ref: b764a3a84d836768c385e9131ab458e0edfe0716
dir: /home/map_objects.asm/
; Functions handling map objects. GetSpritePalette:: push hl push de push bc ld c, a farcall _GetSpritePalette ld a, c pop bc pop de pop hl ret GetSpriteVTile:: push hl push bc ld hl, wUsedSprites + 2 ld c, SPRITE_GFX_LIST_CAPACITY - 1 ld b, a ldh a, [hMapObjectIndex] cp 0 jr z, .nope ld a, b .loop cp [hl] jr z, .found inc hl inc hl dec c jr nz, .loop ld a, [wUsedSprites + 1] scf jr .done .nope ld a, [wUsedSprites + 1] jr .done .found inc hl xor a ld a, [hl] .done pop bc pop hl ret DoesSpriteHaveFacings:: push de push hl ld b, a ldh a, [hROMBank] push af ld a, BANK(_DoesSpriteHaveFacings) rst Bankswitch ld a, b call _DoesSpriteHaveFacings ld c, a pop de ld a, d rst Bankswitch pop hl pop de ret GetPlayerStandingTile:: ld a, [wPlayerStandingTile] call GetTileCollision ld b, a ret CheckOnWater:: ld a, [wPlayerStandingTile] call GetTileCollision sub WATER_TILE ret z and a ret GetTileCollision:: ; Get the collision type of tile a. push de push hl ld hl, TileCollisionTable ld e, a ld d, 0 add hl, de ldh a, [hROMBank] push af ld a, BANK(TileCollisionTable) rst Bankswitch ld e, [hl] pop af rst Bankswitch ld a, e and $f ; lo nybble only pop hl pop de ret CheckGrassTile:: ld d, a and $f0 cp HI_NYBBLE_TALL_GRASS jr z, .grass cp HI_NYBBLE_WATER jr z, .water scf ret .grass ld a, d and LO_NYBBLE_GRASS ret z scf ret ; For some reason, the above code is duplicated down here. .water ld a, d and LO_NYBBLE_GRASS ret z scf ret CheckSuperTallGrassTile:: cp COLL_LONG_GRASS ret z cp COLL_LONG_GRASS_1C ret CheckCutTreeTile:: cp COLL_CUT_TREE ret z cp COLL_CUT_TREE_1A ret CheckHeadbuttTreeTile:: cp COLL_HEADBUTT_TREE ret z cp COLL_HEADBUTT_TREE_1D ret CheckCounterTile:: cp COLL_COUNTER ret z cp COLL_COUNTER_98 ret CheckPitTile:: cp COLL_PIT ret z cp COLL_PIT_68 ret CheckIceTile:: cp COLL_ICE ret z cp COLL_ICE_2B ret z scf ret CheckWhirlpoolTile:: nop cp COLL_WHIRLPOOL ret z cp COLL_WHIRLPOOL_2C ret z scf ret CheckWaterfallTile:: cp COLL_WATERFALL ret z cp COLL_CURRENT_DOWN ret CheckStandingOnEntrance:: ld a, [wPlayerStandingTile] cp COLL_DOOR ret z cp COLL_DOOR_79 ret z cp COLL_STAIRCASE ret z cp COLL_CAVE ret GetMapObject:: ; Return the location of map object a in bc. ld hl, wMapObjects ld bc, MAPOBJECT_LENGTH call AddNTimes ld b, h ld c, l ret CheckObjectVisibility:: ; Sets carry if the object is not visible on the screen. ldh [hMapObjectIndex], a call GetMapObject ld hl, MAPOBJECT_OBJECT_STRUCT_ID add hl, bc ld a, [hl] cp -1 jr z, .not_visible ldh [hObjectStructIndex], a call GetObjectStruct and a ret .not_visible scf ret CheckObjectTime:: ld hl, MAPOBJECT_HOUR add hl, bc ld a, [hl] cp -1 jr nz, .check_hour ld hl, MAPOBJECT_TIMEOFDAY add hl, bc ld a, [hl] cp -1 jr z, .timeofday_always ld hl, .TimesOfDay ld a, [wTimeOfDay] add l ld l, a jr nc, .ok inc h .ok ld a, [hl] ld hl, MAPOBJECT_TIMEOFDAY add hl, bc and [hl] jr nz, .timeofday_always scf ret .timeofday_always and a ret .TimesOfDay: ; entries correspond to TimeOfDay values db MORN db DAY db NITE .check_hour ld hl, MAPOBJECT_HOUR add hl, bc ld d, [hl] ld hl, MAPOBJECT_TIMEOFDAY add hl, bc ld e, [hl] ld hl, hHours ld a, d cp e jr z, .yes jr c, .check_timeofday ld a, [hl] cp d jr nc, .yes cp e jr c, .yes jr z, .yes jr .no .check_timeofday ld a, e cp [hl] jr c, .no ld a, [hl] cp d jr nc, .yes jr .no .yes and a ret .no scf ret CopyMapObjectStruct:: ; unreferenced ldh [hMapObjectIndex], a call GetMapObject call CopyObjectStruct ret UnmaskCopyMapObjectStruct:: ldh [hMapObjectIndex], a call UnmaskObject ldh a, [hMapObjectIndex] call GetMapObject farcall CopyObjectStruct ret ApplyDeletionToMapObject:: ldh [hMapObjectIndex], a call GetMapObject ld hl, MAPOBJECT_OBJECT_STRUCT_ID add hl, bc ld a, [hl] cp -1 ret z ; already hidden ld [hl], -1 push af call .CheckStopFollow pop af call GetObjectStruct farcall DeleteMapObject ret .CheckStopFollow: ld hl, wObjectFollow_Leader cp [hl] jr