Game Boy Advance

Color palette

The GBA uses 15-bit RGB color in BGR555 format — identical to the SNES color space, with 5 bits per channel yielding 32,768 possible colors. In bitmap modes (modes 3–5), any of those 32,768 colors can appear in any pixel. There is no palette indirection: the framebuffer stores raw 15-bit color values directly.

In tiled modes (modes 0–2), the system uses palette-based rendering similar to the SNES. Background and sprite palettes are stored in a dedicated 1 KB palette RAM, divided into 16 palettes of 16 colors each (or 256-color mode with a single 256-entry palette).

The key constraint: none at all (in bitmap modes)

In bitmap modes, the GBA has no palette constraint, no tile-based color restriction, and no attribute clash — it is a direct 15-bit framebuffer where every pixel is independently addressable. This makes it one of the simplest systems to emulate visually: the only real limitations are the 240×160 resolution and the characteristics of the TFT LCD display.

The lack of constraints means dithering is less critical than on palette-limited systems. With 32,768 colors available, most natural images can be represented with reasonable fidelity. Dithering still helps with smooth gradients, but you won’t see the dramatic banding that systems like the Game Boy or NES produce.

In tiled modes, per-tile palette selection applies (similar to the SNES), but bitmapped’s GBA preset targets the bitmap modes where the system’s full color range is available.

Interactive demo

Code example

import { process } from 'bitmapped';
import { getPreset, enumerateColorSpace } from 'bitmapped/presets';
 
const gba = getPreset('gba')!;
 
// Generate the full 32,768-color palette from the 15-bit color space
const fullPalette = enumerateColorSpace(gba.colorSpace!).map((color) => ({
  color,
}));
 
const result = process(imageData, {
  blockSize: 2,
  palette: fullPalette,
  dithering: 'none',
  distanceAlgorithm: 'oklab',
});

Presets

bitmapped includes one Game Boy Advance preset:

• gba — Bitmap mode, 240×160, 15-bit RGB (32,768 colors)