kep-hack/engine/overworld/movement.asm
emaskyesmogon 1893b4c7cf expanded Pokemon size
Rhyperior files are dummies and will need to be properly edited with sprites, Rhydon evo data, etc, but it (and the other files included) show that the trainer and pokemon sprite indexes have been separated, which allows us to add the other KEP mons
2022-08-31 20:47:02 -06:00

893 lines
23 KiB
NASM

DEF MAP_TILESET_SIZE EQU $60
UpdatePlayerSprite:
ld a, [wSpritePlayerStateData2WalkAnimationCounter]
and a
jr z, .checkIfTextBoxInFrontOfSprite
cp $ff
jr z, .disableSprite
dec a
ld [wSpritePlayerStateData2WalkAnimationCounter], a
jr .disableSprite
; check if a text box is in front of the sprite by checking if the lower left
; background tile the sprite is standing on is greater than $5F, which is
; the maximum number for map tiles
.checkIfTextBoxInFrontOfSprite
lda_coord 8, 9
ldh [hTilePlayerStandingOn], a
cp MAP_TILESET_SIZE
jr c, .lowerLeftTileIsMapTile
.disableSprite
ld a, $ff
ld [wSpritePlayerStateData1ImageIndex], a
ret
.lowerLeftTileIsMapTile
call DetectCollisionBetweenSprites
ld h, HIGH(wSpriteStateData1)
ld a, [wWalkCounter]
and a
jr nz, .moving
ld a, [wPlayerMovingDirection]
; check if down
bit PLAYER_DIR_BIT_DOWN, a
jr z, .checkIfUp
xor a ; ld a, SPRITE_FACING_DOWN
jr .next
.checkIfUp
bit PLAYER_DIR_BIT_UP, a
jr z, .checkIfLeft
ld a, SPRITE_FACING_UP
jr .next
.checkIfLeft
bit PLAYER_DIR_BIT_LEFT, a
jr z, .checkIfRight
ld a, SPRITE_FACING_LEFT
jr .next
.checkIfRight
bit PLAYER_DIR_BIT_RIGHT, a
jr z, .notMoving
ld a, SPRITE_FACING_RIGHT
jr .next
.notMoving
; zero the animation counters
xor a
ld [wSpritePlayerStateData1IntraAnimFrameCounter], a
ld [wSpritePlayerStateData1AnimFrameCounter], a
jr .calcImageIndex
.next
ld [wSpritePlayerStateData1FacingDirection], a
ld a, [wFontLoaded]
bit 0, a
jr nz, .notMoving
.moving
ld a, [wd736]
bit 7, a ; is the player sprite spinning due to a spin tile?
jr nz, .skipSpriteAnim
ldh a, [hCurrentSpriteOffset]
add $7
ld l, a
ld a, [hl]
inc a
ld [hl], a
cp 4
jr nz, .calcImageIndex
xor a
ld [hl], a
inc hl
ld a, [hl]
inc a
and $3
ld [hl], a
.calcImageIndex
ld a, [wSpritePlayerStateData1AnimFrameCounter]
ld b, a
ld a, [wSpritePlayerStateData1FacingDirection]
add b
ld [wSpritePlayerStateData1ImageIndex], a
.skipSpriteAnim
; If the player is standing on a grass tile, make the player's sprite have
; lower priority than the background so that it's partially obscured by the
; grass. Only the lower half of the sprite is permitted to have the priority
; bit set by later logic.
ldh a, [hTilePlayerStandingOn]
ld c, a
ld a, [wGrassTile]
cp c
ld a, 0
jr nz, .next2
ld a, OAM_BEHIND_BG
.next2
ld [wSpritePlayerStateData2GrassPriority], a
ret
UnusedReadSpriteDataFunction:
push bc
push af
ldh a, [hCurrentSpriteOffset]
ld c, a
pop af
add c
ld l, a
pop bc
ret
UpdateNPCSprite:
ldh a, [hCurrentSpriteOffset]
swap a
dec a
add a
ld hl, wMapSpriteData
add l
ld l, a
jr nc, .nc
inc h
.nc
ld a, [hl] ; read movement byte 2
ld [wCurSpriteMovement2], a
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
ld l, a
inc l
ld a, [hl] ; x#SPRITESTATEDATA1_MOVEMENTSTATUS
and a
jp z, InitializeSpriteStatus
call CheckSpriteAvailability
ret c ; if sprite is invisible, on tile >=MAP_TILESET_SIZE, in grass or player is currently walking
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
ld l, a
inc l
ld a, [hl] ; x#SPRITESTATEDATA1_MOVEMENTSTATUS
bit 7, a ; is the face player flag set?
