Fuel system

[Matevsz]

Hello, I created a fuel system, but after a while the game starts to lag. Is there something wrong with the code? Yes, I know I still need to add refueling, but I'm trying to figure out why it's lagging so much

Fuel gauge needle angle (fuelNeedle):

- 33 full

- 128 low fuel

- 150 empty

Client

local screenX, screenY = guiGetScreenSize()

local scale = math.min(screenX/1680, screenY/1050)

local function dxDrawRelativeImage(x, y, w, h, image, r, g, b, a, postGUI)
	    return dxDrawImage(x * scale, y * scale, w * scale, h * scale, image, r, g, b, a, postGUI)
end



local fuelNeedle = "Fuel/DALTSHORT.png"
local fuelImage = "Fuel/fuelimage.png"
local lowFuelAngle = 128
local warningShown = false

	function fuelToAngle(fuel) -- fuel = 0.0 to 1.0
    	return 33 + (1 - fuel) * 117
	end

	function angleToFuel(angle)
    	return math.max(0, math.min(1, 1 - (angle - 33) / 117))
	end


	function drawFuelGauge()
    	local vehicle = getPedOccupiedVehicle(localPlayer)
    	if not vehicle or getVehicleType(vehicle) ~= "Plane" then return end

    	local fuel = getElementData(vehicle, "plane:fuel") or 0.18
    	local angle = fuelToAngle(fuel)

		dxDrawRelativeImage(899, 741, 249, 244, fuelImage)
		dxDrawRelativeImage(899 + 15, 741 + 25, 176, 195, fuelNeedle, angle)


    	if angle >= lowFuelAngle and not warningShown then
        	-- low fuel warning
        	warningShown = true
    	elseif angle < lowFuelAngle then
        	warningShown = false
    	end
	end
	addEventHandler("onClientRender", root, drawFuelGauge)


	addEventHandler("onClientKey", root, function(key, press)
		if key == "W" and press and currentVehicle and isPedInVehicle(localPlayer) then
			local fuel = getElementData(vehicle, "plane:fuel") or 0
			if fuel <= 0 then
				cancelEvent()
				-- plane is gliding without speed
			end
		end
	end)

Server 

local fuelUsePerSecond = 1 / 3600 



function angleToFuel(angle)
    return math.max(0, math.min(1, 1 - (angle - 33) / 117))
end


addEventHandler("onVehicleEnter", root, function(player, seat)
    if seat == 0 and getVehicleType(source) == "Plane" then
        local currentFuel = getElementData(source, "plane:fuel")
        if currentFuel == nil or currentFuel == 0 then
            local fuel = angleToFuel(128)
            setElementData(source, "plane:fuel", angleToFuel(128)) -- low fuel
        end
    end
end)


setTimer(function()
    for _, vehicle in ipairs(getElementsByType("vehicle")) do
        if getVehicleType(vehicle) == "Plane" and getVehicleEngineState(vehicle) then
            local driver = getVehicleOccupant(vehicle)
            if driver then
                local fuel = getElementData(vehicle, "plane:fuel") or 0.18
                fuel = fuel - fuelUsePerSecond
                if fuel < 0 then fuel = 0 end
                setElementData(vehicle, "plane:fuel", fuel)
            end
        end
    end
end, 1000, 0)

 

[IIYAMA]

On 09/07/2025 at 15:36, Matevsz said:

but after a while the game starts to lag

Might be because the (player/server) network can't catchup.

-- (un)subscribe to the vehicle fuel element data of a specific vehicle
addEventHandler("onVehicleEnter", getRootElement(), function(thePlayer, seat)
    if seat~=0 then return end
    -- Wiki Note: Before using addElementDataSubscriber you need to setup an initial value of element data in "subscribe" mode, otherwise the subscriber will not be added.
    if not getElementData(source, "plane:fuel") and getVehicleType(source) == "Plane" then
        setElementData(source, "plane:fuel", 0.18, "subscribe", "deny")
    end
    addElementDataSubscriber(source, "plane:fuel", thePlayer)
 end)
 
addEventHandler("onVehicleExit", getRootElement(), function(thePlayer, seat)
    if seat~=0 then return end
    removeElementDataSubscriber(source, "plane:fuel", thePlayer)
 end)

setTimer(function()
    -- Start with all players instead of all vehicles, because there are often more vehicles than players
    local players = getElementsByType("player")
    for i=1, #players do
        local player = players[i]
        local vehicle = getPedOccupiedVehicle(player)
        if vehicle and getVehicleType(vehicle) == "Plane" and getVehicleEngineState(vehicle) then
            local fuel = getElementData(vehicle, "plane:fuel") or 0.18
            if fuel > 0 then -- do not update if fuel is 0 or lower, else you are wasting bandwidth by setting the data to the same value
                fuel = fuel - fuelUsePerSecond
                if fuel < 0 then fuel = 0 end
                setElementData(vehicle, "plane:fuel", fuel, "subscribe", "deny")
            end
        end
    end
end, 1000, 0)

Please let me know if the addElementDataSubscriber function works as expected, haven't used it myself yet.