Adds a few more options for in-game trades.
Can also be used as sort of a trade editor to manage the new options.
For binary FR.
See here for the prequisites and help in installing them.
Open your terminal to whatever folder you want to download this repo into. Then, do the following to download the repo:
$ git clone https://github.com/Zeturic/bpre-trade-stuff.git
$ cd bpre-trade-stuffCopy your ROM to this directory and rename it rom.gba.
Open config.mk in a text editor to set some compile-time configuration.
The build system is smart enough to find enough free space on its own, but if you want it to be inserted at a particular address, you can specify it by updating the definition of START_AT. If the given address is acceptable (i.e. is word-aligned and has enough bytes of free space), it will be inserted there. Otherwise, it will just use START_AT to determine where in the ROM it should start looking for free space.
Make sure to update NUM_INGAME_TRADES if you've repointed and expanded the table.
InGameTrade::abilityNum had to be moved in order to make room for InGameTrade::moveset. If the data in your ROM is already in this format, make sure to set ABILITYNUM_HAS_ALREADY_BEEN_MOVED to 1, otherwise keep it as 0.
If you've previously inserted this hack and just want to update the data without reinserting another copy of the code, you can set INSERT_INGAME_TRADE_HACK to 0. Otherwise, keep it as 1.
Run make src/sInGameTrades.c to extract the in-game trade data from your ROM. Then, you can open the newly created src/sInGameTrades.c in a text editor to modify sInGameTrades as desired.
Keep in mind that you can't add in-game trades by adding more elements to the end of sInGameTrades, because that would overwrite whatever happened to be after the table in your ROM. Instead, repoint sInGameTrades externally first, then use this with an updated NUM_INGAME_TRADES.
Once you're ready, run make. This won't actually modify rom.gba, instead your output will be in test.gba. Naturally, test it in an emulator.
The long and short of it is that this breaks trade editors. This is because it places new data in what used to be padding bytes, and trade editors could easily zero them out because they don't expect them to be meaningful or to need to be preserved.
Even worse, as mentioned above, InGameTrade::abilityNum had to be moved, and obviously trade editors will be looking for it at the old location, which is now part of InGameTrade::moveset, and obviously that would confuse them.
As a result, do not use trade editors with this.
Obviously, this lets you modify your trades when you're inserting this hack via src/sInGameTrades.c, but what if you want to modify them later on, long after you've added this?
This is why the options INSERT_INGAME_TRADE_HACK and ABILITYNUM_HAS_ALREADY_BEEN_MOVED exist in config.mk. They allow you to modify the data in your ROM by modifying src/sInGameTrades.c without reinserting the actual code, acting essentially as a text-based trade editor.
Alternatively, you can edit your trades using a hex editor.
Most of the fields in the InGameTrade struct should be self-explanatory, but I'll explain the new ones anyway.
If level is set to 0, the Pokémon's level will match the level of the Pokémon the player traded away. Otherwise, its level will be set to match the level field.
The ivs are listed in the following order: HP, Attack, Defense, Speed, Special Attack, Special Defense. If any of them are set to 0xFF, that particular IV will be randomly generated. Otherwise, that IV will match the provided value.
An explanation of the ppBonuses byte can be found here.
An explanation of the pokerus byte can be found here.
An explanation of the ball byte can be found here.
The moveset field is a pointer to moveset data. If it is set to NULL, the Pokémon will inherit the default moveset based on its level.
The moveset's format is dead simple; it's just four hwords corresponding to the move indices of the four chosen moves. Just make sure to put it at an address that is hword-aligned (ends in 0, 2, 4, 6, 8, A, C, or E).
For example, if you wanted Reyley's Mimien to know Psychic (0x5E), Shadow Ball (0xF7), and Snatch (0x121), without a fourth move, you'd just do 5E 00 F7 00 21 01 00 00. For the purposes of this example, we'll assume you inserted that at 0x08800900 with a hex editor.
Then, you can set the moveset field to (u16*) 0x08800900 for Reyley's Mimien.
The project structure and some of the build tools are from pokeemerald.