trans.lua

local setGear = GetHashKey('SET_VEHICLE_CURRENT_GEAR') & 0xFFFFFFFF
local function SetVehicleCurrentGear(veh, gear)
	Citizen.InvokeNative(setGear, veh, gear)
end

local nextGear = GetHashKey('SET_VEHICLE_NEXT_GEAR') & 0xFFFFFFFF
local function SetVehicleNextGear(veh, gear)
	Citizen.InvokeNative(nextGear, veh, gear)
end

local function ForceVehicleGear (vehicle, gear)
	SetVehicleCurrentGear(vehicle, gear)
	SetVehicleNextGear(vehicle, gear)
	return gear
end

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local mode

Citizen.CreateThread(function ()
	local vehicle, lastVehicle, ped
	local gear, maxGear
	local nextMode, maxMode

	local braking
	local function HandleVehicleBrake ()
		if gear == 0 then -- Prevent reversing
			DisableControlAction(2, 72, true)
			-- use parking brake once stopped
			if IsDisabledControlPressed(2, 72) then
				SetControlNormal(2, 76, 1.0)
				braking = true
			end
		elseif IsControlPressed(2, 72) then
			braking = true
		end
	end

	local function OnTick()
		braking = false

		-- Reverse
		if mode == 1 then
			DisableControlAction(2, 71, true)
			-- gas
			if IsDisabledControlPressed(2, 71) then
				SetControlNormal(2, 72, GetDisabledControlNormal(2, 71))
			else
				HandleVehicleBrake()
			end

		-- Neutral
		elseif mode == 2 then
			HandleVehicleBrake()
			ForceVehicleGear(vehicle, 1)

			-- gas
			DisableControlAction(2, 71, true)
			if IsDisabledControlPressed(2, 71) then
				SetVehicleCurrentRpm(vehicle, 1.0)
			end
		-- Drive
		else
			HandleVehicleBrake()
			ForceVehicleGear(vehicle, mode - 2)
		end

		-- Brake
		if braking or IsControlPressed(2, 76) then
			SetVehicleBrakeLights(vehicle, true)
			SetVehicleNextGear(vehicle, 0)
			braking = true
		end
	end

	while true do
		ped = PlayerPedId()
		vehicle = GetVehiclePedIsUsing(ped)

		if DoesEntityExist(vehicle) and GetPedInVehicleSeat(vehicle, -1) == ped then
			gear = GetVehicleCurrentGear(vehicle)

			-- Entered vehicle
			if lastVehicle ~= vehicle then
				lastVehicle = vehicle
				maxGear = GetVehicleHighGear(vehicle)
				maxMode = 2 + maxGear

				-- Use current gear | neutral
				if gear >= 1 then
					mode = gear + 2
				else
					mode = 2
				end
			end

			-- Gear up | down
			if IsControlJustPressed(0, 172) then
				nextMode = math.min(mode + 1, maxMode)
			elseif IsControlJustPressed(0, 173) then
				nextMode = math.max(mode - 1, 1)
			else
				nextMode = mode
			end

			-- On Shift
			if nextMode ~= mode then
				mode = nextMode
			end

			OnTick()
		elseif lastVehicle then
			lastVehicle = false
			mode = false
		end

		Wait(0)
	end
end)

--------------------------------------------------------------------------------

function DrawText2d (text, x, y, width, height)
	SetTextEntry("STRING")

	width = width or 1.0
	height = height or width or 1.0

	for k = 0, #text, 99 do
		AddTextComponentString(string.sub(text, k, k + 98))
	end

	SetTextScale(width, height)
	DrawText(x or 0.0, y or 0.0)
end

Citizen.CreateThread(function ()
	local gear
	local text
	local modeText = { 'R', 'N', 'D' }

	while true do
		if mode then
			if mode >=3 then
				text = modeText[3]
				gear = mode - 2
			else
				text = modeText[mode]
				gear = mode - 1 -- GetVehicleCurrentGear(vehicle)
			end

			DrawText2d(text .. ':' .. gear)
		end

		Wait(0)
	end
end)