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Buffers

In this example, we will show you how to use the CreativeEditor SDK’s CreativeEngine to create buffers through the editor API. Buffers can hold arbitrary data.

createBuffer(): string

Create a resizable buffer that can hold arbitrary data.

  • Returns A URI to identify the buffer.
destroyBuffer(uri: string): void

Destroy a buffer and free its resources.

  • uri: The URI of the buffer to destroy.
setBufferData(uri: string, offset: number, data: Uint8Array): void

Set the data of a buffer at a given offset.

  • uri: The URI of the buffer to update.
  • offset: The offset in bytes at which to start writing.
  • data: The data to write.
getBufferData(uri: string, offset: number, length: number): Uint8Array

Get the data of a buffer at a given offset.

  • uri: The URI of the buffer to query.
  • offset: The offset in bytes at which to start reading.
  • length: The number of bytes to read.
  • Returns The data at the given offset.
setBufferLength(uri: string, length: number): void

Set the length of a buffer.

  • uri: The URI of the buffer to update.
  • length: The new length of the buffer in bytes.
getBufferLength(uri: string): number

Get the length of a buffer.

  • uri: The URI of the buffer to query.
  • Returns The length of the buffer in bytes.

Full Code

Here’s the full code:

// Create an audio block and append it to the page
const audioBlock = engine.block.create('audio');
engine.block.appendChild(page, audioBlock);


// Create a buffer
const audioBuffer = engine.editor.createBuffer();


// Reference the audio buffer resource from the audio block
engine.block.setString(audioBlock, 'audio/fileURI', audioBuffer);


// Generate 10 seconds of stereo 48 kHz audio data
const samples = new Float32Array(10 * 2 * 48000);
for (let i = 0; i < samples.length; i += 2) {
  samples[i] = samples[i + 1] = Math.sin((440 * i * Math.PI) / 48000);
}


// Assign the audio data to the buffer
engine.editor.setBufferData(audioBuffer, 0, new Uint8Array(samples.buffer));


// We can get subranges of the buffer data
const chunk = engine.editor.getBufferData(audioBuffer, 0, 4096);


// Get current length of the buffer in bytes
const length = engine.editor.getBufferLength(audioBuffer);


// Reduce the buffer to half its length, leading to 5 seconds worth of audio
engine.editor.setBufferLength(audioBuffer, length / 2);


// Free data
engine.editor.destroyBuffer(audioBuffer);