blank_func = function()
{
};

blank_draw = function()
{
    draw_self();
};

draw_func = blank_draw;
step_func = blank_func;
end_step_func = blank_func;
begin_step_func = blank_func;
draw_begin_func = blank_func;
draw_end_func = blank_func;
pre_draw_func = blank_func;
post_draw_func = blank_func;