arcball camera, eye position


i’ve got a question to arcball camera. As far as I understand
this topic, the mouse coordinates are captured. Then gluUnProject is used to create 3d coordinates.Then a vector
is created from these coordinates to the center point and a
second evector for the new point. Then with the cross product you can compute the rotation axis and the argument between these two vectors to create a quaternion for rotation.

But how do I get an eye point , the position from the camera ?


Dear Sir/Madam

       i am new to opengl,

i have 3 doubts

  1. i want to rotate the 3D Object based on the mouse move
  2. i want to zoom in /out controlled by mouse scroll wheel
    3 i want to draw plane,cylinder,cone,circle in 3d plane(not XY OR YZ OR XZ PLANE)

please how to do that
show me the code or link