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; try to initiate a wild pokemon encounter
; returns success in Z
TryDoWildEncounter:
ld a, [wNPCMovementScriptPointerTableNum]
and a
ret nz
ld a, [wd736]
and a
ret nz
callab IsPlayerStandingOnDoorTileOrWarpTile
jr nc, .notStandingOnDoorOrWarpTile
.CantEncounter
ld a, $1
and a
ret
.notStandingOnDoorOrWarpTile
callab IsPlayerJustOutsideMap
jr z, .CantEncounter
ld a, [wRepelRemainingSteps]
and a
jr z, .next
dec a
jr z, .lastRepelStep
ld [wRepelRemainingSteps], a
.next
; determine if wild pokemon can appear in the half-block we're standing in
; is the bottom right tile (9,9) of the half-block we're standing in a grass/water tile?
coord hl, 9, 9
ld c, [hl]
ld a, [wGrassTile]
cp c
ld a, [wGrassRate]
jr z, .CanEncounter
ld a, $14 ; in all tilesets with a water tile, this is its id
cp c
ld a, [wWaterRate]
jr z, .CanEncounter
; even if not in grass/water, standing anywhere we can encounter pokemon
; so long as the map is "indoor" and has wild pokemon defined.
; ...as long as it's not Viridian Forest or Safari Zone.
ld a, [wCurMap]
cp REDS_HOUSE_1F ; is this an indoor map?
jr c, .CantEncounter2
ld a, [wCurMapTileset]
cp FOREST ; Viridian Forest/Safari Zone
jr z, .CantEncounter2
ld a, [wGrassRate]
.CanEncounter
; compare encounter chance with a random number to determine if there will be an encounter
ld b, a
ld a, [hRandomAdd]
cp b
jr nc, .CantEncounter2
ld a, [hRandomSub]
ld b, a
ld hl, WildMonEncounterSlotChances
.determineEncounterSlot
ld a, [hli]
cp b
jr nc, .gotEncounterSlot
inc hl
jr .determineEncounterSlot
.gotEncounterSlot
; determine which wild pokemon (grass or water) can appear in the half-block we're standing in
ld c, [hl]
ld hl, wGrassMons
aCoord 8, 9
cp $14 ; is the bottom left tile (8,9) of the half-block we're standing in a water tile?
jr nz, .gotWildEncounterType ; else, it's treated as a grass tile by default
ld hl, wWaterMons
; since the bottom right tile of a "left shore" half-block is $14 but the bottom left tile is not,
; "left shore" half-blocks (such as the one in the east coast of Cinnabar) load grass encounters.
.gotWildEncounterType
ld b, 0
add hl, bc
ld a, [hli]
ld [wCurEnemyLVL], a
ld a, [hl]
ld [wcf91], a
ld [wEnemyMonSpecies2], a
ld a, [wRepelRemainingSteps]
and a
jr z, .willEncounter
ld a, [wPartyMon1Level]
ld b, a
ld a, [wCurEnemyLVL]
cp b
jr c, .CantEncounter2 ; repel prevents encounters if the leading party mon's level is higher than the wild mon
jr .willEncounter
.lastRepelStep
ld [wRepelRemainingSteps], a
ld a, TEXT_REPEL_WORE_OFF
ld [hSpriteIndexOrTextID], a
call EnableAutoTextBoxDrawing
call DisplayTextID
.CantEncounter2
ld a, $1
and a
ret
.willEncounter
xor a
ret
WildMonEncounterSlotChances:
; There are 10 slots for wild pokemon, and this is the table that defines how common each of
; those 10 slots is. A random number is generated and then the first byte of each pair in this
; table is compared against that random number. If the random number is less than or equal
; to the first byte, then that slot is chosen. The second byte is double the slot number.
db $32, $00 ; 51/256 = 19.9% chance of slot 0
db $65, $02 ; 51/256 = 19.9% chance of slot 1
db $8C, $04 ; 39/256 = 15.2% chance of slot 2
db $A5, $06 ; 25/256 = 9.8% chance of slot 3
db $BE, $08 ; 25/256 = 9.8% chance of slot 4
db $D7, $0A ; 25/256 = 9.8% chance of slot 5
db $E4, $0C ; 13/256 = 5.1% chance of slot 6
db $F1, $0E ; 13/256 = 5.1% chance of slot 7
db $FC, $10 ; 11/256 = 4.3% chance of slot 8
db $FF, $12 ; 3/256 = 1.2% chance of slot 9