Sync with pokered

1 files changed, 232 insertions, 0 deletions

diff --git a/engine/gfx/sprite_oam.asm b/engine/gfx/sprite_oam.asm
new file mode 100644
index 00000000..01b2c412
--- /dev/null
+++ b/engine/gfx/sprite_oam.asm
@@ -0,0 +1,232 @@
+PrepareOAMData::
+; Determine OAM data for currently visible
+; sprites and write it to wOAMBuffer.
+; Yellow code has been changed to use registers more efficiently
+; as well as tweaking the code to show gbc palettes
+
+	ld a, [wUpdateSpritesEnabled]
+	dec a
+	jr z, .updateEnabled
+
+	cp -1
+	ret nz
+	ld [wUpdateSpritesEnabled], a
+	jp HideSprites
+
+.updateEnabled
+	xor a
+	ldh [hOAMBufferOffset], a
+
+.spriteLoop
+	ldh [hSpriteOffset2], a
+
+	ld e, a
+	ld d, HIGH(wSpriteStateData1)
+
+	ld a, [de] ; [x#SPRITESTATEDATA1_PICTUREID]
+	and a
+	jp z, .nextSprite
+
+	inc e
+	inc e
+	ld a, [de] ; [x#SPRITESTATEDATA1_IMAGEINDEX]
+	ld [wd5cd], a
+	cp $ff ; off-screen (don't draw)
+	jr nz, .visible
+
+	call GetSpriteScreenXY
+	jr .nextSprite
+
+.visible
+	cp $a0 ; is the sprite unchanging like an item ball or boulder?
+	jr c, .usefacing
+
+; unchanging
+	ld a, $0
+	jr .next
+
+.usefacing
+	and $f
+
+.next
+; read the entry from the table
+	ld c, a
+	ld b, 0
+	ld hl, SpriteFacingAndAnimationTable
+	add hl, bc
+	add hl, bc
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+; get sprite priority
+	push de
+	inc d
+	ld a, e
+	add $5
+	ld e, a
+	ld a, [de] ; [x#SPRITESTATEDATA2_GRASSPRIORITY]
+	and $80
+	ldh [hSpritePriority], a ; temp store sprite priority
+	pop de
+
+
+	call GetSpriteScreenXY
+
+	ldh a, [hOAMBufferOffset]
+	add [hl]
+	cp $a0
+	jr z, .hidden
+	jr nc, .asm_4a41
+.hidden
+	call Func_4a7b
+	ld [wd5cd], a
+	ldh a, [hOAMBufferOffset]
+
+	ld e, a
+	ld d, HIGH(wOAMBuffer)
+
+.tileLoop
+	ld a, [hli]
+	ld c, a
+.loop
+	ldh a, [hSpriteScreenY]   ; temp for sprite Y position
+	add $10                  ; Y=16 is top of screen (Y=0 is invisible)
+	add [hl]                 ; add Y offset from table
+	ld [de], a               ; write new sprite OAM Y position
+	inc hl
+	inc e
+	ldh a, [hSpriteScreenX]   ; temp for sprite X position
+	add $8                   ; X=8 is left of screen (X=0 is invisible)
+	add [hl]                 ; add X offset from table
+	ld [de], a
+	inc hl
+	inc e
+	ld a, [wd5cd]
+	add [hl]
+	cp $80
+	jr c, .asm_4a1c
+	ld b, a
+	ldh a, [hFFFC]
+	add b
+.asm_4a1c
+	ld [de], a ; tile id
+	inc hl
+	inc e
+	ld a, [hl]
+	bit 1, a ; is the tile allowed to set the sprite priority bit?
+	jr z, .skipPriority
+	ldh a, [hSpritePriority]
+	or [hl]
+.skipPriority
+	and $f0
+	bit 4, a ; OBP0 or OBP1
+	jr z, .spriteusesOBP0
+	or %100 ; palettes 4-7 are OBP1
+.spriteusesOBP0
+	ld [de], a
+	inc hl
+	inc e
+	dec c
+	jr nz, .loop
+
+	ld a, e
+	ldh [hOAMBufferOffset], a
+.nextSprite
+	ldh a, [hSpriteOffset2]
+	add $10
+	cp LOW($100)
+	jp nz, .spriteLoop
+
+	; Clear unused OAM.
+.asm_4a41
+	ld a, [wd736]
+	bit 6, a ; jumping down ledge or fishing animation?
+	ld c, $a0
+	jr z, .clear
+
+; Don't clear the last 4 entries because they are used for the shadow in the
+; jumping down ledge animation and the rod in the fishing animation.
+	ld c, $90
+
+.clear
+	ldh a, [hOAMBufferOffset]
+	cp c
+	ret nc
+	ld l, a
+	ld h, wOAMBuffer / $100
+	ld a, c
+	ld de, $4 ; entry size
+	ld b, $a0
+.clearLoop
+	ld [hl], b
+	add hl, de
+	cp l
+	jr nz, .clearLoop
+	ret
+
+GetSpriteScreenXY:
+	inc e
+	inc e
+	ld a, [de] ; [x#SPRITESTATEDATA1_YPIXELS]
+	ldh [hSpriteScreenY], a
+	inc e
+	inc e
+	ld a, [de] ; [x#SPRITESTATEDATA1_XPIXELS]
+	ldh [hSpriteScreenX], a
+	ld a, 4
+	add e
+	ld e, a
+	ldh a, [hSpriteScreenY]
+	add 4
+	and $f0
+	ld [de], a ; [x#SPRITESTATEDATA1_YADJUSTED]
+	inc e
+	ldh a, [hSpriteScreenX]
+	and $f0
+	ld [de], a  ; [x#SPRITESTATEDATA1_XADJUSTED]
+	ret
+
+Func_4a7b:
+	push bc
+	ld a, [wd5cd]            ; temp copy of [x#SPRITESTATEDATA1_IMAGEINDEX]
+	swap a                   ; high nybble determines sprite used (0 is always player sprite, next are some npcs)
+	and $f
+
+	; Sprites $a and $b have one face (and therefore 4 tiles instead of 12).
+	; As a result, sprite $b's tile offset is less than normal.
+	cp $b
+	jr nz, .notFourTileSprite
+	ld a, $a * 12 + 4 ; $7c
+	jr .done
+
+.notFourTileSprite
+	; a *= 12
+	add a
+	add a
+	ld c, a
+	add a
+	add c
+.done
+	pop bc
+	ret
+
+INCLUDE "engine/gfx/oam_dma.asm"
+
+_IsTilePassable::
+	ld hl, wTilesetCollisionPtr ; pointer to list of passable tiles
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a ; hl now points to passable tiles
+.loop
+	ld a, [hli]
+	cp a, $ff
+	jr z, .tileNotPassable
+	cp c
+	jr nz, .loop
+	xor a
+	ret
+.tileNotPassable
+	scf
+	ret
+
+INCLUDE "data/tilesets/collision_tile_ids.asm"