ref: b3364f9f8819a87f562ca612199aaa0d4da7fcee
dir: /home/pics.asm/
; uncompresses the front or back sprite of the specified mon
; assumes the corresponding mon header is already loaded
; hl contains offset to sprite pointer ($b for front or $d for back)
UncompressMonSprite::
ld bc, wMonHeader
add hl, bc
ld a, [hli]
ld [wSpriteInputPtr], a ; fetch sprite input pointer
ld a, [hl]
ld [wSpriteInputPtr+1], a
; define (by index number) the bank that a pokemon's image is in
; index = MEW: bank $1
; index = FOSSIL_KABUTOPS: bank $B
; index < $1F: bank $9 ("Pics 1")
; $1F ≤ index < $4A: bank $A ("Pics 2")
; $4A ≤ index < $74: bank $B ("Pics 3")
; $74 ≤ index < $99: bank $C ("Pics 4")
; $99 ≤ index: bank $D ("Pics 5")
ld a, [wcf91]
ld b, a
cp MEW
ld a, BANK(MewPicFront)
jr z, .GotBank
ld a, b
cp FOSSIL_KABUTOPS
ld a, BANK(FossilKabutopsPic)
jr z, .GotBank
ld a, b
cp TANGELA + 1
ld a, BANK("Pics 1")
jr c, .GotBank
ld a, b
cp MOLTRES + 1
ld a, BANK("Pics 2")
jr c, .GotBank
ld a, b
cp BEEDRILL + 2
ld a, BANK("Pics 3")
jr c, .GotBank
ld a, b
cp STARMIE + 1
ld a, BANK("Pics 4")
jr c, .GotBank
ld a, BANK("Pics 5")
.GotBank
jp UncompressSpriteData
; de: destination location
LoadMonFrontSprite::
push de
ld hl, wMonHFrontSprite - wMonHeader
call UncompressMonSprite
ld hl, wMonHSpriteDim
ld a, [hli]
ld c, a
pop de
; fall through
; postprocesses uncompressed sprite chunks to a 2bpp sprite and loads it into video ram
; calculates alignment parameters to place both sprite chunks in the center of the 7*7 tile sprite buffers
; de: destination location
; a,c: sprite dimensions (in tiles of 8x8 each)
LoadUncompressedSpriteData::
push de
and $f
ldh [hSpriteWidth], a ; each byte contains 8 pixels (in 1bpp), so tiles=bytes for width
ld b, a
ld a, $7
sub b ; 7-w
inc a ; 8-w
srl a ; (8-w)/2 ; horizontal center (in tiles, rounded up)
ld b, a
add a
add a
add a
sub b ; 7*((8-w)/2) ; skip for horizontal center (in tiles)
ldh [hSpriteOffset], a
ld a, c
swap a
and $f
ld b, a
add a
add a
add a ; 8*tiles is height in bytes
ldh [hSpriteHeight], a
ld a, $7
sub b ; 7-h ; skip for vertical center (in tiles, relative to current column)
ld b, a
ldh a, [hSpriteOffset]
add b ; 7*((8-w)/2) + 7-h ; combined overall offset (in tiles)
add a
add a
add a ; 8*(7*((8-w)/2) + 7-h) ; combined overall offset (in bytes)
ldh [hSpriteOffset], a
xor a
ld [MBC1SRamBank], a
ld hl, sSpriteBuffer0
call ZeroSpriteBuffer ; zero buffer 0
ld de, sSpriteBuffer1
ld hl, sSpriteBuffer0
call AlignSpriteDataCentered ; copy and align buffer 1 to 0 (containing the MSB of the 2bpp sprite)
ld hl, sSpriteBuffer1
call ZeroSpriteBuffer ; zero buffer 1
ld de, sSpriteBuffer2
ld hl, sSpriteBuffer1
call AlignSpriteDataCentered ; copy and align buffer 2 to 1 (containing the LSB of the 2bpp sprite)
pop de
jp InterlaceMergeSpriteBuffers
; copies and aligns the sprite data properly inside the sprite buffer
; sprite buffers are 7*7 tiles in size, the loaded sprite is centered within this area
AlignSpriteDataCentered::
ldh a, [hSpriteOffset]
ld b, $0
ld c, a
add hl, bc
ldh a, [hSpriteWidth]
.columnLoop
push af
push hl
ldh a, [hSpriteHeight]
ld c, a
.columnInnerLoop
ld a, [de]
inc de
ld [hli], a
dec c
jr nz, .columnInnerLoop
pop hl
ld bc, 7*8 ; 7 tiles
add hl, bc ; advance one full column
pop af
dec a
jr nz, .columnLoop
ret
; fills the sprite buffer (pointed to in hl) with zeros
ZeroSpriteBuffer::
ld bc, SPRITEBUFFERSIZE
.nextByteLoop
xor a
ld [hli], a
dec bc
ld a, b
or c
jr nz, .nextByteLoop
ret
; combines the (7*7 tiles, 1bpp) sprite chunks in buffer 0 and 1 into a 2bpp sprite located in buffer 1 through 2
; in the resulting sprite, the rows of the two source sprites are interlaced
; de: output address
InterlaceMergeSpriteBuffers::
xor a
ld [MBC1SRamBank], a
push de
ld hl, sSpriteBuffer2 + (SPRITEBUFFERSIZE - 1) ; destination: end of buffer 2
ld de, sSpriteBuffer1 + (SPRITEBUFFERSIZE - 1) ; source 2: end of buffer 1
ld bc, sSpriteBuffer0 + (SPRITEBUFFERSIZE - 1) ; source 1: end of buffer 0
ld a, SPRITEBUFFERSIZE/2 ; $c4
ldh [hSpriteInterlaceCounter], a
.interlaceLoop
ld a, [de]
dec de
ld [hld], a ; write byte of source 2
ld a, [bc]
dec bc
ld [hld], a ; write byte of source 1
ld a, [de]
dec de
ld [hld], a ; write byte of source 2
ld a, [bc]
dec bc
ld [hld], a ; write byte of source 1
ldh a, [hSpriteInterlaceCounter]
dec a
ldh [hSpriteInterlaceCounter], a
jr nz, .interlaceLoop
ld a, [wSpriteFlipped]
and a
jr z, .notFlipped
ld bc, 2*SPRITEBUFFERSIZE
ld hl, sSpriteBuffer1
.swapLoop
swap [hl] ; if flipped swap nybbles in all bytes
inc hl
dec bc
ld a, b
or c
jr nz, .swapLoop
.notFlipped
pop hl
ld de, sSpriteBuffer1
ld c, (2*SPRITEBUFFERSIZE)/16 ; $31, number of 16 byte chunks to be copied
ldh a, [hLoadedROMBank]
ld b, a
jp CopyVideoData