jp nz, MakeNPCFacePlayer
ld b, a
ld a, [wFontLoaded]
bit 0, a
jp nz, notYetMoving
ld a, b
cp $2
jp z, UpdateSpriteMovementDelay ; [x#SPRITESTATEDATA1_MOVEMENTSTATUS] == 2
cp $3
jp z, UpdateSpriteInWalkingAnimation ; [x#SPRITESTATEDATA1_MOVEMENTSTATUS] == 3
ld a, [wWalkCounter]
and a
ret nz ; don't do anything yet if player is currently moving (redundant, already tested in CheckSpriteAvailability)
call InitializeSpriteScreenPosition
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add $6
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA2_MOVEMENTBYTE1
inc a
jr z, .randomMovement ; value STAY
inc a
jr z, .randomMovement ; value WALK
; scripted movement
dec a
ld [hl], a ; increment movement byte 1 (movement data index)
dec a
push hl
ld hl, wNPCNumScriptedSteps
dec [hl] ; decrement wNPCNumScriptedSteps
pop hl
ld de, wNPCMovementDirections
call LoadDEPlusA ; a = [wNPCMovementDirections + movement byte 1]
cp NPC_CHANGE_FACING
jp z, ChangeFacingDirection
cp STAY
jr nz, .next
; reached end of wNPCMovementDirections list
ld [hl], a ; store $ff in movement byte 1, disabling scripted movement
ld hl, wd730
res 0, [hl]
xor a
ld [wSimulatedJoypadStatesIndex], a
ld [wWastedByteCD3A], a
ret
.next
cp WALK
jr nz, .determineDirection
; current NPC movement data is WALK ($fe). this seems buggy
ld [hl], $1 ; set movement byte 1 to $1
ld de, wNPCMovementDirections
call LoadDEPlusA ; a = [wNPCMovementDirections + $fe] (?)
jr .determineDirection
.randomMovement
call GetTileSpriteStandsOn
call Random
.determineDirection
ld b, a
ld a, [wCurSpriteMovement2]
cp DOWN
jr z, .moveDown
cp UP
jr z, .moveUp
cp LEFT
jr z, .moveLeft
cp RIGHT
jr z, .moveRight
ld a, b
cp NPC_MOVEMENT_UP ; NPC_MOVEMENT_DOWN <= a < NPC_MOVEMENT_UP: down (or left)
jr nc, .notDown
ld a, [wCurSpriteMovement2]
cp LEFT_RIGHT
jr z, .moveLeft
.moveDown
ld de, 2*SCREEN_WIDTH
add hl, de ; move tile pointer two rows down
lb de, 1, 0
lb bc, 4, SPRITE_FACING_DOWN
jr TryWalking
.notDown
cp NPC_MOVEMENT_LEFT ; NPC_MOVEMENT_UP <= a < NPC_MOVEMENT_LEFT: up (or right)
jr nc, .notUp
ld a, [wCurSpriteMovement2]
cp LEFT_RIGHT
jr z, .moveRight
.moveUp
ld de, -2*SCREEN_WIDTH
add hl, de ; move tile pointer two rows up
lb de, -1, 0
lb bc, 8, SPRITE_FACING_UP
jr TryWalking
.notUp
cp NPC_MOVEMENT_RIGHT ; NPC_MOVEMENT_LEFT <= a < NPC_MOVEMENT_RIGHT: left (or up)
jr nc, .notLeft
ld a, [wCurSpriteMovement2]
cp UP_DOWN
jr z, .moveUp
.moveLeft
dec hl
dec hl ; move tile pointer two columns left
lb de, 0, -1
lb bc, 2, SPRITE_FACING_LEFT
jr TryWalking
.notLeft ; NPC_MOVEMENT_RIGHT <= a: right (or down)
ld a, [wCurSpriteMovement2]
cp UP_DOWN
jr z, .moveDown
.moveRight
inc hl
inc hl ; move tile pointer two columns right
lb de, 0, 1
lb bc, 1, SPRITE_FACING_RIGHT
jr TryWalking
; changes facing direction by zeroing the movement delta and calling TryWalking
