Show Rider Names v2 for SAPP

-- Show Rider Names v2
-- Designed for Halo PC/CE

-- Script will show names of teammates who enter the same vehicle, or are in the same vehicle and types 'WHO IS'

-- changelog
    -- 7/31/2016 -- re-wrote entire script
    -- 1/17/2017 -- edited some passenger values as it sometimes would not show passenger names

-- don't edit --
api_version = "1.9.0.0"
player_seat = {}
vehicles = {}

function OnScriptLoad()
    register_callback(cb['EVENT_GAME_START'],"OnNewGame")
    register_callback(cb['EVENT_GAME_END'], "OnGameEnd")
    register_callback(cb['EVENT_JOIN'],"OnPlayerJoin")
    register_callback(cb['EVENT_LEAVE'],"OnPlayerLeave")
    register_callback(cb['EVENT_DIE'], "OnPlayerDeath")
    register_callback(cb['EVENT_CHAT'], "OnPlayerChat")
    register_callback(cb['EVENT_VEHICLE_ENTER'], "OnVehicleEnter")
    register_callback(cb['EVENT_VEHICLE_EXIT'], "OnVehicleEject")

    if get_var(0, "$gt") ~= "n/a" then
        game_started = true
        -- if script is reloaded during a game, repopulate player_seat values
        for PlayerIndex=1,16 do
            if player_present(PlayerIndex) then
                player_seat[PlayerIndex] = {}
                local player_object = get_dynamic_player(PlayerIndex)
                local player_object_id = read_dword(get_player(PlayerIndex) + 0x34)
                if (player_object ~= 0) then
                    local vehicle_id = read_dword(player_object + 0x11C)
                    if (vehicle_id ~= 0xFFFFFFFF) then
                        local veh_obj = get_object_memory(vehicle_id)
                        if (veh_obj ~= 0) then
                            local passenger = read_dword(veh_obj + 0x32C)
                            if (vehicles[vehicle_id] == nil) then
                                vehicles[vehicle_id] = {}
                            end
                            if (read_byte(player_object + 0x2F0) == 0) then -- << driver
                                player_seat[PlayerIndex].vehicleid = vehicle_id
                                player_seat[PlayerIndex].seat = 0
                                player_seat[PlayerIndex].vehobj = veh_obj
                                vehicles[vehicle_id].driver = PlayerIndex
                            elseif (read_byte(player_object + 0x2F0) == 1) then -- << passenger
                                player_seat[PlayerIndex].vehicleid = vehicle_id
                                player_seat[PlayerIndex].seat = 1
                                player_seat[PlayerIndex].vehobj = veh_obj
                                vehicles[vehicle_id].passenger = PlayerIndex
                                if (passenger == 0xFFFFFFFF) then
                                    write_dword(player_seat[PlayerIndex].vehobj + 0x32C, player_object_id)
                                end
                            elseif (read_byte(player_object + 0x2F0) == 2) then -- << gunner
                                player_seat[PlayerIndex].vehicleid = vehicle_id
                                player_seat[PlayerIndex].seat = 2
                                player_seat[PlayerIndex].vehobj = veh_obj
                                vehicles[vehicle_id].gunner = PlayerIndex
                            elseif (read_byte(player_object + 0x2F0) == 0xFFFFFFFF) then -- << invalid/dead/not in vehicle
                                player_seat[PlayerIndex] = {}
                            end
                        end
                    end
                else
                    player_seat[PlayerIndex] = {}
                end
            end
        end
    end
end

function OnScriptUnload()
    player_seat = {}
    vehicles = {}
end

function OnNewGame()
    game_started = true
    for i=1,16 do
        if player_present(i) then
            player_seat[i] = {}
        end
    end
end

function OnGameEnd()
    game_started = false
    vehicles = {}
    for i=1,16 do
        if player_present(i) then
            player_seat[i] = nil
        end
    end
end

function OnPlayerJoin(PlayerIndex)
    player_seat[PlayerIndex] = {}
end

function OnPlayerLeave(PlayerIndex)
    if (player_seat[PlayerIndex].seat == 1) then
        write_dword(player_seat[PlayerIndex].vehobj + 0x32C, 0xFFFFFFFF)
    end
    player_seat[PlayerIndex] = {}
end

function OnPlayerDeath(PlayerIndex, KillerIndex)
    if game_started then
        if (player_seat[PlayerIndex].seat == 1) then
            if (player_seat[PlayerIndex].vehobj ~= nil) then
                write_dword(player_seat[PlayerIndex].vehobj + 0x32C, 0xFFFFFFFF)
            end
            player_seat[PlayerIndex] = {}
        end
        player_seat[PlayerIndex] = {}
    end
end

