1/*
2neocyclist.mjs - event scheduler like cyclist, except recieves clock pulses from clockworker in order to sync across multiple instances.
3Copyright (C) 2022 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/core/neocyclist.mjs>
4This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
5*/
6
7import { logger } from './logger.mjs';
8import { ClockCollator, cycleToSeconds } from './util.mjs';
9
10export class NeoCyclist {
11  constructor({ onTrigger, onToggle, getTime }) {
12    this.started = false;
13    this.cps = 0.5;
14    this.getTime = getTime; // get absolute time
15    this.time_at_last_tick_message = 0;
16    // the clock of the worker and the audio context clock can drift apart over time
17    // aditionally, the message time of the worker pinging the callback to process haps can be inconsistent.
18    // we need to keep a rolling average of the time difference between the worker clock and audio context clock
19    // in order to schedule events consistently.
20    this.collator = new ClockCollator({ getTargetClockTime: getTime });
21    this.onToggle = onToggle;
22    this.latency = 0.1; // fixed trigger time offset
23    this.cycle = 0;
24    this.id = Math.round(Date.now() * Math.random());
25    this.worker = new SharedWorker(new URL('./clockworker.js', import.meta.url));
26    this.worker.port.start();
27    this.channel = new BroadcastChannel('strudeltick');
28    const tickCallback = (payload) => {
29      const { cps, begin, end, cycle, time } = payload;
30      this.cps = cps;
31      this.cycle = cycle;
32      const currentTime = this.collator.calculateOffset(time) + time;
33      processHaps(begin, end, currentTime);
34      this.time_at_last_tick_message = currentTime;
35    };
36
37    const processHaps = (begin, end, currentTime) => {
38      if (this.started === false) {
39        return;
40      }
41      const haps = this.pattern.queryArc(begin, end, { _cps: this.cps, cyclist: 'neocyclist' });
42      haps.forEach((hap) => {
43        if (hap.hasOnset()) {
44          const timeUntilTrigger = cycleToSeconds(hap.whole.begin - this.cycle, this.cps);
45          const targetTime = timeUntilTrigger + currentTime + this.latency;
46          const duration = cycleToSeconds(hap.duration, this.cps);
47          onTrigger?.(hap, 0, duration, this.cps, targetTime);
48        }
49      });
50    };
51
52    // receive messages from worker clock and process them
53    this.channel.onmessage = (message) => {
54      if (!this.started) {
55        return;
56      }
57      const { payload, type } = message.data;
58
59      switch (type) {
60        case 'tick': {
61          tickCallback(payload);
62        }
63      }
64    };
65  }
66  sendMessage(type, payload) {
67    this.worker.port.postMessage({ type, payload, id: this.id });
68  }
69
70  now() {
71    const gap = (this.getTime() - this.time_at_last_tick_message) * this.cps;
72    return this.cycle + gap;
73  }
74  setCps(cps = 1) {
75    this.sendMessage('cpschange', { cps });
76  }
77  setCycle(cycle) {
78    this.sendMessage('setcycle', { cycle });
79  }
80  setStarted(started) {
81    this.sendMessage('toggle', { started });
82    this.started = started;
83    this.onToggle?.(started);
84  }
85  start() {
86    logger('[cyclist] start');
87    this.setStarted(true);
88  }
89  stop() {
90    logger('[cyclist] stop');
91    this.collator.reset();
92    this.setStarted(false);
93  }
94  setPattern(pat, autostart = false) {
95    this.pattern = pat;
96    if (autostart && !this.started) {
97      this.start();
98    }
99  }
100
101  log(begin, end, haps) {
102    const onsets = haps.filter((h) => h.hasOnset());
103    console.log(`${begin.toFixed(4)} - ${end.toFixed(4)} ${Array(onsets.length).fill('I').join('')}`);
104  }
105}