jesse
d45f35736a
Four independent bugs kept the car immobile at the world origin: 1. Wheels collided with their own chassis. Wheel inner edge sits at 2.80 vs body edge 3.00, and wheel top -0.20 vs body bottom -0.70. The overlap is intentional styling, but in one collision group the wheels ground against the body: motors spun ~1 rad/s against 20,000 torque. Wheels now use a CarWheel group that ignores CarChassis. 2. Suspension exploded on spawn. PrismaticConstraint+SpringConstraint between a 0.6-stud hub and the ballasted body was unstable enough to fling knuckles ~10,000,000 studs out, past FallenPartsDestroyHeight, deleting the wheels. Replaced with a rigid welded hub mount. 3. Car spawned at world origin, not the pad. MapBuilder made a SpawnPad part but no SpawnLocation, so characters spawned at (0,0,0) and Sit() dragged the car to them. Added a real SpawnLocation and the model is now pivoted after parenting, with the character teleported first. 4. AntiCheat snapped that legitimate spawn teleport back. An ~8,500-stud server move reads as a teleport hack. Added AntiCheat.grant() so server-initiated moves are exempt for a short grace window. Verified in Studio: 881 studs in 6s, 496 studs/s top speed, 152 deg steering, braking 33 -> 0 studs/s, chassis stays upright.
96 lines
3.0 KiB
Luau
96 lines
3.0 KiB
Luau
--!strict
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--[[
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AntiCheat.luau (SERVER)
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MVP-level movement sanity check. Not a fortress — a speed bump that catches
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obvious speed/teleport hacks. Because money & car ownership are ALREADY
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server-authoritative (Economy validates everything), the main client attack
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surface left is movement, so we watch that.
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Approach: sample each player's HRP position periodically; if they cover
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ground implying a sustained speed above MaxPlausibleSpeed, snap them back
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to their last valid position. Generous threshold to avoid false positives
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from legit fast cars.
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]]
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local Players = game:GetService("Players")
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local RunService = game:GetService("RunService")
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local ReplicatedStorage = game:GetService("ReplicatedStorage")
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local GameConfig = require(ReplicatedStorage.Shared.GameConfig)
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local AntiCheat = {}
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type Track = { lastPos: Vector3, lastValid: CFrame }
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local tracked: { [Player]: Track } = {}
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local SAMPLE_INTERVAL = 0.5
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-- Server-initiated teleports (car spawn onto the pad, respawn, mode resets)
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-- legitimately move a player thousands of studs in one frame, which trips the
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-- speed check and snaps them straight back -- dragging their car with them.
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-- Callers announce those moves via AntiCheat.grant() so the next sample is
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-- accepted as the new baseline instead of treated as a hack.
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local graceUntil: { [Player]: number } = {}
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local GRACE_SECONDS = 2
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--- Exempt a player from the speed check briefly after a legitimate teleport.
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function AntiCheat.grant(player: Player, seconds: number?)
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graceUntil[player] = os.clock() + (seconds or GRACE_SECONDS)
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end
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local function hrpOf(player: Player): BasePart?
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local char = player.Character
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return char and char:FindFirstChild("HumanoidRootPart") :: BasePart?
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end
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function AntiCheat.init()
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local function watch(player: Player)
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player.CharacterAdded:Connect(function(char)
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local hrp = char:WaitForChild("HumanoidRootPart", 10) :: BasePart?
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if hrp then
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tracked[player] = { lastPos = hrp.Position, lastValid = hrp.CFrame }
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end
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end)
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end
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for _, p in ipairs(Players:GetPlayers()) do
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watch(p)
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end
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Players.PlayerAdded:Connect(watch)
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Players.PlayerRemoving:Connect(function(p)
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tracked[p] = nil
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end)
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local accum = 0
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RunService.Heartbeat:Connect(function(dt)
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accum += dt
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if accum < SAMPLE_INTERVAL then
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return
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end
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local interval = accum
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accum = 0
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for player, track in pairs(tracked) do
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local hrp = hrpOf(player)
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if not hrp then
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continue
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end
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local pos = hrp.Position
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-- Falling doesn't count (avoid flagging big drops). Only guard XZ plane.
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local horizontal = Vector3.new(pos.X - track.lastPos.X, 0, pos.Z - track.lastPos.Z).Magnitude
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local hSpeed = horizontal / interval
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local inGrace = (graceUntil[player] or 0) > os.clock()
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if hSpeed > GameConfig.MaxPlausibleSpeed and not inGrace then
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-- Snap back: likely a speed/teleport hack.
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hrp.CFrame = track.lastValid
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hrp.AssemblyLinearVelocity = Vector3.zero
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else
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track.lastValid = hrp.CFrame
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end
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track.lastPos = hrp.Position
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end
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end)
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end
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return AntiCheat
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