Routines
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678A: Handler: Display Room
Used by the routines at LoadFromTape, MovePlayerToRoom and Action_Look.
Draw the current location, its exits and the objects that are here.
Handler_DisplayRoom 678A PUSH DE Remember whether the caller asked for the picture.
678B CALL ClearScreen Call ClearScreen to clear the screen.
678E POP DE Restore that request.
678F LD A,($62CA) Fetch how many rooms have a picture.
6792 OR A No room has a picture.
6793 JR Z,Handler_DisplayRoom_Step4
6795 LD A,($6223) Fetch the current room.
6798 LD HL,($62CC) Fetch the list of rooms that have a picture.
679B LD BC,($62CA) Fetch how many rooms have a picture.
679F CPIR Find this room in the list of pictures.
67A1 JR NZ,Handler_DisplayRoom_Step4 This room has no picture.
67A3 LD A,($62CA) Fetch how many rooms have a picture.
67A6 INC C Recover this room's slot in the picture list.
67A7 SUB C
67A8 LD C,A
67A9 XOR A A nonzero request draws the picture even when it has been seen.
67AA OR E
67AB JR NZ,Handler_DisplayRoom_Step2 Skip the seen-flag test when the picture was requested again.
67AD LD HL,$6213 Check whether this room's picture has been shown.
67B0 LD A,C The picture slot selects its seen flag.
Handler_DisplayRoom_Loop1 67B1 CP $08 Jump to Handler_DisplayRoom_Step1 when the picture slot is below 08, in this flag byte.
67B3 JR C,Handler_DisplayRoom_Step1
67B5 SUB $08 Move to the next flag byte while the slot is past this one.
67B7 INC HL
67B8 JR Handler_DisplayRoom_Loop1 Continue at Handler_DisplayRoom_Loop1 to test the next picture-seen flag.
Handler_DisplayRoom_Step1 67BA LD B,A Build the bit that belongs to this picture.
67BB INC B
67BC LD D,$00
Handler_DisplayRoom_Loop2 67BE RL D Shift that bit into place.
67C0 DJNZ Handler_DisplayRoom_Loop2 Repeat until the bit lines up with this picture.
67C2 LD A,(HL) Read the seen flags for these pictures.
67C3 AND D See whether this picture has already been shown.
67C4 JR NZ,Handler_DisplayRoom_Step4 Skip the picture when it has already been shown.
67C6 LD A,(HL) Remember that this picture has now been shown.
67C7 OR D
67C8 LD (HL),A
Handler_DisplayRoom_Step2 67C9 LD A,$08 Start the picture on text row 08.
67CB LD ($629B),A
67CE LD HL,$620F The display flags record the room picture.
67D1 SET 0,(HL) Remember to wait for a key once the picture is drawn.
67D3 LD IX,($62CE) Fetch the room-picture handlers.
67D7 LD E,C The picture slot selects its drawing routine.
67D8 CALL GetTableEntry Call GetTableEntry to look up the table entry.
Handler_DisplayRoom_Step3 67DB LD DE,$67E0 Draw the picture, then continue with the room text.
67DE PUSH DE
67DF JP (HL)
Handler_DisplayRoom_Step4 67E0 CALL SetScreenPosition Call SetScreenPosition to move the cursor to the stored row.
67E3 LD A,$18 Continue the description on text row 18.
67E5 LD ($629B),A
67E8 LD A,($6223) Fetch the current room.
67EB LD IX,($62D0) Fetch the room-description table.
67EF LD E,A The current room selects its description.
67F0 CALL GetTableEntry Call GetTableEntry to look up the table entry.
67F3 CALL PrintStringAndANewline Print the room description and start a new line.
67F6 LD HL,$620F The display flags record a picture waiting for a key.
67F9 BIT 0,(HL) No picture is waiting for a key.
67FB JR Z,Handler_DisplayRoom_Step5
67FD RES 0,(HL) The picture no longer waits for a key.
67FF CALL GetUserInput Call GetUserInput to wait for a keypress.
Handler_DisplayRoom_Step5 6802 CALL GetRoomPointer Call GetRoomPointer to find the exit record.