function OnVehicleEnter(PlayerIndex, Seat)
    if player_present(PlayerIndex) then
        local player_object = get_dynamic_player(PlayerIndex)
        local player_object_id = read_dword(get_player(PlayerIndex) + 0x34)
        local vehicle_id = read_dword(player_object + 0x11C)
        if (player_object ~= 0) then
            if (vehicle_id ~= 0xFFFFFFFF) then
                if (vehicles[vehicle_id] == nil) then
                    vehicles[vehicle_id] = {}
                end
                local veh_obj = get_object_memory(vehicle_id)
                if (veh_obj ~= 0) then
                    if (Seat == "0") then
                        player_seat[PlayerIndex].vehicleid = vehicle_id
                        player_seat[PlayerIndex].seat = 0
                        player_seat[PlayerIndex].vehobj = veh_obj
                        vehicles[vehicle_id].driver = PlayerIndex
                    elseif (Seat == "1") then
                        write_dword(veh_obj + 0x32C, player_object_id)
                        player_seat[PlayerIndex].vehicleid = vehicle_id
                        player_seat[PlayerIndex].seat = 1
                        player_seat[PlayerIndex].vehobj = veh_obj
                        vehicles[vehicle_id].passenger = PlayerIndex
                    elseif (Seat == "2") then
                        player_seat[PlayerIndex].vehicleid = vehicle_id
                        player_seat[PlayerIndex].seat = 2
                        player_seat[PlayerIndex].vehobj = veh_obj
                        vehicles[vehicle_id].gunner = PlayerIndex
                    end
                    showplayers = timer(34, "Show_Players", vehicle_id)
                end
            end
        end
    end
end

function OnVehicleEject(PlayerIndex)
    if player_alive(PlayerIndex) then
        if (player_seat[PlayerIndex].seat == 1) then
            if (player_seat[PlayerIndex].vehobj ~= nil) then
                write_dword(player_seat[PlayerIndex].vehobj + 0x32C, 0xFFFFFFFF)
            end
            player_seat[PlayerIndex] = {}
        else
            player_seat[PlayerIndex] = {}
        end
    end
end

function OnPlayerChat(PlayerIndex, Message)
    local response = nil
    local name = get_var(PlayerIndex,"$name")
    local Message = string.lower(Message)
    if (Message == "whois") or (Message == "who is") or (Message == "/whois") or (Message == "/who is") then
        response = false
        local player_object = get_dynamic_player(PlayerIndex)
        if game_started then
            if (player_object ~= 0) then
                local vehicle_id = read_dword(player_object + 0x11C)
                if (vehicle_id ~= 0xFFFFFFFF) then
                    local veh_obj = get_object_memory(vehicle_id)
                    if (veh_obj ~= 0) then
                        message_players(getdriverplayer(veh_obj), getgunnerplayer(veh_obj), getpassengerplayer(veh_obj))
                    end
                else
                    say(PlayerIndex, "**Who Is** You must be in a vehicle to use this feature.")
                end
            end
        else
            say(PlayerIndex, "**Who Is** You must for new game to use this feature.")
        end
    end
    return response
end

function Show_Players(vehicle_id)
    if (vehicle_id == 0xFFFFFFFF) or (vehicle_id == nil) then return end
    local veh_obj = get_object_memory(vehicle_id)
    if (veh_obj ~= 0) then
        message_players(getdriverplayer(veh_obj), getgunnerplayer(veh_obj), getpassengerplayer(veh_obj))
    end
    return false
end

function ObjectIDtoPlayer(ObjectID) -- returns PlayerIndex from an ObjectID
    local object = get_object_memory(ObjectID)
    if object ~= 0 then
    local playerId = read_word(object + 0xC0)
    return to_player_index(playerId) ~= 0 and playerId or nil end
end

function getpassengerobjid(veh_obj) -- returns passenger object id
    if (veh_obj == nil) then return end
    return read_dword(veh_obj + 0x32C)
end

function getdriverplayer(veh_obj) -- returns the DriverIndex of vehicle
    if (veh_obj == nil) then say_all("driver veh_obj nil") return end
    local obj_id = read_dword(veh_obj + 0x324)
    if obj_id and (obj_id ~= 0xFFFFFFFF) then return ObjectIDtoPlayer(obj_id) end
end

function getgunnerplayer(veh_obj) -- returns the GunnerIndex of vehicle
    if (veh_obj == nil) then return say_all("gunner veh_obj nil") end
    local obj_id = read_dword(veh_obj + 0x328)
    if obj_id and (obj_id ~= 0xFFFFFFFF) then return ObjectIDtoPlayer(obj_id) end
end

function getpassengerplayer(veh_obj) -- returns the PassengerIndex of vehicle
    if (veh_obj == nil) then return end
    local obj_id = getpassengerobjid(veh_obj)
    if obj_id and (obj_id ~= 0xFFFFFFFF)  then return ObjectIDtoPlayer(obj_id) end
end

function message_players(driver, gunner, passenger) -- returns the seats and names of players in the vehicle
    local t,n = {}, {}
    if driver then
        table.insert(t, driver)
        table.insert(n, "Driver")
    end
    if gunner then
        table.insert(t, gunner)
        table.insert(n, "Gunner")
    end
    if passenger then
        table.insert(t, passenger)
        table.insert(n, "Passenger")
    end
    for k,v in pairs(t) do
        for key,value in pairs(t) do
            if (v ~= value) then
                rprint(to_player_index(v), n[key] .. ": " .. get_var(to_player_index(value), "$name"))
            end
        end
    end
end

-- assign passenger seat player to vehicle
-- overcomes defect in reliability of passenger seat reading for scripts
function assignpassenger(veh_obj, player_object_id)
    if (veh_obj == nil) or (player_object_id == nil) then return false end
    if game_started then
        write_dword(veh_obj + 0x32C, player_object_id)
    end
    return false
end

-- resets passenger seat to empty if player exits, dies or leaves
function resetpassenger(PlayerIndex)
    if (player_seat[PlayerIndex].vehobj == nil) then return false end
    write_dword(player_seat[PlayerIndex].vehobj + 0x32C, 0xFFFFFFFF)
    player_seat[PlayerIndex] = {}
    return false
end

function OnError(Message)
    print(debug.traceback())
end

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