1 files changed, 196 insertions, 0 deletions
diff --git a/home/pics.asm b/home/pics.asm
new file mode 100644
index 00000000..02683db7
--- /dev/null
+++ b/home/pics.asm
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+; 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 = Kabutops fossil, bank $B
+; index < $1F, bank 9
+; $1F ≤ index < $4A, bank $A
+; $4A ≤ index < $74, bank $B
+; $74 ≤ index < $99, bank $C
+; $99 ≤ index,       bank $D
+	ld a, [wcf91] ; XXX name for this ram location
+	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(TangelaPicFront)
+	jr c, .GotBank
+	ld a, b
+	cp MOLTRES + 1
+	ld a, BANK(MoltresPicFront)
+	jr c, .GotBank
+	ld a, b
+	cp BEEDRILL + 2
+	ld a, BANK(BeedrillPicFront)
+	jr c, .GotBank
+	ld a, b
+	cp STARMIE + 1
+	ld a, BANK(StarmiePicFront)
+	jr c, .GotBank
+	ld a, BANK(VictreebelPicFront)
+.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
+	ld [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)
+	ld [hSpriteOffset], a
+	ld a, c
+	swap a
+	and $f
+	ld b, a
+	add a
+	add a
+	add a     ; 8*tiles is height in bytes
+	ld [hSpriteHeight], a
+	ld a, $7
+	sub b      ; 7-h         ; skip for vertical center (in tiles, relative to current column)
+	ld b, a
+	ld 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)
+	ld [hSpriteOffset], a
+	xor a
+	ld [$4000], 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::
+	ld a, [hSpriteOffset]
+	ld b, $0
+	ld c, a
+	add hl, bc
+	ld a, [hSpriteWidth]
+.columnLoop
+	push af
+	push hl
+	ld 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 [$4000], 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
+	ld [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
+	ld a, [hSpriteInterlaceCounter]
+	dec a
+	ld [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
+	ld a, [hLoadedROMBank]
+	ld b, a
+	jp CopyVideoData