tag

#affine

2 posts

RetrogamingDeep Dive October 4, 2026 10 min read

GBA Affine Backgrounds: Fixed-Point Matrices and Scanline Reference Accumulators

Implement Game Boy Advance affine backgrounds correctly: 8.8 transform steps, signed reference points, per-scanline accumulators, pivots, and wrap behavior.

#game-boy-advance#gba#affine

RetrogamingDeep Dive October 4, 2026 8 min read

Game Boy Advance Affine OBJ: OAM Matrix Slots, Fixed-Point Mapping, and Double Size

Decode GBA affine OBJ state across OAM attributes and interleaved PA/PB/PC/PD slots, then map pixels with signed 8.8 coefficients.

#game-boy-advance#gba#obj