], instruments.length);
}
}
var triggernote = false;
// note trigger
if (r[i][0] != -1) {
if (r[i][0] == 96) {
// release note, FIXME once envelopes are implemented
ch.release = 1;
} else {
// assume linear frequency table (flags header & 1 == 1)
// is this true in kamel.xm?
var inst = ch.inst;
if (inst === undefined) {
continue;
}
var note = r[i][0] + inst.note;
ch.note = note;
triggernote = true;
// if there's an instrument and a note, set the volume
ch.pan = inst.pan;
ch.vol = inst.vol;
}
}
if (r[i][2] != -1) { // volume column
// FIXME: panning
var v = r[i][2];
if (v < 0x10) {
console.log("channel", i, "invalid volume", v.toString(16));
} else if (v <= 0x50) {
ch.vol = v - 0x10;
} else if (v >= 0x80 && v < 0x90) { // fine volume slide down
ch.vol = Math.max(0, ch.vol - (v & 0x0f));
} else if (v >= 0x90 && v < 0xa0) { // fine volume slide up
ch.vol = Math.min(64, ch.vol + (v & 0x0f));
} else if (v >= 0xc0 && v < 0xd0) { // set panning
ch.pan = 16 * (v & 0x0f);
console.log("channel", i, "pan", ch.pan);
} else {
console.log("channel", i, "volume effect", v.toString(16));
}
}
ch.effect = r[i][3];
ch.effectdata = r[i][4];
if (ch.effect < 16) {
ch.effectfn = effects_t1[ch.effect];
if (effects_t0[ch.effect](ch, ch.effectdata)) {
triggernote = false;
}
} else {
console.log("channel", i, "effect > 16", ch.effect);
}
// special handling for portamentos: don't trigger the note
if (ch.effect == 3 || ch.effect == 5) {
if (r[i][0] != -1) {
ch.periodtarget = PeriodForNote(ch, ch.note);
}
triggernote = false;
if (ch.release) {
// reset envelopes if note was released but leave offset/pitch/etc
// alone
ch.envtick = 0;
ch.release = 0;
ch.env_vol = new EnvelopeFollower(inst.env_vol);
ch.env_pan = new EnvelopeFollower(inst.env_pan);
}
}
if (triggernote) {
ch.off = 0;
ch.release = 0;
ch.envtick = 0;
ch.vibratopos = 0;
ch.env_vol = new EnvelopeFollower(inst.env_vol);
ch.env_pan = new EnvelopeFollower(inst.env_pan);
UpdateChannelNote(ch, note);
}
}
var debug = document.getElementById("debug");
debug.innerHTML = 'pat ' + cur_pat + ' row ' + (cur_row-1);
var pat = document.getElementById("pattern");
patdisplay.push(pretty_row.join(" "));
if (patdisplay.length > 16) {
patdisplay.shift();
}
pat.innerHTML = patdisplay.join("\n");
}
function Envelope(points, type, sustain, loopstart, loopend) {
this.points = points;
this.type = type;
this.sustain = sustain;
this.loopstart = loopstart;
this.loopend = loopend;
}
Envelope.prototype.Get = function(ticks) {
// TODO: optimize follower with ptr
// or even do binary search here
var y0;
var env = this.points;
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;
}
function EnvelopeFollower(env) {
this.env = env;
this.tick = 0;
}
EnvelopeFollower.prototype.Tick = function(release, defaultval) {
if (this.env === undefined) {
return defaultval;
}
var value = this.env.Get(this.tick);
if (this.env.type & 1) { // sustain?
// if we're sustaining a note, stop advancing the tick counter
if (!release &&
this.tick >= this.env.points[this.env.sustain*2]) {
return this.env.points[this.env.sustain*2 + 1];
}
}
this.tick++;
if (this.env.type & 2) { // envelope loop?
if (!release &&
this.tick > this.env.loopend) {
this.tick -= this.env.loopend - this.env.loopstart;
}
}
return value;
}
function next_tick() {
cur_tick++;
if (cur_tick >= tempo) {
cur_tick = 0;
next_row();
}
for (var j = 0; j < nchan; j++) {
var ch = channelinfo[j];
var inst = ch.inst;
if (ch.effectfn) {
ch.effectfn(ch);
}
if (inst === undefined) continue;
ch.volE = ch.env_vol.Tick(ch.release, 64);
ch.panE = ch.env_pan.Tick(ch.release, 32);
}
}
// This function gradually brings the channel back down to zero if it isn't
// already to avoid clicks and pops when samples end.
