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Routines |
| Prev: 6A27 | Up: Map | Next: 6AB5 |
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This first wipes the visible tiles array then sets up interior doors, gets the room definition pointer then uses that to setup boundaries, set up interior masks and finally plot all objects into the visible tile array.
Used by the routines at enter_room, pick_up_item, process_player_input, wake_up, end_of_breakfast, select_room_and_plot and action_shovel.
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| setup_room | 6A35 | CALL wipe_visible_tiles | Wipe the visible tiles array | |
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Form the address of rooms_and_tunnels[room_index - 1] in HL.
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| 6A38 | LD A,($68A0) | Fetch the global current room index | ||
| 6A3B | ADD A,A | Double it so we can index rooms_and_tunnels[] | ||
| 6A3C | LD HL,$6BAB | Point HL at rooms_and_tunnels rooms_and_tunnels[-1] | ||
| 6A3F | ADD A,L | HL + A | ||
| 6A40 | LD L,A | |||
| 6A41 | JR NC,setup_room_0 | |||
| 6A43 | INC H | |||
| setup_room_0 | 6A44 | LD A,(HL) | Fetch room pointer in HL | |
| 6A45 | INC HL | |||
| 6A46 | LD H,(HL) | |||
| 6A47 | LD L,A | |||
| 6A48 | PUSH HL | Push it | ||
| 6A49 | CALL setup_doors | Setup interior doors | ||
| 6A4C | POP HL | Pop it | ||
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Copy the count of boundaries into state.
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| 6A4D | LD DE,$81BE | Point DE at roomdef_bounds_index roomdef_bounds_index | ||
| 6A50 | LDI | Copy first byte of roomdef into roomdef_bounds_index. (DE, HL incremented). | ||
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DE now points to roomdef_object_bounds_count
Copy all boundary structures into state, if any.
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| 6A52 | LD A,(HL) | Fetch count of boundaries | ||
| 6A53 | AND A | Is it zero? | ||
| 6A54 | LD (DE),A | Store it irrespectively | ||
| 6A55 | JR NZ,setup_room_1 | No, jump to copying step | ||
| 6A57 | INC HL | Skip roomdef count of boundaries | ||
| 6A58 | JR setup_room_2 | Jump to mask copying | ||
| setup_room_1 | 6A5A | ADD A,A | Multiply A by four (size of boundary structures) then add one (skip current counter) == size of boundary structures | |
| 6A5B | ADD A,A | |||
| 6A5C | INC A | |||
| 6A5D | LD C,A | Copy all boundary structures | ||
| 6A5E | LD B,$00 | |||
| 6A60 | LDIR | |||
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Copy interior mask into interior_mask_data.
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| setup_room_2 | 6A62 | LD DE,$81DA | Point DE at interior_mask_data | |
| 6A65 | LD A,(HL) | Get count of interior masks | ||
| 6A66 | INC HL | Step | ||
| 6A67 | LD (DE),A | Write it out | ||
| 6A68 | AND A | Is the count non-zero? | ||
| 6A69 | JR Z,setup_room_4 | Jump if not | ||
| 6A6B | INC DE | Skip over the written count | ||
| 6A6C | LD B,A | B is our loop counter | ||
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Start loop
interior_mask_data holds indices into interior_mask_data_source[].
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| setup_room_3 | 6A6D | PUSH BC | ||
| 6A6E | PUSH HL | |||
| 6A6F | LD L,(HL) | Fetch an index (from roomdef?) | ||
| 6A70 | LD H,$00 | |||
| 6A72 | LD B,H | BC = HL | ||
| 6A73 | LD C,L | |||
| 6A74 | ADD HL,HL | Multiply it by eight | ||
| 6A75 | ADD HL,HL | |||
| 6A76 | ADD HL,HL | |||
| 6A77 | AND A | Clear the carry flag | ||
| 6A78 | SBC HL,BC | Final offset is index * 7 | ||
| 6A7A | LD BC,$EA7C | Point at interior_mask_data_source | ||
| 6A7D | ADD HL,BC | Form the address of the mask data | ||
| 6A7E | LD BC,$0007 | Width of mask data | ||
| 6A81 | LDIR | Copy it | ||
| 6A83 | LD A,$20 | Constant final byte is always 32 | ||
| 6A85 | LD (DE),A | |||
| 6A86 | INC DE | |||
| 6A87 | POP HL | |||
| 6A88 | INC HL | |||
| 6A89 | POP BC | |||
| 6A8A | DJNZ setup_room_3 | ...loop | ||
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Plot all objects (as tiles).
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| setup_room_4 | 6A8C | LD B,(HL) | Count of objects | |
| 6A8D | LD A,B | |||
| 6A8E | AND A | Is it zero? | ||
| 6A8F | RET Z | Return if so | ||
| 6A90 | INC HL | Skip the count | ||
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Start loop: for every object in the roomdef
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| setup_room_5 | 6A91 | PUSH BC | ||
| 6A92 | LD C,(HL) | Fetch the object index | ||
| 6A93 | INC HL | |||
| 6A94 | LD A,(HL) | Fetch the column | ||
| 6A95 | INC HL | |||
| 6A96 | PUSH HL | |||
| 6A97 | LD L,(HL) | |||
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Plot the object into the visible tiles array
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| 6A98 | LD H,$00 | DE = $F0F8 + row * 24 + column. | ||
| 6A9A | ADD HL,HL | |||
| 6A9B | ADD HL,HL | |||
| 6A9C | ADD HL,HL | |||
| 6A9D | LD E,L | |||
| 6A9E | LD D,H | |||
| 6A9F | ADD HL,HL | |||
| 6AA0 | ADD HL,DE | |||
| 6AA1 | ADD A,L | |||
| 6AA2 | LD L,A | |||
| 6AA3 | JR NC,setup_room_6 | |||
| 6AA5 | INC H | |||
| setup_room_6 | 6AA6 | LD DE,$F0F8 | ||
| 6AA9 | ADD HL,DE | |||
| 6AAA | EX DE,HL | |||
| 6AAB | LD A,C | |||
| 6AAC | CALL expand_object | Expand RLE-encoded object out to a set of tile references | ||
| 6AAF | POP HL | |||
| 6AB0 | POP BC | |||
| 6AB1 | INC HL | |||
| 6AB2 | DJNZ setup_room_5 | ...loop | ||
| 6AB4 | RET | Return | ||
| Prev: 6A27 | Up: Map | Next: 6AB5 |