IconDrawingNotes.txt

all offsets are FE8U as always

02026E10 is an indexed array of icon ids (0x20 entries). The Index in the array corresponds to the VRAM "slot" the icon graphics occupies.

Icon Root Tile Index = 0x300 - (slot+1)*4
Which means that item icons take at most tiles 0x280 to 0x300 excluded (0x80 tiles for 0x20 possible simultaneous icons)

That ones cool, simple system that works. The other one is less cool I'd say

02026A90 is an array of *224* 4 bytes long structs that dictates usage and other stuff for *each single icon*

There's two problems that arise here:
	1. the array having 224 entries, it means that the game supports only 224 icons max. (Reyson's fix works around that tho)
	2. only 2 of the 4 bytes of the array appear to be used

DrawIcon: // Out is r0, IconID is r1, UnknownParameter is r2
{
	if (IconID < 0) {
		Out[0] = 0;
		Out[1] = 0;
		Out[0x20 + 0] = 0;
		Out[0x20 + 1] = 0;
	} else {
		short TileIndex = GetIconTileIndex(IconID) + UnknownParameter;
		
		Out[0x00 + 0] = TileIndex + 0;
		Out[0x00 + 1] = TileIndex + 1;
		Out[0x20 + 0] = TileIndex + 2;
		Out[0x20 + 1] = TileIndex + 3;
	}
}

GetIconTileIndex: // IconID is r0, IconInfoArray is 02026A90
{
	IconInfo* info = (IconInfoArray + IconID*4);
	
	if (info->gfxIndex) {
		if (info->usageCount < 0xFF)
			info->usageCount++;
	} else {
		info->usageCount++;
		info->gfxIndex = (GetIconGfxIndex(IconID) + 1);
		
		RegisterTileGfx(IconGraphics + 0x80 * IconID, 0x6000000 + GetIconGfxTileIndex(info->gfxIndex), 0x80);
	}
	
	return GetIconGfxTileIndex(info->gfxIndex);
}