Underwurlde: Routine at 57439

Used by the routine at Run_Game.

Starts a bubble at the bottom of the room every now and then.

Nothing happens in a special room (a room y below 16), or when the type of Sabreman is 60 or more, which means that he is dying or being carried. The bubble takes one of the four bubble records that start at First_Bubble_Record, if one is free. A bubble is only made when the low byte of the frame counter plus 26 has its low six bits clear.

The record is a copy of the record of Sabreman, so the bubble is in his room. Its type is 88 its y position is 191 (the bottom of the room), its attribute is 70 (yellow) and its x position is 64 or 192 depending on bit 7 of the tick counter. The handler is Handle_Bubble.

Used by the routine at Run_Game. Starts a bubble at the bottom of the room every now and then. Nothing happens in a special room (a room y below 16), or when the type of Sabreman is 60 or more, which means that he is dying or being carried. The bubble takes one of the four bubble records that start at First_Bubble_Record, if one is free. A bubble is only made when the low byte of the frame counter plus 26 has its low six bits clear. The record is a copy of the record of Sabreman, so the bubble is in his room. Its type is 88 its y position is 191 (the bottom of the room), its attribute is 70 (yellow) and its x position is 64 or 192 depending on bit 7 of the tick counter. The handler is Handle_Bubble.
Spawn_Bubble	57439	LD A,(36634)	Fetch the type of Sabreman.
	57442	CP 60	Return if the type is 60 or more.
	57444	RET NC	Return if the type is 60 or more.
	57445	LD A,(36638)	Fetch the room y of Sabreman.
	57448	CP 16	Return if it is a special room.
	57450	RET C	Return if it is a special room.
	57451	LD HL,36698	Point HL at First_Bubble_Record.
	57454	LD DE,16	Set DE to the size of an object record.
	57457	LD B,4	Set a counter in B for the four bubble records.
Spawn_Bubble_Find_Record	57459	LD A,(HL)	Fetch the type of the record.
	57460	AND A	Jump to Spawn_Bubble_Create if the record is free.
	57461	JR Z,Spawn_Bubble_Create	Jump to Spawn_Bubble_Create if the record is free.
	57463	ADD HL,DE	Move on to the next record.
	57464	DJNZ Spawn_Bubble_Find_Record	Decrease the record counter and loop back for the next record.
	57466	RET	Return, as all four bubble records are in use.
Spawn_Bubble_Create	57467	EX DE,HL	Point DE at the free record.
	57468	LD HL,36634	Point HL at Sabreman_Record.
	57471	LD A,(23672)	Fetch the low byte of the frame counter.
	57474	ADD A,L	Add the low byte of the address of the record of Sabreman.
	57475	AND %00111111	Keep only the low six bits.
	57477	RET NZ	Return unless they are zero.
	57478	LD BC,15	Set a counter of 15 bytes.
	57481	PUSH DE	Stash the address of the bubble record.
	57482	LDIR	Copy the record of Sabreman to the bubble record, except for the redraw flags.
	57484	POP HL	Restore the address of the bubble record to HL.
	57485	LD A,88	Set the type to 88.
	57487	LD (HL),A	Set the type to 88.
	57488	LD A,(36566)	Fetch the tick counter.
	57491	AND %10000000	Keep only bit 7.
	57493	ADD A,64	Add 64 which makes 64 or 192.
	57495	INC HL	Move to the x position.
	57496	LD (HL),A	Set the x position.
	57497	INC HL	Move to the y position.
	57498	INC HL	Move to the y position.
	57499	LD (HL),191	Set the y position to 191.
	57501	INC HL	Move to the attribute.
	57502	INC HL	Move to the attribute.
	57503	LD (HL),70	Set the attribute to 70 (yellow).
	57505	LD A,1	A=1 (the value of the redraw flags).
	57507	LD DE,10	Set the offset from the attribute to the redraw flags of the record (10).
	57510	ADD HL,DE	Move to the redraw flags.
	57511	LD (HL),A	Set the redraw flags to 1 so that the bubble is drawn without being erased first.
	57512	RET	Return.