Skeetendo

UPDATE: it works!

I hope you aren't all sick of me yet :P I'm just really eager to learn how these games work, and I've been learning quite a lot from here! Anyways, as the title implies, I am trying to add Foresight to Red version. I'm pretty sure I have converted the code correctly, but whenever I use the attack, the game just freezes. Let me walk you through my process. I'm sorry for how verbose this is, I just wanted to make this as detailed as possible.

First, I went in to wram.asm and added a W_PLAYERBATTSTATUS4 and W_ENEMYBATTSTATUS4 to d06e and d073 respectively. This bytes seemed not to be used, so I thought it might be okay. Anyways, after that, I added in some variables in to the end of status_constants:

;volatile statuses 4
HasNightmare    EQU 0
UsingCurse      EQU 1
UsingProtect    EQU 2
BeenIdentified  EQU 3
UsingPerishSong EQU 4
UsingEndure     EQU 5
HasAnEncore        EQU 6
UsedDefenseCurl   EQU 7 ;unused

....these are just placeholders for eventual other moves of course, but what we care about is BeenIdentified, $3. I also replaced the type matchup table with the exact one pokecrystal used.

anyways, I went and looked at the original code for Foresight in pokecrystal's code, and it LOOKS like there are only two critical components to it. They look like the following:

BattleCommand_Foresight: ; 376a0
; foresight

    ld a, [AttackMissed]
    and a
    jr nz, .failed

    call CheckHiddenOpponent
    jr nz, .failed

    ld a, BATTLE_VARS_SUBSTATUS1_OPP
    call GetBattleVarAddr
    bit SUBSTATUS_IDENTIFIED, [hl]
    jr nz, .failed

    set SUBSTATUS_IDENTIFIED, [hl]
    call AnimateCurrentMove
    ld hl, IdentifiedText
    jp StdBattleTextBox

.failed
    jp FailForesight
; 376c2

which was inside foresight.asm, and:

.TypesLoop:
    ld a, [hli]

    cp $ff
    jr z, .end

    ; foresight
    cp $fe
    jr nz, .SkipForesightCheck
    ld a, BATTLE_VARS_SUBSTATUS1_OPP
    call GetBattleVar
    bit SUBSTATUS_IDENTIFIED, a
    jr nz, .end

    jr .TypesLoop

.SkipForesightCheck:
    cp b
    jr nz, .SkipType
    ld a, [hl]
    cp d
    jr z, .GotMatchup
    cp e
    jr z, .GotMatchup
    jr .SkipType

.GotMatchup:
etc....

which is part of the code that determines the type of a move for effectiveness. ANYWAY! I rewrote both of those, inserting the latter in to the type loop in pokered's Core.asm:

.loop
    ld a,[hli] ; a = "attacking type" of the current type pair
    cp a,$ff
    jr z,.done
    
    ; foresight
    cp $fe
    jr nz, .SkipForesightCheck
    ;jp nz, PrintDidntAffectText
    ;ld bc, W_ENEMYBATTSTATUS4
    ld a,[W_ENEMYBATTSTATUS4]
    bit BeenIdentified, a
    jr nz, .done

    jr .loop
    
.SkipForesightCheck:
    cp b ; does move type match "attacking type"?
    jr nz,.nextTypePair
        etc......

and then the actual effect code, in e_2.asm .....why there? I dunno. Do you have a better idea? Please advise.

ForesightEffect_: ; 376a0
; foresight
    callab MoveHitTest
    ld a, [W_MOVEMISSED] ; W_MOVEMISSED
    and a
    jr nz, .failed
    
    ld a, [W_ENEMYBATTSTATUS1]
    bit Invulnerable, a
    jr nz, .failed
 
    ld a,[W_ENEMYBATTSTATUS4]
    bit BeenIdentified, [hl]
    jr nz, .failed

    set BeenIdentified, [hl]
    call PlayMoveAnimation
    ld hl, IdentifiedText
    jp PrintText
.failed
    jp PrintButItFailedText_
    
IdentifiedText: ; 3fb49 (f:7b49)
    TX_FAR _IdentifiedText
    db "@"
; 376c2

....now just from a glance it LOOKS like I rewrote these correctly, but.........the game freezes whenever I use the attack. In addition to obviously adding the text for the command, I also added ForesightEffect to the effect pointer table (as well as made an effect constant for it) but then also defined this in core.asm:

ForesightEffect:
    ld hl, ForesightEffect_
    ld b, BANK(ForesightEffect_)
    jp Bankswitch

the same way stuff like transform does it, etc.

Now, I'm pretty sure I'm understanding how the original code works, and functionally, it LOOKS like I rewrote it to work in red version correctly. But like I said, the game freezes. I'm sure there'a glaringly obvious error in what I've done and I'm hoping someone will point that out for me. Particularly, I'm pretty confused by what BATTLE_VARS_SUBSTATUS1_OPP and GetBattleVar are supposed to be, so I tried to aproximate their functionality? I SUSPECT that the issue is NOT in the routine from core.asm, as the game functions perfectly when the move is not used, but then again I could be wrong. Sorry for how verbose this post is, like I said, I just wanted to be as detailed as possible.

Last edited by KeiTaRo (2017-03-12 03:02:36)