Author Topic: Chrono Trigger Tech rom data  (Read 1737 times)

JorenJoestar

  • Iokan (+1)
  • *
  • Posts: 3
    • View Profile
Chrono Trigger Tech rom data
« on: October 21, 2021, 04:31:19 am »
Hello everybody,
   I am trying to read tech data from the ROM, and reading the mythical offsets.txt I read this:

0C213F   0C214A   DATA   N   Tech Data 12 byte set - nothing   2008.07.14

And in Data Format.txt:

Tech Properties   00   FF   1   Unknown   2008.02.06
Tech Properties   01   FF   1   Success Chance (0xFF == 100%)   2008.02.06
Tech Properties   02   FF   A   Unknown   2008.02.06

I remember reading about a tech editor, is there a more recent version of the ROM content ?

I would like to repro the gameplay of Chrono Trigger, and I can successfully read the weapons, armor, items and character data thanks for those text files.

Thanks!

JorenJoestar

  • Iokan (+1)
  • *
  • Posts: 3
    • View Profile
Re: Chrono Trigger Tech rom data
« Reply #1 on: October 21, 2021, 04:38:00 am »
Ok...so I finally found this:

https://www.chronocompendium.com/Term/Tech_Data_Notes.html

And it seems to contain most of the data!
Now I am missing the damage formulas for tech :)

Mauron

  • Guru of Reason Emeritus
  • Errare Explorer (+1500)
  • *
  • Posts: 1763
  • Nu-chan
    • View Profile
    • Maurtopia
Re: Chrono Trigger Tech rom data
« Reply #2 on: October 21, 2021, 02:20:39 pm »
I've been inconsistent about updating the Encyclopedia entry on that.

Here's the tech editor, it lists the (unsimplified) damage formulas on the effect header.

JorenJoestar

  • Iokan (+1)
  • *
  • Posts: 3
    • View Profile
Re: Chrono Trigger Tech rom data
« Reply #3 on: October 22, 2021, 07:53:21 am »
That is an amazing work! I wanted to do a simple stat viewer (I am a coder myself) while I am having a look at this :)
How did you manage to understand the formulas ?

Thanks !

Mauron

  • Guru of Reason Emeritus
  • Errare Explorer (+1500)
  • *
  • Posts: 1763
  • Nu-chan
    • View Profile
    • Maurtopia
Re: Chrono Trigger Tech rom data
« Reply #4 on: October 22, 2021, 02:37:47 pm »
I looked at the assembly, and just wrote down the same calculations they did.

Code: [Select]
$C1/E106 BD 63 5E LDA $5E63,x[$7E:5E63] // Mirror of Power Stat.
$C1/E109 AA TAX
$C1/E10A 86 28 STX $28    [$00:0028]
$C1/E10C A9 0C LDA #$0C
$C1/E10E AA TAX
$C1/E10F 86 2A STX $2A    [$00:002A]
$C1/E111 20 0B C9 JSR $C90B  [$C1:C90B]
$C1/E114 A6 2C LDX $2C    [$00:002C]
$C1/E116 86 0A STX $0A    [$00:000A]
$C1/E118 AE F4 B1 LDX $B1F4  [$7E:B1F4]
$C1/E11B BD 70 5E LDA $5E70,x[$7E:5E70] // Weapon Power
$C1/E11E AA TAX
$C1/E11F 86 28 STX $28    [$00:0028]
$C1/E121 A9 05 LDA #$05
$C1/E123 AA TAX
$C1/E124 86 2A STX $2A    [$00:002A]
$C1/E126 20 0B C9 JSR $C90B  [$C1:C90B]
$C1/E129 C2 20 REP #$20
$C1/E12B A5 2C LDA $2C    [$00:002C]
$C1/E12D 18 CLC
$C1/E12E 65 0A ADC $0A    [$00:000A]
$C1/E130 85 30 STA $30    [$00:0030]

$C1/C90B multiplies $28 and $2A.