SNES Palette Structure for ALTTP

SNES Palette Memory Layout

The SNES has 256 color palette entries organized as:

• 16 palette rows of 16 colors each
• Each row starts with color index 0, which is transparent
• Palettes must be aligned to 16-color boundaries

Example Layout

Row 0: Colors 0-15   (Color 0 = transparent)
Row 1: Colors 16-31  (Color 16 = transparent)
Row 2: Colors 32-47  (Color 32 = transparent)
...

ALTTP Palette Groups - Corrected Structure

Background Palettes (BG)

Overworld Main (35 colors per set)

• Structure: 2 full rows + 3 colors
  • Row 0: Colors 0-15 (transparent + 15 colors)
  • Row 1: Colors 16-31 (transparent + 15 colors)
  • Row 2: Colors 32-34 (3 colors)
• ROM: 0xDE6C8
• Sets: 60 (20 LW, 20 DW, 20 Special)

Overworld Auxiliary (21 colors per set)

• Structure: 1 full row + 5 colors
  • Row 0: Colors 0-15 (transparent + 15 colors)
  • Row 1: Colors 16-20 (5 colors)
• ROM: 0xDE86C
• Sets: 20

Overworld Animated (7 colors per set)

• Structure: Half-row without transparent
  • Colors 0-6 (7 colors, no transparent marker as these overlay existing)
• ROM: 0xDE604
• Sets: 14

Dungeon Main (90 colors per set)

• Structure: 5 full rows + 10 colors
  • Row 0: Colors 0-15 (transparent + 15 colors)
  • Row 1: Colors 16-31 (transparent + 15 colors)
  • Row 2: Colors 32-47 (transparent + 15 colors)
  • Row 3: Colors 48-63 (transparent + 15 colors)
  • Row 4: Colors 64-79 (transparent + 15 colors)
  • Row 5: Colors 80-89 (10 colors)
• ROM: 0xDD734
• Sets: 20 (one per dungeon)

Sprite Palettes (OAM)

Sprite palettes use rows 8-15 (colors 128-255).

Global Sprites (60 colors total)

• Structure: 4 rows (each with 15 actual colors + transparent)
  • Row 8: Colors 128-143 (Sprite Palette 0: transparent + 15 colors)
  • Row 9: Colors 144-159 (Sprite Palette 1: transparent + 15 colors)
  • Row 10: Colors 160-175 (Sprite Palette 2: transparent + 15 colors)
  • Row 11: Colors 176-191 (Sprite Palette 3: transparent + 15 colors)
• ROM LW: 0xDD218
• ROM DW: 0xDD290
• Total: 2 sets (LW and DW)

Sprites Auxiliary 1 (7 colors per palette)

• Structure: 12 palettes, each occupying half a row
  • Palette 0: 7 colors (indices 1-7 of first half-row)
  • Palette 1: 7 colors (indices 9-15 of second half-row)
  • ...and so on
• ROM: 0xDD39E
• Palettes: 12

Sprites Auxiliary 2 (7 colors per palette)

• Structure: 11 palettes, each occupying half a row
• ROM: 0xDD446
• Palettes: 11

Sprites Auxiliary 3 (7 colors per palette)

• Structure: 24 palettes, each occupying half a row
• ROM: 0xDD4E0
• Palettes: 24

Equipment/Link Palettes

Armor/Link (15 colors per palette)

• Structure: Full row minus transparent
  • Each palette: transparent + 15 colors
• ROM: 0xDD308
• Palettes: 5 (Green Mail, Blue Mail, Red Mail, Bunny, Electrocuted)

Swords (3 colors per palette)

• Structure: 3 colors within row (no transparent needed as overlay)
• ROM: 0xDD630
• Palettes: 4 (Fighter, Master, Tempered, Golden)

Shields (4 colors per palette)

• Structure: 4 colors within row (no transparent needed as overlay)
• ROM: 0xDD648
• Palettes: 3 (Fighter, Fire, Mirror)

HUD Palettes

HUD (32 colors per set)

• Structure: 2 full rows
  • Row 0: Colors 0-15 (transparent + 15 colors)
  • Row 1: Colors 16-31 (transparent + 15 colors)
• ROM: 0xDD660
• Sets: 2

Special Colors

Grass (3 individual colors)

• LW: 0x5FEA9
• DW: 0x5FEB3
• Special: 0x75640

3D Objects (8 colors per palette)

• Triforce: 0x64425
• Crystal: 0xF4CD3

Overworld Mini Map (128 colors per set)

• Structure: 8 full rows
• ROM: 0x55B27
• Sets: 2

Key Principles

1. Transparent Color: Always at indices 0, 16, 32, 48, 64, etc. (multiples of 16)
2. Row Alignment: Palettes should respect 16-color row boundaries
3. Overlay Palettes: Some palettes (like animated, swords, shields) overlay existing colors and don't have their own transparent
4. Sub-Palettes: Multiple small palettes can share a row if they're 8 colors or less

Implementation Notes

When loading palettes, we must:

1. Mark color index 0 of each 16-color row as transparent
2. For palettes < 16 colors, understand if they're standalone (need transparent) or overlays (don't need transparent)
3. Display palettes in UI with proper row alignment for clarity