How to retrieve points information on a rendered window?

Say, a window has been created and there have been some points rendered. Which openGL function can I use to get x,y,z,r,g,b values of all the points rendered on that screen? Thank you very much!

i am afraid i don’t quite understand your meaning.If you don’t know the x,y,z of a vertex first,how do you render them in the window?or you should kown some other information of the vertex.
:confused: :slight_smile:

glReadPixels is probably what you are looking for.