Building Tank Commander

The design brief was the cockpit, not the battlefield: sit inside a real armored-vehicle crew station and physically operate every control — a battery master switch, a starter you have to hold until the engine catches, twin tillers for the tracks, a turret joystick, a breech lever you cycle by hand to reload, a rocket console behind a flip-up safety cover. The battlefields, enemy waves, and the eventual jeep, plane, biplane, helicopter, and on-foot runner mode all got built around that one physically- operated seat, not the other way around.

Nothing in the game is an imported asset — every mesh comes out of a custom MeshKit builder at runtime, every texture is procedurally generated, every sound and voice line is synthesized. That constraint is also why the biggest bug below was even possible: with no imported reference geometry to compare against, the entire pipeline — generator and validator alike — could quietly agree on the same wrong convention for a long time before anyone noticed.

The tank cockpit went through several real-front-view passes before it actually read correctly in stereo — the turret's exterior armor box never had an opening cut into it at all, so no amount of widening the interior slit could ever have shown terrain through it. The fix cut an actual driver's window through the exterior plate, shrank and repositioned the breech so it stopped intruding on the driver's space (the rear face had been sitting five centimeters from the eye), and moved the rocket pods from directly over the side hatches to a rear mount clear of the sightlines — verified with a seven-angle seated render sweep instead of a single forward-only shot.

A drivable jeep followed, mirror-imaged from the tank's own thumbstick conventions — left stick drives and steers, right stick swings a full-360 rear-mounted gun — with a steering wheel grip, throttle lever, and a red cannon button standing in for the tank's breech ritual at jeep speed. Later still, on-foot mode got real traversal: terrain collision bodies became climbable across every cliff and rim, and the grapple's attach mask widened from a set of world-object layers that had never actually been populated to any solid surface in the game — cliffs, buildings, vehicles, all of it.

Some of that traversal work caught its own bug in the same pass: a new render-check tool built to verify the dressed-up soldier avatars found that the arm-IK solver mixed world-space shoulder positions with avatar-local hand targets, so arms solved toward the map origin instead of the avatar — invisible in an origin-staged test scene, blatant (pole-arms pointing at nothing) for an NPC gunner, a remote co-op player, or your own body in third person.

LAN co-op already existed — one headset drives and mans the machine guns, the other runs the turret, both rendered to each other as fully procedural avatars — but every session needed a local host actually on the network to find. The fix ported Swing City's Cloudflare Worker + Durable Object relay pattern almost directly: no server-side physics or game state, every client trusted to report its own position and effects, the WebSocket Hibernation API so an idle room of open sockets never pins the Durable Object in memory. What's different here is the relay is deliberately generic — instead of hardcoding Tank Commander's own message types into the Worker the way Swing City's joust/ poke/knock protocol is baked into its relay, this one re-broadcasts any message type it doesn't specially recognize, stamped with the sender's id. Round timers, scoring, host-granted map/mode/bot control, seat-switching — all of that can be added client-side without ever touching or redeploying the Worker itself.

The same Worker took on a second, unrelated job: a plain POST /logs endpoint backed by a KV namespace, so crash logs and session data can come in from a headset that isn't even on the same network as the machine debugging it — no adb cable, no requirement that every test headset physically be in the room. Wireless adb over the LAN covers the rest: whichever headsets are on-site get paired once, then pulled from without a cable ever again.