Enemy missiles travel down the screen quite quickly, when they are spawned by an Enemy we pass the enemies direction of travel to the missile and then make the missile veer either left or right accordingly, so if the enemy was going left when they fired the missile then the missile will also veer left.
EVENT SPRITETYPE3
;======= ENEMY MISSILES ============
;======================================
; VARIABLES
; =======================================================
; DIRECTION - DIRECTION OF ENEMY TRAVEL WHEN RELEASED
; SETTINGA - availabe for use in your game
; SETTINGB - availabe for use in your game
; AIRBORNE - availabe for use in your game
; JUMPSPEED - availabe for use in your game
; ========================================================
SPRITEINK 71 ; bright white
SPRITEDOWN ; go down fast (3 times
SPRITEDOWN
SPRITEDOWN
IF DIRECTION = 0 ; was alien going down when fired?
ELSE ; if so, do nothing
IF DIRECTION < 8 ; was alien going right?
SPRITERIGHT ; make missile veer right
ELSE
IF DIRECTION = 8 ; was alien going straight up?
ELSE ; do nothing
SPRITELEFT ; alien was going left, veer missile left
ENDIF
ENDIF
ENDIF
IF COLLISION PLAYER ; has missile collided with player?
IF X > M ; is missile to the right of player?
SUBTRACT M FROM X ; subtract M to find out how far to the right
IF RND <= 10 ; its a hit!
OTHER ; switch to the player
LET DIRECTION = 99 ; trigger the player explosion
ENDSPRITE ; switch back to this event
LET DIRECTION = 99 ; explode the missile
ENDIF
ADD M TO X
ELSE ; not to the right
IF X < M ; is missile to the left?
SUBTRACT X FROM M ; yes, how far to left?
IF M <= 8 ; its a hit!
OTHER ;switch to the player
LET DIRECTION = 99 ; trigger the player explosion
ENDSPRITE ; switch back to this event
LET DIRECTION = 99 ; explode the missile
ENDIF
ADD X TO M ; reset M
ELSE ; must have been a direct hit
OTHER ; switch to the player
LET DIRECTION = 99 ; trigger the player explosion
ENDSPRITE ; switch back to this event
ENDIF
ENDIF
ENDIF
IF DIRECTION = 99 ; Explosion requested
LET TYPE = 6 ; switch to the explosion type
LET IMAGE = 4 ; and explosion image
LET FRAME = 0 ; and the first frame
LET DIRECTION = 2 ; and tell the explosion its an enemy missile
ENDIF
IF Y >= 188 ; has missile reached bottom of the screen
REMOVE ; remove it
SUBTRACT 1 FROM S ; decrement the sprite counter
ENDIF