How to add a new trainer back pic

Content

Quick Summary
The Graphics
The Data
- 4. Defining the trainer back pic
Usage

Quick Summary

If you’ve done this before and just need a quick lookup, here’s what files you need:

Place graphics in graphics/trainers/back_pics.
Point game to where graphic files are found: src/data/graphics/trainers.
Add trainer to include/constants/trainers.h,

We will start with a graphic that we want to use for our new trainer pic. Unlike with adding Pokémon, the trainer sprites aren’t sorted in individual folders, but rather in one folder: graphics/trainers/back_pics. Trainers sprites cannot be more than 16 - this includes the color that will be transparent, which is the first slot of the palette.

2. Register the sprites

Sadly, just putting the image files into the graphics folder is not enough. To use the sprites we have to register them by linking the graphic files in src/data/graphics/trainers.h:

 const u8 gTrainerBackPic_Wally[] = INCBIN_U8("graphics/trainers/back_pics/wally.4bpp");
 const u8 gTrainerBackPic_Steven[] = INCBIN_U8("graphics/trainers/back_pics/steven.4bpp");
+const u8 gTrainerBackPic_NewOne[] = INCBIN_U8("graphics/trainers/back_pics/new_one.4bpp");

 const u16 gTrainerBackPicPalette_Red[] = INCBIN_U16("graphics/trainers/back_pics/red.gbapal");
 const u16 gTrainerBackPicPalette_Leaf[] = INCBIN_U16("graphics/trainers/back_pics/leaf.gbapal");
+const u16 gTrainerBackPicPalette_NewOne[] = INCBIN_U16("graphics/trainers/back_pics/new_one.gbapal");

3. Connecting the Pictures to the Data

The last few things we have to do is prepare the graphics for usage. In src/data/graphics/trainers.h you’ll find the gTrainerBacksprites struct, we need to add the trainer to this. You can just copy the last trainer type defined and edit it, but this is what it does: Connects the new trainer with the image we defined earlier.

So, finally, it needs to look like this:

 #define TRAINER_BACK_SPRITE(trainerPic, yOffset, sprite, pal, anim)                          \
     [trainerPic] =                                                                           \
     {                                                                                        \
         .coordinates = {.size = 8, .y_offset = yOffset},                                     \
         .backPic = {.data = sprite, .size = TRAINER_PIC_SIZE, .relativeFrames = TRUE},       \
         .palette = {.data = pal, .tag = trainerPic},                                         \
         .animation = anim,                                                                   \
     }

 const struct TrainerBacksprite gTrainerBacksprites[] =
 {
     TRAINER_BACK_SPRITE(TRAINER_BACK_PIC_BRENDAN, 4, gTrainerBackPic_Brendan, gTrainerPalette_Brendan, sBackAnims_Hoenn),
     ...
     TRAINER_BACK_SPRITE(TRAINER_BACK_PIC_STEVEN, 4, gTrainerBackPic_Steven, gTrainerPalette_Steven, sBackAnims_Hoenn),
+    TRAINER_BACK_SPRITE(TRAINER_BACK_PIC_NEW_ONE, 4, gTrainerBackPic_NewOne, gTrainerBackPicPalette_NewOne, sBackAnims_Hoenn),
};

Note: Trainer back pics can have 4 or 5 frames of animation. Trainers with 5 frames must have their yOffset set to 5, and their anim set to sBackAnims_Kanto.

The Data

4. Defining the trainer back pic

Finally, let’s bring it all together by defining our new trainer pic in include/constants/trainers.h:

 #define TRAINER_BACK_PIC_WALLY                  6
 #define TRAINER_BACK_PIC_STEVEN                 7
+#define TRAINER_BACK_PIC_NEW_ONE                8

Remember to count the number next to the trainer pic up by one!

Usage

You can test your new trainer back pic by going to src/data/battle_partners.party and change the Pic field. The syntax should match the constant (TRAINER_BACK_PIC_NEW_ONE) with the underscore replaced by spaces. For example:

 === PARTNER_STEVEN ===
 Name: STEVEN
 Class: Rival
-Pic: Steven
+Pic: New One
 Gender: Male
 Music: Male

Otherwise if you use src/data/battle_partners.h, change the trainerPic field instead. For example:

     [DIFFICULTY_NORMAL][PARTNER_STEVEN] =
     {
         .trainerName = _("STEVEN"),
         .trainerClass = TRAINER_CLASS_RIVAL,
-        .trainerPic = TRAINER_BACK_PIC_STEVEN,
+        .trainerPic = TRAINER_BACK_PIC_NEW_ONE,
         .encounterMusic_gender = TRAINER_ENCOUNTER_MUSIC_MALE,

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