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FindPathToPlayer:
xor a
ld hl, hFindPathNumSteps
ld [hli], a ; hFindPathNumSteps
ld [hli], a ; hFindPathFlags
ld [hli], a ; hFindPathYProgress
ld [hl], a ; hFindPathXProgress
ld hl, wNPCMovementDirections2
ld de, $0
.loop
ldh a, [hFindPathYProgress]
ld b, a
ldh a, [hNPCPlayerYDistance] ; Y distance in steps
call CalcDifference
ld d, a
and a
jr nz, .asm_f8da
ldh a, [hFindPathFlags]
set 0, a ; current end of path matches the player's Y coordinate
ldh [hFindPathFlags], a
.asm_f8da
ldh a, [hFindPathXProgress]
ld b, a
ldh a, [hNPCPlayerXDistance] ; X distance in steps
call CalcDifference
ld e, a
and a
jr nz, .asm_f8ec
ldh a, [hFindPathFlags]
set 1, a ; current end of path matches the player's X coordinate
ldh [hFindPathFlags], a
.asm_f8ec
ldh a, [hFindPathFlags]
cp $3 ; has the end of the path reached the player's position?
jr z, .done
; Compare whether the X distance between the player and the current of the path
; is greater or if the Y distance is. Then, try to reduce whichever is greater.
ld a, e
cp d
jr c, .yDistanceGreater
; x distance is greater
ldh a, [hNPCPlayerRelativePosFlags]
bit 1, a
jr nz, .playerIsLeftOfNPC
ld d, NPC_MOVEMENT_RIGHT
jr .next1
.playerIsLeftOfNPC
ld d, NPC_MOVEMENT_LEFT
.next1
ldh a, [hFindPathXProgress]
add 1
ldh [hFindPathXProgress], a
jr .storeDirection
.yDistanceGreater
ldh a, [hNPCPlayerRelativePosFlags]
bit 0, a
jr nz, .playerIsAboveNPC
ld d, NPC_MOVEMENT_DOWN
jr .next2
.playerIsAboveNPC
ld d, NPC_MOVEMENT_UP
.next2
ldh a, [hFindPathYProgress]
add 1
ldh [hFindPathYProgress], a
.storeDirection
ld a, d
ld [hli], a
ldh a, [hFindPathNumSteps]
inc a
ldh [hFindPathNumSteps], a
jp .loop
.done
ld [hl], $ff
ret
CalcPositionOfPlayerRelativeToNPC:
xor a
ldh [hNPCPlayerRelativePosFlags], a
ld a, [wSpritePlayerStateData1YPixels]
ld d, a
ld a, [wSpritePlayerStateData1XPixels]
ld e, a
ld hl, wSpriteStateData1
ldh a, [hNPCSpriteOffset]
add l
add SPRITESTATEDATA1_YPIXELS
ld l, a
jr nc, .noCarry
inc h
.noCarry
ld a, d
ld b, a
ld a, [hli] ; NPC sprite screen Y position in pixels
call CalcDifference
jr nc, .NPCSouthOfOrAlignedWithPlayer
.NPCNorthOfPlayer
push hl
ld hl, hNPCPlayerRelativePosFlags
bit 0, [hl]
set 0, [hl]
pop hl
jr .divideYDistance
.NPCSouthOfOrAlignedWithPlayer
push hl
ld hl, hNPCPlayerRelativePosFlags
bit 0, [hl]
res 0, [hl]
pop hl
.divideYDistance
push hl
ld hl, hDividend2
ld [hli], a
ld a, 16
ld [hli], a
call DivideBytes ; divide Y absolute distance by 16
ld a, [hl] ; quotient
ldh [hNPCPlayerYDistance], a
pop hl
inc hl
ld b, e
ld a, [hl] ; NPC sprite screen X position in pixels
call CalcDifference
jr nc, .NPCEastOfOrAlignedWithPlayer
.NPCWestOfPlayer
push hl
ld hl, hNPCPlayerRelativePosFlags
bit 1, [hl]
set 1, [hl]
pop hl
jr .divideXDistance
.NPCEastOfOrAlignedWithPlayer
push hl
ld hl, hNPCPlayerRelativePosFlags
bit 1, [hl]
res 1, [hl]
pop hl
.divideXDistance
ldh [hDividend2], a
ld a, 16
ldh [hDivisor2], a
call DivideBytes ; divide X absolute distance by 16
ldh a, [hQuotient2]
ldh [hNPCPlayerXDistance], a
ldh a, [hNPCPlayerRelativePosPerspective]
and a
ret z
ldh a, [hNPCPlayerRelativePosFlags]
cpl
and $3
ldh [hNPCPlayerRelativePosFlags], a
ret
ConvertNPCMovementDirectionsToJoypadMasks:
ldh a, [hNPCMovementDirections2Index]
ld [wNPCMovementDirections2Index], a
dec a
ld de, wSimulatedJoypadStatesEnd
ld hl, wNPCMovementDirections2
add l
ld l, a
jr nc, .loop
inc h
.loop
ld a, [hld]
call ConvertNPCMovementDirectionToJoypadMask
ld [de], a
inc de
ldh a, [hNPCMovementDirections2Index]
dec a
ldh [hNPCMovementDirections2Index], a
jr nz, .loop
ret
ConvertNPCMovementDirectionToJoypadMask:
push hl
ld b, a
ld hl, NPCMovementDirectionsToJoypadMasksTable
.loop
ld a, [hli]
cp $ff
jr z, .done
cp b
jr z, .loadJoypadMask
inc hl
jr .loop
.loadJoypadMask
ld a, [hl]
.done
pop hl
ret
NPCMovementDirectionsToJoypadMasksTable:
db NPC_MOVEMENT_UP, D_UP
db NPC_MOVEMENT_DOWN, D_DOWN
db NPC_MOVEMENT_LEFT, D_LEFT
db NPC_MOVEMENT_RIGHT, D_RIGHT
db $ff
; unreferenced
ret
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