Coordinate system: cells, leptons, and distance
How the original engine measures space — map cells, sub-cell leptons, the cell↔world conversion, 16-bit facing, and the distance measure that feeds range checks. Verified across Tiberian Sun, Red Alert 2, and Yuri's Revenge.
Fixed-point math and frame timers
How the original engine converts floats to integers, rescales fixed-point facing values between bit widths, and runs frame-counted countdown timers. Verified: Tiberian Sun, Red Alert 2, Yuri's Revenge.
The randomizer — deterministic sequences
The original engine's deterministic pseudo-random generator — table, indices, ranged draws, and the per-game divergences that keep the sequence identical. Verified: Tiberian Sun, Red Alert 2, Yuri's Revenge.