Development: Trainer interrupting battles

[Blah]

R&D on Pokemon Trainer's Interrupting battles:

Before I begin, skip to 5:50 and watch till 5:55 of this video to see what I'm talking about: https://www.youtube.com/watch?v=W609NJs9h-o

I want to implement that in Fire Red. So recently I've been reading, researching and tracking down different routines in battles in FireRed to basically find a point in the game which is run once per turn. Well I found that point. The game seems to have a "turn counter" which is incremented once at the end of each turn at 0x8013CB0

From there I need to call my own routine. A routine whose purpose was simply to check if the opponent was on their last Pokemon, and to check if their last Pokemon is lower than Half health.
In the newer games this, "trainer interrupt" happens 100% in these two conditions vs important NPCs.
So I should do an interrupt at those two stages.

The next problem is knowing which text to execute. The solution to that imo is simple. I decided the best way to do it, is to make a table of pointers to strings, and just use a variable to browse these pointers. (Getting the battle to display this string is another issue in itself).

The last, and probably the biggest problem is the trainer sliding in and out in both of these scenarios.

So right now, what I have done is the main routine that does the check of whether or not to do the trainer sliding process, and a helper function which basically just gives information about the opponents team.

Code for Main:

Spoiler:

.text
.align 2
.thumb
.thumb_func
 
@Main function. This checks whether to execute a slide + text and then does it.
@If no slide + text to be executed, restores previous instructions
@Uses a separate called checkPokemon which I wrote
 
main:
        push {r2-r5, lr}
        ldr r0, .checkPokemon @check trainer's pokemon
        bl checkPokemon
        cmp r1, #0x0 @check if last pokemon
        bne skip
        mov r1, #0x39
        mov r3, r0 @save r0
        ldr r5, VAR2
        cmp r5, #0x0 @if last Pokemon and we haven't displayed text before display
        beq text
        ldr r2, = (0x803FBE8 + 1) @check if last Pokemon less than half
        bl linkerTwo
        mov r4, r0 @r4 = currentHP
        mov r0, r3
        mov r1, #3A
        bl linkerTwo
        mov r1, #0x2
        mul r4, r4, r1
        cmp r0, r4
        ble skip @if more than half, no text display
 
text:
        @slide trainer (todo)
        @
        @below is the text, for some reason it appears to come on screen delayed :/
        @
        mov r0, #0x1 @set a flag (cover cases player spamming growl, doing no dmg..ect)
        strb r0, [r5]
        ldr r1, .VAR @get pointer number var from table. Var is index
        ldrb r1, [r1]
        ldr r0, .TABLE
        lsl r1, #0x2
        add r0, r0, r1
        ldr r0, [r0] @r0 contains pointer
        mov r1, #0x0  @check that it's a valid pointer, not free space
        ldrb r0, [r1]
        cmp r1, #0xFF
        beq skip
        ldr r1, =(0x80D77F4 +1) @battle text functions
        bl linkerOne
        mov r1, #0x18
        ldr r2, =(0x80D87BC +1)
        bl linkerTwo
        @unslide trainer (todo)
 
skip:
        ldr r1, = 0x3004F90
        ldrb r0, [r1, #0x13]
        cmp r0, #0xFE
        bhi replacer
        add r0, #0x1
        strb r0, [r1, #0x13]
 
replacer:
        ldr r2, = (0x8013CBC + 1)
 
linkerTwo:
        bx r2
 
linkerOne:
        bx r1
 
 
 
.align 2
.VAR:
        .word 0x020270B4 + (0x8001 * 2)
 
.VAR2:
        .word 0x020270B4 + (0x8002 * 2)
 
.TABLE:
        .word (0x8xxxxxx) @table of string pointers
 
.checkPokemon
        .word (0x8xxxxxx) @need to insert still

Here's the checkPokemon used in the routine above:

Spoiler:

.text
.align 2
.thumb
.thumb_func
 
@Loops trainers pokemon, returns amount alive
@if last pokemon, return's that pokemon's address in r0
@else gives scalar number of pokemon alive in r0
@ready for checking last pokemon is half HP flag
 
main:
        push {lr}
        mov r3, #0x0 @pokeslot zero
        mov r2, r3 @r2 holds number of alive pokemon
        b loop
 
loop:
        cmp r3, #0x5 @if all pokemon looped through, finish
        bge finalizeReturn
        ldr r0, =(0x202402C) @get pokemon at slot
        mov r1, #0x64
        mul r1, r1, r3
        add r0, r0, r1
        mov r1, #0x39
        ldr r4, =(0x803FBE8 +1)
        bl caller
        cmp r0,  #0x0 @check current HP zero
        bne increment   @if not zero increment r2
        add r3, r3, #0x1 @go next slot
        b loop
 
increment:
        add r2, r2, #0x1
        add r3, r3, #0x1 @also have to do slot increment
        mov r5, r0 @store in r5, last alive pokemon's location
        b loop
 
caller:
        bx r4
 
finalizeReturn:
        cmp r2, #0x1 @check if only 1 alive
        bne end
        mov r0, r5 @if 1 pokemon alive it must be in r5, put it in r0
        mov r1, #0x0 @r1 is a boolean r1: 0 means 1 alive pokemon
        pop {pc}
 
end
        mov r0, r2 @r0 = number of alive pokemon
        mov r1, #0x1 @r1: 1 means more than 1 alive
        pop {pc}
 
.align 2

As you can tell, all I have to really do is to "Slide trainer" and "Unslide" the trainer in the battle. Followed by, fixing the text glitch I'm getting.

