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Routines |
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The handler for the tack, the washer and the bolt (IDs 30 to 35), which chase Charlie. Every 16 frames the actor works out which way Charlie is from it, and stores this in byte 6 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 2 in either direction.
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| HandleTackWasherBolt | 27030 | CALL StoreEntity | Record the position of the sprite using StoreEntity. | |||||
| 27033 | LD HL,24347 | Point HL at ActorsInPlay. | ||||||
| 27036 | INC (HL) | Increase the number of actors in play by one. | ||||||
| 27037 | CALL TestCharlieCollision | Test whether the actor has hit Charlie using TestCharlieCollision. | ||||||
| 27040 | DEC E | Has Charlie been hit (is E now zero)? | ||||||
| 27041 | JP Z,LoseHat | Jump to LoseHat if Charlie has been hit. | ||||||
| 27044 | CALL TestFlourCollision | Test whether a flour shot has hit the actor using TestFlourCollision. | ||||||
| 27047 | BIT 7,(IX+0) | Jump to HandleHitActor if the actor has been hit. | ||||||
| 27051 | JP NZ,HandleHitActor | |||||||
| 27054 | LD (IX+3),69 | Set the actor colour to 69 (cyan). | ||||||
| 27058 | LD A,(IX+7) | Fetch the frame counter (byte 7 of the actor). | ||||||
| 27061 | AND %00001111 | Keep only bits 0-3. | ||||||
| 27063 | JR NZ,ChangeActorSpeeds | Jump to ChangeActorSpeeds if the counter is not a multiple of 16. | ||||||
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Work out which direction Charlie is in.
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| 27065 | LD C,0 | Set the direction to 0 (left and up). | ||||||
| 27067 | LD HL,24374 | Point HL at ActorCharlie_X. | ||||||
| 27070 | LD A,(IX+1) | Fetch the horizontal co-ordinate. | ||||||
| 27073 | SUB (HL) | Subtract Charlie's horizontal co-ordinate. | ||||||
| 27074 | JR NC,HandleTackWasherBolt_Vertical | Jump to HandleTackWasherBolt_Vertical if the actor is to the right of Charlie. | ||||||
| 27076 | LD C,2 | The actor is left of Charlie, so set the direction to 2 (right). | ||||||
| HandleTackWasherBolt_Vertical | 27078 | INC HL | Move on to Charlie's vertical co-ordinate. | |||||
| 27079 | LD A,(IX+2) | Fetch the vertical co-ordinate. | ||||||
| 27082 | SUB (HL) | Subtract Charlie's vertical co-ordinate. | ||||||
| 27083 | JR NC,HandleTackWasherBolt_SetDirection | Jump to HandleTackWasherBolt_SetDirection if the actor is below Charlie. | ||||||
| 27085 | SET 0,C | The actor is above Charlie, so set bit 0 of the direction (down). | ||||||
| HandleTackWasherBolt_SetDirection | 27087 | LD (IX+6),C | Set the direction of the actor (byte 6 of the actor). | |||||
| 27090 | JR ChangeActorSpeeds | Jump to ChangeActorSpeeds. | ||||||
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