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INCLUDE "constants.asm"
SECTION "engine/overworld/object_collision.asm@GetSpritesNextTile", ROMX
; Get the tile that the sprite will walk onto next
GetSpritesNextTile:
ld hl, OBJECT_NEXT_MAP_X
add hl, bc
ld d, [hl]
ld hl, OBJECT_NEXT_MAP_Y
add hl, bc
ld e, [hl]
push bc
call GetCoordTile
pop bc
ret
; Sets carry flag if the object (bc) next tile is a collision
_IsObjectCollisionTileSolid:
call GetSpritesNextTile
ld e, a
ld d, 0
ld hl, CollisionTypeTable
add hl, de
ld a, BANK(CollisionTypeTable)
call GetFarByte
and ALWAYS_SOLID ; also covers SOMETIMES_SOLID
ret z
scf
ret
SECTION "engine/overworld/object_collision.asm@_CheckObjectCollision", ROMX
; returns the carry flag if a sprite is at coords d, e
; will not collide with sprite index stored in hEventCollisionException
_CheckObjectCollision:
ld bc, wObjectStructs
xor a
.loop
ldh [hObjectStructIndexBuffer], a
ld hl, OBJECT_SPRITE
add hl, bc
ld a, [hl]
and a
jr z, .next
ld hl, OBJECT_NEXT_MAP_X
add hl, bc
ld a, [hl]
cp d
jr nz, .check_last_position
ld hl, OBJECT_NEXT_MAP_Y
add hl, bc
ld a, [hl]
cp e
jr nz, .check_last_position
ldh a, [hEventCollisionException]
ld l, a
ldh a, [hObjectStructIndexBuffer]
cp l
jr nz, .collision
.check_last_position
ld hl, OBJECT_MAP_X
add hl, bc
ld a, [hl]
cp d
jr nz, .next
ld hl, OBJECT_MAP_Y
add hl, bc
ld a, [hl]
cp e
jr nz, .next
ldh a, [hEventCollisionException]
ld l, a
ldh a, [hObjectStructIndexBuffer]
cp l
jr nz, .collision
.next
ld hl, OBJECT_LENGTH
add hl, bc
ld b, h
ld c, l
ldh a, [hObjectStructIndexBuffer]
inc a
cp NUM_OBJECT_STRUCTS
jr nz, .loop
and a
ret
.collision
scf
ret
SECTION "engine/overworld/object_collision.asm@_CheckPlayerObjectCollision", ROMX
; Sets the carry flag if the player will collide with another sprite's current or next position
_CheckPlayerObjectCollision:
ld a, [wPlayerNextMapX]
ld d, a
ld a, [wPlayerNextMapY]
ld e, a
ld bc, wObjectStructs
xor a
.loop
ldh [hObjectStructIndexBuffer], a
ld hl, OBJECT_SPRITE
add hl, bc
ld a, [hl]
and a
jr z, .next
ld hl, OBJECT_NEXT_MAP_Y
add hl, bc
ld a, [hl]
cp e
jr nz, .check_last_position
ld hl, OBJECT_NEXT_MAP_X
add hl, bc
ld a, [hl]
cp d
jr nz, .check_last_position
; skip the player sprite
ldh a, [hObjectStructIndexBuffer]
cp PLAYER_OBJECT_INDEX
jr z, .next
jr .collision
.check_last_position
ld hl, OBJECT_MAP_Y
add hl, bc
ld a, [hl]
cp e
jr nz, .next
ld hl, OBJECT_MAP_X
add hl, bc
ld a, [hl]
cp d
jr nz, .next
jr .collision
.next
ld hl, OBJECT_LENGTH
add hl, bc
ld b, h
ld c, l
ldh a, [hObjectStructIndexBuffer]
inc a
cp NUM_OBJECT_STRUCTS
jr nz, .loop
xor a
ret
.collision
scf
ret
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