Froxel

The word is a portmanteau of "frustum" and "voxel": a cell in a 3D grid that follows the camera's view — x and y span the screen, z runs along depth, often distributed exponentially so cells near the camera stay small. Because the grid already lives in screen space, finding which cell a pixel falls into is cheap. Froxels appeared around 2014 as the shared building block for two jobs: volumetric fog, where each cell stores in-scattered light, and clustered shading, where each cell lists the lights that reach it. Same data structure, two unrelated problems.