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Routines |
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Used by the routine at ApplyCollisionEffects.
Bounces the player's ship off an object, by exchanging half of the speed of each of them.
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| BounceShip | 8FCA | LD D,(IY+$19) | Fetch the horizontal speed of the player into DE. | |||||||
| 8FCD | LD E,(IY+$1A) | |||||||||
| 8FD0 | LD H,(IX+$07) | Fetch the horizontal speed of the object into HL. | ||||||||
| 8FD3 | LD L,(IX+$08) | |||||||||
| 8FD6 | SRA H | Halve it. | ||||||||
| 8FD8 | RR L | |||||||||
| 8FDA | CALL NegateNumber | Negate it. | ||||||||
| 8FDD | LD (IX+$07),H | Store it as the new speed of the object. | ||||||||
| 8FE0 | LD (IX+$08),L | |||||||||
| 8FE3 | ADD HL,DE | Add the speed of the player. | ||||||||
| 8FE4 | LD (IY+$19),H | Store the result as the new speed of the player. | ||||||||
| 8FE7 | LD (IY+$1A),L | |||||||||
| 8FEA | LD D,(IY+$1B) | Fetch the vertical speed of the player into DE. | ||||||||
| 8FED | LD E,(IY+$1C) | |||||||||
| 8FF0 | LD H,(IX+$09) | Fetch the vertical speed of the object into HL. | ||||||||
| 8FF3 | LD L,(IX+$0A) | |||||||||
| 8FF6 | SRA H | Halve it. | ||||||||
| 8FF8 | RR L | |||||||||
| 8FFA | CALL NegateNumber | Negate it. | ||||||||
| 8FFD | LD (IX+$09),H | Store it as the new speed of the object. | ||||||||
| 9000 | LD (IX+$0A),L | |||||||||
| 9003 | ADD HL,DE | Add the speed of the player. | ||||||||
| 9004 | LD (IY+$1B),H | Store the result as the new speed of the player. | ||||||||
| 9007 | LD (IY+$1C),L | |||||||||
| 900A | RET | Return. | ||||||||
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