[OpenGL facilities] Alpha blending provides a means to create transparent objects. Using alpha information, an object can be defined as anything from totally transparent to totally opaque. [Needs] 
Opacity
P i c t u r e s
P a t h s
T r a n s f o r m a t i o n
S e l e c t i o n
O p a c i t y
A n t i - a l i a s i n g
A n i m a t i o n
S p e e d