pokered/engine/overworld/movement.asm
2014-09-08 23:32:33 -07:00

859 lines
19 KiB
NASM

UpdatePlayerSprite: ; 4e31 (1:4e31)
ld a, [wSpriteStateData2]
and a
jr z, .checkIfTextBoxInFrontOfSprite
cp $ff
jr z, .disableSprite
dec a
ld [wSpriteStateData2], 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 $5F, which is
; the maximum number for map tiles
.checkIfTextBoxInFrontOfSprite
aCoord 8, 9
ld [$ff93], a
cp $60
jr c, .lowerLeftTileIsMapTile
.disableSprite
ld a, $ff
ld [wSpriteStateData1 + 2], a
ret
.lowerLeftTileIsMapTile
call DetectCollisionBetweenSprites
ld h, $c1
ld a, [wWalkCounter] ; wcfc5
and a
jr nz, .asm_4e90
ld a, [wd528]
bit 2, a
jr z, .asm_4e65
xor a
jr .asm_4e86
.asm_4e65
bit 3, a
jr z, .asm_4e6d
ld a, $4
jr .asm_4e86
.asm_4e6d
bit 1, a
jr z, .asm_4e75
ld a, $8
jr .asm_4e86
.asm_4e75
bit 0, a
jr z, .asm_4e7d
ld a, $c
jr .asm_4e86
.asm_4e7d
xor a
ld [wSpriteStateData1 + 7], a
ld [wSpriteStateData1 + 8], a
jr .asm_4eab
.asm_4e86
ld [wSpriteStateData1 + 9], a
ld a, [wcfc4]
bit 0, a
jr nz, .asm_4e7d
.asm_4e90
ld a, [wd736]
bit 7, a
jr nz, .asm_4eb6
ld a, [H_CURRENTSPRITEOFFSET]
add $7
ld l, a
ld a, [hl]
inc a
ld [hl], a
cp $4
jr nz, .asm_4eab
xor a
ld [hl], a
inc hl
ld a, [hl]
inc a
and $3
ld [hl], a
.asm_4eab
ld a, [wSpriteStateData1 + 8]
ld b, a
ld a, [wSpriteStateData1 + 9]
add b
ld [wSpriteStateData1 + 2], a
.asm_4eb6
ld a, [$ff93]
ld c, a
ld a, [W_GRASSTILE]
cp c
ld a, $0
jr nz, .asm_4ec3
ld a, $80
.asm_4ec3
ld [wSpriteStateData2 + $07], a
ret
Func_4ec7: ; 4ec7 (1:4ec7)
push bc
push af
ld a, [$ffda]
ld c, a
pop af
add c
ld l, a
pop bc
ret
Func_4ed1: ; 4ed1 (1:4ed1)
ld a, [H_CURRENTSPRITEOFFSET]
swap a
dec a
add a
ld hl, W_MAPSPRITEDATA ; wd4e4
add l
ld l, a
ld a, [hl] ; read movement byte 2
ld [wCurSpriteMovement2], a
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
ld l, a
inc l
ld a, [hl] ; c1x1
and a
jp z, InitializeSpriteStatus
call CheckSpriteAvailability
ret c ; if sprite is invisible, on tile >=$60, in grass or player is currently walking
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
ld l, a
inc l
ld a, [hl] ; c1x1
bit 7, a
jp nz, InitializeSpriteFacingDirection ; c1x1 >= $80
ld b, a
ld a, [wcfc4]
bit 0, a
jp nz, notYetMoving
ld a, b
cp $2
jp z, UpdateSpriteMovementDelay ; c1x1 == 2
cp $3
jp z, UpdateSpriteInWalkingAnimation ; c1x1 == 3
ld a, [wWalkCounter] ; wcfc5
and a
ret nz ; don't do anything yet if player is currently moving (redundant, already tested in CheckSpriteAvailability)
call InitializeSpriteScreenPosition
ld h, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $6
ld l, a
ld a, [hl] ; c2x6: movement byte 1
inc a
jr z, .asm_4f59 ; value $FF
inc a
jr z, .asm_4f59 ; value $FE
dec a
ld [hl], a ; (temporarily) increment movement byte 1
dec a
push hl
ld hl, wcf0f
dec [hl] ; decrement wcf0f
pop hl
ld de, wcc5b
call LoadDEPlusA ; a = [wcc5b + movement byte 1]
cp $e0
jp z, ChangeFacingDirection
cp $ff
jr nz, .asm_4f4b
ld [hl], a ; reset movement byte 1 to initial value
ld hl, wd730
res 0, [hl]
xor a
ld [wcd38], a
ld [wcd3a], a
ret
.asm_4f4b
cp $fe
jr nz, .asm_4f5f
ld [hl], $1 ; set movement byte 1 to $1
ld de, wcc5b
call LoadDEPlusA ; a = [wcc5b + $fe] (?)
