   About Draw points with OpenGL.
  With  FBO + PBO + VBO, I first render into FBO, then, using data of FBO as vertex, I draw many points. the problem is, most of the point(i.e. the data in FBO) are the same, can OpenGL or GPU optimize it by drawing only one point when there are many same points. Or, just draw points one by one ?   
  indexed triangles .... :)   