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Routines |
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The handler for a trapdoor that is open (sprite ID 19). If the low byte of the random number seed at RandomSeed is not zero then the trapdoor is used by FallThroughTrapdoor. Otherwise HandlerTrap_Toggle closes it.
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| HandlerTrapOpen | 91C5 | LD A,($5E05) | Fetch the random seed from RandomSeed. | |||||
| 91C8 | AND A | Test whether it is zero. | ||||||
| 91C9 | JP NZ,FallThroughTrapdoor | Jump to FallThroughTrapdoor if it is not. | ||||||
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This entry point is used by the routine at HandlerTrapClosed.
Change the trapdoor from open to closed or the other way round. It is erased and drawn again with a temporary attribute.
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| HandlerTrap_Toggle | 91CC | LD A,(IX+$05) | Fetch the attribute of the trapdoor. | |||||
| 91CF | PUSH AF | Stash it on the stack. | ||||||
| 91D0 | OR %00000011 | Set bits 0-1, which is temporary. | ||||||
| 91D2 | LD (IX+$05),A | Update the attribute of the trapdoor. | ||||||
| 91D5 | CALL DrawItemGraphic | Call DrawItemGraphic to erase the trapdoor. | ||||||
| 91D8 | LD A,(IX+$00) | Fetch the sprite ID of the trapdoor. | ||||||
| 91DB | XOR %00000001 | Flip bit 0, which changes the trapdoor from open to closed or the other way round. | ||||||
| 91DD | LD (IX+$00),A | Update the sprite ID of the trapdoor. | ||||||
| 91E0 | CALL DrawItemGraphic | Call DrawItemGraphic to draw the trapdoor. | ||||||
| 91E3 | POP AF | Restore the attribute of the trapdoor from the stack. | ||||||
| 91E4 | LD (IX+$05),A | Write it to the attribute of the trapdoor. | ||||||
| 91E7 | CALL HandlerRoomItem | Call HandlerRoomItem to handle a room item that does nothing. | ||||||
| 91EA | JP SoundsDoor | Jump to SoundsDoor to make the sound of a door. | ||||||
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