unrolled main mixing loop
This commit is contained in:
Andy Sloane
parent
efec2d7273
commit
5645739edb
2 changed files with 139 additions and 64 deletions
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@ -7,7 +7,6 @@
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code: <a href="http://github.com/a1k0n/jsxm/">github.com/a1k0n/jsxm</a>
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tune: my dirty old kamel - <a href="http://zalza.bandcamp.com">Zalza</a>
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todo:
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- unroll mixer code loops
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- multi-sample instruments
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- missing XM effects (in rough order of priority):
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- Rxy - retrigger
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202
xm.js
202
xm.js
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@ -262,7 +262,11 @@ function next_tick() {
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if (cur_tick != 0 && ch.effectfn) {
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ch.effectfn(ch);
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}
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if (inst === undefined) continue;
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if (inst == undefined) continue;
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if (ch.env_vol == undefined) {
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console.log("channel", j, "env_vol defined but not inst?", ch);
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continue;
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}
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ch.volE = ch.env_vol.Tick(ch.release, 64);
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ch.panE = ch.env_pan.Tick(ch.release, 32);
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UpdateChannelPeriod(ch, ch.period + ch.periodoffset);
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@ -299,7 +303,7 @@ function MixChannelIntoBuf(ch, start, end, dataL, dataR) {
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var inst = ch.inst;
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var samp, sample_end;
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var loop = false;
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var looplen = 0;
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var looplen = 0, loopstart = 0;
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// nothing on this channel, just filter the last dc offset back down to zero
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if (inst == undefined || ch.mute) {
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@ -310,8 +314,9 @@ function MixChannelIntoBuf(ch, start, end, dataL, dataR) {
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sample_end = inst.len;
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if ((inst.type & 3) == 1) { // todo: support pingpong
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loop = true;
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loopstart = inst.loop;
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looplen = inst.looplen;
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sample_end = looplen + inst.loop;
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sample_end = loopstart + looplen;
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}
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var samplen = inst.len;
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var volE = ch.volE / 64.0; // current volume envelope
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@ -330,50 +335,125 @@ function MixChannelIntoBuf(ch, start, end, dataL, dataR) {
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var k = ch.off;
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var dk = ch.doff;
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var Vrms = 0;
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for (var i = start; i < end; i++) {
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var f0 = ch.filter[0], f1 = ch.filter[1], f2 = ch.filter[2];
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var fs0 = ch.filterstate[0], fs1 = ch.filterstate[1], fs2 = ch.filterstate[2];
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// we also low-pass filter volume changes with a simple one-zero,
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// one-pole filter to avoid pops and clicks when volume changes.
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var vL = popfilter_alpha * ch.vL + (1 - popfilter_alpha) * (volL + ch.vLprev) * 0.5;
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var vR = popfilter_alpha * ch.vR + (1 - popfilter_alpha) * (volR + ch.vRprev) * 0.5;
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var pf_8 = Math.pow(popfilter_alpha, 8);
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ch.vLprev = volL;
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ch.vRprev = volR;
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// we can mix up to this many bytes before running into a sample end/loop
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var i = start;
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while (i < end) {
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if (k >= sample_end) { // TODO: implement pingpong looping
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if (loop) {
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k %= looplen;
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k = loopstart + (k - loopstart) % looplen;
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} else {
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// kill sample
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ch.inst = undefined;
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// fill rest of buf with filtered dc offset using loop above
