OK.
Well all those vbo, fbo, shaders and other opengl related things are still quite fuzzy to me. I must confess that i don't really understand your example 
But i will dig into it.
Note that every circle can have its own color.
So basically, what are the major steps ?
What i understand is :
- create points
- add points to a vbo
- pass the vbo to a shader
- compute position and draw the circle in the vertex shader (pass mouse position to the shader for the interactivity)
- color is applied by a fragment shader ?
am i right ?
here is the result so far (without using shader or vbo :