jr .asm_4f5f
.asm_4f59
call getTileSpriteStandsOn
call Random
.asm_4f5f
ld b, a
ld a, [wCurSpriteMovement2]
cp $d0
jr z, .moveDown ; movement byte 2 = $d0 forces down
cp $d1
jr z, .moveUp ; movement byte 2 = $d1 forces up
cp $d2
jr z, .moveLeft ; movement byte 2 = $d2 forces left
cp $d3
jr z, .moveRight ; movement byte 2 = $d3 forces right
ld a, b
cp $40 ; a < $40: down (or left)
jr nc, .notDown
ld a, [wCurSpriteMovement2]
cp $2
jr z, .moveLeft ; movement byte 2 = $2 only allows left or right
.moveDown
ld de, 2*20
add hl, de ; move tile pointer two rows down
ld de, $100
ld bc, $400
jr TryWalking
.notDown
cp $80 ; $40 <= a < $80: up (or right)
jr nc, .notUp
ld a, [wCurSpriteMovement2]
cp $2
jr z, .moveRight ; movement byte 2 = $2 only allows left or right
.moveUp
ld de, -2*20 ; $ffd8
add hl, de ; move tile pointer two rows up
ld de, $ff00
ld bc, $804
jr TryWalking
.notUp
cp $c0 ; $80 <= a < $c0: left (or up)
jr nc, .notLeft
ld a, [wCurSpriteMovement2]
cp $1
jr z, .moveUp ; movement byte 2 = $1 only allows up or down
.moveLeft
dec hl
dec hl ; move tile pointer two columns left
ld de, $ff
ld bc, $208
jr TryWalking
.notLeft ; $c0 <= a: right (or down)
ld a, [wCurSpriteMovement2]
cp $1
jr z, .moveDown ; movement byte 2 = $1 only allows up or down
.moveRight
inc hl
inc hl ; move tile pointer two columns right
ld de, $1
ld bc, $10c
jr TryWalking
; changes facing direction by zeroing the movement delta and calling TryWalking
ChangeFacingDirection: ; 4fc8 (1:4fc8)
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 wlak onto
; set carry on failure, clears carry on success
TryWalking: ; 4fcb (1:4fcb)
push hl
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
add $9
ld l, a
ld [hl], c ; c1x9 (update facing direction)
ld a, [H_CURRENTSPRITEOFFSET]
add $3
ld l, a
ld [hl], d ; c1x3 (update Y movement delta)
inc l
inc l
ld [hl], e ; c1x5 (update X movement delta)
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, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $4
ld l, a
ld a, [hl] ; c2x4: Y position
add d
ld [hli], a ; update Y position
ld a, [hl] ; c2x5: X position
add e
ld [hl], a ; update X position
ld a, [H_CURRENTSPRITEOFFSET]
ld l, a
ld [hl], $10 ; c2x0=16: walk animation counter
dec h
inc l
ld [hl], $3 ; c1x1: set movement status to walking
jp UpdateSpriteImage
; update the walking animation parameters for a sprite that is currently walking
UpdateSpriteInWalkingAnimation: ; 4ffe (1:4ffe)
ld a, [H_CURRENTSPRITEOFFSET]
add $7
ld l, a
ld a, [hl] ; c1x7 (counter until next walk animation frame)
inc a
ld [hl], a ; c1x7 += 1
cp $4
jr nz, .noNextAnimationFrame
xor a
ld [hl], a ; c1x7 = 0
inc l
ld a, [hl] ; c1x8 (walk animation frame)
inc a
and $3
ld [hl], a ; advance to next animation frame every 4 ticks (16 ticks total for one step)
.noNextAnimationFrame
ld a, [H_CURRENTSPRITEOFFSET]
add $3
ld l, a
ld a, [hli] ; c1x3 (movement Y delta)
ld b, a
ld a, [hl] ; c1x4 (screen Y position)
add b
ld [hli], a ; update screen Y position
ld a, [hli] ; c1x5 (movement X delta)
ld b, a
ld a, [hl] ; c1x6 (screen X position)
add b
ld [hl], a ; update screen X position
ld a, [H_CURRENTSPRITEOFFSET]
ld l, a
inc h
ld a, [hl] ; c2x0 (walk animantion counter)
dec a
ld [hl], a ; update walk animantion counter
ret nz
ld a, $6 ; walking finished, update state
add l
ld l, a
ld a, [hl] ; c2x6 (movement byte 1)
cp $fe
jr nc, .initNextMovementCounter ; values $fe and $ff
ld a, [H_CURRENTSPRITEOFFSET]
inc a
ld l, a
dec h
ld [hl], $1 ; c1x1 = 1 (movement status ready)
ret
.initNextMovementCounter
call Random
ld a, [H_CURRENTSPRITEOFFSET]
add $8
ld l, a
ld a, [hRandomAdd]
and $7f
ld [hl], a ; c2x8: set next movement delay to a random value in [0,$7f]
dec h ; note that value 0 actually makes the delay $100 (bug?)
