Dynamite Dan: Routine at D9EC

D9EC: Update the raft

Used by the routines at C800 and D3EC.
D9EC	LD A,($D9EA)	Put the room the raft is in (D9EA) in B.
D9EF	LD B,A	Put the room the raft is in (D9EA) in B.
D9F0	LD A,($CFCA)	Put the current room (CFCA) in C.
D9F3	LD C,A	Put the current room (CFCA) in C.
D9F4	LD DE,($D9E8)	Get the raft x-cordinate and frame (D9E8, D9E9) in DE.
D9F8	LD HL,$D9EB	Decrement the tick count and jump forward until it reaches 0.
D9FB	DEC (HL)
D9FC	JR NZ,$DA1B
D9FE	LD (HL),$03	Reset the tick count to 3.
DA00	INC E	Move to the next animation frame.
DA01	LD A,E	Has it reached 4?
DA02	CP $04	Has it reached 4?
DA04	JR NZ,$DA37	No, so move forward.
The raft needs moving.
DA06	LD E,$00	Otherwise set it back to 0.
DA08	DEC D	Move left one column.
DA09	LD A,D	Has the raft reached the edge of the screen?
DA0A	CP $FC	Has the raft reached the edge of the screen?
DA0C	JR NZ,$DA37	Jump forward if it hasn't.
DA0E	LD D,$1C	Put the raft on the right of the screen.
DA10	INC B	Put the raft in the room to the left.
DA11	LD A,B	Ensure the room cycles between 0 - 7.
DA12	AND $07
DA14	LD B,A
DA15	LD A,C	Is the raft in this room?
DA16	CP B	Is the raft in this room?
DA17	JR NZ,$DA1B	Jump forward if it's not.
The raft is in this room.
DA19	LD D,$1F
DA1B	LD A,C
DA1C	CP $08
DA1E	JR NC,$DA33
DA20	INC A
DA21	CP B
DA22	JR C,$DA2E
DA24	LD A,B
DA25	CP $02
DA27	JR C,$DA33
DA29	LD A,C
DA2A	DEC A
DA2B	CP B
DA2C	JR C,$DA33
DA2E	LD A,C
DA2F	DEC A
DA30	AND $07
DA32	LD B,A
DA33	LD A,B
DA34	LD ($D9EA),A
DA37	LD ($D9E8),DE
DA3B	LD A,C
DA3C	CP B
DA3D	RET NZ
The raft is in the current room, so draw it
DA3E	LD A,E	Get the X co-ordinate of the raft graphic.
DA3F	ADD A,A	Multiply by 32 to get an appropriate offset.
DA40	ADD A,A
DA41	ADD A,A
DA42	ADD A,A
DA43	ADD A,A
DA44	LD C,A	Put this in BC.
DA45	LD B,$00	Put this in BC.
DA47	LD HL,$6899	Add the offset of the raft graphic. (6899)
DA4A	ADD HL,BC	Add the offset of the raft graphic. (6899)
DA4B	LD C,D	Get the y co-ordinate of the raft.
DA4C	LD DE,$5040	Get the basic y screen position of the raft.
DA4F	EX DE,HL
DA50	LD A,C
DA51	CP $20
DA53	JR NC,$DA56
DA55	ADD HL,BC	Add the offset to get the current graphic.
DA56	LD B,$04	Draw 4 columns.
DA58	LD A,C
DA59	CP $20
DA5B	JR C,$DA66
DA5D	PUSH HL
DA5E	LD HL,$0008
DA61	ADD HL,DE
DA62	EX DE,HL
DA63	POP HL
DA64	JR $DA7A
DA66	PUSH BC
DA67	PUSH HL
DA68	LD B,$08
DA6A	LD A,(DE)
DA6B	LD (HL),A
DA6C	INC H
DA6D	INC DE
DA6E	DJNZ $DA6A
DA70	POP HL
DA71	POP BC
DA72	LD H,$5A	Set to the next to bottom row of the screen.
DA74	LD A,$02	Fill with red on black.
DA76	LD (HL),A	Fill with red on black.
DA77	LD H,$50
DA79	INC L
DA7A	INC C	Move to the next column.
DA7B	DJNZ $DA58	Loop until all columns drawn.
DA7D	LD A,C
DA7E	CP $20
DA80	RET NC
DA81	LD H,$5A
DA83	LD A,$45
DA85	LD (HL),A
DA86	RET