Custom UI graphics tutorial!

[Alice]

@Kimeru_el_perro a fix has been made:

@Alice

World Map MMB

Formerly “World Map Minimug Box Palette Fix”

In Vanilla FE8, the Minimug Box during Chapters uses a different palette than the rest of the UI.
Main UI palette (Blue): 5B6BB4
Minimug Box palette (Blue): A1738C

But for some reason, the World Map version of the Minimug Box uses the Main UI palette. But also, the game seems to be hardcoded to rewrite the Vanilla palette to a different address each time you try to overwrite it. Even if you use Hex Editing. This can be cumbersome if you want to make a Custom UI.

This patch makes the World Map Minimug Box use the same palette as the Minimug Box during chapters.

Before VS After:

In the Installer, you can define all 4 palettes. The default values are the same as the in-chapter MMB palettes. But you can redefine them as you wish.

#define WorldMapMMB_Blue  (0x08A1738C)
#define WorldMapMMB_Red   (0x08A173AC)
#define WorldMapMMB_Green (0x08A173CC) // Unused? In Vanilla, there are no Green Units on the World Map.
//---
#define WorldMapMMB_4th   (0x08A98E8C) // Gray palette used for Location markers.

Thank you to @Zane for the new code template and the 4th palette address.

C code

#include "gbafe.h"

extern u16 WorldMapMMB_Blue[];
extern u16 WorldMapMMB_Red[];
extern u16 WorldMapMMB_Green[];
extern u16 WorldMapMMB_4th[];

// Helper: apply the correct unit MMB palette based on faction
static void ApplyUnitMapUiFramePal(int faction, int palId)
{
    const u16* pal;

    switch (faction)
    {
        case FACTION_BLUE:
            pal = WorldMapMMB_Blue;
            break;

        case FACTION_RED:
            pal = WorldMapMMB_Red;
            break;

        case FACTION_GREEN:
            pal = WorldMapMMB_Green;
            break;

        default:
            pal = WorldMapMMB_4th; // safety fallback
            break;
    }

    ApplyPalette(pal, palId);
}

// Replacement for the vanilla world map MMB palette function
// IMPORTANT: This must be named sub_80BE5B4 so lyn overwrites the real function.
void sub_80BE5B4(int faction, int palId)
{
    switch (faction)
    {
        case FACTION_BLUE:
        case FACTION_RED:
        case FACTION_GREEN:
            ApplyUnitMapUiFramePal(faction, palId);
            break;

        default:
            // 4th palette: location signs / non‑unit markers
            ApplyPalette(WorldMapMMB_4th, palId);
            break;
    }
}

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Old code:
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