Web/API/WebGL2RenderingContext/getBufferSubData

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The WebGL2RenderingContext.getBufferSubData() method of the WebGL 2 API reads data from a buffer binding point and writes them to an ArrayBuffer or SharedArrayBuffer.

Syntax

void gl.getBufferSubData(target, srcByteOffset, ArrayBufferView dstData, optional dstOffset, optional length);

Parameters

target: A GLenum specifying the binding point (target). Possible values:

gl.ARRAY_BUFFER

Buffer containing vertex attributes, such as vertex coordinates, texture coordinate data, or vertex color data.
gl.ELEMENT_ARRAY_BUFFER: Buffer used for element indices.
gl.COPY_READ_BUFFER: Buffer for copying from one buffer object to another.
gl.COPY_WRITE_BUFFER: Buffer for copying from one buffer object to another.
gl.TRANSFORM_FEEDBACK_BUFFER: Buffer for transform feedback operations.
gl.UNIFORM_BUFFER: Buffer used for storing uniform blocks.
gl.PIXEL_PACK_BUFFER: Buffer used for pixel transfer operations.
gl.PIXEL_UNPACK_BUFFER: Buffer used for pixel transfer operations.

srcByteOffset: A GLintptr specifying the byte offset from which to start reading from the buffer.
dstData: An ArrayBuffer or SharedArrayBuffer to which to write the buffer data.
srcOffset Optional: A GLuint specifying the element index offset where to start reading the buffer.
length Optional: A GLuint defaulting to 0.

Return value

None.

Exceptions

An INVALID_VALUE error is generated if:

offset + returnedData.byteLength would extend beyond the end of the buffer
returnedData is null
offset is less than zero.

An INVALID_OPERATION error is generated if:

zero is bound to target
target is TRANSFORM_FEEDBACK_BUFFER, and any transform feedback object is currently active.

Examples

var buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);

var arrBuffer = new ArrayBuffer(vertices.length * Float32Array.BYTES_PER_ELEMENT);
gl.getBufferSubData(gl.ARRAY_BUFFER, 0, arrBuffer);

Specifications

Specification	Status	Comment
WebGL 2.0The definition of 'getBufferSubData' in that specification.	Editor's Draft	Initial definition.

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`getBufferSubData`	Chrome Full support 56	Edge Full support 79	Firefox Full support 51	IE No support No	Opera Full support 43	Safari No support No	WebView Android Full support 58	Chrome Android Full support 58	Firefox Android Full support 51	Opera Android Full support 43	Safari iOS No support No	Samsung Internet Android Full support 7.0
`SharedArrayBuffer` as a parameter	Chrome Full support 60	Edge Full support 79	Firefox Full support 79	IE No support No	Opera Full support 47	Safari No support No	WebView Android Full support 60	Chrome Android Full support 60	Firefox Android ?	Opera Android Full support 44	Safari iOS No support No	Samsung Internet Android Full support 8.0

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown