mirror of
https://github.com/Tonejs/Tone.js
synced 2024-12-31 22:18:44 +00:00
63 lines
2.2 KiB
TypeScript
63 lines
2.2 KiB
TypeScript
import { getContext, setContext } from "../Global";
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import { Seconds } from "../type/Units";
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import { OfflineContext } from "./OfflineContext";
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import { ToneAudioBuffer } from "./ToneAudioBuffer";
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/**
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* Generate a buffer by rendering all of the Tone.js code within the callback using the OfflineAudioContext.
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* The OfflineAudioContext is capable of rendering much faster than real time in many cases.
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* The callback function also passes in an offline instance of [[Context]] which can be used
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* to schedule events along the Transport.
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* @param callback All Tone.js nodes which are created and scheduled within this callback are recorded into the output Buffer.
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* @param duration the amount of time to record for.
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* @return The promise which is invoked with the ToneAudioBuffer of the recorded output.
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* @example
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* //render 2 seconds of the oscillator
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* Tone.Offline(() => {
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* //only nodes created in this callback will be recorded
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* var oscillator = new Tone.Oscillator().toDestination().start(0)
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* //schedule their events
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* }, 2).then((buffer) => {
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* //do something with the output buffer
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* })
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* @example
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* //can also schedule events along the Transport
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* //using the passed in Offline Transport
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* Tone.Offline(({ transport }) => {
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* var osc = new Tone.Oscillator().toDestination()
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* transport.schedule(function(time){
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* osc.start(time).stop(time + 0.1)
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* }, 1)
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* transport.start(0.2)
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* }, 4).then((buffer) => {
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* //do something with the output buffer
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* })
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* @category Core
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*/
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export async function Offline(
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callback: (context: OfflineContext) => Promise<void> | void,
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duration: Seconds,
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channels: number = 2,
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sampleRate: number = getContext().sampleRate,
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): Promise<ToneAudioBuffer> {
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// set the OfflineAudioContext based on the current context
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const originalContext = getContext();
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const context = new OfflineContext(channels, duration, sampleRate);
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setContext(context);
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// invoke the callback/scheduling
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await callback(context);
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// then render the audio
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const bufferPromise = context.render();
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// return the original AudioContext
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setContext(originalContext);
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// await the rendering
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const buffer = await bufferPromise;
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// return the audio
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return new ToneAudioBuffer(buffer);
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}
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