FiveM Vehicle Bump Speed Boost Fix

Call this code when someone enters a vehicle:

local OR, XOR, AND = 1, 3, 4
local function bitOper(flag, checkFor, oper)
    local result, mask, sum = 0, 2 ^ 31
    repeat
        sum, flag, checkFor = flag + checkFor + mask, flag % mask, checkFor % mask
        result, mask = result + mask * oper % (sum - flag - checkFor), mask / 2
    until mask < 1
    return result
end

local function addDownforceFlag(vehicle)
    local adv_flags = GetVehicleHandlingInt(vehicle, 'CCarHandlingData', 'strAdvancedFlags')
    local hasDownforceFlag = bitOper(adv_flags, 134217728, AND) == 134217728

    -- Remove flags 512 and 2048 if present
    if not hasDownforceFlag then
        adv_flags = bitOper(adv_flags, 134217728, OR)
    end

    local newFlags = math.floor(adv_flags)
    SetVehicleHandlingField(vehicle, 'CCarHandlingData', 'strAdvancedFlags', newFlags)

end

This is code that will add the strAdvancedFlags flag CF_USE_DOWNFORCE_BIAS. This is defined as:

Changes the way Downforce and spoiler tuning works, uses the setup found on Open-Wheel class vehicles in the vanilla game. Each spoiler/bumper tuning has to be given AdvancedData values to affect downforce. Adjusts initial downforce from fDownforceModifier. ‘Curb - boosting’ seems to be nullified. Previously known as _AF_DOWNFORCE_KERBFIX

IMPORTANT All vehicles must have the CCarHandlingData field already defined or else FiveM will NOT be able to set the advanced flags. You do not have to define the strAdvancedFlags field just CCarHandlingData:

<Item type="CCarHandlingData"> </Item>

Or if it doesn’t have sub-handling:

<SubHandlingData>
	<Item type="CCarHandlingData"></Item>
</SubHandlingData>```