Cameras

"Camera" requires two arguments, a "name" and a "type". Parameters can be set the usual way after these two arguments.

At the moment, there is just one type of camera, "perspective", with four parameters that can be set: "from", "to", "tilt" and "fov". "From" and "to" control camera position and center-of-interest. "Tilt" twists the camera around its view axis. "Fov" controls the field-of-view.

Cameras are also affected by the current transformation in the graphics state, as is shown here in a brief demonstration:

  (set! time 0)

  ; loop for thirty frames
  (while (< time 30)
    (begin

     (world
      (separator
	(rotate (* (/ time 29) 360) '(0 1 0))
        (camera "main" "perspective" 'from '(0 .25 1.5) 'to '(0 0 0))
       )
      (read-det "skull.obj" "smooth")
     )

     ; set the frame name to "Frames/frame."
     ((render 'to-file) (string-append "Frames/frame." 
                                       (number->string time)))

     ; render from the point of view of the camera called "main"
     (render "main")

     ; increment the value of time by one
     (set! time (+ time 1))
     )
   )