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return Vrms + MixSilenceIntoBuf(ch, i+1, end, dataL, dataR);
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return Vrms + MixSilenceIntoBuf(ch, i, end, dataL, dataR);
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}
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}
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var s = samp[k|0];
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// TODO: robustify, then remove these NaN checks from the inner loops
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if (isNaN(s)) {
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console.log("NaN sample idx", samp.length, k|0);
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tempo = 10000;
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break;
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var next_event = Math.min(end, i + (sample_end - k) / dk);
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// this is the inner loop of the player
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// unrolled 8x
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for (; i + 8 < next_event; i+=8) {
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i] += vL * y;
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dataR[i] += vR * y;
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Vrms += (vL + vR) * y * y;
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i+1] += vL * y;
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dataR[i+1] += vR * y;
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Vrms += (vL + vR) * y * y;
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i+2] += vL * y;
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dataR[i+2] += vR * y;
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Vrms += (vL + vR) * y * y;
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i+3] += vL * y;
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dataR[i+3] += vR * y;
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Vrms += (vL + vR) * y * y;
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i+4] += vL * y;
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dataR[i+4] += vR * y;
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Vrms += (vL + vR) * y * y;
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i+5] += vL * y;
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dataR[i+5] += vR * y;
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Vrms += (vL + vR) * y * y;
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i+6] += vL * y;
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dataR[i+6] += vR * y;
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Vrms += (vL + vR) * y * y;
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var s = samp[k|0];
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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k += dk;
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dataL[i+7] += vL * y;
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dataR[i+7] += vR * y;
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Vrms += (vL + vR) * y * y;
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vL = pf_8 * vL + (1 - pf_8) * volL;
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vR = pf_8 * vR + (1 - pf_8) * volR;
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}
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// we low-pass filter here since we are resampling some arbitrary
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// frequency to f_smp; this is an anti-aliasing filter and is
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// implemented as an IIR butterworth filter (usually we'd use an FIR
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// brick wall filter, but this is much simpler computationally and
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// sounds fine)
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var si = ch.filter[0] * (s + ch.filterstate[0]) +
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ch.filter[1]*ch.filterstate[1] + ch.filter[2]*ch.filterstate[2];
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if (isNaN(si)) {
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console.log("NaN after filter sample idx", samp, k|0, ch.filter, ch.filterstate, s);
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break;
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for (; i < next_event; i++) {
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var s = samp[k|0];
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// we low-pass filter here since we are resampling some arbitrary
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// frequency to f_smp; this is an anti-aliasing filter and is
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// implemented as an IIR butterworth filter (usually we'd use an FIR
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// brick wall filter, but this is much simpler computationally and
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// sounds fine)
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var y = f0 * (s + fs0) + f1*fs1 + f2*fs2;
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fs2 = fs1; fs1 = y; fs0 = s;
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dataL[i] += vL * y;
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dataR[i] += vR * y;
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Vrms += (vL + vR) * y * y;
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k += dk;
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}
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ch.filterstate[2] = ch.filterstate[1];
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ch.filterstate[1] = si; ch.filterstate[0] = s;
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// we also low-pass filter volume changes with a simple one-zero,
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// one-pole filter to avoid pops and clicks when volume changes.
