Web/API/WebGLRenderingContext/bufferSubData

The WebGLRenderingContext.bufferSubData() method of the WebGL API updates a subset of a buffer object's data store.

Syntax

// WebGL1: 
void gl.bufferSubData(target, offset, ArrayBuffer srcData); 
void gl.bufferSubData(target, offset, ArrayBufferView srcData); 

// WebGL2: 
void gl.bufferSubData(target, dstByteOffset, ArrayBufferView srcData, srcOffset, 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.
• When using a WebGL 2 context, the following values are available additionally:

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.

dstByteOffset

A GLintptr specifying an offset in bytes where the data replacement will start.

srcData Optional

An ArrayBuffer, SharedArrayBuffer or one of the ArrayBufferView typed array types that will be copied into the data store.

srcOffset

A GLuint specifying the element index offset where to start reading the buffer.

length Optional

A GLuint defaulting to 0.

Return value

None.

Exceptions

• A gl.INVALID_VALUE error is thrown if the data would be written past the end of the buffer or if data is null.
• A gl.INVALID_ENUM error is thrown if target is not one of the allowed enums.

Examples

Using bufferSubData

var canvas = document.getElementById('canvas');
var gl = canvas.getContext('webgl');
var buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, 1024, gl.STATIC_DRAW);
gl.bufferSubData(gl.ARRAY_BUFFER, 512, data);

Specifications

Specification	Status	Comment
WebGL 1.0The definition of 'bufferSubData' in that specification.	Recommendation	Initial definition for WebGL.
OpenGL ES 2.0The definition of 'glBufferSubData' in that specification.	Standard	Man page of the OpenGL ES 2 API.
OpenGL ES 3.0The definition of 'glBufferSubData' in that specification.	Standard	Man page of the (similar) OpenGL ES 3 API. Adds new target buffers: gl.COPY_READ_BUFFER, gl.COPY_WRITE_BUFFER, gl.TRANSFORM_FEEDBACK_BUFFER, gl.UNIFORM_BUFFER, gl.PIXEL_PACK_BUFFER, gl.PIXEL_UNPACK_BUFFER.

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
bufferSubData	Chrome Full support 9	Edge Full support 12	Firefox Full support 4	IE Full support 11	Opera Full support 12	Safari Full support 5.1	WebView Android Full support Yes	Chrome Android Full support 25	Firefox Android Full support Yes	Opera Android Full support 12	Safari iOS Full support 8	Samsung Internet Android Full support 1.5
WebGL2	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

Legend

Full support  

Full support

No support  

No support

See also

• WebGLRenderingContext.createBuffer()
• WebGLRenderingContext.bufferData()
• Other buffers: WebGLFramebuffer, WebGLRenderbuffer

WebGLRenderingContext.bufferSubData() by Mozilla Contributors is licensed under CC-BY-SA 2.5.