the aspect ratio that determines the field of view in the x direction. The aspect ratio is the ratio of x (width) to y (height)
the field of view angle, in degrees, in the y direction
the distance from the viewer to the far clipping plane (always positive)
the distance from the viewer to the near clipping plane (always positive)
Stage perspective definition. #ClutterPerspective is only used by the fixed point version of clutter_stage_set_perspective().