Rex (Side A): Routine at 9D71

9D71: Handle Rex visibility during teleporting

Used by the routine at 947A.
9D71	LD A,($A060)	Return if Rex is not teleporting
9D74	OR A
9D75	RET Z
9D76	LD A,($A05D)	Return if Rex not visible
9D79	OR A
9D7A	RET Z
9D7B	LD A,($A0B7)	Computes into HL the address pointer into room graphic data for Rex position
9D7E	LD L,A
9D7F	LD H,$00
9D81	ADD HL,HL
9D82	ADD HL,HL
9D83	ADD HL,HL
9D84	ADD HL,HL
9D85	ADD HL,HL
9D86	LD A,($A0B6)
9D89	SRL A
9D8B	SRL A
9D8D	SRL A
9D8F	LD E,A
9D90	LD D,$00
9D92	ADD HL,DE
9D93	LD DE,$E89F
9D96	ADD HL,DE
9D97	LD C,$00	Set C the graphic data to draw
9D99	LD A,($A05E)	Set B to the number of lines to hide from Rex sprite
9D9C	LD B,A	Set B to the number of lines to hide from Rex sprite
9D9D	CALL $9DF6	Hide a portion of Rex to simulate teleporting
9DA0	LD DE,$001D	Garble randomly the last three lines of the Rex sprite not hidden
9DA3	LD B,$03
9DA5	PUSH BC
9DA6	LD B,$03
9DA8	PUSH BC
9DA9	CALL $A375
9DAC	AND (HL)
9DAD	LD (HL),A
9DAE	INC HL
9DAF	POP BC
9DB0	DJNZ $9DA8
9DB2	ADD HL,DE
9DB3	POP BC
9DB4	DJNZ $9DA5
9DB6	LD A,($A062)	Jump forward if teleporting Rex dead
9DB9	OR A
9DBA	JP NZ,$9DCE
9DBD	LD A,($A05E)	Decrement number of lines to hide
9DC0	DEC A
9DC1	LD ($A05E),A
9DC4	OR A	Return if number of lines is not zero
9DC5	RET NZ	Return if number of lines is not zero
9DC6	JP $9DDF	Jump to finish teleporting
Code not reached!
9DC9	LD A,$64
9DCB	LD ($A061),A
Handle teleporting Rex after dead. This entry point is used by the routine at 9D71.
9DCE	LD A,($A05E)	Increment the number of lines to hide
9DD1	INC A
9DD2	LD ($A05E),A
9DD5	CP $12	Return if number of lines is not 18
9DD7	RET NZ	Return if number of lines is not 18
9DD8	XOR A	Set Rex invisible
9DD9	LD ($A05D),A	Set Rex invisible
9DDC	JP $9DE8	Jump to reset teleporting counter
Rex has teleported completely
9DDF	XOR A	Stop teleporting
9DE0	LD ($A060),A	Stop teleporting
9DE3	LD A,$01	Set Rex visible
9DE5	LD ($A05D),A	Set Rex visible
Reset teleporting loop counter
9DE8	LD A,$1E	Reset the teleporting loop counter
9DEA	LD ($A061),A	Reset the teleporting loop counter
9DED	RET
Code not reached!
9DEE	LD A,($A05F)
9DF1	OR A
9DF2	CALL NZ,$9E02
9DF5	RET
Hide B lines of Rex (used in teleporting animation) beginning from top of sprite
9DF6	LD DE,$001E	Set DE to the increment for point to the next line of pixels
9DF9	LD (HL),C	Copy the graphic data from C into room graphic data
9DFA	INC HL
9DFB	LD (HL),C
9DFC	INC HL
9DFD	LD (HL),C
9DFE	ADD HL,DE	Increment HL to the next line
9DFF	DJNZ $9DF9	Jump back until all the lines of Rex are hidden
9E01	RET