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The Virtual Sphere


  1. Define portion of screen to be projection of virtual sphere.
  2. Get two sequential samples of mouse position, S and T.
  3. Map 2D point S to 3D unit vector on sphere.
  4. Map 2D vector to 3D tangental velocity .
  5. Normalize .
  6. Axis: .
  7. Angle: .
    (Choose so a rotation can be obtained.)
  8. Save T to use as S for next time.

CS488/688: Introduction to Interactive Computer Graphics
University of Waterloo
Computer Graphics Lab