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Routines |
| Prev: B7BC | Up: Map | Next: B87E |
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Move the bomb by its speed. A hit on the alien base scores 3000 and writes 01 to Missile_Destroyed_Flag.
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Move the thrown bomb by its speed.
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| FlyThrownBomb | B810 | CALL TickObjectTimer | Call TickObjectTimer. | |||||
| B813 | LD A,($5EA3) | Fetch RoverCargoFlag. | ||||||
| B816 | AND A | Jump to FlyThrownBomb_Move if it is not zero. | ||||||
| B817 | JR NZ,FlyThrownBomb_Move | |||||||
| B819 | CALL CompareActorDistance | Call CompareActorDistance. | ||||||
| B81C | JR C,FlyThrownBomb_CollectRover | Jump to FlyThrownBomb_CollectRover if the bomb is close to the rover. | ||||||
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Move the bomb along and check the ground line.
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| FlyThrownBomb_Move | B81E | CALL MoveBySpeed | Call MoveBySpeed. | |||||
| B821 | CP $AF | Jump to FlyThrownBomb_Land if the new Y is on or below the ground line. | ||||||
| B823 | JR NC,FlyThrownBomb_Land | |||||||
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Test the bomb against the alien base.
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| B825 | LD (IX+$04),A | Write the actor Y. | ||||||
| B828 | CALL FlyThrownBomb_TestBase | Call FlyThrownBomb_TestBase. | ||||||
| B82B | JP NC,CollectBomb_Loop | Jump to CollectBomb_Loop if the bomb missed the base. | ||||||
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Turn the object slots into craters and explosions and record the hit on the base.
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| B82E | CALL Handler_Missile_ConvertExploding | Call Handler_Missile_ConvertExploding. | ||||||
| B831 | LD A,$01 | Write 01 to Missile_Destroyed_Flag. | ||||||
| B833 | LD ($6195),A | |||||||
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Destroying the alien base adds 3000 points.
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| B836 | LD BC,$3000 | Set the points to award in BC to 3000. | ||||||
| B839 | CALL AddPointsToScore | Call AddPointsToScore. | ||||||
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Put the bomb on the ground line and change its type to C0.
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| FlyThrownBomb_Land | B83C | LD (IX+$04),$AF | Write AF to the actor Y. | |||||
| B840 | CALL DrawCurrentActor_Draw | Call DrawCurrentActor_Draw. | ||||||
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""Crater"".
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| B843 | LD (IX+$00),$C0 | Write type C0. | ||||||
| B847 | RET | Return. | ||||||
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Flag the bomb as collected by the rover.
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| FlyThrownBomb_CollectRover | B848 | SET 2,(IX+$08) | Set bit 2 of the actor flags. | |||||
| B84C | LD A,$01 | Write 01 to RoverCargoFlag. | ||||||
| B84E | LD ($5EA3),A | |||||||
| B851 | JP DrawCurrentActor_Draw | Jump to DrawCurrentActor_Draw. | ||||||
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Test the bomb against the alien-base slot.
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| FlyThrownBomb_TestBase | B854 | LD E,$18 | E=18. | |||||
| B856 | LD L,(IX+$02) | Fetch the bomb world X. | ||||||
| B859 | LD H,(IX+$03) | Fetch the high byte. | ||||||
| B85C | LD BC,$0018 | Add a 18 window. | ||||||
| B85F | ADD HL,BC | |||||||
| B860 | LD BC,($6182) | Fetch AlienBase_WorldX. | ||||||
| B864 | AND A | Subtract the alien base world X. | ||||||
| B865 | SBC HL,BC | |||||||
| B867 | LD A,H | Copy the high byte of the difference. | ||||||
| B868 | AND %00011111 | Keep only bits 0-4. | ||||||
| B86A | RET NZ | Return if the result is not zero. | ||||||
| B86B | LD A,L | Copy the low byte of the difference. | ||||||
| B86C | CP $20 | Return if it is at least 20. | ||||||
| B86E | RET NC | |||||||
| B86F | LD A,($6184) | Fetch the base Y from 6184. | ||||||
| B872 | SUB $04 | Subtract 04. | ||||||
| B874 | SUB (IX+$04) | Subtract the bomb Y. | ||||||
| B877 | JP P,FlyThrownBomb_CompareY | Jump to FlyThrownBomb_CompareY if the result is positive. | ||||||
| B87A | NEG | Negate it. | ||||||
| FlyThrownBomb_CompareY | B87C | CP E | Compare it with the window. | |||||
| B87D | RET | Return. | ||||||
| Prev: B7BC | Up: Map | Next: B87E |