Vehicles: boats + buoyancy and aircraft beyond the RWD jeep

[drsnuggles8]

Problem

Only one vehicle type exists: a 4-wheel rear-wheel-drive ground vehicle (VehicleComponent + JoltScene::CreateVehicle). No boats, no water buoyancy, no aircraft/helicopters. FWD/AWD differentials aren't exposed either (Jolt supports them).

Why it matters (Tier 3)

Far Cry has driveable boats and (series-wide) aircraft; water traversal needs buoyancy. Optional but expected for the open-world feel.

Proposed approach

• Buoyancy: sample the water surface height (existing water rendering) → apply buoyant + drag forces per submerged volume sample; build a boat controller on top.
• Aircraft/helicopter: lift/thrust/torque model via Jolt forces (not the wheeled-vehicle constraint).
• Expose FWD/AWD + differential config on VehicleComponent.

Acceptance criteria

• A boat floats and drives on water; a basic aircraft flies with stable controls; the existing jeep is unaffected.

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Tier 3 — content/gameplay.

Score

capability: 3
craft: 5
stability: 1
decay: 1
effort: 5
confidence: 0.8
learning: 3
fun: 3
kano: delighter
blocked_by: []
blocks: []

_{Rated per issue-scoring · score = confidence × (capability + craft + stability + decay) / effort, derived by the picker.}