6805 LD D,H There are six exits to count.
6806 LD E,L
6807 LD B,$06
6809 LD C,$00
680B XOR A A zero byte means that direction is closed.
Count the open exits so they can be listed.
Handler_DisplayRoom_Loop3 680C CP (HL) Count this exit when it is open.
680D JR Z,Handler_DisplayRoom_Step6
680F INC C
Handler_DisplayRoom_Step6 6810 INC HL Move on to the next direction.
6811 DJNZ Handler_DisplayRoom_Loop3
6813 OR C See whether any exit is open.
6814 JR Z,Handler_DisplayRoom_Step12 Skip the exit list when the room has none.
6816 LD A,C One open exit uses the singular wording.
6817 CP $01 More than one open exit uses the plural line.
6819 JR NZ,Handler_DisplayRoom_Step8
681B LD HL,$6347 Print There is an exit on the same line.
681E CALL PrintString
6821 LD H,D Return to the exit record and the direction names.
6822 LD L,E
6823 LD IX,$646D
6827 XOR A
6828 JR Handler_DisplayRoom_Step7
Handler_DisplayRoom_Loop4 682A INC HL Skip a closed exit and its direction name.
682B INC IX
682D INC IX
Handler_DisplayRoom_Step7 682F CP (HL) Keep skipping while this exit is closed.
6830 JR Z,Handler_DisplayRoom_Loop4
6832 LD L,(IX+$00) Read the name of this open exit.
6835 LD H,(IX+$01)
6838 CALL PrintString Call PrintString to print the message.
683B JR Handler_DisplayRoom_Step11 Continue at Handler_DisplayRoom_Step11 to end the list of exits.
Handler_DisplayRoom_Step8 683D LD HL,$6334 Print There are exits:-.
6840 CALL PrintStringAndANewline
6843 LD H,D Return to the exit record and the direction names.
6844 LD L,E
6845 LD IX,$646D
6849 XOR A
684A JR Handler_DisplayRoom_Step9
Handler_DisplayRoom_Loop5 684C EX DE,HL Hold the exit record while the next name is printed.
Handler_DisplayRoom_Loop6 684D INC HL Skip a closed exit and its direction name.
684E INC IX
6850 INC IX
Handler_DisplayRoom_Step9 6852 CP (HL) Keep skipping while this exit is closed.
6853 JR Z,Handler_DisplayRoom_Loop6
6855 EX DE,HL Bring the exit record back after printing a name.
6856 LD L,(IX+$00) Read the name of this open exit.
6859 LD H,(IX+$01)
685C CALL PrintString Call PrintString to print the message.
685F DEC C One fewer exit name remains.
6860 LD A,C
6861 CP $01 Finish the list when no exit name remains.
6863 JR C,Handler_DisplayRoom_Step11
6865 JR Z,Handler_DisplayRoom_Step10 The last remaining exit is joined with "and".
6867 LD A,$2C Separate these exit names with a comma.
6869 CALL PrintCharacter Call PrintCharacter to print the character.
686C XOR A Prepare to test the next exit.
686D JR Handler_DisplayRoom_Loop5 Continue at Handler_DisplayRoom_Loop5 to name another open exit.
Handler_DisplayRoom_Step10 686F LD HL,$6330 Print & on the same line.
6872 CALL PrintString
6875 XOR A Prepare to test the next exit.
6876 JR Handler_DisplayRoom_Loop5 Continue at Handler_DisplayRoom_Loop5 to name the last open exit.
Handler_DisplayRoom_Step11 6878 LD HL,$646B Print ..
687B CALL PrintStringAndANewline
Handler_DisplayRoom_Step12 687E LD A,($6223) Fetch the current room.
6881 CALL IsObjectPresent Call IsObjectPresent to see whether anything is in the room.
6884 RET NZ Return when the room is empty.
6885 LD HL,$6321 Print You can see:-.
6888 CALL PrintStringAndANewline
688B LD A,($6223) Fetch the current room.
688E CALL PrintObjects Call PrintObjects to list the objects here.
6891 RET Return.
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