GPUBuffer: mapState property

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is available in Web Workers.

The mapState read-only property of the GPUBuffer interface represents the mapped state of the GPUBuffer.

Value

An enumerated value. Possible values are:

unmapped

The buffer is not mapped. GPUBuffer.getMappedRange() cannot be used to access the contents of the GPUBuffer in JavaScript. This could be because:

GPUBuffer.mapAsync() has not yet been called.
The GPUBuffer was previously mapped, and then unmapped again with GPUBuffer.unmap().

pending

The buffer is not yet mapped. GPUBuffer.mapAsync() has been called, but its Promise is currently pending. GPUBuffer.getMappedRange() cannot currently be used to access the contents of the GPUBuffer in JavaScript.

mapped

The buffer is mapped. The GPUBuffer.mapAsync() Promise has fulfilled, and GPUBuffer.getMappedRange() can now be used to access the contents of the GPUBuffer in JavaScript.

Examples

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

console.log(stagingBuffer.mapState); // "unmapped"

// …

await stagingBuffer.mapAsync(
  GPUMapMode.READ,
  0, // Offset
  BUFFER_SIZE, // Length
);

console.log(stagingBuffer.mapState); // "mapped"