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GPUBuffer: mapState property

files/en-us/web/api/gpubuffer/mapstate/index.md

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{{APIRef("WebGPU API")}}{{SecureContext_Header}}{{AvailableInWorkers}}

The mapState read-only property of the {{domxref("GPUBuffer")}} interface represents the mapped state of the GPUBuffer.

Value

An enumerated value. Possible values are:

  • unmapped
    • : The buffer is not mapped. {{domxref("GPUBuffer.getMappedRange()")}} cannot be used to access the contents of the GPUBuffer in JavaScript. This could be because:
      • {{domxref("GPUBuffer.mapAsync()")}} has not yet been called.
      • The GPUBuffer was previously mapped, and then unmapped again with {{domxref("GPUBuffer.unmap()")}}.
  • pending
    • : The buffer is not yet mapped. {{domxref("GPUBuffer.mapAsync()")}} has been called, but its {{jsxref("Promise")}} is currently pending. {{domxref("GPUBuffer.getMappedRange()")}} cannot currently be used to access the contents of the GPUBuffer in JavaScript.
  • mapped
    • : The buffer is mapped. The {{domxref("GPUBuffer.mapAsync()")}} {{jsxref("Promise")}} has fulfilled, and {{domxref("GPUBuffer.getMappedRange()")}} can now be used to access the contents of the GPUBuffer in JavaScript.

Examples

js
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"

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also