Graphics 1024, 768, 16, 2

timer = CreateTimer(30)

AutoMidHandle True 
img_ship = LoadImage("ship.png")
img_bullet = LoadImage("bullet.png")
img_alien = LoadImage("alien.png")
img_bomb = LoadImage("bomb.png")
MaskImage img_alien, 255,255,255 

;bullet type
Type bullet
	Field x
	Field y
End Type

;bomb type
Type bomb
	Field x
	Field y
End Type	


;alien type
Type alien
	Field x
	Field y
End Type 

;set starting coords for player
x = 512
y = 700

;set alien speed
amx = 1

level = 1
lives = 3
score = 0
lines = 2

SetBuffer BackBuffer()

;generate alien
For z = 1 To 7
	For w = 1 To lines
		a.alien = New alien
		a\x = 120 + 100*z
		a\y = 150 + 50*w
	Next
Next

;start main loop----------------------------------------------------------------------------
While Not KeyDown(1)
	
	
	Cls
	DrawImage img_ship, x, y
	
	;update player position
	If KeyDown(203) Then x = x - 5
	If KeyDown(205) Then x = x + 5


	
	;firing bullets
	If KeyHit(57) Then
		b.bullet = New bullet
		b\x = x
		b\y = y - 50
	EndIf
	
	;update and draw bullets
	For b.bullet = Each bullet
		b\y = b\y - 8
		DrawImage img_bullet, b\x, b\y
		If b\y < 0 Then Delete b
	Next
	
	;update and draw aliens
	For a.alien = Each alien
		
		a\x = a\x + amx 
		If a\x > 996 Then amx = - amx
		If a\x < 30 Then amx = - amx
	
		DrawImage img_alien, a\x, a\y
		For b.bullet = Each bullet
			If ImagesCollide(img_bullet, b\x, b\y, 0, img_alien, a\x, a\y,0) Then
				Delete b
				Delete a
				score = score + 10
				Exit
			EndIf 
		Next
	Next
	
	;generating bombs
	If Rand(200) = 25 Then
		bombs.bomb = New bomb
		bombs\x = a\x
		bombs\y = a\y + 20
	EndIf
	
	;update an draw bombs
	For bombs.bomb = Each bomb
		bombs\y = bombs\y + 6
		DrawImage img_bomb, bombs\x, bombs\y
		
			If ImagesCollide(img_bomb, bombs\x, bombs\y, 0, img_ship, x, y, 0) Then
				Delete bombs
				lives = lives - 1
			ElseIf bombs\y > 1040 Then 
				Delete bombs
			EndIf
	
	Next
	
	;endgame screen
	If lives = 0 Then
		Text 512, 384, "GAME OVER!" , 1, 1
		Flip
		Delay 3000
		End
	EndIf

	
	;life counter
	Text 50, 720, "LIVES " + lives
	
	;score counter
	Text 925, 720,"SCORE " + score
	
	
	
	WaitTimer(timer)
	

	Flip

;end main loop---------------------------------------------------------------------------------
Wend

End 

Each

Null

	;update and draw aliens
	For a.alien = Each alien
		
		a\x = a\x + amx 
		If a\x > 996 Then amx = - amx
		If a\x < 30 Then amx = - amx
	
		DrawImage img_alien, a\x, a\y
		For b.bullet = Each bullet
			If ImagesCollide(img_bullet, b\x, b\y, 0, img_alien, a\x, a\y,0) Then
				Delete b
				Delete a
				score = score + 10
				Exit
			EndIf 
		Next
	        ;generating bombs
	        If Rand(200) = 25 Then
		        bombs.bomb = New bomb
		        bombs\x = a\x
		        bombs\y = a\y + 20
	        EndIf
	Next