ChangeFacingDirection:
ld de, $0
; fall through
; b: direction (1,2,4 or 8)
; c: new facing direction (0,4,8 or $c)
; d: Y movement delta (-1, 0 or 1)
; e: X movement delta (-1, 0 or 1)
; hl: pointer to tile the sprite would walk onto
; set carry on failure, clears carry on success
TryWalking:
push hl
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
add $9
ld l, a
ld [hl], c ; x#SPRITESTATEDATA1_FACINGDIRECTION
ldh a, [hCurrentSpriteOffset]
add $3
ld l, a
ld [hl], d ; x#SPRITESTATEDATA1_YSTEPVECTOR
inc l
inc l
ld [hl], e ; x#SPRITESTATEDATA1_XSTEPVECTOR
pop hl
push de
ld c, [hl] ; read tile to walk onto
call CanWalkOntoTile
pop de
ret c ; cannot walk there (reinitialization of delay values already done)
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add $4
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA2_MAPY
add d
ld [hli], a ; update Y position
ld a, [hl] ; x#SPRITESTATEDATA2_MAPX
add e
ld [hl], a ; update X position
ldh a, [hCurrentSpriteOffset]
ld l, a
ld [hl], $10 ; [x#SPRITESTATEDATA2_WALKANIMATIONCOUNTER] = 16
dec h
inc l
ld [hl], $3 ; x#SPRITESTATEDATA1_MOVEMENTSTATUS
jp UpdateSpriteImage
; update the walking animation parameters for a sprite that is currently walking
UpdateSpriteInWalkingAnimation:
ldh a, [hCurrentSpriteOffset]
add $7
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA1_INTRAANIMFRAMECOUNTER
inc a
ld [hl], a ; [x#SPRITESTATEDATA1_INTRAANIMFRAMECOUNTER]++
cp $4
jr nz, .noNextAnimationFrame
xor a
ld [hl], a ; [x#SPRITESTATEDATA1_INTRAANIMFRAMECOUNTER] = 0
inc l
ld a, [hl] ; x#SPRITESTATEDATA1_ANIMFRAMECOUNTER
inc a
and $3
ld [hl], a ; advance to next animation frame every 4 ticks (16 ticks total for one step)
.noNextAnimationFrame
ldh a, [hCurrentSpriteOffset]
add $3
ld l, a
ld a, [hli] ; x#SPRITESTATEDATA1_YSTEPVECTOR
ld b, a
ld a, [hl] ; x#SPRITESTATEDATA1_YPIXELS
add b
ld [hli], a ; update [x#SPRITESTATEDATA1_YPIXELS]
ld a, [hli] ; x#SPRITESTATEDATA1_XSTEPVECTOR
ld b, a
ld a, [hl] ; x#SPRITESTATEDATA1_XPIXELS
add b
ld [hl], a ; update [x#SPRITESTATEDATA1_XPIXELS]
ldh a, [hCurrentSpriteOffset]
ld l, a
inc h
ld a, [hl] ; x#SPRITESTATEDATA2_WALKANIMATIONCOUNTER
dec a
ld [hl], a ; update walk animation counter
ret nz
ld a, $6 ; walking finished, update state
add l
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA2_MOVEMENTBYTE1
cp WALK
jr nc, .initNextMovementCounter ; values WALK or STAY
ldh a, [hCurrentSpriteOffset]
inc a
ld l, a
dec h
ld [hl], $1 ; [x#SPRITESTATEDATA1_MOVEMENTSTATUS] = 1 (movement status ready)
ret
.initNextMovementCounter
call Random
ldh a, [hCurrentSpriteOffset]
add $8
ld l, a
ldh a, [hRandomAdd]
and $7f
ld [hl], a ; x#SPRITESTATEDATA2_MOVEMENTDELAY:
; set next movement delay to a random value in [0,$7f]
; note that value 0 actually makes the delay $100 (bug?)