ld a, [H_CURRENTSPRITEOFFSET]
inc a
ld l, a
ld [hl], $2 ; c1x1 = 2 (movement status)
inc l
inc l
xor a
ld b, [hl] ; c1x3 (movement Y delta)
ld [hli], a ; reset movement Y delta
inc l
ld c, [hl] ; c1x5 (movement X delta)
ld [hl], a ; reset movement X delta
ret
; update delay value (c2x8) for sprites in the delayed state (c1x1)
UpdateSpriteMovementDelay: ; 5057 (1:5057)
ld h, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $6
ld l, a
ld a, [hl] ; c2x6: movement byte 1
inc l
inc l
cp $fe
jr nc, .tickMoveCounter ; values $fe or $ff
ld [hl], $0
jr .moving
.tickMoveCounter
dec [hl] ; c2x8: frame counter until next movement
jr nz, notYetMoving
.moving
dec h
ld a, [H_CURRENTSPRITEOFFSET]
inc a
ld l, a
ld [hl], $1 ; c1x1 = 1 (mark as ready to move)
notYetMoving: ; 5073 (1:5073)
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
add $8
ld l, a
ld [hl], $0 ; c1x8 = 0 (walk animation frame)
jp UpdateSpriteImage
InitializeSpriteFacingDirection: ; 507f (1:507f)
ld a, [wd72d]
bit 5, a
jr nz, notYetMoving
res 7, [hl]
ld a, [wd52a]
bit 3, a
jr z, .notFacingDown
ld c, $0 ; make sprite face down
jr .facingDirectionDetermined
.notFacingDown
bit 2, a
jr z, .notFacingUp
ld c, $4 ; make sprite face up
jr .facingDirectionDetermined
.notFacingUp
bit 1, a
jr z, .notFacingRight
ld c, $c ; make sprite face right
jr .facingDirectionDetermined
.notFacingRight
ld c, $8 ; make sprite face left
.facingDirectionDetermined
ld a, [H_CURRENTSPRITEOFFSET]
add $9
ld l, a
ld [hl], c ; c1x9: set facing direction
jr notYetMoving
InitializeSpriteStatus: ; 50ad (1:50ad)
ld [hl], $1 ; $c1x1: set movement status to ready
inc l
ld [hl], $ff ; $c1x2: set sprite image to $ff (invisible/off screen)
inc h
ld a, [H_CURRENTSPRITEOFFSET]
add $2
ld l, a
ld a, $8
ld [hli], a ; $c2x2: set Y displacement to 8
ld [hl], a ; $c2x3: set X displacement to 8
ret
; calculates the spprite's scrren position form its map position and the player position
InitializeSpriteScreenPosition: ; 50bd (1:50bd)
ld h, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $4
ld l, a
ld a, [W_YCOORD] ; wd361
ld b, a
ld a, [hl] ; c2x4 (Y position + 4)
sub b ; relative to player position
swap a ; * 16
sub $4 ; - 4
dec h
ld [hli], a ; c1x4 (screen Y position)
inc h
ld a, [W_XCOORD] ; wd362
ld b, a
ld a, [hli] ; c2x6 (X position + 4)
sub b ; relative to player position
swap a ; * 16
dec h
ld [hl], a ; c1x6 (screen X position)
ret
; tests if sprite is off screen or otherwise unable to do anything
CheckSpriteAvailability: ; 50dc (1:50dc)
predef IsObjectHidden
ld a, [$ffe5]
and a
jp nz, .spriteInvisible
ld h, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $6
ld l, a
ld a, [hl] ; c2x6: movement byte 1
cp $fe
jr c, .skipXVisibilityTest ; movement byte 1 < $fe
ld a, [H_CURRENTSPRITEOFFSET]
add $4
ld l, a
ld b, [hl] ; c2x4: Y pos (+4)
ld a, [W_YCOORD] ; wd361
cp b
jr z, .skipYVisibilityTest
jr nc, .spriteInvisible ; above screen region
add $8 ; screen is 9 tiles high
cp b
jr c, .spriteInvisible ; below screen region
