* Make the gl renderer aware of BR_MATF_TWO_SIDED and BR_MATF_ALWAYS_VISIBLE
Prevent the gl renderer from culling back-faced textures if the material
is two-sided or always visible.
Due to the wrong order of vertices in the model, oil spill object is
subject to back face culling, preventing it from being rendered. Set
the oil spill material as two-sided, allowing it to be displayed.
Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
a1504075cc