├── README.md
└── worklet.js


/README.md:
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 1 | # better-oscillator
 2 | 
 3 | Improved oscillator for the WebAudio API using the new Audio Worklet API. It is currently only usable in Chrome.
 4 | 
 5 | Exposes the following parameters:
 6 | * `frequency`:
 7 |   * Min: 1
 8 |   * Max: Infinity
 9 |   * Default: 440
10 |   * Description: Frequency at which the oscillator will vibrate at.
11 | * `wave`:
12 |   * Min: 0
13 |   * Max: 4
14 |   * Default: 3
15 |   * Description: Sets the waveform of the oscillator. If the number is not an integer, it will be rounded down.
16 |     * 0 - triangle
17 |     * 1 - pulse
18 |     * 2 - sawtooth
19 |     * 3 - sine
20 |     * 4 - noise
21 | * `phase`:
22 |   * Min: 0
23 |   * Max: Infinity
24 |   * Default: 0
25 |   * Description: Controls the phase offset of the waveform.
26 | * `sync`:
27 |   * Min: 0
28 |   * Max: Infinity
29 |   * Default: 0
30 |   * Description: Sets the frequency that the oscillator will [hard sync](https://en.wikipedia.org/wiki/Oscillator_sync#Hard_Sync) to.
31 | * `duty`:
32 |   * Min: 0
33 |   * Max: 1
34 |   * Default: 0.5
35 |   * Description: Controls the duty cycle of the current oscillator **ONLY** if it is a pulsewave.
36 | 


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/worklet.js:
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 1 | const saw = v => v - Math.floor(v);
 2 | 
 3 | class BetterOscillatorProcessor extends AudioWorkletProcessor {
 4 |   constructor() {
 5 |     super();
 6 |     this.phase = 0;
 7 |     this.sync_phase = 0;
 8 |     this.prev_sync_phase = 0
 9 |   }
10 |   static get parameterDescriptors() {
11 |     return [
12 |       {
13 |         name: "phase",
14 |         defaultValue: 0,
15 |         max: 1,
16 |         min: 0
17 |       },
18 |       {
19 |         name: "duty",
20 |         defaultValue: 0.5,
21 |         min: 0,
22 |         max: 1
23 |       },
24 |       {
25 |         name: "frequency",
26 |         defaultValue: 440,
27 |         min: Number.EPSILON
28 |       },
29 |       {
30 |         name: "wave",
31 |         defaultValue: 3,
32 |         min: 0,
33 |         max: 3
34 |       },
35 |       {
36 |         name: "sync",
37 |         defaultValue: 0,
38 |         min: 0,
39 |       }
40 |     ];
41 |   }
42 |   process(input, outputs, params) {
43 |     for (let z = 0; z < outputs.length; z++) {
44 |       const out = outputs[z][0];
45 |       const outlen = out.length;
46 |       const freq = params.frequency.length === 1;
47 |       const phase = params.phase.length === 1;
48 |       const wave = params.wave.length === 1;
49 |       const duty = params.duty.length === 1;
50 |       const sync = params.sync.length === 1
51 |       const inp = input[0][0].length === 0;
52 |       let back = 0
53 |       for (let x = 0; x < outlen; x++) {
54 |         this.sync_phase = (this.prev_sync_phase) % (params.sync[sync ? 0 : x]/sampleRate)
55 |         if (params.sync[sync ? 0 : x] !== 0 && this.prev_sync_phase >= (params.sync[sync ? 0 : x]/sampleRate)) {
56 |           this.phase = 0
57 |           back = x
58 |         
59 |         }
60 |         this.prev_sync_phase = this.sync_phase
61 |         const main = (params.frequency[freq ? 0 : x] * (x-back)) / sampleRate;
62 |         // noise
63 |         if (params.wave[wave ? 0 : x] >= 4) {
64 |           out[x] = (Math.random() * 2) - 1
65 |         } else if (params.wave[wave ? 0 : x] >= 3) {
66 |           // sine wave made using bulit-in Math.sin
67 |           out[x] = Math.sin(
68 |             (main + this.phase + params.phase[phase ? 0 : x]) * 2 * Math.PI
69 |           );
70 |           // sawtooth wave using linear piecewise floor
71 |         } else if (params.wave[wave ? 0 : x] >= 2) {
72 |           out[x] = 2 * saw(main + this.phase + params.phase[phase ? 0 : x]) - 1;
73 |           // pulse wave using difference of phase shifted saws and variable DC threshold
74 |         } else if (params.wave[wave ? 0 : x] >= 1) {
75 |           const temp = main + this.phase + params.phase[phase ? 0 : x];
76 |           out[x] = (saw(temp) - saw(temp + params.duty[duty ? 0 : x])) > 0 ? 1 : -1
77 |           // triangle wave using absolute value of amplitude shifted sawtooth wave
78 |         } else if (params.wave[wave ? 0 : x] >= 0) {
79 |           out[x] =
80 |             4 *
81 |             Math.abs(
82 |               saw(main + this.phase + params.phase[phase ? 0 : x]) - 1 / 2
83 |             ) - 1;
84 |         }
85 |         this.prev_sync_phase += 1 / sampleRate;
86 |       }
87 |       this.phase +=
88 |         (params.frequency[freq ? 0 : outlen - 1] * outlen) / sampleRate;
89 |       this.phase %= sampleRate;
90 |       return true;
91 |     }
92 |   }
93 | }
94 | 
95 | registerProcessor("better-oscillator", BetterOscillatorProcessor);
96 | 


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