Jewels of Babylon: Routine at 49533

Used by the routine at GameLoop.

This routine manages two types of in-game events:

1. Turn-Based Events: These are timer-based hazards that count down with each game turn. When a turn counter reaches zero, the associated event handler is called via a jump table.
2. Scenic Events: Mostly atmospheric events that randomly appear in different locations to add flavor to the game world (like seagulls appearing at the beach).; The routine maintains a table of current locations for each scenic event. On each turn, it checks if any scenic event is NOT in the current room, then randomly relocates it to one of its valid rooms.; Each scenic event has a predefined group of rooms where the event can appear.

The routine ensures that:

Multiple turn-based dangers can threaten the player simultaneously
Scenic events don't repeatedly trigger in the same room
The game world feels dynamic with events occurring in different locations

Used by the routine at GameLoop. This routine manages two types of in-game events: 1. Turn-Based Events These are timer-based hazards that count down with each game turn. When a turn counter reaches zero, the associated event handler is called via a jump table. 2. Scenic Events Mostly atmospheric events that randomly appear in different locations to add flavor to the game world (like seagulls appearing at the beach). The routine maintains a table of current locations for each scenic event. On each turn, it checks if any scenic event is NOT in the current room, then randomly relocates it to one of its valid rooms. Each scenic event has a predefined group of rooms where the event can appear. The routine ensures that: Multiple turn-based dangers can threaten the player simultaneously Scenic events don't repeatedly trigger in the same room The game world feels dynamic with events occurring in different locations
First process the turn-based events (if any are active).
GameEventsProcessor	49533	LD A,(48230)	Load *Flag_TurnBasedEventState into A.
	49536	OR A	Jump to GameScenicEventsProcessor if no turn-based events are currently active.
	49537	JR Z,GameScenicEventsProcessor
One of the events has triggered, find which one.
	49539	LD C,A	Copy the turn-based event flags into C.
	49540	LD B,8	Set a counter in B for the number of possible turn-based events (8).
Keep shifting the event flags one-by-one to find which bits are set.
GameEventChecker_Loop	49542	SRL C	Shift C one position left to check the next event flag bit.
	49544	JR NC,GameEventChecker_Next	Jump to GameEventChecker_Next if this event bit isn't set.
The currently processed turn-based event is active, so process it. This is: Counter_Crab+(8-the current event counter).
	49546	LD DE,0	Calculate the turn-based event index and store it in HL.
	49549	LD HL,48231
	49552	LD A,8
	49554	SUB B
	49555	LD E,A
	49556	ADD HL,DE
	49557	DEC (HL)	Decrease the turn-based event counter at *HL by one.
	49558	JR NZ,GameEventChecker_Next	Jump to GameEventChecker_Next if the event turn counter at *HL was still more than zero.
The event turn counter is zero, so activate the event itself.
	49560	LD IX,(48398)	Load *Pointer_TurnBasedEvents_Jump into IX.
	49564	SLA E	Double the index as this table contains addresses.
	49566	ADD IX,DE	Add this offset to IX to point to the current handler.
	49568	LD L,(IX+0)	Get the handler address and store it in HL.
	49571	LD H,(IX+1)	Get the handler address and store it in HL.
	49574	PUSH BC	Stash the bit index and event flag byte on the stack.
	49575	LD DE,49580	Push GameEventChecker_Return onto the stack so that the next return will go on to continue processing events.
	49578	PUSH DE
	49579	JP (HL)	Jump to the routine pointed to by *HL to action the current event.
Once the event handler has run, this is where the routine will resume.
GameEventChecker_Return	49580	POP BC	Restore the event bit index counter and event flag byte from the stack.
GameEventChecker_Next	49581	DJNZ GameEventChecker_Loop	Decrease the event bit counter by one and loop back to GameEventChecker_Loop until all the event status bits have been processed.
Process scenic events.
GameScenicEventsProcessor	49583	NOP	No operation.
	49584	LD HL,48248	Load HL with Table_ScenicEventLocations.
	49587	LD A,(48432)	Load *Count_ScenicEvents into A.
	49590	OR A	Jump to GameEventsProcessor_Return if there are no more scenic events to run (the count is zero).
	49591	JR Z,GameEventsProcessor_Return
	49593	LD B,A	Copy *Count_ScenicEvents into B as an event counter for the loop.
	49594	JR GameScenicEventChecker	Jump to GameScenicEventChecker.
This is the main scenic event loop.
GameScenicEventChecker_Loop	49596	INC HL	Increment the scenic event pointer location by one.
GameScenicEventChecker	49597	LD A,(HL)	Jump to GameScenicEventChecker_Next if the event room is 0 (deactivated).
	49598	OR A
	49599	JR Z,GameScenicEventChecker_Next
	49601	LD A,(48331)	Jump to GameScenicEventChecker_Next if *CurrentRoom is equal to the event room.
	49604	CP (HL)
	49605	JR Z,GameScenicEventChecker_Next
	49607	PUSH HL	Stash the scenic event location pointer and event counter on the stack.
	49608	PUSH BC
This is: E=*Count_ScenicEvents-B.
	49609	LD A,(48432)	Calculate the index of the currently processed event.
	49612	SUB B
	49613	LD E,A
	49614	LD IX,48332	Load Table_ScenicEventRooms into IX.
The routine at GetTableEntry is usually used to fetch an address from the given table, but here it's used to move IX to point to the index of the currently processed event (and this routine will fetch the address itself).
	49618	CALL GetTableEntry	Call GetTableEntry.
	49621	CALL FetchFrames	Load a random number from FetchFrames into B.
	49624	LD B,A	Load a random number from FetchFrames into B.
	49625	LD A,255	Set A to 255 (the room group terminator) for the comparison.
The table at Table_ScenicEventRooms is indexed by event (there are 8 entries), but each address points to a "group" of room IDs where this event could occur. Each set of room IDs for the event is terminated using 255.
GameScenicEvent_FetchRoomGroup	49627	LD L,(IX+0)	Get the room group address pointer and store it in HL.
	49630	LD H,(IX+1)	Get the room group address pointer and store it in HL.
	49633	JR GameScenicEvent_CountRoomsInGroup	Jump to GameScenicEvent_CountRoomsInGroup.
Use the random number to select a room from the group - this loops through the rooms using B as a counter.
GameScenicEvent_CountRooms_Loop	49635	INC HL	Move to the next room ID in the group.
GameScenicEvent_CountRoomsInGroup	49636	CP (HL)	Jump to GameScenicEvent_FetchRoomGroup if the terminator is read from *HL.
	49637	JR Z,GameScenicEvent_FetchRoomGroup
	49639	DJNZ GameScenicEvent_CountRooms_Loop	Decrease the random counter by one and loop back to GameScenicEvent_CountRooms_Loop until the counter is zero.
	49641	LD A,(HL)	Load the current room ID into A.
	49642	POP BC	Restore the event counter and scenic event location pointer from the stack.
	49643	POP HL
	49644	LD (HL),A	Update the scenic event location with the newly selected room.
GameScenicEventChecker_Next	49645	DJNZ GameScenicEventChecker_Loop	Decrease the scenic event counter by one and loop back to GameScenicEventChecker_Loop until all scenic events have been processed.
All done, now return.
GameEventsProcessor_Return	49647	RET	Return.