dec h ; HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
inc a
ld l, a
ld [hl], $2 ; [x#SPRITESTATEDATA1_MOVEMENTSTATUS] = 2 (movement status)
inc l
inc l
xor a
ld b, [hl] ; x#SPRITESTATEDATA1_YSTEPVECTOR
ld [hli], a ; [x#SPRITESTATEDATA1_YSTEPVECTOR] = 0
inc l
ld c, [hl] ; x#SPRITESTATEDATA1_XSTEPVECTOR
ld [hl], a ; [x#SPRITESTATEDATA1_XSTEPVECTOR] = 0
ret
; update [x#SPRITESTATEDATA2_MOVEMENTDELAY] for sprites in the delayed state (x#SPRITESTATEDATA1_MOVEMENTSTATUS)
UpdateSpriteMovementDelay:
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add $6
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA2_MOVEMENTBYTE1
inc l
inc l
cp WALK
jr nc, .tickMoveCounter ; values WALK or STAY
ld [hl], $0
jr .moving
.tickMoveCounter
dec [hl] ; x#SPRITESTATEDATA2_MOVEMENTDELAY
jr nz, notYetMoving
.moving
dec h
ldh a, [hCurrentSpriteOffset]
inc a
ld l, a
ld [hl], $1 ; [x#SPRITESTATEDATA1_MOVEMENTSTATUS] = 1 (mark as ready to move)
notYetMoving:
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA1_ANIMFRAMECOUNTER
ld l, a
ld [hl], $0 ; [x#SPRITESTATEDATA1_ANIMFRAMECOUNTER] = 0 (walk animation frame)
jp UpdateSpriteImage
MakeNPCFacePlayer:
; Make an NPC face the player if the player has spoken to him or her.
; Check if the behaviour of the NPC facing the player when spoken to is
; disabled. This is only done when rubbing the S.S. Anne captain's back.
ld a, [wd72d]
bit 5, a
jr nz, notYetMoving
res 7, [hl]
ld a, [wPlayerDirection]
bit PLAYER_DIR_BIT_UP, a
jr z, .notFacingDown
ld c, SPRITE_FACING_DOWN
jr .facingDirectionDetermined
.notFacingDown
bit PLAYER_DIR_BIT_DOWN, a
jr z, .notFacingUp
ld c, SPRITE_FACING_UP
jr .facingDirectionDetermined
.notFacingUp
bit PLAYER_DIR_BIT_LEFT, a
jr z, .notFacingRight
ld c, SPRITE_FACING_RIGHT
jr .facingDirectionDetermined
.notFacingRight
ld c, SPRITE_FACING_LEFT
.facingDirectionDetermined
ldh a, [hCurrentSpriteOffset]
add $9
ld l, a
ld [hl], c ; [x#SPRITESTATEDATA1_FACINGDIRECTION]: set facing direction
jr notYetMoving
InitializeSpriteStatus:
ld [hl], $1 ; [x#SPRITESTATEDATA1_MOVEMENTSTATUS] = ready
inc l
ld [hl], $ff ; [x#SPRITESTATEDATA1_IMAGEINDEX] = invisible/off screen
inc h ; HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add $2
ld l, a
ld a, $8
ld [hli], a ; [x#SPRITESTATEDATA2_YDISPLACEMENT] = 8
ld [hl], a ; [x#SPRITESTATEDATA2_XDISPLACEMENT] = 8
ret
; calculates the sprite's screen position from its map position and the player position
InitializeSpriteScreenPosition:
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA2_MAPY
ld l, a
ld a, [wYCoord]
ld b, a
ld a, [hl] ; x#SPRITESTATEDATA2_MAPY
sub b ; relative to player position
swap a ; * 16
sub $4 ; - 4
dec h
ld [hli], a ; [x#SPRITESTATEDATA1_YPIXELS]
inc h
ld a, [wXCoord]
ld b, a
ld a, [hli] ; x#SPRITESTATEDATA2_MAPX
sub b ; relative to player position
swap a ; * 16
dec h
ld [hl], a ; [x#SPRITESTATEDATA1_XPIXELS]
ret
; tests if sprite is off screen or otherwise unable to do anything
CheckSpriteAvailability:
predef IsObjectHidden
ldh a, [hIsHiddenMissableObject]
and a
jp nz, .spriteInvisible
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA2_MOVEMENTBYTE1
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA2_MOVEMENTBYTE1
cp WALK
jr c, .skipXVisibilityTest ; movement byte 1 < WALK (i.e. the sprite's movement is scripted)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA2_MAPY