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ch.vL = popfilter_alpha * ch.vL + (1 - popfilter_alpha) * (volL + ch.vLprev) * 0.5;
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ch.vR = popfilter_alpha * ch.vR + (1 - popfilter_alpha) * (volR + ch.vRprev) * 0.5;
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ch.vLprev = volL;
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ch.vRprev = volR;
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dataL[i] += ch.vL * si;
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dataR[i] += ch.vR * si;
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Vrms += (ch.vL + ch.vR) * si * si;
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k += dk;
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}
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ch.off = k;
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ch.doff = dk;
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ch.filterstate[0] = fs0;
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ch.filterstate[1] = fs1;
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ch.filterstate[2] = fs2;
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ch.vL = vL;
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ch.vR = vR;
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return Vrms * 0.5;
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}
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@ -383,15 +463,9 @@ function audio_cb(e) {
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var dataL = e.outputBuffer.getChannelData(0);
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var dataR = e.outputBuffer.getChannelData(1);
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// backward compat w/ no array.fill
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if (dataL.fill === undefined) {
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for (var i = 0; i < buflen; i++) {
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dataL[i] = 0;
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dataR[i] = 0;
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}
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} else {
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dataL.fill(0);
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dataR.fill(0);
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for (var i = 0; i < buflen; i++) {
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dataL[i] = 0;
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dataR[i] = 0;
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}
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var offset = 0;
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@ -413,22 +487,24 @@ function audio_cb(e) {
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buflen -= tickduration;
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}
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// update VU meters
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var canvas = document.getElementById("vu");
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var ctx = canvas.getContext("2d");
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ctx.fillStyle = '#000';
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ctx.fillRect(0, 0, 16 * nchan, 64);
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ctx.fillStyle = '#0f0';
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for (var j = 0; j < nchan; j++) {
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var rms = VU[j] / e.outputBuffer.length;
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var y = -Math.log(rms)*10;
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ctx.fillRect(j*16, y, 15, 64-y);
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}
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window.requestAnimationFrame(function() {
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// update VU meters
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var canvas = document.getElementById("vu");
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var ctx = canvas.getContext("2d");
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ctx.fillStyle = '#000';
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ctx.fillRect(0, 0, 16 * nchan, 64);
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ctx.fillStyle = '#0f0';
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for (var j = 0; j < nchan; j++) {
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var rms = VU[j] / e.outputBuffer.length;
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var y = -Math.log(rms)*10;
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ctx.fillRect(j*16, y, 15, 64-y);
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}
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var debug = document.getElementById("debug");
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debug.innerHTML = 'pat ' + cur_pat + ' row ' + (cur_row-1);
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var pat = document.getElementById("pattern");
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pat.innerHTML = patdisplay.join("\n");
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var debug = document.getElementById("debug");
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debug.innerHTML = 'pat ' + cur_pat + ' row ' + (cur_row-1);
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var pat = document.getElementById("pattern");
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pat.innerHTML = patdisplay.join("\n");
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});
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}
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function eff_t0_0(ch, data) { // arpeggio
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@ -692,7 +768,7 @@ function UnrollSampleLoop(inst) {
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samp[i] = inst.sampledata[i];
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}
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for (var j = 0; j < nloops; j++) {
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if (j&1 && pingpong) {
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if ((j&1) && pingpong) {
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for (var k = inst.looplen - 1; k >= 0; k--) {
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samp[i++] = inst.sampledata[inst.loop + k];
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}
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@ -702,9 +778,10 @@ function UnrollSampleLoop(inst) {
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}
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}
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}
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console.log("unrolled sample loop", inst.number, "looplen", inst.looplen, "x", nloops, " = ", samplesiz);
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inst.sampledata = samp;
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inst.looplen = nloops * inst.looplen;
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inst.type &= ~2;
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inst.type = 1;
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}
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function playXM(arrayBuf) {
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@ -725,8 +802,6 @@ function playXM(arrayBuf) {
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for (var i = 0; i < nchan; i++) {
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channelinfo.push({
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filterstate: new Float32Array(3),
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popfilter: FilterCoeffs(200.0 / 44100.0),
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popfilterstate: [new Float32Array(3), new Float32Array(3)],
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vol: 0,
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pan: 128,
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vL: 0, vR: 0, // left right volume envelope followers (changes per sample)
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@ -855,6 +930,7 @@ function playXM(arrayBuf) {
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idx += totalsamples;
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inst = {
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'name': instname,
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'number': i,
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'len': samplen, 'loop': samploop,
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'looplen': samplooplen, 'note': sampnote, 'fine': sampfinetune,
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'pan': samppan, 'type': samptype, 'vol': sampvol,
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@ -869,7 +945,7 @@ function playXM(arrayBuf) {
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}
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// unroll short loops and any pingpong loops
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if ((inst.type & 1) && (inst.looplen < 2048 || (inst.type & 2))) {
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if ((inst.type & 3) && (inst.looplen < 2048 || (inst.type & 2))) {
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UnrollSampleLoop(inst);
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}
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