.skipYVisibilityTest
inc l
ld b, [hl] ; c2x5: X pos (+4)
ld a, [W_XCOORD] ; wd362
cp b
jr z, .skipXVisibilityTest
jr nc, .spriteInvisible ; left of screen region
add $9 ; screen is 10 tiles wide
cp b
jr c, .spriteInvisible ; right of screen region
.skipXVisibilityTest
call getTileSpriteStandsOn
ld d, $60
ld a, [hli]
cp d
jr nc, .spriteInvisible ; standing on tile with ID >=$60 (bottom left tile)
ld a, [hld]
cp d
jr nc, .spriteInvisible ; standing on tile with ID >=$60 (bottom right tile)
ld bc, -20 ; $ffec
add hl, bc ; go back one row of tiles
ld a, [hli]
cp d
jr nc, .spriteInvisible ; standing on tile with ID >=$60 (top left tile)
ld a, [hl]
cp d
jr c, .spriteVisible ; standing on tile with ID >=$60 (top right tile)
.spriteInvisible
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
add $2
ld l, a
ld [hl], $ff ; c1x2
scf
jr .done
.spriteVisible
ld c, a
ld a, [wWalkCounter] ; wcfc5
and a
jr nz, .done ; if player is currently walking, we're done
call UpdateSpriteImage
inc h
ld a, [H_CURRENTSPRITEOFFSET]
add $7
ld l, a
ld a, [W_GRASSTILE]
cp c
ld a, $0
jr nz, .notInGrass
ld a, $80
.notInGrass
ld [hl], a ; c2x7
and a
.done
ret
UpdateSpriteImage: ; 5157 (1:5157)
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
add $8
ld l, a
ld a, [hli] ; c1x8: walk animation frame
ld b, a
ld a, [hl] ; c1x9: facing direction
add b
ld b, a
ld a, [$ff93] ; current sprite offset
add b
ld b, a
ld a, [H_CURRENTSPRITEOFFSET]
add $2
ld l, a
ld [hl], b ; c1x2: sprite to display
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: ; 516e (1:516e)
ld h, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $6
ld l, a
ld a, [hl] ; c2x6 (movement byte 1)
cp $fe
jr nc, .canMove ; values $fe and $ff
and a
ret
.canMove
ld a, [W_TILESETCOLLISIONPTR]
ld l, a
ld a, [W_TILESETCOLLISIONPTR+1]
ld h, a
.tilePassableLoop
ld a, [hli]
cp $ff
jr z, .impassable
cp c
jr nz, .tilePassableLoop
ld h, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $6
ld l, a
ld a, [hl] ; $c2x6 (movement byte 1)
inc a
jr z, .impassable ; if $ff, no movement allowed (however, changing direction is)
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
add $4
ld l, a
ld a, [hli] ; c1x4 (screen Y pos)
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] ; c1x6 (screen X pos)
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, $c1
ld a, [H_CURRENTSPRITEOFFSET]
add $c
ld l, a
ld a, [hl] ; c1xc (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, $c2
ld a, [H_CURRENTSPRITEOFFSET]
add $2
ld l, a
ld a, [hli] ; c2x2 (sprite Y displacement, 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
cp $5
jr c, .impassable ; if c2x2+d < 5, don't go ;bug: this tests probably were supposed to prevent sprites
jr .checkHorizontal ; from walking out too far, but this line makes sprites get stuck
.upwards ; whenever they walked upwards 5 steps
sub $1 ; on the other hand, the amount a sprite can walk out to the
jr c, .impassable ; if d2x2 == 0, don't go ; right of bottom is not limited (until the counter overflows)
