GPUBuffer: getMappedRange() method

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 getMappedRange() method of the GPUBuffer interface returns an ArrayBuffer containing the mapped contents of the GPUBuffer in the specified range.

This can only happen once the GPUBuffer has been successfully mapped with GPUBuffer.mapAsync() (this can be checked via GPUBuffer.mapState). While the GPUBuffer is mapped it cannot be used in any GPU commands.

When you have finished working with the GPUBuffer values, call GPUBuffer.unmap() to unmap it, making it accessible to the GPU again. A TypeError is thrown if an attempt is made to detach the ArrayBuffer in any way other than via GPUBuffer.unmap(), such as by calling transfer().

Syntax

getMappedRange()
getMappedRange(offset)
getMappedRange(offset, size)

Parameters

offset Optional: A number representing the offset, in bytes, from the start of the GPUBuffer's mapped range to the start of the range to be returned in the ArrayBuffer. If offset is omitted, it defaults to 0.
size Optional: A number representing the size, in bytes, of the ArrayBuffer to return. If size is omitted, the range extends to the end of the GPUBuffer's mapped range.

Return value

An ArrayBuffer.

Validation

The following criteria must be met when calling getMappedRange(), otherwise an OperationError DOMException is thrown:

offset is a multiple of 8.
The total range to be mapped (size if specified, or mapped range length - offset if not) is a multiple of 4.
The total range is inside the bounds of the mapped range and does not overlap with the ArrayBuffer ranges specified by any other active getMappedRange() calls.