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Routines |
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Used by the routine at 49632.
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Follows the previous routine. When Maroc enters a room this routine calculates doors and brickwork patterns based on the room's data set at 25001.
See Trivia: Setting the scene(ry) for an explanation of how this routine evaluates the DOORS and BRICKWORK from the room data set.
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| 49679 | LD (60287),A | Store the above byte (in the A register calculated in the previous routine at 49653) | ||||||||
| 49682 | LD A,(60286) | Get the current room data byte (from the current room data banks at 25001) | ||||||||
| 49685 | RLA | Shift bits (6 & 7) left x 2 | ||||||||
| 49686 | RL C | ...Shifting them into bits 0 & 1 of the C register | ||||||||
| 49688 | RLA | |||||||||
| 49689 | RL C | |||||||||
| 49691 | LD (60286),A | First two bits moved - now re-store the data byte for further shifts of the next ones later | ||||||||
| 49694 | LD A,C | We're only interested in bits 0 and 1 of the C register | ||||||||
| 49695 | AND 3 | So filter any others out | ||||||||
| 49697 | LD C,A | |||||||||
| 49698 | AND 1 | Check bit 0. If set, this indicates that there's a DOOR here. | ||||||||
| 49700 | JR Z,49765 | ...If it's NOT set, skip over the next routine to check for BRICKWORK patterns | ||||||||
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DOOR identified from room data set. Check where in the room it is:
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| 49702 | LD A,(60281) | Item's vertical position within current room, in pixels, from top of room area. | ||||||||
| 49705 | LD (60234),A | ...Copy byte into store | ||||||||
| 49708 | LD A,(60280) | Horizontal position within current room, in half-character (4 pixel) steps. | ||||||||
| 49711 | LD (60232),A | ...Copy byte into store | ||||||||
| 49714 | LD A,(60287) | 0 = back wall, 1 = right wall, 2 = left wall | ||||||||
| 49717 | LD (60230),A | ...Copy byte into store | ||||||||
| 49720 | LD A,2 | Graphic type = 2 (Door) | ||||||||
| 49722 | LD (60227),A | |||||||||
| 49725 | CALL 57520 | Copy the 16 bytes in the item's working data buffer at 60227 into a room item data set at 31744. | ||||||||
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DOOR FRAMES - set up/mirror graphics
Each door has a door frame, which is a separate graphic to be handled
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| 49728 | LD A,1 | Graphics type = 1 (fixed room scenery item, in this case a door frame) | ||||||||
| 49730 | LD (60227),A | |||||||||
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The byte calculated earlier (0, 1 or 2) indicates whether the item is on the back wall, right wall or left wall, so the following instructions use this information to work out the graphics address offset (in C register).
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| 49733 | LD C,20 | Redundant instruction as C value (offset) is set either at 49742 (20) or 49748 (21) | ||||||||
| 49735 | LD A,(60287) | 0 = Back wall door, 1 = Right wall door or 2 = Left wall door | ||||||||
| 49738 | CP 0 | |||||||||
| 49740 | JR NZ,49748 | |||||||||
| 49742 | LD C,20 | Back wall - Graphics offset = (20-1)*2 + 38851 = 38889 (Door frame - back wall) | ||||||||
| 49744 | LD A,1 | Frame offset (= no offset needed) | ||||||||
| 49746 | JR 49750 | |||||||||
| 49748 | LD C,21 | Side wall - Graphics offset = (21-1)*2 + 38851 = 38891 (Door frame - side wall) | ||||||||
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Set up and mirror graphics for door frame
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| 49750 | LD (60240),A | Store calculated frame offset | ||||||||
| 49753 | LD A,(60279) | Get level style offset (for to graphic pointers at 38851). This is 12 if room number >=84 (cavern levels), otherwise 0 (brick levels). |
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| 49756 | ADD A,C | Add the offset (20 or 21) to graphics offset addresses depending on whether the door frame is on the back or side wall | ||||||||
| 49757 | CALL 57538 | Call setup graphics routine (copy graphics address pointers), mirror any relevant graphic data | ||||||||
| 49760 | CALL 57520 | Copy the 16 bytes of calculated graphics data from the working buffer at 60227 into one of the the room item data sets at 31744. | ||||||||
| 49763 | JR 49858 | |||||||||
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