Pokédex data structure (Generation III)
Specs
A Pokédex data structure is a 37-byte piece of data.
Every Pokémon species in the Generation III games has a Pokédex data stored in the game that is used in Pokédex related functions and also by some moves like Low Kick.
| Pokédex Data | |
|---|---|
| Effect | byte |
| Padding | byte |
| Species | 12 bytes |
| Height (* 10^(-1) m) | 2 bytes |
| Weight (* 10^(-1) Kg) | 2 bytes |
| Description pointer start | 4 bytes |
| Description pointer end | 4 bytes |
| Pokémon scale | 2 bytes |
| Pokémon offset | byte |
| Offset +/- | byte |
| Trainer scale | 2 bytes |
| Trainer offset | byte |
| Padding | 2 bytes |
Notes
- Species is 12 bytes long and comes in capital letters. 0x00 fills possible empty bytes.
- Height is actually a word (2 bytes) and comes in decimetres (10^(-1) metres), it is then converted to other unites in some games.
- Weight is actually a word (2 bytes) and comes in hectogrammes (10^(-1) kilogrammes), it is then converted to other unites in some games.
- Description pointers show to the game where the description for the particular Pokémon is; they are reversed of course (little endian format). The 4th byte is always set to 0x08 (8), so this matches a BRANCH instruction (B) in assembly. For example, if the location is 0x123456, it will appear here as 0x56341208.
- Offset +/- determines whether the Pokémon offset will be negative or not.
Size compare function
In the Generation III, there's a size page on the Pokédex, which uses data from the Pokédex to create a silhouette of the Pokémon standing next to the trainer. The size of both the trainer and Pokémon are determined by this formula:
x = (y × 256/z) pixels
Where y is the sprite size (64 pixels in our case) and z is the appropriate scale in hex and x rounded down is the size of silhouette. The game then resized the sprite in a way similar a computer would do (without anti-aliasing of course).
The offset determines where exactly the silhouette will be placed. For example if Pokémon offset = 10 then the silhouette of the Pokémon will be 10 pixels from the top and 10 pixels from the left. (for some reason, that cannot be exactly simulated outside of the game).
If Offset +/- is equal to 0xFF then the actual Pokémon offset will be equal to -(256 - Pokémon offset), otherwise the actual Pokémon offset stays the same.