function MixSilenceIntoBuf(ch, start, end, dataL, dataR) {
var s = ch.filterstate[1];
for (var i = start; i < end; i++) {
if (Math.abs(s) < 1.526e-5) // == 1/65536.0
break;
dataL[i] += s * ch.vL;
dataR[i] += s * ch.vR;
s *= popfilter_alpha;
}
ch.filterstate[1] = s;
ch.filterstate[2] = s;
return 0;
}
function MixChannelIntoBuf(ch, start, end, dataL, dataR) {
var inst = ch.inst;
var samp, sample_end;
var loop = false;
var looplen = 0;
// nothing on this channel, just filter the last dc offset back down to zero
if (inst === undefined || ch.mute) {
return MixSilenceIntoBuf(ch, start, end, dataL, dataR);
}
samp = inst.sampledata;
sample_end = inst.len;
if ((inst.type & 3) == 1) { // todo: support pingpong
loop = true;
looplen = inst.looplen;
sample_end = looplen + inst.loop;
}
var samplen = inst.len;
var volE = ch.volE / 64.0; // current volume envelope
var panE = 4*(ch.panE - 32); // current panning envelope
var p = panE + ch.pan - 128; // final pan
var volL = volE * (128 - p) * ch.vol / 8192.0;
var volR = volE * (128 + p) * ch.vol / 8192.0;
if (volL < 0) volL = 0;
if (volR < 0) volR = 0;
if (volR == 0 && volL == 0)
return;
var k = ch.off;
var dk = ch.doff;
var Vrms = 0;
for (var i = start; i < end; i++) {
var s = 0;
// if ((k|0) != (k-dk)|0)
s = samp[k|0];
// we low-pass filter here since we are resampling some arbitrary
// frequency to f_smp; this is an anti-aliasing filter and is
// implemented as an IIR butterworth filter (usually we'd use an FIR
// brick wall filter, but this is much simpler computationally and
// sounds fine)
var si = ch.filter[0] * (s + ch.filterstate[0]) +
ch.filter[1]*ch.filterstate[1] + ch.filter[2]*ch.filterstate[2];
ch.filterstate[2] = ch.filterstate[1];
ch.filterstate[1] = si; ch.filterstate[0] = s;
// we also low-pass filter volume changes with a simple one-zero,
// one-pole filter to avoid pops and clicks when volume changes.
ch.vL = popfilter_alpha * ch.vL + (1 - popfilter_alpha) * (volL + ch.vLprev) * 0.5;
ch.vR = popfilter_alpha * ch.vR + (1 - popfilter_alpha) * (volR + ch.vRprev) * 0.5;
ch.vLprev = volL;
ch.vRprev = volR;
dataL[i] += ch.vL * si;
dataR[i] += ch.vR * si;
Vrms += (ch.vL + ch.vR) * si * si;
k += dk;
if (k >= sample_end) { // TODO: implement pingpong looping
if (loop) {
k -= looplen;
} else {
// kill sample
ch.inst = undefined;
// fill rest of buf with filtered dc offset using loop above
return Vrms + MixSilenceIntoBuf(ch, i+1, end, dataL, dataR);
}
}
}
ch.off = k;
ch.doff = dk;
return Vrms * 0.5;
}
function audio_cb(e) {
f_smp = audioctx.sampleRate;
var buflen = e.outputBuffer.length;
var dataL = e.outputBuffer.getChannelData(0);
var dataR = e.outputBuffer.getChannelData(1);
// backward compat w/ no array.fill
if (dataL.fill === undefined) {
for (var i = 0; i < buflen; i++) {
dataL[i] = 0;
dataR[i] = 0;
}
} else {
dataL.fill(0);
dataR.fill(0);
}
var offset = 0;
var ticklen = 0|(f_smp * 2.5 / bpm);
var VU = new Float32Array(nchan);
while(buflen > 0) {
if (cur_ticksamp >= ticklen) {
next_tick(f_smp);
cur_ticksamp -= ticklen;
}
var tickduration = Math.min(buflen, ticklen - cur_ticksamp);
for (var j = 0; j < nchan; j++) {
VU[j] += MixChannelIntoBuf(
channelinfo[j], offset, offset + tickduration, dataL, dataR);
}
offset += tickduration;
cur_ticksamp += tickduration;
buflen -= tickduration;
}
// update VU meters
var canvas = document.getElementById("vu");
var ctx = canvas.getContext("2d");
ctx.fillStyle = '#000';
ctx.fillRect(0, 0, 300, 64);
ctx.fillStyle = '#0f0';
for (var j = 0; j < nchan; j++) {
var rms = VU[j] / e.outputBuffer.length;
var y = -Math.log(rms)*10;
ctx.fillRect(j*16, y, 15, 64-y);
}
}
function eff_t0_0(ch, data) { // arpeggio
// nothing to do here, arpeggio will be done on ch.effectdata
}
function eff_t0_1(ch, data) { // pitch slide up
if (data != 0) {
ch.slideupspeed = data;
}
}
function eff_t0_2(ch, data) { // pitch slide down
if (data != 0) {
ch.slidedownspeed = data;
}
}
function eff_t0_3(ch, data) { // portamento
if (data != 0) {
ch.portaspeed = data;
}
}
function eff_t0_4(ch, data) { // vibrato
if (data & 0x0f) {
ch.vibratodepth = data & 0x0f;
}
if (data >> 4) {
ch.vibratospeed = data >> 4;
}
eff_t1_4(ch, data);
}
function eff_t0_a(ch, data) { // volume slide
if (data) {
if (data & 0x0f) {
