Chunky-to-planar (C2P)
A routine that repacks a chunky pixel buffer into the Amiga's bitplane format — the bridge between easy-to-write graphics and the hardware that must display them.
Amiga graphics are stored as bitplanes: each bit of a pixel's colour index lives in its own memory layer. That is efficient for panning and scrolling but awkward for effects like texture mapping and voxels, where you would rather deal in one byte per pixel — chunky. Chunky-to-planar, C2P, is the routine that turns the chunky buffer back into planar every frame before it is blitted to screen.
When the PC showed off texture-mapped 3D in the mid-1990s, the Amiga scene wanted to answer, and C2P became the bottleneck: a fast routine on a 68020/030 could free up half the frame for everything else. Coders competed with table-driven and blitter-assisted variants, and a well-tuned C2P became something of the era's signature hack.