testing

packages/core/clockworker.js

@@ -5,8 +5,9 @@
 
 function getTime() {
   const precision = 10 ** 4;
-  const seconds = performance.now() / 1000;
+  const seconds = performance.now() * .001;
-  return Math.round(seconds * precision) / precision;
+  return seconds
+  // return Math.round(seconds * precision) / precision;
 }
 
 let num_cycles_at_cps_change = 0;
@@ -41,10 +42,8 @@ const sendTick = (phase, duration, tick, time) => {
     begin,
     end,
     cps,
-    tickdeadline,
+    time:  num_seconds_at_cps_change + num_seconds_since_cps_change + tickdeadline,
     num_cycles_at_cps_change,
-    num_seconds_at_cps_change,
-    num_seconds_since_cps_change,
     cycle,
   });
   num_ticks_since_cps_change++;

packages/core/neocyclist.mjs

@@ -5,6 +5,7 @@ This program is free software: you can redistribute it and/or modify it under th
 */
 
 import { logger } from './logger.mjs';
+import { ClockCollator, cycleToSeconds } from './util.mjs';
 
 export class NeoCyclist {
   constructor({ onTrigger, onToggle, getTime }) {
@@ -13,65 +14,30 @@ export class NeoCyclist {
     this.lastTick = 0; // absolute time when last tick (clock callback) happened
     this.getTime = getTime; // get absolute time
     this.time_at_last_tick_message = 0;
-
-    this.num_cycles_at_cps_change = 0;
-    this.onToggle = onToggle;
-    this.latency = 0.1; // fixed trigger time offset
-    this.cycle = 0;
-    this.id = Math.round(Date.now() * Math.random());
-    this.worker_time_dif;
-    this.worker = new SharedWorker(new URL('./clockworker.js', import.meta.url));
-    this.worker.port.start();
-
-    this.channel = new BroadcastChannel('strudeltick');
-    let weight = 0; // the amount of weight that is applied to the current average when averaging a new time dif
-    const maxWeight = 20;
-    const precision = 10 ** 3; //round off time diff to prevent accumulating outliers
-
     // the clock of the worker and the audio context clock can drift apart over time
     // aditionally, the message time of the worker pinging the callback to process haps can be inconsistent.
     // we need to keep a rolling weighted average of the time difference between the worker clock and audio context clock
     // in order to schedule events consistently.
-    const setTimeReference = (num_seconds_at_cps_change, num_seconds_since_cps_change, tickdeadline) => {
+    this.collator = new ClockCollator({ getTargetClockTime: getTime });
-      const time_dif = getTime() - (num_seconds_at_cps_change + num_seconds_since_cps_change) + tickdeadline;
+    this.onToggle = onToggle;
-      if (this.worker_time_dif == null) {
+    this.latency = 0.1; // fixed trigger time offset
-        this.worker_time_dif = time_dif;
+    this.cycle = 0;
-      } else {
+    this.id = Math.round(Date.now() * Math.random());
-        const w = 1; //weight of new time diff;
+    this.worker = new SharedWorker(new URL('./clockworker.js', import.meta.url));
-        const new_dif =
+    this.worker.port.start();
-          Math.round(((this.worker_time_dif * weight + time_dif * w) / (weight + w)) * precision) / precision;
+    this.channel = new BroadcastChannel('strudeltick');
-
-        if (new_dif != this.worker_time_dif) {
-          // reset the weight so the clock recovers faster from an audio context freeze/dropout if it happens
-          weight = 4;
-        }
-        this.worker_time_dif = new_dif;
-      }
-      weight = Math.min(weight + 1, maxWeight);
-    };
-
     const tickCallback = (payload) => {
-      const {
+      const { num_cycles_at_cps_change, cps, begin, end, cycle, time } = payload;
-        num_cycles_at_cps_change,
-        cps,
-        num_seconds_at_cps_change,
-        num_seconds_since_cps_change,
-        begin,
-        end,
-        tickdeadline,
-        cycle,
-      } = payload;
       this.cps = cps;
       this.cycle = cycle;
-
+      const currentTime = cycleToSeconds(num_cycles_at_cps_change + this.cycle, this.cps)
-      setTimeReference(num_seconds_at_cps_change, num_seconds_since_cps_change, tickdeadline);
+      console.log(time, currentTime, this.cycle)
-
+      processHaps(begin, end, currentTime, num_cycles_at_cps_change);
-      processHaps(begin, end, num_cycles_at_cps_change, num_seconds_at_cps_change);
-
       this.time_at_last_tick_message = this.getTime();
+
     };
  
