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


// 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);


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.
A GLintptr specifying an offset in bytes where the data replacement will start.
srcData Optional
An ArrayBufferSharedArrayBuffer or one of the ArrayBufferView typed array types that will be copied into the data store.
A GLuint specifying the element index offset where to start reading the buffer.
length Optional
A GLuint defaulting to 0.

Return value



  • 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.


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);


Specification Status Comment
WebGL 1.0
The definition of 'bufferSubData' in that specification.
Recommendation Initial definition for WebGL.
OpenGL ES 2.0
The definition of 'glBufferSubData' in that specification.
Standard Man page of the OpenGL ES 2 API.
OpenGL ES 3.0
The definition of 'glBufferSubData' in that specification.
Standard Man page of the (similar) OpenGL ES 3 API.

Adds new target buffers:

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
bufferSubDataChrome Full support 9Edge Full support 12Firefox Full support 4IE Full support 11Opera Full support 12Safari Full support 5.1WebView Android Full support YesChrome Android Full support 25Firefox Android Full support YesOpera Android Full support 12Safari iOS Full support 8Samsung Internet Android Full support 1.5
WebGL2Chrome Full support 56Edge Full support 79Firefox Full support 51IE No support NoOpera Full support 43Safari No support NoWebView Android Full support 58Chrome Android Full support 58Firefox Android Full support 51Opera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 7.0


Full support  
Full support
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See also