Routines
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35016: AnimateCrewB
Animates marker channel B — the blinking box cursor on a candidate room (placed by PlaceRoomMarkerB 35128). Identical logic to 34967 (AnimateCrewA) but uses a faster frame rate (counter resets to 5 rather than 10), the B-set animation table at 26861, and the B-channel screen address at SpriteDestAddr (33688). Cycles through four cursor shapes (RoomCursor0-3) at twice the speed of the crew walk animation.
Input
Used by the routines at 36457, 38379 and 42821.
35016 LD A,(31264) A = animation-freeze / frame-phase byte (31264)
35019 BIT 7,A bit 7 = freeze flag
35021 RET NZ frozen: skip
35022 LD HL,33690 HL = frame counter B ($83CA)
35025 DEC (HL) tick down counter
35026 RET NZ not expired
35027 LD (HL),5 reset to 5 frames per phase (2× speed of set A)
35029 LD B,2 draw 2 sprite rows
This entry point is used by the routine at 42821.
35031 PUSH BC
35032 LD E,A E = frame phase (0-3)
35033 LD D,0
35035 LD HL,26861 base of crew-B animation table (26861)
35038 ADD HL,DE index by phase × 2
35039 ADD HL,DE
35040 LD A,(HL) read 16-bit sprite bitmap pointer
35041 INC HL
35042 LD H,(HL)
35043 LD L,A HL = pointer to sprite row data
35044 EX DE,HL DE = sprite data source
35045 LD HL,(33688) HL = screen destination address (33688)
35048 CALL 35065 XOR-blit 3 bytes × 12 rows onto screen
35051 POP BC
35052 DEC B
35053 RET Z
35054 LD A,(31264) advance frame phase
35057 INC A
35058 AND 3 wrap 0-3
35060 LD (31264),A
35063 JR 35031
This entry point is used by the routine at 34967.
35065 LD C,12
35067 LD B,3
35069 LD A,(DE)
35070 XOR (HL)
35071 LD (HL),A
35072 INC HL
35073 INC DE
35074 DJNZ 35069
35076 DEC HL
35077 DEC HL
35078 DEC HL
35079 PUSH DE
35080 CALL 31393
35083 POP DE
35084 DEC C
35085 JR NZ,35067
35087 RET
GetRoomMarkerAddr: A = room id (0-33) -> HL = display-file address of the room's indicator box on its deck map, from RoomMarkerAddrTable (26569).
35088 ADD A,A
35089 LD D,0
35091 LD E,A
35092 LD HL,26569 RoomMarkerAddrTable + room*2
35095 ADD HL,DE
35096 LD A,(HL)
35097 INC HL
35098 LD H,(HL)
35099 LD L,A HL = the room's marker screen address
35100 RET
This entry point is used by the routine at 31634. PlaceRoomMarkerA: aim marker channel A (the walking crew figure that marks the viewed room on the deck map) at the current room (31242) and draw its first frame; no marker on the Narcissus (deck type 3). Channel A then keeps animating via AnimateCrewA (34967).
35101 LD A,(31243) on the Narcissus (type 3)?
35104 CP 3
35106 RET NC yes: no marker
35107 LD A,(31242) A = the viewed room
35110 CALL 35088
35113 LD (33686),HL channel A dest = its marker address
35116 LD HL,31263
35119 RES 7,(HL) unfreeze channel A
35121 LD A,(HL) A = current phase
35122 LD B,1
35124 CALL 34982 XOR-blit one frame (place the box)
35127 RET
This entry point is used by the routines at 34684 and 35338. PlaceRoomMarkerB: aim marker channel B (the "candidate room" blinker) at room A and draw its first frame. Used for the exit row under the cursor in the room view (UpdateRoomMarkerB 34933) and for a room picked from the Indicate Location list (LocationListAction 35338). Channel B then keeps blinking via AnimateCrewB (35016).
35128 CALL 35088 HL = marker address of room A
35131 LD (33688),HL channel B dest = it
35134 LD HL,31264
35137 RES 7,(HL) unfreeze channel B
35139 LD A,(HL) A = current phase
35140 LD B,1
35142 CALL 35031 XOR-blit one frame (place the box)
35145 RET
This entry point is used by the routine at 34684. EraseRoomMarkerB: if marker channel B is live, XOR-blit its current frame once more (which removes it from the screen) and freeze the channel.
35146 LD HL,31264
35149 BIT 7,(HL) already frozen?
35151 RET NZ yes: nothing to erase
35152 PUSH HL
35153 LD A,(HL) A = current phase
35154 LD B,1
35156 CALL 35031 XOR-blit once = erase
35159 POP HL
35160 SET 7,(HL) freeze the channel
35162 RET
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