mirror of
https://github.com/pret/pokeyellow.git
synced 2026-05-15 15:29:45 -05:00
232 lines
3.9 KiB
NASM
232 lines
3.9 KiB
NASM
PrepareOAMData: ; 499b (1:499b)
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; Determine OAM data for currently visible
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; sprites and write it to wOAMBuffer.
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; Yellow code has been changed to use registers more efficiently
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; as well as tweaking the code to show gbc palettes
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ld a, [wUpdateSpritesEnabled]
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dec a
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jr z, .updateEnabled
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cp $ff
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ret nz
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ld [wUpdateSpritesEnabled], a
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jp HideSprites
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.updateEnabled
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xor a
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ld [hOAMBufferOffset], a
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.spriteLoop
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ld [hSpriteOffset2], a
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ld e, a
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ld d, wSpriteStateData1 / $100
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ld a, [de] ; c1x0
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and a
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jp z, .nextSprite
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inc e
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inc e
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ld a, [de] ; c1x2 (facing/anim)
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ld [wd5cd], a
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cp $ff ; off-screen (don't draw)
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jr nz, .visible
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call GetSpriteScreenXY
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jr .nextSprite
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.visible
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cp $a0 ; is the sprite unchanging like an item ball or boulder?
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jr c, .usefacing
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; unchanging
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ld a, $0
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jr .next
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.usefacing
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and $f
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.next
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; read the entry from the table
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ld c, a
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ld b, 0
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ld hl, SpriteFacingAndAnimationTable
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add hl, bc
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add hl, bc
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ld a, [hli]
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ld h, [hl]
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ld l, a
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; get sprite priority
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push de
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inc d
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ld a, e
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add $5
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ld e, a
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ld a, [de] ; c2x7
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and $80
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ld [hSpritePriority], a ; temp store sprite priority
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pop de
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call GetSpriteScreenXY
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ld a, [hOAMBufferOffset]
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add [hl]
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cp $a0
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jr z, .hidden
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jr nc, .asm_4a41
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.hidden
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call Func_4a7b
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ld [wd5cd], a
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ld a, [hOAMBufferOffset]
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ld e, a
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ld d, wOAMBuffer / $100
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.tileLoop
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ld a, [hli]
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ld c, a
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.loop
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ld a, [hSpriteScreenY] ; temp for sprite Y position
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add $10 ; Y=16 is top of screen (Y=0 is invisible)
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add [hl] ; add Y offset from table
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ld [de], a ; write new sprite OAM Y position
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inc hl
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inc e
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ld a, [hSpriteScreenX] ; temp for sprite X position
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add $8 ; X=8 is left of screen (X=0 is invisible)
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add [hl] ; add X offset from table
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ld [de], a
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inc hl
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inc e
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ld a, [wd5cd]
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add [hl]
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cp $80
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jr c, .asm_4a1c
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ld b, a
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ld a, [$fffc]
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add b
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.asm_4a1c
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ld [de], a ; tile id
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inc hl
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inc e
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ld a, [hl]
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bit 1, a ; is the tile allowed to set the sprite priority bit?
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jr z, .skipPriority
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ld a, [hSpritePriority]
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or [hl]
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.skipPriority
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and $f0
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bit 4, a ; OBP0 or OBP1
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jr z, .spriteusesOBP0
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or %100 ; palettes 4-7 are OBP1
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.spriteusesOBP0
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ld [de], a
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inc hl
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inc e
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dec c
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jr nz, .loop
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ld a, e
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ld [hOAMBufferOffset], a
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.nextSprite
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ld a, [hSpriteOffset2]
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add $10
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cp $100 % $100
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jp nz, .spriteLoop
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; Clear unused OAM.
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.asm_4a41
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ld a, [wd736]
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bit 6, a ; jumping down ledge or fishing animation?
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ld c, $a0
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jr z, .clear
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; Don't clear the last 4 entries because they are used for the shadow in the
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; jumping down ledge animation and the rod in the fishing animation.
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ld c, $90
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.clear
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ld a, [hOAMBufferOffset]
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cp c
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ret nc
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ld l, a
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ld h, wOAMBuffer / $100
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ld a, c
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ld de, $4 ; entry size
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ld b, $a0
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.clearLoop
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ld [hl], b
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add hl, de
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cp l
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jr nz, .clearLoop
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ret
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GetSpriteScreenXY: ; 4a5f (1:4a5f)
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inc e
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inc e
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ld a, [de] ; c1x4
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ld [hSpriteScreenY], a
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inc e
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inc e
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ld a, [de] ; c1x6
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ld [hSpriteScreenX], a
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ld a, 4
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add e
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ld e, a
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ld a, [hSpriteScreenY]
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add 4
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and $f0
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ld [de], a ; c1xa (y)
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inc e
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ld a, [hSpriteScreenX]
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and $f0
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ld [de], a ; c1xb (x)
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ret
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Func_4a7b: ; 4a7b (1:4a7b)
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push bc
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ld a, [wd5cd] ; temp copy of c1x2
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swap a ; high nybble determines sprite used (0 is always player sprite, next are some npcs)
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and $f
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; Sprites $a and $b have one face (and therefore 4 tiles instead of 12).
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; As a result, sprite $b's tile offset is less than normal.
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cp $b
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jr nz, .notFourTileSprite
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ld a, $a * 12 + 4 ; $7c
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jr .done
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.notFourTileSprite
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; a *= 12
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add a
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add a
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ld c, a
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add a
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add c
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.done
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pop bc
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ret
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INCLUDE "engine/oam_dma.asm"
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_IsTilePassable:: ; 4aaa (1:4aaa)
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ld hl,wTilesetCollisionPtr ; pointer to list of passable tiles
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ld a,[hli]
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ld h,[hl]
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ld l,a ; hl now points to passable tiles
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.loop
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ld a,[hli]
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cp a,$ff
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jr z,.tileNotPassable
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cp c
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jr nz,.loop
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xor a
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ret
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.tileNotPassable
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scf
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ret
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INCLUDE "data/collision.asm" ; probably |