(Here I eat my words on Meta about posting Unity questions on Unity Answers... since that site is less responsive than this one.) Unity provides cell-based Occlusion Culling (via Umbra, I believe). ...
Problem Imagine that we have a 2D uniform grid of dimensions N x N. For this grid we have also pre-computed a visibility look-up table, e.g. with DDA, which answers the boolean query is cell X visible ...