I use the gluPerspective and glLookAt to set my projection matrix and view matrix. If I want to get the coordinate of the eye, it's the first three arguments in the gluLookAt, right?
However, now I need to get the projection plane, that is, the position of the screen in the world coordinate system. You know, if I can calculate the left-bottom corner point and the right-top corner point, the plane is right there!
Could anyone give me a hint about how to do this calculation?