ld l, a
ld b, [hl] ; x#SPRITESTATEDATA2_MAPY
ld a, [wYCoord]
cp b
jr z, .skipYVisibilityTest
jr nc, .spriteInvisible ; above screen region
add SCREEN_HEIGHT / 2 - 1
cp b
jr c, .spriteInvisible ; below screen region
.skipYVisibilityTest
inc l
ld b, [hl] ; x#SPRITESTATEDATA2_MAPX
ld a, [wXCoord]
cp b
jr z, .skipXVisibilityTest
jr nc, .spriteInvisible ; left of screen region
add SCREEN_WIDTH / 2 - 1
cp b
jr c, .spriteInvisible ; right of screen region
.skipXVisibilityTest
; make the sprite invisible if a text box is in front of it
; $5F is the maximum number for map tiles
call GetTileSpriteStandsOn
ld d, MAP_TILESET_SIZE
ld a, [hli]
cp d
jr nc, .spriteInvisible ; standing on tile with ID >=MAP_TILESET_SIZE (bottom left tile)
ld a, [hld]
cp d
jr nc, .spriteInvisible ; standing on tile with ID >=MAP_TILESET_SIZE (bottom right tile)
ld bc, -SCREEN_WIDTH
add hl, bc ; go back one row of tiles
ld a, [hli]
cp d
jr nc, .spriteInvisible ; standing on tile with ID >=MAP_TILESET_SIZE (top left tile)
ld a, [hl]
cp d
jr c, .spriteVisible ; standing on tile with ID >=MAP_TILESET_SIZE (top right tile)
.spriteInvisible
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA1_IMAGEINDEX
ld l, a
ld [hl], $ff ; x#SPRITESTATEDATA1_IMAGEINDEX
scf
jr .done
.spriteVisible
ld c, a
ld a, [wWalkCounter]
and a
jr nz, .done ; if player is currently walking, we're done
call UpdateSpriteImage
inc h
ldh a, [hCurrentSpriteOffset]
add $7
ld l, a
ld a, [wGrassTile]
cp c
ld a, 0
jr nz, .notInGrass
ld a, OAM_BEHIND_BG
.notInGrass
ld [hl], a ; x#SPRITESTATEDATA2_GRASSPRIORITY
and a
.done
ret
UpdateSpriteImage:
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
add $8
ld l, a
ld a, [hli] ; x#SPRITESTATEDATA1_ANIMFRAMECOUNTER
ld b, a
ld a, [hl] ; x#SPRITESTATEDATA1_FACINGDIRECTION
add b
ld b, a
ldh a, [hTilePlayerStandingOn]
add b
ld b, a
ldh a, [hCurrentSpriteOffset]
add $2
ld l, a
ld [hl], b ; x#SPRITESTATEDATA1_IMAGEINDEX
ret
; tests if sprite can walk the specified direction
; b: direction (1,2,4 or 8)
; c: ID of tile the sprite would walk onto
; d: Y movement delta (-1, 0 or 1)
; e: X movement delta (-1, 0 or 1)
; set carry on failure, clears carry on success
CanWalkOntoTile:
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA2_MOVEMENTBYTE1
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA2_MOVEMENTBYTE1
cp WALK
jr nc, .notScripted ; values WALK or STAY
; always allow walking if the movement is scripted
and a
ret
.notScripted
ld a, [wTilesetCollisionPtr]
ld l, a
ld a, [wTilesetCollisionPtr+1]
ld h, a
.tilePassableLoop
ld a, [hli]
cp $ff
jr z, .impassable
cp c
jr nz, .tilePassableLoop
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add $6
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA2_MOVEMENTBYTE1
inc a
jr z, .impassable ; if $ff, no movement allowed (however, changing direction is)
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA1_YPIXELS
ld l, a
ld a, [hli] ; x#SPRITESTATEDATA1_YPIXELS
add $4 ; align to blocks (Y pos is always 4 pixels off)
add d ; add Y delta
cp $80 ; if value is >$80, the destination is off screen (either $81 or $FF underflow)
jr nc, .impassable ; don't walk off screen
inc l
ld a, [hl] ; x#SPRITESTATEDATA1_XPIXELS
add e ; add X delta
cp $90 ; if value is >$90, the destination is off screen (either $91 or $FF underflow)
jr nc, .impassable ; don't walk off screen
push de
push bc