.checkHorizontal
ld d, a
ld a, [hl] ; c2x3 (sprite X displacement, 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 d2x3 == 0, don't go
.passable
ld [hld], a ; update c2x3
ld [hl], d ; update c2x2
and a ; clear carry (marking success)
ret
.impassable
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
inc a
ld l, a
ld [hl], $2 ; c1x1 = 2 (set movement status to delayed)
inc l
inc l
xor a
ld [hli], a ; c1x3 = 0 (clear Y movement delta)
inc l
ld [hl], a ; c1x5 = 0 (clear X movement delta)
inc h
ld a, [H_CURRENTSPRITEOFFSET]
add $8
ld l, a
call Random
ld a, [hRandomAdd]
and $7f
ld [hl], a ; c2x8: set next movement delay 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 stancs on
; this is always the lower left tile of the 2x2 tile blocks all sprites are snapped to
; hl: output pointer
getTileSpriteStandsOn: ; 5207 (1:5207)
ld h, $c1
ld a, [H_CURRENTSPRITEOFFSET]
add $4
ld l, a
ld a, [hli] ; c1x4: screen Y position
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] ; c1x6: screen Y position
srl a
srl a
srl a ; screen X tile
add $14 ; screen X tile + 20
ld d, $0
ld e, a
ld hl, wTileMap
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: ; 522f (1:522f)
add e
ld e, a
jr nc, .noCarry
inc d
.noCarry
ld a, [de]
ret
Func_5236: ; 5236 (1:5236)
ld a, [wd730]
bit 7, a
ret z
ld hl, wd72e
bit 7, [hl]
set 7, [hl]
jp z, Func_52a6
ld hl, wcc97
ld a, [wcd37]
add l
ld l, a
jr nc, .asm_5251
inc h
.asm_5251
ld a, [hl]
cp $40
jr nz, .asm_525f
call Func_52b2
ld c, $4
ld a, $fe
jr .asm_5289
.asm_525f
cp $0
jr nz, .asm_526c
call Func_52b2
ld c, $0
ld a, $2
jr .asm_5289
.asm_526c
cp $80
jr nz, .asm_5279
call Func_52b7
ld c, $8
ld a, $fe
jr .asm_5289
.asm_5279
cp $c0
jr nz, .asm_5286
call Func_52b7
ld c, $c
ld a, $2
jr .asm_5289
.asm_5286
cp $ff
ret
.asm_5289
ld b, a
ld a, [hl]
add b
ld [hl], a
ld a, [H_CURRENTSPRITEOFFSET]
add $9
ld l, a
ld a, c
ld [hl], a
call Func_52c3
ld hl, wcf18
dec [hl]
ret nz
ld a, $8
ld [wcf18], a
ld hl, wcd37
inc [hl]
ret
Func_52a6: ; 52a6 (1:52a6)
xor a
ld [wcd37], a
ld a, $8
ld [wcf18], a
jp Func_52c3
Func_52b2: ; 52b2 (1:52b2)
ld a, $4
ld b, a
jr asm_52ba
Func_52b7: ; 52b7 (1:52b7)
ld a, $6
ld b, a
asm_52ba: ; 52ba (1:52ba)
ld hl, wSpriteStateData1
ld a, [H_CURRENTSPRITEOFFSET]
add l
add b
ld l, a
ret
Func_52c3: ; 52c3 (1:52c3)
ld hl, wSpriteStateData2
ld a, [H_CURRENTSPRITEOFFSET]
add $e
ld l, a
ld a, [hl]
dec a
swap a
ld b, a
ld hl, wSpriteStateData1
ld a, [H_CURRENTSPRITEOFFSET]
add $9
ld l, a
ld a, [hl]
cp $0
jr z, .asm_52ea
cp $4
jr z, .asm_52ea
cp $8
jr z, .asm_52ea
cp $c
jr z, .asm_52ea
ret
.asm_52ea
add b
ld b, a
ld [$ffe9], a
call Func_5301
ld hl, wSpriteStateData1
ld a, [H_CURRENTSPRITEOFFSET]
add $2
ld l, a
ld a, [$ffe9]
ld b, a
ld a, [$ffea]
add b
ld [hl], a
ret
Func_5301: ; 5301 (1:5301)
ld a, [H_CURRENTSPRITEOFFSET]
add $7
ld l, a
ld a, [hl]
inc a
ld [hl], a
cp $4
ret nz
xor a
ld [hl], a
inc l
ld a, [hl]
inc a
and $3
ld [hl], a
ld [$ffea], a
ret