www-client/firefox and seamonkey can be built with OpenGL (EGL & GLES2) support. This code looks complete, but looks like developers maintain it for Maemo and some sub-options (gles2 and rendering side) need to be changed in code now for "--enable-egl-xrender-composite" can be processed. Reproducible: Always I will post ebuild patch for firefox 11 ebuild as example, but I use similar changes with seamonkey from mercurial. Better to test it in various combinations first with mesa[+egl,-gles2] (I use both "+" only in both packages). And you need REQUIRED_USE="gles2? ( egl )" or workaround (how about "xrender" - I don't know). I just ignore USE dependences by various reasons, it works anymore. More about useflags added (egl, gles2, xrender) see comments in patch.
Created attachment 307875 [details, diff] firefox --enable-egl-xrender-composite Additional: you can also unlock hardware blacklist for OpenGL from mozilla. I have some code, but I add it in my ebuild year[s] ago and not check now - it just live or dead in my seamonkey. But I sure - mozilla's blacklist is "distro production" list and must be removed in Gentoo, with recomendations to use "about:config" - "search: webgl" instead. User can test your drivers self. This is my old code: sed -i -e 's:if (mIsMesa):if (0):' widget/src/xpwidgets/GfxInfoX11.cpp sed -i -e 's%return nsIGfxInfo::FEATURE_BLOCKED_[A-Z0-9_]*%return nsIGfxInfo::FEATURE_NO_INFO%g' "${S1}"/widget/src/xpwidgets/*.cpp
EGL is only supported for maemo builds. It is not intented to be used for anything else. If you are wanting to see it supported for other builds, you should propose such change to upstream with a proper patch.