ch.volumeslide = -(data & 0x0f);
} else {
ch.volumeslide = data >> 4;
}
}
}
function eff_unimplemented_t0(ch, data) {
console.log("unimplemented effect", ch.effect.toString(16), data.toString(16));
}
var effects_t0 = [ // effect functions on tick 0
eff_t0_0,
eff_t0_1,
eff_t0_2,
eff_t0_3,
eff_t0_4,
eff_unimplemented_t0, // 5
eff_unimplemented_t0, // 6
eff_unimplemented_t0, // 7
eff_unimplemented_t0, // 8
eff_unimplemented_t0, // 9
eff_t0_a,
eff_unimplemented_t0, // b
eff_unimplemented_t0, // c
eff_unimplemented_t0, // d
eff_unimplemented_t0, // e
eff_unimplemented_t0, // f
];
function eff_t1_0(ch) { // arpeggio
if (ch.effectdata != 0) {
var arpeggio = [0, ch.effectdata>>4, ch.effectdata&15];
var note = ch.note + arpeggio[cur_tick % 3];
UpdateChannelNote(ch, note);
}
}
function eff_t1_1(ch) { // pitch slide up
if (ch.slideupspeed !== undefined) {
ch.period -= ch.slideupspeed;
UpdateChannelPeriod(ch, ch.period);
}
}
function eff_t1_2(ch) { // pitch slide down
if (ch.slidedownspeed !== undefined) {
ch.period += ch.slidedownspeed;
UpdateChannelPeriod(ch, ch.period);
}
}
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);
}
UpdateChannelPeriod(ch, ch.period);
}
}
function eff_t1_4(ch) { // vibrato
ch.period += Math.sin(ch.vibratopos * Math.PI / 32) * ch.vibratodepth;
UpdateChannelPeriod(ch, ch.period);
ch.vibratopos += ch.vibratospeed;
ch.vibratopos &= 63;
}
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_unimplemented() {}
var effects_t1 = [ // effect functions on tick 1+
eff_t1_0,
eff_t1_1,
eff_t1_2,
eff_t1_3,
eff_t1_4,
eff_unimplemented, // 5
eff_unimplemented, // 6
eff_unimplemented, // 7
eff_unimplemented, // 8
eff_unimplemented, // 9
eff_t1_a, // a
eff_unimplemented, // b
eff_unimplemented, // c
eff_unimplemented, // d
eff_unimplemented, // e
eff_unimplemented, // f
];
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) {
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({
filterstate: new Float32Array(3),
popfilter: FilterCoeffs(200.0 / 44100.0),
popfilterstate: [new Float32Array(3), new Float32Array(3)],
vol: 0,
pan: 128,
vL: 0, vR: 0, // left right volume envelope followers (changes per sample)
vLprev: 0, vRprev: 0,
mute: 0,
volE: 0, panE: 0
})
}
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 = 0, effparam = 0;
if (byte0 & 0x80) {
if (byte0 & 0x01) {
note = dv.getUint8(idx) - 1; 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 {
// 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++;
effparam = dv.getUint8(idx); idx++;
}
pretty_row.push(prettify_notedata(note, inst, vol, efftype, effparam));
row.push([note, inst, vol, efftype, effparam]);
}
if (i == 12)
console.log(pretty_row.join(" "));
pattern.push(row);
}
patterns.push(pattern);
}
// 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);
var env_npan = dv.getUint8(idx+226);
var env_pan_type = dv.getUint8(idx+234);
var env_pan_sustain = dv.getUint8(idx+230);
var env_pan_loop_start = dv.getUint8(idx+231);
var env_pan_loop_end = dv.getUint8(idx+232);
env_vol = [];
for (var j = 0; j < env_nvol*2; j++) {
env_vol.push(dv.getUint16(idx+129+j*2, true));
}
env_pan = [];
for (var j = 0; j < env_npan*2; j++) {
env_pan.push(dv.getUint16(idx+177+j*2, 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);
console.log(" vol env", env_vol, env_vol_sustain,
env_vol_loop_start, env_vol_loop_end, "type", env_vol_type);
console.log(" pan env", env_pan, env_pan_sustain,
env_pan_loop_start, env_pan_loop_end, "type", env_pan_type);
idx += samplen + samphdrsiz;
}
inst = {
'name': instname,
'len': samplen, 'loop': samploop,
'looplen': samplooplen, 'note': sampnote, 'fine': sampfinetune,
'pan': samppan, 'type': samptype, 'vol': sampvol,
'fine': sampfinetune,
'sampledata': ConvertSample(new Uint8Array(arrayBuf, sampleoffset, samplen), samptype & 4),
};
if (env_vol_type) {
inst.env_vol = new Envelope(
env_vol,
env_vol_type,
env_vol_sustain,
env_vol_loop_start,
env_vol_loop_end);
}
if (env_pan_type) {
inst.env_pan = new Envelope(
env_pan,
env_pan_type,
env_pan_sustain,
env_pan_loop_start,
env_pan_loop_end);
}
instruments.push(inst);
} else {
instruments.push(null);
}
}
audioctx = new audioContext();
gainNode = audioctx.createGain();
gainNode.gain.value = 0.1; // 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);