ref: 4ecff22f716aad9e9ad034cb0feae6cae273162e
dir: /engine/overworld/movement.asm/
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, $80 .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 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, $c2 ldh a, [hCurrentSpriteOffset] add $6 ld l, a ld a, [hl] ; x#SPRITESTATEDATA2_MOVEMENTBYTE1 inc a jr z, .randomMovement ; value $FF inc a jr z, .randomMovement ; value $FE ; 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 $e0 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 $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 $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*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 $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*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 $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 lb de, 0, -1 lb bc, 2, SPRITE_FACING_LEFT 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 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, $c2 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 $fe jr nc, .initNextMovementCounter ; values $fe and $ff 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 $fe jr nc, .tickMoveCounter ; values $fe or $ff 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 $fe jr c, .skipXVisibilityTest ; movement byte 1 < $fe (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 $8 ; screen is 9 tiles high 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 $9 ; screen is 10 tiles wide 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, -20 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, $80 .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 $fe jr nc, .notScripted ; values $fe and $ff ; 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, $c2 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