The createBuffer() method of the GPUDevice interface creates a GPUBuffer in which to store raw data to use in GPU operations.

descriptor

An object containing the following properties:

label Optional

A string providing a label that can be used to identify the object, for example in GPUError messages or console warnings.

mappedAtCreation Optional

A boolean. If set to true, the buffer will be mapped upon creation, meaning that you can set the values inside the buffer immediately by calling GPUBuffer.getMappedRange(). The default value is false.

Note that it is valid to set mappedAtCreation: true so you can set the buffer's initial data, even if the GPUBufferUsage.MAP_READ or GPUBufferUsage.MAP_WRITE usage flags are not set.

size

A number representing the size of the buffer, in bytes.

usage

The bitwise flags representing the allowed usages for the GPUBuffer. The possible values are in the GPUBuffer.usage value table.

Note that multiple possible usages can be specified by separating values with pipe symbols, for example:

js

usage: GPUBufferUsage.COPY_SRC | GPUBufferUsage.MAP_WRITE;

A GPUBuffer object instance.

The following criteria must be met when calling createBuffer(), otherwise a GPUValidationError is generated and an invalid GPUBuffer object is returned:

• A valid usage is specified.
• GPUBufferUsage.MAP_READ is specified, and no additional flags are specified other than GPUBufferUsage.COPY_DST.
• GPUBufferUsage.MAP_WRITE is specified, and no additional flags are specified other than GPUBufferUsage.COPY_SRC.
• mappedAtCreation: true is specified, and the specified size is a multiple of 4.

In our basic compute demo, we create an output buffer to read GPU calculations to, and a staging buffer to be mapped for JavaScript access.

const output = device.createBuffer({
  size: BUFFER_SIZE,
  usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_SRC,
});

const stagingBuffer = device.createBuffer({
  size: BUFFER_SIZE,
  usage: GPUBufferUsage.MAP_READ | GPUBufferUsage.COPY_DST,
});

• The WebGPU API