left.setup_frame(base_camera, offset_axis*-eye_spacing, frustum_skew, params);
right.setup_frame(base_camera, offset_axis*eye_spacing, -frustum_skew, params);
left.setup_frame(base_camera, offset_axis*-eye_spacing, frustum_skew, params);
right.setup_frame(base_camera, offset_axis*eye_spacing, -frustum_skew, params);