call DetectCollisionBetweenSprites
pop bc
pop de
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
add $c
ld l, a
ld a, [hl] ; x#SPRITESTATEDATA1_COLLISIONDATA (directions in which sprite collision would occur)
and b ; check against chosen direction (1,2,4 or 8)
jr nz, .impassable ; collision between sprites, don't go there
ld h, HIGH(wSpriteStateData2)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA2_YDISPLACEMENT
ld l, a
ld a, [hli] ; x#SPRITESTATEDATA2_YDISPLACEMENT (initialized at $8, keep track of where a sprite did go)
bit 7, d ; check if going upwards (d=$ff)
jr nz, .upwards
add d
; bug: these tests against $5 probably were supposed to prevent
; sprites from walking out too far, but this line makes sprites get
; stuck whenever they walked upwards 5 steps
; on the other hand, the amount a sprite can walk out to the
; right of bottom is not limited (until the counter overflows)
cp $5
jr c, .impassable ; if [x#SPRITESTATEDATA2_YDISPLACEMENT]+d < 5, don't go
jr .checkHorizontal
.upwards
sub $1
jr c, .impassable ; if [x#SPRITESTATEDATA2_YDISPLACEMENT] == 0, don't go
.checkHorizontal
ld d, a
ld a, [hl] ; x#SPRITESTATEDATA2_XDISPLACEMENT (initialized at $8, keep track of where a sprite did go)
bit 7, e ; check if going left (e=$ff)
jr nz, .left
add e
cp $5 ; compare, but no conditional jump like in the vertical check above (bug?)
jr .passable
.left
sub $1
jr c, .impassable ; if [x#SPRITESTATEDATA2_XDISPLACEMENT] == 0, don't go
.passable
ld [hld], a ; update x#SPRITESTATEDATA2_XDISPLACEMENT
ld [hl], d ; update x#SPRITESTATEDATA2_YDISPLACEMENT
and a ; clear carry (marking success)
ret
.impassable
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
inc a
ld l, a
ld [hl], $2 ; [x#SPRITESTATEDATA1_MOVEMENTSTATUS] = 2 (delayed)
inc l
inc l
xor a
ld [hli], a ; [x#SPRITESTATEDATA1_YSTEPVECTOR] = 0
inc l
ld [hl], a ; [x#SPRITESTATEDATA1_XSTEPVECTOR] = 0
inc h
ldh a, [hCurrentSpriteOffset]
add $8
ld l, a
call Random
ldh a, [hRandomAdd]
and $7f
ld [hl], a ; x#SPRITESTATEDATA2_MOVEMENTDELAY: set to a random value in [0,$7f] (again with delay $100 if value is 0)
scf ; set carry (marking failure to walk)
ret
; calculates the tile pointer pointing to the tile the current sprite stands on
; this is always the lower left tile of the 2x2 tile blocks all sprites are snapped to
; hl: output pointer
GetTileSpriteStandsOn:
ld h, HIGH(wSpriteStateData1)
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA1_YPIXELS
ld l, a
ld a, [hli] ; x#SPRITESTATEDATA1_YPIXELS
add $4 ; align to 2*2 tile blocks (Y position is always off 4 pixels to the top)
and $f0 ; in case object is currently moving
srl a ; screen Y tile * 4
ld c, a
ld b, $0
inc l
ld a, [hl] ; x#SPRITESTATEDATA1_XPIXELS
srl a
srl a
srl a ; screen X tile
add SCREEN_WIDTH ; screen X tile + 20
ld d, $0
ld e, a
hlcoord 0, 0
add hl, bc
add hl, bc
add hl, bc
add hl, bc
add hl, bc
add hl, de ; wTileMap + 20*(screen Y tile + 1) + screen X tile
ret
; loads [de+a] into a
LoadDEPlusA:
add e
ld e, a
jr nc, .noCarry
inc d
.noCarry
ld a, [de]
ret
DoScriptedNPCMovement:
; This is an alternative method of scripting an NPC's movement and is only used
; a few times in the game. It is used when the NPC and player must walk together
; in sync, such as when the player is following the NPC somewhere. An NPC can't
; be moved in sync with the player using the other method.
