opengles: port sidewall drawing code
opengles: port field background code
opengles: port fragment of destroyed enemy code
opengles: port spark code
opengles: port destructable bullet code
opengles: port crystal code
opengles: port ship code
opengles: port ship code
opengles: port sight code
opengles: port more ship code
opengles: port shot code
opengles: port title screen
opengles: port turret code
opengles: port luminous screen