1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
CheckForCollisionWhenPushingBoulder: ; c356 (3:4356)
call GetTileTwoStepsInFrontOfPlayer
call IsTilePassable
jr c, .done
ld hl, TilePairCollisionsLand
call CheckForTilePairCollisions2
ld a, $ff
jr c, .done ; if there is an elevation difference between the current tile and the one two steps ahead
ld a, [wTileInFrontOfBoulderAndBoulderCollisionResult]
cp $15 ; stairs tile
ld a, $ff
jr z, .done ; if the tile two steps ahead is stairs
call CheckForBoulderCollisionWithSprites
.done
ld [wTileInFrontOfBoulderAndBoulderCollisionResult], a
ret
; sets a to $ff if there is a collision and $00 if there is no collision
CheckForBoulderCollisionWithSprites: ; c378 (3:4378)
ld a, [wBoulderSpriteIndex]
dec a
swap a
ld d, 0
ld e, a
ld hl, wSpriteStateData2 + $14
add hl, de
ld a, [hli] ; map Y position
ld [$ffdc], a
ld a, [hl] ; map X position
ld [$ffdd], a
ld a, [wNumSprites]
ld c, a
ld de, $f
ld hl, wSpriteStateData2 + $14
ld a, [$ffdb]
and $3 ; facing up or down?
jr z, .pushingHorizontallyLoop
.pushingVerticallyLoop
inc hl
ld a, [$ffdd]
cp [hl]
jr nz, .nextSprite1 ; if X coordinates don't match
dec hl
ld a, [hli]
ld b, a
ld a, [$ffdb]
rrca
jr c, .pushingDown
; pushing up
ld a, [$ffdc]
dec a
jr .compareYCoords
.pushingDown
ld a, [$ffdc]
inc a
.compareYCoords
cp b
jr z, .failure
.nextSprite1
dec c
jr z, .success
add hl, de
jr .pushingVerticallyLoop
.pushingHorizontallyLoop
ld a, [hli]
ld b, a
ld a, [$ffdc]
cp b
jr nz, .nextSprite2
ld b, [hl]
ld a, [$ffdb]
bit 2, a
jr nz, .pushingLeft
; pushing right
ld a, [$ffdd]
inc a
jr .compareXCoords
.pushingLeft
ld a, [$ffdd]
dec a
.compareXCoords
cp b
jr z, .failure
.nextSprite2
dec c
jr z, .success
add hl, de
jr .pushingHorizontallyLoop
.failure
ld a, $ff
ret
.success
xor a
ret
|