ld a, [wd730]
bit 7, a
ret z
ld hl, wd72e
bit 7, [hl]
set 7, [hl]
jp z, InitScriptedNPCMovement
ld hl, wNPCMovementDirections2
ld a, [wNPCMovementDirections2Index]
add l
ld l, a
jr nc, .noCarry
inc h
.noCarry
ld a, [hl]
; check if moving up
cp NPC_MOVEMENT_UP
jr nz, .checkIfMovingDown
call GetSpriteScreenYPointer
ld c, SPRITE_FACING_UP
ld a, -2
jr .move
.checkIfMovingDown
cp NPC_MOVEMENT_DOWN
jr nz, .checkIfMovingLeft
call GetSpriteScreenYPointer
ld c, SPRITE_FACING_DOWN
ld a, 2
jr .move
.checkIfMovingLeft
cp NPC_MOVEMENT_LEFT
jr nz, .checkIfMovingRight
call GetSpriteScreenXPointer
ld c, SPRITE_FACING_LEFT
ld a, -2
jr .move
.checkIfMovingRight
cp NPC_MOVEMENT_RIGHT
jr nz, .noMatch
call GetSpriteScreenXPointer
ld c, SPRITE_FACING_RIGHT
ld a, 2
jr .move
.noMatch
cp $ff
ret
.move
ld b, a
ld a, [hl]
add b
ld [hl], a
ldh a, [hCurrentSpriteOffset]
add $9
ld l, a
ld a, c
ld [hl], a ; facing direction
call AnimScriptedNPCMovement
ld hl, wScriptedNPCWalkCounter
dec [hl]
ret nz
ld a, 8
ld [wScriptedNPCWalkCounter], a
ld hl, wNPCMovementDirections2Index
inc [hl]
ret
InitScriptedNPCMovement:
xor a
ld [wNPCMovementDirections2Index], a
ld a, 8
ld [wScriptedNPCWalkCounter], a
jp AnimScriptedNPCMovement
GetSpriteScreenYPointer:
ld a, SPRITESTATEDATA1_YPIXELS
ld b, a
jr GetSpriteScreenXYPointerCommon
GetSpriteScreenXPointer:
ld a, SPRITESTATEDATA1_XPIXELS
ld b, a
GetSpriteScreenXYPointerCommon:
ld hl, wSpriteStateData1
ldh a, [hCurrentSpriteOffset]
add l
add b
ld l, a
ret
AnimScriptedNPCMovement:
ld hl, wSpriteStateData2
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA2_IMAGEBASEOFFSET
ld l, a
ld a, [hl] ; VRAM slot
dec a
swap a
ld b, a
ld hl, wSpriteStateData1
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA1_FACINGDIRECTION
ld l, a
ld a, [hl] ; facing direction
cp SPRITE_FACING_DOWN
jr z, .anim
cp SPRITE_FACING_UP
jr z, .anim
cp SPRITE_FACING_LEFT
jr z, .anim
cp SPRITE_FACING_RIGHT
jr z, .anim
ret
.anim
add b
ld b, a
ldh [hSpriteVRAMSlotAndFacing], a
call AdvanceScriptedNPCAnimFrameCounter
ld hl, wSpriteStateData1
ldh a, [hCurrentSpriteOffset]
add SPRITESTATEDATA1_IMAGEINDEX
ld l, a
ldh a, [hSpriteVRAMSlotAndFacing]
ld b, a
ldh a, [hSpriteAnimFrameCounter]
add b
ld [hl], a
ret
AdvanceScriptedNPCAnimFrameCounter:
ldh a, [hCurrentSpriteOffset]
add $7
ld l, a
ld a, [hl] ; intra-animation frame counter
inc a
ld [hl], a
cp 4
ret nz
xor a
ld [hl], a ; reset intra-animation frame counter
inc l
ld a, [hl] ; animation frame counter
inc a
and $3
ld [hl], a
ldh [hSpriteAnimFrameCounter], a
ret