How do I enable Glamor mode which accelerates 2D graphics with OpenGL on Ubuntu?
See Choose acceleration method on Arch Linux wiki.
GLAMOR is an acceleration library merged into the X.Org Server 1.16 that provides 2D acceleration implemented over OpenGL so X.Org DDX drivers no longer need to implement 2D-specific code-paths. GLAMOR is designed to be universal amongst OpenGL / OpenGL ES supported hardware.
For Trusty the package to install is:
And you also have to manually edit