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

The WebGL2RenderingContext.readBuffer() method of the WebGL 2 API selects a color buffer as the source for pixels for subsequent calls to copyTexImage2D, copyTexSubImage2D, copyTexSubImage3D or readPixels.


void gl.readBuffer(src);


A GLenum specifying a color buffer. Possible values:
  • gl.BACK: Reads from the back color buffer.
  • gl.NONE: Reads from no color buffer.
  • gl.COLOR_ATTACHMENT{0-15}: Reads from one of the 16 color attachment buffers.

Return value





Specification Status Comment
WebGL 2.0
The definition of 'readBuffer' in that specification.
Editor's Draft Initial definition for WebGL.
OpenGL ES 3.0
The definition of 'glReadBuffer' in that specification.
Standard Man page of the (similar) OpenGL API.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
readBufferChrome Full support 56Edge No support NoFirefox Full support 51IE No support NoOpera Full support 43Safari No support NoWebView Android Full support 58Chrome Android Full support 58Edge Mobile No support NoFirefox Android Full support 51Opera Android Full support 43Safari iOS No support NoSamsung Internet Android Full support 7.0


Full support  
Full support
No support  
No support

See also

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Contributors to this page: mdnwebdocs-bot, fscholz, teoli
Last updated by: mdnwebdocs-bot,