restrict internal trackball theta to range of 0-2pi
restrict internal trackball theta to range of 0-2pi
seanisom/vtp,markraz/vtp,nakijun/vtp,nakijun/vtp,seanisom/vtp,markraz/vtp,seanisom/vtp,nakijun/vtp,seanisom/vtp,markraz/vtp,nakijun/vtp,seanisom/vtp,nakijun/vtp,markraz/vtp,markraz/vtp