Basically the text comes out at the same time as the normal battle text. And one is overwriting pieces of the other, which causes this:

I have looked into battlescripts, but honestly, I don't know if I really even need to use one. Maybe using one would help with the text appearing, I haven't tested (and don't have experience on it to really know)

The reason I'm making the thread is to seek help/expertise of someone who's done this kind of thing before. Or perhaps knows how. Currently I'm at a wall, and am not quite sure what to do.

Things I've tried (though maybe unsuccessfully):
calling 0803227C: trainer enter field
Using Oak's tutorial text routines


If you have questions, optimizations, suggestions or solutions please do voice them :)

 

[Derlo]

you could try to take a look at the kind of battle where the oak explain how to fight.
in it, the texts are loaded when it afflicts / takes damage; when using the bag, trying to get out of the fight or decreases stats pokemon.
about the trainer sprite... could try to see how the routine that ends the battle is, to be able to use as a base.

edit: here a very, very old data of T.battle 0x09 that I researched. maybe help or not. xD

=> 080E837c (off the texts before starting the battle)
=> 08036114 (inflict damege text off)
=> 080ea5ec & 080ea5f0 (low stats)
=> 0812207e substitute 00 to 0812210f [92 bytes] (choose pokemon and stock menu when using potion)
=> 080E85a8 substitute 083fcdb3 [exit text]
=> 080ea5f4 until 080ea647 [00] mesnsagem when you win!
=> 0803853c put 0x00 (defeat message!) 1byte

 

[kearnseyboy6]

On a broader more scale you might need to implement if the variable is 0x0 then skip entirely, so this doesn't occur with every single trainer.

Might it also be worth researching on the battle string "It's super effective!"?

Edit: Found a battle string table at 0x3FDF3C and really contains heaps of pointers to text strings. "It's super effective!" appears to be pointer 207 (0xCF). Also the table goes past a byte and reaches up to 0x175 so limits is not a problem.

I think finding how these are called will give you your answer.

Also 0x0751C4 seems to be possibly the trainer slide function? See the IDA file by knizz labelled battle_side_get_owner

 

[Blah]

you could try to take a look at the kind of battle where the oak explain how to fight.
in it, the texts are loaded when it afflicts / takes damage; when using the bag, trying to get out of the fight or decreases stats pokemon.
about the trainer sprite... could try to see how the routine that ends the battle is, to be able to use as a base.

edit: here a very, very old data of T.battle 0x09 that I researched. maybe help or not. xD

Hmm, I don't think we need to use the Oak text. The reason it creates this text error is because it's overlapping somewhere. I'm not sure where :D

On a broader more scale you might need to implement if the variable is 0x0 then skip entirely, so this doesn't occur with every single trainer.

Might it also be worth researching on the battle string "It's super effective!"?

Edit: Found a battle string table at 0x3FDF3C and really contains heaps of pointers to text strings. "It's super effective!" appears to be pointer 207 (0xCF). Also the table goes past a byte and reaches up to 0x175 so limits is not a problem.

I think finding how these are called will give you your answer.

Also 0x0751C4 seems to be possibly the trainer slide function? See the IDA file by knizz labelled battle_side_get_owner

I've tried calling those functions, the game freezes in place. I'm probably calling incorrectly or maybe there are some assumptions set in place when that function is called. It'll take some investigating.

 

[Touched]

I did like a thing which added an extra trainer to the screen at the start and then slid them out. So like, maybe that'll help. :P

 

[Blah]

I did like a thing which added an extra trainer to the screen at the start and then slid them out. So like, maybe that'll help. :P

Sounds like it will help. Feel free to explain :D

 

[Zehn]

You could try displaying text as if you where in the old Man tut

 

[daniilS]

You could try displaying text as if you where in the old Man tut

It's better to use a regular text printing function, and that isn't a problem at all. The only real problem left is sliding the trainer out in a way that won't glitch everything.

 

[Blah]

Oh dear, I started working on this project again. The initial direction of young, FBI Agent of November 24th, 2014 (07:52 PM) seems to be an incorrect way to tackle this problem. I'm now in the works of researching and polishing up a potential solution.

So far, I've learned to slide the trainer in and out. Currently fixing a text spawn solution as well as a few glitches with the tiles. Once all of that is finished (maybe within the next 24 hours) I'll post an update.

 

[kleenexfeu]

Oh dear, I started working on this project again. The initial direction of young, FBI Agent of November 24th, 2014 (07:52 PM) seems to be an incorrect way to tackle this problem. I'm now in the works of researching and polishing up a potential solution.

So far, I've learned to slide the trainer in and out. Currently fixing a text spawn solution as well as a few glitches with the tiles. Once all of that is finished (maybe within the next 24 hours) I'll post an update.

To display the text, you can simply use the setword command, used for many abilities/moves

 

[Blah]

Spoiler: nsfw language

zzz, I hate Gary, I hate hacking, I just wanna cry :C

 

[Blah]

Source code when I can make it more cleaner and customizable.