Carmack suffers brain seizure

John Carmack, lead programmer and co-founder of id Software, has long been known for his geekish tendencies, but during an interview with Voodoo Extreme he finally blew a gasket... "None of the Quake games have had what I would call a BSP based VSD algorithm", JC gibbered (that's pronounced with a soft g by the way!). "The visibility associated with Quake is a cluster to cluster potentially visible set (PVS) algorithm, masked by an area connectivity graph (in Q2 and Q3), followed by hierarchical frustum culling (which does use the BSP). The software renderers then performed an edge based scan-line rasterization algorithm, which resulted in zero-overdraw for the world."

"Early in Q1's development, I pursued "beam trees", which were truly a BSP based visibility algorithm that did exact visibility by tracking unfilled screen geometry going front to back, but the log2 complexity scaling factor lost out to the constant complexity factor from the PVS."

Um .. ok, then. Any more questions?