Driver Is Temporary Gunner - for SAPP

--[[ Driver Is Temporary Gunner by H® Shaft ]]--

-- Driver Is Temporary Gunner (primarily for warthogs)

    -- Gun Seat Entry
    -- if entering gun seat and there is no driver
    -- places player in gun seat, then moves to driver seat (driver is also gunner)
    -- gunner and passenger can still enter, when gunner enters, driver ceases to be gunner

    -- Driver Seat Entry
    -- if entering driver seat, and there is no gunner
    -- places player in gun seat, then move to driver seat (driver is also gunner)
    -- gunner and passenger can still enter, when gunner enters, driver ceases to be gunner

    -- Notes:
    -- If the gunner dies, driver must exit and re-enter the warthog to resume being both driver and gunner
    -- when a driver is also gunner, there is no aiming reticle, and the driver camera is tilted down, which makes aiming difficult - so
    -- (look up) center your target in the screen and fire, reload works, but reticle & reload icon do not display on screen for driver gunners.

-- SAPP api version --
api_version = "1.8.0.0"

function OnScriptLoad()
    register_callback(cb['EVENT_VEHICLE_ENTER'], "OnVehicleEnter")
end

function OnScriptUnload()
end

function OnVehicleEnter(PlayerIndex, Seat)
    local m_object = get_dynamic_player(PlayerIndex)
    local vehicleId = read_dword(m_object + 0x11C)
    local veh_obj = get_object_memory(vehicleId)

    -- gunner seat
    if Seat == "2" then
        if (veh_obj ~= 0) then
            local driver = read_dword(veh_obj + 0x324)
            local gunner = read_dword(veh_obj + 0x328)
            if (driver == 0xFFFFFFFF) then
                enter_vehicle(vehicleId, PlayerIndex, 0)
                enter_vehicle(vehicleId, PlayerIndex, 2)
                enter_vehicle(vehicleId, PlayerIndex, 0)
                say(PlayerIndex, get_var(PlayerIndex, "$name") .. ": You are driver and gunner! " )
            elseif (driver ~= 0xFFFFFFFF) then
                enter_vehicle(vehicleId, PlayerIndex, 2)
            end
        end

    -- driver seat
    elseif Seat == "0" then
        if (veh_obj ~= 0) then
            local driver = read_dword(veh_obj + 0x324)
            local gunner = read_dword(veh_obj + 0x328)
            if (gunner == 0xFFFFFFFF) then
                enter_vehicle(vehicleId, PlayerIndex, 2)
                enter_vehicle(vehicleId, PlayerIndex, 0)
                say(PlayerIndex, get_var(PlayerIndex, "$name") .. ": You are driver and gunner! " )
            else
                enter_vehicle(vehicleId, PlayerIndex, 0)
            end
        end

    end

end

-- Created by H® Shaft
-- Visit http://halorace.org