It surprised me how hard it is to find a really simple demo that uses OpenGL ES 2.0, and most of those are for Android or iOS.
So for future googlability, here is one that uses EGL on X and fits in a single, independent file:
http://cgit.freedesktop.org/mesa/demos/tree/src/egl/opengles2/es2tri.c
So for future googlability, here is one that uses EGL on X and fits in a single, independent file:
http://cgit.freedesktop.org/mesa/demos/tree/src/egl/opengles2/es2tri.c
