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Routines |
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The handler for the tack, the washer and the bolt (IDs 1E to 23), which chase Charlie. Every 10 frames the actor works out which way Charlie is from it, and stores this in byte 06 of the actor (bit 0 is set when Charlie is below the actor, bit 1 is set when Charlie is to the right). The horizontal and vertical speeds are then changed by one every other frame towards that direction, up to a maximum speed of 02 in either direction.
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| HandleTackWasherBolt | 6996 | CALL StoreEntity | Record the position of the sprite using StoreEntity. | |||||
| 6999 | LD HL,$5F1B | Point HL at ActorsInPlay. | ||||||
| 699C | INC (HL) | Increase the number of actors in play by one. | ||||||
| 699D | CALL TestCharlieCollision | Test whether the actor has hit Charlie using TestCharlieCollision. | ||||||
| 69A0 | DEC E | Has Charlie been hit (is E now zero)? | ||||||
| 69A1 | JP Z,LoseHat | Jump to LoseHat if Charlie has been hit. | ||||||
| 69A4 | CALL TestFlourCollision | Test whether a flour shot has hit the actor using TestFlourCollision. | ||||||
| 69A7 | BIT 7,(IX+$00) | Jump to HandleHitActor if the actor has been hit. | ||||||
| 69AB | JP NZ,HandleHitActor | |||||||
| 69AE | LD (IX+$03),$45 | Set the actor colour to 45 (cyan). | ||||||
| 69B2 | LD A,(IX+$07) | Fetch the frame counter (byte 07 of the actor). | ||||||
| 69B5 | AND %00001111 | Keep only bits 0-3. | ||||||
| 69B7 | JR NZ,ChangeActorSpeeds | Jump to ChangeActorSpeeds if the counter is not a multiple of 10. | ||||||
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Work out which direction Charlie is in.
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| 69B9 | LD C,$00 | Set the direction to 00 (left and up). | ||||||
| 69BB | LD HL,$5F36 | Point HL at ActorCharlie_X. | ||||||
| 69BE | LD A,(IX+$01) | Fetch the horizontal co-ordinate. | ||||||
| 69C1 | SUB (HL) | Subtract Charlie's horizontal co-ordinate. | ||||||
| 69C2 | JR NC,HandleTackWasherBolt_Vertical | Jump to HandleTackWasherBolt_Vertical if the actor is to the right of Charlie. | ||||||
| 69C4 | LD C,$02 | The actor is left of Charlie, so set the direction to 02 (right). | ||||||
| HandleTackWasherBolt_Vertical | 69C6 | INC HL | Move on to Charlie's vertical co-ordinate. | |||||
| 69C7 | LD A,(IX+$02) | Fetch the vertical co-ordinate. | ||||||
| 69CA | SUB (HL) | Subtract Charlie's vertical co-ordinate. | ||||||
| 69CB | JR NC,HandleTackWasherBolt_SetDirection | Jump to HandleTackWasherBolt_SetDirection if the actor is below Charlie. | ||||||
| 69CD | SET 0,C | The actor is above Charlie, so set bit 0 of the direction (down). | ||||||
| HandleTackWasherBolt_SetDirection | 69CF | LD (IX+$06),C | Set the direction of the actor (byte 06 of the actor). | |||||
| 69D2 | JR ChangeActorSpeeds | Jump to ChangeActorSpeeds. | ||||||
| Prev: 6930 | Up: Map | Next: 69D4 |