// Stereo.inc - Viktor Ferenczi 2002
//
// Usage:
//
// Create an animation with even number of frames.
// Even frames will be the left, odd frames will be the right images.
// Use clk on the place of clock and stereo_fnum on the place of frame_number for animations.
//
// #declare cyclic_animation 1;  // Declare this for cyclic animation only
// #include "Stereo.inc"
//
// ...
//
// camera {
//   StereoCamera1(<0,0.5,-1>, <0,0,0>, image_width/image_height,1,0.6, 0.065,0)
// }

#if(final_frame>initial_frame)
  #local df=frame_number-initial_frame;
  #local fn=final_frame-initial_frame+1;
  #local cd=final_clock-initial_clock;
  #declare stereo_fnum=div(df,2);
  #declare stereo_side=1-mod(df,2)*2;
  #ifdef(cyclic_animation)
    #declare clk=initial_clock+cd*stereo_fnum/div(fn+2,2);
  #else
    #declare clk=initial_clock+cd*stereo_fnum/div(fn,2);
  #end
#else
  #declare stereo_fnum=0;
  #declare stereo_side=0;
  #declare clk=initial_clock
#end

#macro StereoCamera1(loc,look,rvs,uvs,dist,base,roll)
  // loc=average location of eyes
  // look=look_at destination
  // rvs=right vector size (for aspect ratio and camera angle control)
  // uvs=up vector size (for aspect ratio and camera angle control)
  // dist=distance of the image plane from the eyes (equal for left and right one)
  // base=stereo base (distance of the right eye from the left one)
  // roll=angle of the line between the left and right eyes and the XZ plane
  #local dv=look-loc;
  #local dvn=vnormalize(dv);
  #local rvn=vcross(dvn,-y);
  #if(vlength(rvn)<0.5)
    #local rvn=x;
  #end
  #local uvn=vcross(dvn,rvn);
  #local ssh=rvn*base*0.5*stereo_side;
/*
  #debug "dv="
  #debug concat(str(dv.x,0,3),",")
  #debug concat(str(dv.y,0,3),",")
  #debug concat(str(dv.z,0,3)," ")
  #debug "dvn="
  #debug concat(str(dvn.x,0,3),",")
  #debug concat(str(dvn.y,0,3),",")
  #debug concat(str(dvn.z,0,3)," ")
  #debug "rvn="
  #debug concat(str(rvn.x,0,3),",")
  #debug concat(str(rvn.y,0,3),",")
  #debug concat(str(rvn.z,0,3)," ")
  #debug "uvn="
  #debug concat(str(uvn.x,0,3),",")
  #debug concat(str(uvn.y,0,3),",")
  #debug concat(str(uvn.z,0,3)," ")
*/
  location loc+ssh
  direction dvn*dist-ssh
  right rvn*rvs
  up uvn*uvs
#end