class manage an array of enemy
objects, moving them in preset direction, acting like a formation of invaders.
Before constructing a formation
object, user should build a st_formation_param
structure containing valid pointers to st_item
and st_formation_move arrays.
Examples for how to do this in create_invaders_formation()
Each st_item contains an enemy object pointer and additional info that is used by formation
(e.g. item state)
Each st_formation_move, defines the direction of x,y movement for the formation
and times field that tells how many times to repeat this direction.
Once committed times movements in certain direction, the int_to_next_move field tells the formation
what is the next move. Thus a loop of moves can be done.
The protected member attack_ok helps to co-ordinate a "halt attack" state for all object derived from formation
Check out the base.h
file to learn more about available functions for this class. object.
For each frame user have to call the remove()