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Routines |
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No collision between a creature missile and Maroc (jump from 53540), or the missile has been fired by Maroc (jump from 53531)
Missiles hitting a wall will bounce off like any other room objects.
 
Check for collisions with room walls:
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| 53550 | CALL 56008 | Check that the missile isn't moving below the bottom of the room boundary. Return any adjusted vertical pixel position in the E register | ||
| 53553 | CALL 57401 | Run collision detection routine for room walls, adjusting horizontal position if needed. | ||
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Missiles have varied lifespans. Note from the animated images how the VAPORIZE spell bolt lasts longer than the MISSILE spell.
The second byte in the missile sets at 27868 holds this information.
Reduce this missile's timer, and make it disappear if its timer has run out.
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| 53556 | LD A,(60238) | Item properties byte. For missiles, the value contained in the top 4 bits of this byte tells holds the duration this missile will appear/travel for before it disappears. |
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| 53559 | SUB 16 | Reduce the time/distance of this value by 16 (initial values are between 144 and 240) | ||
| 53561 | JR C,53569 | |||
| 53563 | LD (60238),A | If the missile is still with us, jump out to the next routine | ||
| 53566 | JP 53885 | |||
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Jump here from 53408 if missile is off-screen, or the missile's lifespan has finished/fizzled out
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| 53569 | LD A,(60227) | Object type | ||
| 53572 | CP 5 | Type 5 = Missile fired by a creature/warlock | ||
| 53574 | JR Z,53581 | |||
| 53576 | LD HL,60306 | Missile fired by Maroc | ||
| 53579 | JR 53584 | |||
| 53581 | LD HL,60305 | Missile fired by creature/warlock | ||
| 53584 | DEC (HL) | Maroc's missile - decrement Maroc's missile count (from one to zero) Creature missile - decrement number of creature missiles in room (from one to zero) |
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| 53585 | LD A,0 | |||
| 53587 | LD (60227),A | Missile has fizzled out, so set item type to 0 | ||
| 53590 | LD A,(60238) | Get item properties byte | ||
| 53593 | OR 4 | Set bit 2 (4) - this indicates the graphic will need erasing | ||
| 53595 | LD (60238),A | ...and re-store. | ||
| 53598 | JP 53885 | |||
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