Draw-layer submission and Y-order
The five draw layers, Ground-only depth sorting, and stable equal-key ordering. Verified: TS/Firestorm, Red Alert 2, Yuri's Revenge.
Tactical world-to-client projection
World-to-client isometric projection, height adjustment, and the inverse mapping. Verified: TS/Firestorm, Red Alert 2, Yuri's Revenge.