WEBGL_draw_buffers not supported on latest Firefox / Chrome

Question

A google search would show all sorts of people using multiple render targets (aka MRT) with the WEBGL_draw_buffers extension. The search would also show that both Firefox and Chrome are supposedly supporting it, and that one might have to enable a flag in about:config / about:flags respectively that would allow the usage of extensions that are still in draft status.

However, none of the above gave me access to the extension. I changed the configuration on both Firefox Aurora and Chrome Canary, and no luck.

Is there any solution?

Answer 1

First of all, no idea about Chrome. Sorry. My answer will be about Firefox.

both Firefox and Chrome are supposedly supporting it

"Supporting" might be an over statement... There is alpha or beta grade code that is under active development and testing, and that is deliberately disabled by default for that very reason.

In Firefox Beta 24 and later you may toggle the webgl.enable-draft-extensions preference in about:config to enable WEBGL_draw_buffers.

I tested that on a MacBook Air (Intel HD Graphics 3000), OSX Lion and the Khronos WebGL test suite:

• Beta 24: Crash!
• Aurora 25: Crash!

• Nightly 26: All tests passed, in particular

  PASS Successfully enabled WEBGL_draw_buffers extension
  PASS WEBGL_draw_buffers listed as supported and getExtension succeeded
  

Answer 2

I managed to get the WEBGL_draw_buffers extension enabled on chrome by enabling these two flags:

Enable WebGL Draft Extensions Mac, Windows, Linux, Chrome OS, Android

Enable D3D11 Windows

You should also be able to get access to the extension by adding the flag --use-gl:desktop, however I have not managed to get that last option to work.