[GtkGLExt] How to show text?

[YangXi <jiandingzhe msn com>]

In OpenGL, it seems I should use glWindowPos() and glDrawPixels() to show texts on screen.

However, I still don't know how to get text bitmap from Pango, and what is the usage of gdk_gl_font_use_pango_font().

Any hints? Thanks a lot!