z, .ok ld hl, wObjectFollow_Follower cp [hl] ret nz .ok farcall StopFollow ld a, -1 ld [wObjectFollow_Leader], a ld [wObjectFollow_Follower], a ret DeleteObjectStruct:: call ApplyDeletionToMapObject call MaskObject ret CopyPlayerObjectTemplate:: push hl call GetMapObject ld d, b ld e, c ld a, -1 ld [de], a inc de pop hl ld bc, MAPOBJECT_LENGTH - 1 call CopyBytes ret DeleteFollowerMapObject: ; unreferenced call GetMapObject ld hl, MAPOBJECT_OBJECT_STRUCT_ID add hl, bc ld a, [hl] push af ld [hl], -1 inc hl ld bc, MAPOBJECT_LENGTH - 1 xor a call ByteFill pop af cp -1 ret z cp NUM_OBJECT_STRUCTS ret nc ld b, a ld a, [wObjectFollow_Leader] cp b jr nz, .ok ld a, -1 ld [wObjectFollow_Leader], a .ok ld a, b call GetObjectStruct farcall DeleteMapObject ret LoadMovementDataPointer:: ; Load the movement data pointer for object a. ld [wMovementObject], a ldh a, [hROMBank] ld [wMovementDataBank], a ld a, l ld [wMovementDataAddress], a ld a, h ld [wMovementDataAddress + 1], a ld a, [wMovementObject] call CheckObjectVisibility ret c ld hl, OBJECT_MOVEMENTTYPE add hl, bc ld [hl], SPRITEMOVEDATA_SCRIPTED ld hl, OBJECT_STEP_TYPE add hl, bc ld [hl], STEP_TYPE_RESET ld hl, wVramState set 7, [hl] and a ret FindFirstEmptyObjectStruct:: ; Returns the index of the first empty object struct in A and its address in HL, then sets carry. ; If all object structs are occupied, A = 0 and Z is set. ; Preserves BC and DE. push bc push de ld hl, wObjectStructs ld de, OBJECT_LENGTH ld c, NUM_OBJECT_STRUCTS .loop ld a, [hl] and a jr z, .break add hl, de dec c jr nz, .loop xor a jr .done .break ld a, NUM_OBJECT_STRUCTS sub c scf .done pop de pop bc ret GetSpriteMovementFunction:: ld hl, OBJECT_MOVEMENTTYPE add hl, bc ld a, [hl] cp NUM_SPRITEMOVEDATA jr c, .ok xor a .ok ld hl, SpriteMovementData + SPRITEMOVEATTR_MOVEMENT ld e, a ld d, 0 rept NUM_SPRITEMOVEDATA_FIELDS add hl, de endr ld a, [hl] ret GetInitialFacing:: push bc push de ld e, a ld d, 0 ld hl, SpriteMovementData + SPRITEMOVEATTR_FACING rept NUM_SPRITEMOVEDATA_FIELDS add hl, de endr ld a, BANK(SpriteMovementData) call GetFarByte add a add a maskbits NUM_DIRECTIONS, 2 pop de pop bc ret CopySpriteMovementData:: ld l, a ldh a, [hROMBank] push af ld a, BANK(SpriteMovementData) rst Bankswitch ld a, l push bc call .CopyData pop bc pop af rst Bankswitch ret .CopyData: ld hl, OBJECT_MOVEMENTTYPE add hl, de ld [hl], a push de ld e, a ld d, 0 ld hl, SpriteMovementData + SPRITEMOVEATTR_FACING rept NUM_SPRITEMOVEDATA_FIELDS add hl, de endr ld b, h ld c, l pop de ld a, [bc] inc bc rlca rlca maskbits NUM_DIRECTIONS, 2 ld hl, OBJECT_FACING add hl, de ld [hl], a ld a, [bc] inc bc ld hl, OBJECT_ACTION add hl, de ld [hl], a ld a, [bc] inc bc ld hl, OBJECT_FLAGS1 add hl, de ld [hl], a ld a, [bc] inc bc ld hl, OBJECT_FLAGS2 add hl, de ld [hl], a ld a, [bc] inc bc ld hl, OBJECT_PALETTE add hl, de ld [hl], a ret _GetMovementByte:: ; Switch to the movement data bank ldh a, [hROMBank] push af ld a, [hli] rst Bankswitch ; Load the current script byte as given by OBJECT_MOVEMENT_BYTE_INDEX, and increment OBJECT_MOVEMENT_BYTE_INDEX ld a, [hli] ld d, [hl] ld hl, OBJECT_MOVEMENT_BYTE_INDEX add hl, bc add [hl] ld e, a ld a, d adc 0 ld d, a inc [hl] ld a, [de] ld h, a pop af rst Bankswitch ld a, h ret SetVramState_Bit0:: ; unreferenced ld hl, wVramState set 0, [hl] ret ResetVramState_Bit0:: ; unreferenced ld hl, wVramState res 0, [hl] ret UpdateSprites:: ld a, [wVramState] bit 0, a ret z farcall UpdateAllObjectsFrozen farcall _UpdateSprites ret GetObjectStruct:: ld bc, OBJECT_LENGTH ld hl, wObjectStructs call AddNTimes ld b, h ld c, l ret DoesObjectHaveASprite:: ld hl, OBJECT_SPRITE add hl, bc ld a, [hl] and a ret SetSpriteDirection:: ; preserves other flags push af ld hl, OBJECT_FACING add hl, bc ld a, [hl] and %11110011 ld e, a pop af maskbits NUM_DIRECTIONS, 2 or e ld [hl], a ret GetSpriteDirection:: ld hl, OBJECT_FACING add hl, bc ld a, [hl] maskbits NUM_DIRECTIONS, 2 ret