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Routines |
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Used by the routine at Handler_Cars.
Handles a car driving left across the screen. When it reaches the left boundary it turns around and drives right at ground level until reaching the right edge, then reinitialises.
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| Handler_CarType2 | 28557 | LD IX,56008 | IX=Sprite02_3Wide_X_Position. | |||||
| 28561 | LD HL,29195 | HL=CarSpeed (car speed). | ||||||
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If the room is being initialised, set up the car.
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| 28564 | LD A,(24507) | Jump to Handler_CarType2_Initialise if *RespawnFlag is set. | ||||||
| 28567 | OR A | |||||||
| 28568 | JR NZ,Handler_CarType2_Initialise | |||||||
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If the car crash timer is active, handle the crash animation.
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| 28570 | LD A,(29192) | Jump to Handler_Car_Type1_0 if *CarCrashTimer is active. | ||||||
| 28573 | OR A | |||||||
| 28574 | JP NZ,Handler_Car_Type1_0 | |||||||
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Check which road the car is on.
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| 28577 | LD A,(IX+1) | A=*IX+1 (car Y position). | ||||||
| 28580 | CP 144 | Jump to Handler_CarType2_DriveRight if on the upper road. | ||||||
| 28582 | JR Z,Handler_CarType2_DriveRight | |||||||
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Car is on the lower road (Y=160) — driving left.
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| 28584 | LD A,(IX+0) | A=*IX+0 (car X position). | ||||||
| 28587 | SUB (HL) | A-=*HL (subtract speed). | ||||||
| 28588 | CP 104 | Jump to Handler_CarType2_TurnAround if at the left boundary (turn around). | ||||||
| 28590 | JR C,Handler_CarType2_TurnAround | |||||||
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This entry point is used by the routine at Handler_CarType3.
Update positions and set driving left frames.
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| Handler_CarType2_UpdateLeft | 28592 | LD (IX+0),A | Write A to *IX+0 (front X). | |||||
| 28595 | ADD A,16 | A+=16. | ||||||
| 28597 | LD (IX+4),A | Write A to *IX+4 (rear X). | ||||||
| 28600 | LD (IX+1),160 | Write 160 to *IX+1 (front Y: lower road). | ||||||
| 28604 | LD (IX+5),160 | Write 160 to *IX+5 (rear Y: lower road). | ||||||
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| 28608 | LD (IX+3),30 | Write 30 to *IX+3 (front frame: driving left). | ||||||
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| 28612 | LD (IX+7),31 | Write 31 to *IX+7 (rear frame: driving left). | ||||||
| 28616 | JP Handler_Car_Type1_2 | Jump to Handler_Car_Type1_2. | ||||||
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Car is on the upper road (Y=144) — driving right.
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| Handler_CarType2_DriveRight | 28619 | LD A,(IX+0) | A=*IX+0 (car X position). | |||||
| 28622 | ADD A,(HL) | A+=*HL (add speed). | ||||||
| 28623 | CP 222 | Jump to Handler_CarType2_Initialise if at the right edge (reinitialise). | ||||||
| 28625 | JR NC,Handler_CarType2_Initialise | |||||||
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This entry point is used by the routine at Handler_CarType3.
Update positions and set driving right frames.
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| Handler_CarType2_UpdateRight | 28627 | LD (IX+0),A | Write A to *IX+0 (front X). | |||||
| 28630 | ADD A,16 | A+=16. | ||||||
| 28632 | LD (IX+4),A | Write A to *IX+4 (rear X). | ||||||
| 28635 | LD (IX+1),144 | Write 144 to *IX+1 (front Y: upper road). | ||||||
| 28639 | LD (IX+5),144 | Write 144 to *IX+5 (rear Y: upper road). | ||||||
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| 28643 | LD (IX+3),28 | Write 28 to *IX+3 (front frame: driving right). | ||||||
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| 28647 | LD (IX+7),29 | Write 29 to *IX+7 (rear frame: driving right). | ||||||
| 28651 | JP Handler_Car_Type1_1 | Jump to Handler_Car_Type1_1. | ||||||
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Car reached the left boundary — turn around. Pick a new random speed and colour, then start driving right from the left boundary.
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| Handler_CarType2_TurnAround | 28654 | PUSH HL | Stash HL on the stack. | |||||
| 28655 | CALL GenerateRandomNumber | Call GenerateRandomNumber. | ||||||
| 28658 | POP HL | Restore HL from the stack. | ||||||
| 28659 | AND %00000011 | Keep only bits 0-1 (random speed 0-3). | ||||||
| 28661 | INC A | Increment the random number by one (speed 1-4). | ||||||
| 28662 | LD (HL),A | Write the new speed to *HL. | ||||||
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Pick a new colour, rejecting BLUE.
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| PickCarColour | 28663 | PUSH HL | Stash HL on the stack. | |||||
| 28664 | CALL GenerateRandomNumber | Call GenerateRandomNumber. | ||||||
| 28667 | POP HL | Restore HL from the stack. | ||||||
| 28668 | AND %00000011 | Keep only bits 0-1 (random colour from BLACK,BLUE,RED,MAGENTA). | ||||||
| 28670 | CP 1 | Jump to PickCarColour if the colour is BLUE (pick again). | ||||||
| 28672 | JR Z,PickCarColour | |||||||
| 28674 | LD (IX+2),A | Write A to *IX+2 (front colour). | ||||||
| 28677 | LD (IX+6),A | Write A to *IX+6 (rear colour). | ||||||
| 28680 | LD A,104 | A=104 (left boundary X position). | ||||||
| 28682 | JR Handler_CarType2_UpdateRight | Jump to Handler_CarType2_UpdateRight. | ||||||
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Initialise car type 2 — start from the right edge driving left with a random speed and colour.
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| Handler_CarType2_Initialise | 28684 | PUSH HL | Stash HL on the stack. | |||||
| 28685 | CALL GenerateRandomNumber | Call GenerateRandomNumber. | ||||||
| 28688 | POP HL | Restore HL from the stack. | ||||||
| 28689 | AND %00000011 | Keep only bits 0-1 (random speed 0-3). | ||||||
| 28691 | INC A | Increment the random speed by one (speed 1-4). | ||||||
| 28692 | LD (HL),A | Write the new speed to *HL. | ||||||
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Pick a colour, using the range 4-7 (bright colours).
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| 28693 | PUSH HL | Stash HL on the stack. | ||||||
| 28694 | CALL GenerateRandomNumber | Call GenerateRandomNumber. | ||||||
| 28697 | POP HL | Restore HL from the stack. | ||||||
| 28698 | AND %00000011 | Keep only bits 0-1. | ||||||
| 28700 | ADD A,4 | A+=4 (bright colour range). | ||||||
| 28702 | LD (IX+2),A | Write A to *IX+2 (front colour). | ||||||
| 28705 | LD (IX+6),A | Write A to *IX+6 (rear colour). | ||||||
| 28708 | LD A,222 | A=222 (right edge X position). | ||||||
| 28710 | JR Handler_CarType2_UpdateLeft | Jump to Handler_CarType2_UpdateLeft. | ||||||
| Prev: 28500 | Up: Map | Next: 28712 |
