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; set attributes for [hl] sprites starting from wOAM + [wOAMOffset] / 4
; return carry if reached end of wOAM before finishing
SetManyObjectsAttributes: ; 950 (0:950)
push hl
ld a, [wOAMOffset]
ld c, a
ld b, HIGH(wOAM)
cp 40 * 4
jr nc, .beyond_oam
pop hl
ld a, [hli] ; [hl] = how many obj?
.copy_obj_loop
push af
ld a, [hli]
add e
ld [bc], a ; Y Position <- [hl + 1 + 4*i] + e
inc bc
ld a, [hli]
add d
ld [bc], a ; X Position <- [hl + 2 + 4*i] + d
inc bc
ld a, [hli]
ld [bc], a ; Tile/Pattern Number <- [hl + 3 + 4*i]
inc bc
ld a, [hli]
ld [bc], a ; Attributes/Flags <- [hl + 4 + 4*i]
inc bc
ld a, c
cp 40 * 4
jr nc, .beyond_oam
pop af
dec a
jr nz, .copy_obj_loop
or a
.done
ld hl, wOAMOffset
ld [hl], c
ret
.beyond_oam
pop hl
scf
jr .done
; for the sprite at wOAM + [wOAMOffset] / 4, set its attributes from registers e, d, c, b
; return carry if [wOAMOffset] > 40 * 4 (beyond the end of wOAM)
SetOneObjectAttributes:
push hl
ld a, [wOAMOffset]
ld l, a
ld h, HIGH(wOAM)
cp 40 * 4
jr nc, .beyond_oam
ld [hl], e ; Y Position
inc hl
ld [hl], d ; X Position
inc hl
ld [hl], c ; Tile/Pattern Number
inc hl
ld [hl], b ; Attributes/Flags
inc hl
ld a, l
ld [wOAMOffset], a
pop hl
or a
ret
.beyond_oam
pop hl
scf
ret
; set the Y Position and X Position of all sprites in wOAM to $00
ZeroObjectPositions:
xor a
ld [wOAMOffset], a
ld hl, wOAM
ld c, 40
xor a
.loop
ld [hli], a
ld [hli], a
inc hl
inc hl
dec c
jr nz, .loop
ret
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