Rampage: Routine at 62091

62091: Handler: Spawn Helicopters

Used by the routine at RunHandlers.
Just return if the number of active helicopters is already at the maximum amount for this level.
Handler_SpawnHelicopters	62091	LD A,(53778)	Return if NumberActiveHelicopters is equal to MaxHelicopterCount.
	62094	LD B,A
	62095	LD A,(54261)
	62098	CP B
	62099	RET Z
Add a hint of randomness to whether we proceed or not. Roughly 50% chance.
	62100	CALL RandomNumber	A=random number between 0-255.
	62103	CP 128	Return if A is higher than 128.
	62105	RET NC	Return if A is higher than 128.
Loop to find an empty slot.
	62106	LD HL,53906	HL=53906 (Table_Helicopters-3).
Handler_SpawnHelicopters_FindSlot	62109	INC HL	Move the table pointer to the next helicopter table data.
	62110	INC HL
	62111	INC HL
	62112	LD A,(HL)	Jump to Handler_SpawnHelicopters_FindSlot if this helicopter is already active.
	62113	AND A
	62114	JR NZ,Handler_SpawnHelicopters_FindSlot
50/50 chance of jumping to Handler_SpawnForegroundHelicopter.
	62116	CALL RandomNumber	Get a random number of either zero or one.
	62119	AND %00000001	Get a random number of either zero or one.
	62121	JR Z,Handler_SpawnForegroundHelicopter	Jump to Handler_SpawnForegroundHelicopter if the result is zero.
Creates a background helicopter.
	62123	LD (HL),64	Write 64 (background) to helicopter state.
	62125	INC HL	Increment the helicopter table pointer by one.
	62126	LD (HL),252	Write 252 to helicopter X position.
	62128	JR Handler_Helicopter_SetYPos	Jump to Handler_Helicopter_SetYPos.
Creates a foreground helicopter.
Handler_SpawnForegroundHelicopter	62130	LD (HL),128	Write 128 (foreground) to helicopter state.
	62132	INC HL	Increment the helicopter table pointer by one.
	62133	LD (HL),36	Write 36 to helicopter X position.
Handler_Helicopter_SetYPos	62135	INC HL	Increment the helicopter table pointer by one.
	62136	LD (HL),3	Write 3 to helicopter Y position.
25% chance of jumping to Helicopter_Update_Count.
	62138	CALL RandomNumber	Get a random number between 0-3.
	62141	AND %00000011	Get a random number between 0-3.
	62143	JR Z,Helicopter_Update_Count	Jump to Helicopter_Update_Count if the random number is 0.
	62145	LD (HL),A	Write the random number to helicopter Y position.
Keep track of the number of active helicopters.
Helicopter_Update_Count	62146	LD A,(54261)	Increment *NumberActiveHelicopters by one.
	62149	INC A
	62150	LD (54261),A
	62153	RET	Return.