This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

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

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support No support [2] Nightly build [1] No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support No support No support No support No support

[1] WebGL 2 is enabled by default in Firefox Nightly. To enable it in a release version of Firefox, set the preference webgl.enable-prototype-webgl2 to true in about:config.

[2] To use an experimental implementation of WebGL 2 in Chrome, you have to start Chrome with the runtime flag --enable-unsafe-es3-apis.

See also

Document Tags and Contributors

 Contributors to this page: fscholz
 Last updated by: fscholz,