mirror of
https://github.com/pret/pokered.git
synced 2024-10-22 22:55:31 +00:00
201 lines
4 KiB
NASM
201 lines
4 KiB
NASM
FindPathToPlayer:
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xor a
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ld hl, hFindPathNumSteps
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ld [hli], a ; hFindPathNumSteps
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ld [hli], a ; hFindPathFlags
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ld [hli], a ; hFindPathYProgress
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ld [hl], a ; hFindPathXProgress
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ld hl, wNPCMovementDirections2
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ld de, $0
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.loop
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ldh a, [hFindPathYProgress]
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ld b, a
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ldh a, [hNPCPlayerYDistance] ; Y distance in steps
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call CalcDifference
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ld d, a
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and a
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jr nz, .stillHasYProgress
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ldh a, [hFindPathFlags]
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set 0, a ; current end of path matches the player's Y coordinate
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ldh [hFindPathFlags], a
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.stillHasYProgress
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ldh a, [hFindPathXProgress]
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ld b, a
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ldh a, [hNPCPlayerXDistance] ; X distance in steps
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call CalcDifference
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ld e, a
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and a
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jr nz, .stillHasXProgress
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ldh a, [hFindPathFlags]
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set 1, a ; current end of path matches the player's X coordinate
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ldh [hFindPathFlags], a
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.stillHasXProgress
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ldh a, [hFindPathFlags]
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cp $3 ; has the end of the path reached the player's position?
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jr z, .done
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; Compare whether the X distance between the player and the current of the path
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; is greater or if the Y distance is. Then, try to reduce whichever is greater.
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ld a, e
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cp d
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jr c, .yDistanceGreater
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; x distance is greater
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ldh a, [hNPCPlayerRelativePosFlags]
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bit 1, a
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jr nz, .playerIsLeftOfNPC
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ld d, NPC_MOVEMENT_RIGHT
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jr .next1
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.playerIsLeftOfNPC
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ld d, NPC_MOVEMENT_LEFT
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.next1
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ldh a, [hFindPathXProgress]
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add 1
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ldh [hFindPathXProgress], a
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jr .storeDirection
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.yDistanceGreater
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ldh a, [hNPCPlayerRelativePosFlags]
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bit 0, a
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jr nz, .playerIsAboveNPC
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ld d, NPC_MOVEMENT_DOWN
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jr .next2
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.playerIsAboveNPC
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ld d, NPC_MOVEMENT_UP
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.next2
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ldh a, [hFindPathYProgress]
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add 1
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ldh [hFindPathYProgress], a
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.storeDirection
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ld a, d
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ld [hli], a
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ldh a, [hFindPathNumSteps]
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inc a
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ldh [hFindPathNumSteps], a
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jp .loop
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.done
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ld [hl], $ff
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ret
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CalcPositionOfPlayerRelativeToNPC:
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xor a
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ldh [hNPCPlayerRelativePosFlags], a
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ld a, [wSpritePlayerStateData1YPixels]
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ld d, a
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ld a, [wSpritePlayerStateData1XPixels]
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ld e, a
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ld hl, wSpriteStateData1
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ldh a, [hNPCSpriteOffset]
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add l
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add SPRITESTATEDATA1_YPIXELS
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ld l, a
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jr nc, .noCarry
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inc h
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.noCarry
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ld a, d
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ld b, a
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ld a, [hli] ; NPC sprite screen Y position in pixels
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call CalcDifference
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jr nc, .NPCSouthOfOrAlignedWithPlayer
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.NPCNorthOfPlayer
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push hl
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ld hl, hNPCPlayerRelativePosFlags
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bit 0, [hl]
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set 0, [hl]
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pop hl
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jr .divideYDistance
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.NPCSouthOfOrAlignedWithPlayer
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push hl
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ld hl, hNPCPlayerRelativePosFlags
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bit 0, [hl]
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res 0, [hl]
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pop hl
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.divideYDistance
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push hl
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ld hl, hDividend2
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ld [hli], a
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ld a, 16
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ld [hli], a
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call DivideBytes ; divide Y absolute distance by 16
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ld a, [hl] ; quotient
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ldh [hNPCPlayerYDistance], a
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pop hl
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inc hl
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ld b, e
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ld a, [hl] ; NPC sprite screen X position in pixels
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call CalcDifference
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jr nc, .NPCEastOfOrAlignedWithPlayer
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.NPCWestOfPlayer
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push hl
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ld hl, hNPCPlayerRelativePosFlags
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bit 1, [hl]
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set 1, [hl]
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pop hl
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jr .divideXDistance
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.NPCEastOfOrAlignedWithPlayer
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push hl
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ld hl, hNPCPlayerRelativePosFlags
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bit 1, [hl]
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res 1, [hl]
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pop hl
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.divideXDistance
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ldh [hDividend2], a
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ld a, 16
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ldh [hDivisor2], a
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call DivideBytes ; divide X absolute distance by 16
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ldh a, [hQuotient2]
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ldh [hNPCPlayerXDistance], a
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ldh a, [hNPCPlayerRelativePosPerspective]
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and a
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ret z
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ldh a, [hNPCPlayerRelativePosFlags]
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cpl
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and $3
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ldh [hNPCPlayerRelativePosFlags], a
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ret
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ConvertNPCMovementDirectionsToJoypadMasks:
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ldh a, [hNPCMovementDirections2Index]
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ld [wNPCMovementDirections2Index], a
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dec a
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ld de, wSimulatedJoypadStatesEnd
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ld hl, wNPCMovementDirections2
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add l
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ld l, a
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jr nc, .loop
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inc h
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.loop
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ld a, [hld]
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call ConvertNPCMovementDirectionToJoypadMask
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ld [de], a
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inc de
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ldh a, [hNPCMovementDirections2Index]
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dec a
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ldh [hNPCMovementDirections2Index], a
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jr nz, .loop
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ret
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ConvertNPCMovementDirectionToJoypadMask:
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push hl
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ld b, a
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ld hl, NPCMovementDirectionsToJoypadMasksTable
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.loop
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ld a, [hli]
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cp $ff
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jr z, .done
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cp b
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jr z, .loadJoypadMask
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inc hl
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jr .loop
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.loadJoypadMask
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ld a, [hl]
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.done
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pop hl
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ret
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NPCMovementDirectionsToJoypadMasksTable:
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db NPC_MOVEMENT_UP, D_UP
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db NPC_MOVEMENT_DOWN, D_DOWN
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db NPC_MOVEMENT_LEFT, D_LEFT
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db NPC_MOVEMENT_RIGHT, D_RIGHT
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db $ff
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; unreferenced
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ret
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