-    const processHaps = (begin, end, num_cycles_at_cps_change, seconds_at_cps_change) => {
+    const processHaps = (begin, end, currentTime, num_cycles_at_cps_change) => {
       if (this.started === false) {
         return;
       }
@@ -80,12 +46,10 @@ export class NeoCyclist {
 
       haps.forEach((hap) => {
         if (hap.hasOnset()) {
-          const targetTime =
+         const target = cycleToSeconds(hap.whole.begin - num_cycles_at_cps_change, this.cps)
-            (hap.whole.begin - num_cycles_at_cps_change) / this.cps +
+          // const target = (hap.whole.begin - num_cycles_at_cps_change) / this.cps;
-            seconds_at_cps_change +
+          const targetTime = this.collator.calculateTimestamp(currentTime, target) + this.latency;
-            this.latency +
+          const duration = cycleToSeconds(hap.duration, this.cps)
-            this.worker_time_dif;
-          const duration = hap.duration / this.cps;
           onTrigger?.(hap, 0, duration, this.cps, targetTime);
         }
       });
@@ -129,8 +93,8 @@ export class NeoCyclist {
     this.setStarted(true);
   }
   stop() {
-    this.worker_time_dif = null;
     logger('[cyclist] stop');
+    this.collator.reset()
     this.setStarted(false);
   }
   setPattern(pat, autostart = false) {

packages/core/util.mjs

@@ -363,6 +363,66 @@ export function objectMap(obj, fn) {
   }
   return Object.fromEntries(Object.entries(obj).map(([k, v], i) => [k, fn(v, k, i)]));
 }
+export function cycleToSeconds(cycle, cps) {
+  return cycle / cps;
+}
+
+// utility for averaging two clocks together to account for drift
+export class ClockCollator {
+  constructor({
+    getTargetClockTime = () => Date.now() * 0.001,
+    weight = 16,
+    offsetDelta = 0.005,
+    checkAfterTime = 2,
+    resetAfterTime = 8,
+  }) {
+    this.offsetTime;
+    this.timeAtPrevOffsetSample;
+    this.prevOffsetTimes = [];
+    this.getTargetClockTime = getTargetClockTime;
+    this.weight = weight;
+    this.offsetDelta = offsetDelta;
+    this.checkAfterTime = checkAfterTime;
+    this.resetAfterTime = resetAfterTime;
+    this.reset = () => {
+      this.prevOffsetTimes = [];
+      this.offsetTime = null;
+      this.timeAtPrevOffsetSample = null;
+    };
+  }
+
+  calculateTimestamp(currentTime, targetTime) {
+    const targetClockTime = this.getTargetClockTime();
+    const diffBetweenTimeSamples = targetClockTime - this.timeAtPrevOffsetSample;
+    const newOffsetTime = targetClockTime - currentTime;
+    // recalcuate the diff from scratch if the clock has been paused for some time.
+    if (diffBetweenTimeSamples > this.resetAfterTime) {
+      this.reset();
+    }
+
+    if (this.offsetTime == null) {
+      this.offsetTime = newOffsetTime;
+    }
+    this.prevOffsetTimes.push(newOffsetTime);
+    if (this.prevOffsetTimes.length > this.weight) {
+      this.prevOffsetTimes.shift();
+    }
+
+    // after X time has passed, the average of the previous weight offset times is calculated and used as a stable reference
+    // for calculating the timestamp
+    if (this.timeAtPrevOffsetSample == null || diffBetweenTimeSamples > this.checkAfterTime) {
+      this.timeAtPrevOffsetSample = targetClockTime;
+      const rollingOffsetTime = averageArray(this.prevOffsetTimes);
+      //when the clock offsets surpass the delta, set the new reference time
+      if (Math.abs(rollingOffsetTime - this.offsetTime) > this.offsetDelta) {
+        this.offsetTime = rollingOffsetTime;
+      }
+    }
+
+    const timestamp = this.offsetTime + targetTime;
+    return timestamp;
+  }
+}
 
 // Floating point versions, see Fraction for rational versions
 // // greatest common divisor