Routines
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763C: Handler: Fuel
Used by the routine at Game_Loop.
Handler_Fuel 763C CALL $7420 Call 7420.
763F LD HL,($783C) HL=*Fuel.
7642 LD A,H Jump to ProcessFuelConsumption if H is lower than 80.
7643 CP $80
7645 JR C,ProcessFuelConsumption
7647 LD HL,($782E) HL=*LevelProgressPointer.
764A LD A,(HL) A=*HL.
764B DEC A Decrease A by one.
764C JR Z,TriggerOutOfFuel Jump to TriggerOutOfFuel if A is zero.
764E CP $31 Call EBF3 if A is higher than 31.
7650 CALL NC,$EBF3
7653 CP $2D Call EBF3 if A is lower than 2D.
7655 CALL C,$EBF3
7658 NOP No operation.
7659 NOP
765A NOP
765B NOP
Start the "Out Of Fuel" sequence.
TriggerOutOfFuel 765C CALL RemoveSprites Call RemoveSprites.
765F LD A,($7822) A=*Speed.
7662 BIT 7,A Check the direction bit.
7664 LD A,$87 Load the base player sprite into A (87).
7666 JR NZ,SetWheelieSprite Jump to SetWheelieSprite if the player is moving left.
7668 ADD A,$40 Modify the player sprite ID for the player moving right (C7).
SetWheelieSprite 766A LD ($7834),A Write the player sprite ID to *PlayerSpriteID.
766D CALL Handler: PlayerSprite Call Handler: PlayerSprite.
Print the "OUT OF FUEL" messaging in the footer.
out-of-fuel
7670 LD A,$A9 A=A9 (INK: BLUE, PAPER: CYAN FLASH: ON).
7672 LD HL,$BA86 HL=Messaging_OutOfFuel.
7675 CALL PrintFooterColourString Call PrintFooterColourString.
Play the "out of fuel" audio.
7678 LD D,$10 Set an outer loop count in D for 10 iterations.
767A LD C,$01 Set the initial tone value in C to 01.
PlayFuelSound_OuterLoop 767C LD HL,$1E00 Set the tone duration counter in HL to 1E00.
767F LD A,C Get current tone value.
PlayFuelSound_ToneLoop 7680 LD B,C Set inner delay counter.
7681 OUT ($FE),A Send to the speaker.
7683 XOR %00010000 Flip the speaker bit.
PlayFuelSound_InnerDelayLoop 7685 DJNZ PlayFuelSound_InnerDelayLoop Decrease the inner delay counter by one and loop back to PlayFuelSound_InnerDelayLoop until the counter is zero.
7687 DEC L Decrease the tone duration low byte by one.
7688 JR NZ,PlayFuelSound_ToneLoop Jump back to PlayFuelSound_ToneLoop until the tone duration low byte is zero.
768A DEC H Decrease the tone duration high byte by one.
768B JR NZ,PlayFuelSound_ToneLoop Jump back to PlayFuelSound_ToneLoop until the tone duration high byte is zero.
768D INC C Increase the tone frequency by one (higher pitch).
768E DEC D Decrease the outer loop counter by one.
768F JR NZ,PlayFuelSound_OuterLoop Jump back to PlayFuelSound_OuterLoop until the outer loop counter is zero.
Reset the players fuel and restart the game.
7691 LD HL,$3400 Write 3400 to *Fuel.
7694 LD ($783C),HL
7697 JP $7161 Jump to 7161.
Normal fuel consumption processing.
ProcessFuelConsumption 769A LD A,($7822) A=*Speed.
769D BIT 7,A Check the direction bit.
769F JR NZ,CalculateFuelConsumption Jump to CalculateFuelConsumption if the player is moving backwards.
The player is moving forwards.
76A1 CPL Invert the speed for forward movement calculation.
CalculateFuelConsumption 76A2 SUB $7E Calculate the fuel consumption rate in DE; (speed-7E)/02.
76A4 SRL A
76A6 LD E,A
76A7 LD D,$00
76A9 AND A Subtract the consumption from the players fuel level.
76AA SBC HL,DE
76AC LD ($783C),HL Write the updated fuel value back to *Fuel.
76AF JR C,Handler_Fuel_0 Jump to Handler_Fuel_0 if the fuel value is negative.
Update the fuel gauge display.
76B1 LD A,H Get the fuel high byte.
76B2 SRL A Divide it by 04.
76B4 SRL A
76B6 CPL Invert the byte for the gauge display.
76B7 SUB $0C Abjust by an offset of 0C bytes for where the gauge displays.
76B9 LD L,A Set this value in L.
76BA LD H,$BA Load the high byte in H with BA.
76BC LD DE,$5A65 Point DE to the gauge position 5A65 (attribute buffer location).
76BF CALL CopyTwelveBytes Call CopyTwelveBytes.
Handle fuel-related audio effects during gameplay.
76C2 LD HL,($783C) HL=*Fuel.
76C5 LD A,H Call 6D50 if the fuel level is 0400 or higher, or for every 40 fuel units (which creates pulses as the fuel decreases).
76C6 CP $04
76C8 CALL NC,$6D50
76CB BIT 6,L
76CD CALL NZ,$6D50
Handler_Fuel_0 76D0 JP $EBF3 Jump to EBF3.
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