M-GEAR system

// This is a comment
// uncomment the line below if you want to write a filterscript
#define FILTERSCRIPT

#include <a_samp> // thanks to samp team

#define PRESSED(%0) \
    (((newkeys & (%0)) == (%0)) && ((oldkeys & (%0)) != (%0)))

#define SpeedCheck(%0,%1,%2,%3,%4) floatround(floatsqroot(%4?(%0*%0+%1*%1+%2*%2):(%0*%0+%1*%1) ) *%3*1.6) // i dunno who made this

new GearLimit[MAX_PLAYERS];
new Gear[MAX_VEHICLES];
new Text:Geartxd[MAX_PLAYERS];

#define MAX_GEAR 4
#define VEHICLE_GEAR_SPEED 30 //use this to set the gear max speed ( speed = Gear[vehicleid] * VEHICLE_GEAR_SPEED )

#if defined FILTERSCRIPT

public OnFilterScriptInit()
{
    print("\n--------------------------------------");
    print(" MANUAL TRANSMISSION BY MAHAR!  LOADED  ");
    print("--------------------------------------\n");
    return 1;
}

public OnFilterScriptExit()
{
    print("\n--------------------------------------");
    print(" MANUAL TRANSMISSION BY MAHAR! UNLOADED ");
    print("--------------------------------------\n");
    return 1;
}

#else

main()
{
   return 1;
}

#endif

public OnGameModeInit()
{
    return 1;
}

public OnGameModeExit()
{
    return 1;
}

public OnPlayerRequestClass(playerid, classid)
{
    return 1;
}

public OnPlayerConnect(playerid)
{
    Geartxd[playerid] = TextDrawCreate(478,413,"_"); // the gear textdraw
    TextDrawLetterSize(Geartxd[playerid],0.37,1.099999);
    TextDrawSetOutline(Geartxd[playerid],1);
    GearLimit[playerid] = 0;
    return 1;
}

public OnPlayerDisconnect(playerid, reason)
{
    TextDrawDestroy(Geartxd[playerid]);
    GearLimit[playerid] = 0;
    return 1;
}

public OnPlayerSpawn(playerid)
{
    GearLimit[playerid] = 0;
    return 1;
}

public OnPlayerDeath(playerid, killerid, reason)
{
    GearLimit[playerid] = 0;
    return 1;
}

public OnVehicleSpawn(vehicleid)
{
    Gear[vehicleid] = 0;
    return 1;
}

public OnVehicleDeath(vehicleid, killerid)
{
    Gear[vehicleid] = 0;
    return 1;
}

public OnPlayerText(playerid, text[])
{
    return 1;
}

public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger)
{
    GearLimit[playerid] = Gear[vehicleid] * 20;
    if(GetVehicleModel(vehicleid) == 481 || GetVehicleModel(vehicleid) == 509 || GetVehicleModel(vehicleid) == 510)
    {
        GearLimit[playerid] = 999;
    }
    return 1;
}

public OnPlayerExitVehicle(playerid, vehicleid)
{
    GearLimit[playerid] = 0;
    return 1;
}

public OnPlayerStateChange(playerid, newstate, oldstate)
{
    return 1;
}

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
    if (PRESSED(KEY_YES)) // Gear UP
    {
        new string[128];
        if(GetVehicleModel(GetPlayerVehicleID(playerid)) == 481 || GetVehicleModel(GetPlayerVehicleID(playerid)) == 509 || GetVehicleModel(GetPlayerVehicleID(playerid)) == 510) return GameTextForPlayer(playerid, "~n~~r~ This Vhicle Doesnt Have Engine", 1000, 2);
        if(Gear[GetPlayerVehicleID(playerid)] <= MAX_GEAR)
        {

            Gear[GetPlayerVehicleID(playerid)] ++;
            format(string, sizeof(string), "~n~~w~Vehicle Gear ~r~( ~g~%d ~r~)", Gear[GetPlayerVehicleID(playerid)]);
            GameTextForPlayer(playerid, string, 3000, 3);
        }
        else
        {
            GameTextForPlayer(playerid, "~n~~r~ Max Vehicle Gear", 3000, 3);
        }
    }
    if (PRESSED(KEY_NO)) // Gear Down
    {
        new string[128];
        if(GetVehicleModel(GetPlayerVehicleID(playerid)) == 481 || GetVehicleModel(GetPlayerVehicleID(playerid)) == 509 || GetVehicleModel(GetPlayerVehicleID(playerid)) == 510) return GameTextForPlayer(playerid, "~n~~r~ This Vhicle Doesnt Have Engine", 1000, 2);
        if(Gear[GetPlayerVehicleID(playerid)] > -1)
        {
            Gear[GetPlayerVehicleID(playerid)] --;
            format(string, sizeof(string), "~w~Vehicle Gear ~r~( ~g~%d ~r~)", Gear[GetPlayerVehicleID(playerid)]);
            if(Gear[GetPlayerVehicleID(playerid)] == -1)
            {
                format(string, sizeof(string), "~w~Vehicle Gear ~r~( ~g~R ~r~)");
            }
            GameTextForPlayer(playerid, string, 3000, 3);
        }
    }
    return 1;
}
stock ModifyVehicleSpeed(vehicleid,mph) //Miles Per Hour
{
    new Float:Vx,Float:Vy,Float:Vz,Float:DV,Float:multiple;
    GetVehicleVelocity(vehicleid,Vx,Vy,Vz);
    DV = floatsqroot(Vx*Vx + Vy*Vy + Vz*Vz);
    if(DV > 0) //Directional velocity must be greater than 0 (display strobes if 0)
    {
        multiple = ((mph + DV * 100) / (DV * 100)); //Multiplying DV by 100 calculates speed in MPH
        return SetVehicleVelocity(vehicleid,Vx*multiple,Vy*multiple,Vz*multiple);
    }
    return 0;
}

stock IsVehicleDrivingBackwards(vehicleid) // By Joker
{
    new
        Float:Float[3]
    ;
    if(GetVehicleVelocity(vehicleid, Float[1], Float[2], Float[0]))
    {
        GetVehicleZAngle(vehicleid, Float[0]);
        if(Float[0] < 90)
        {
            if(Float[1] > 0 && Float[2] < 0) return true;
        }
        else if(Float[0] < 180)
        {
            if(Float[1] > 0 && Float[2] > 0) return true;
        }
        else if(Float[0] < 270)
        {
            if(Float[1] < 0 && Float[2] > 0) return true;
        }
        else if(Float[1] < 0 && Float[2] < 0) return true;
    }
    return false;
}

stock GetVehicleSpeed(vehicleid, get3d)
{
    new Float:x, Float:y, Float:z;
    GetVehicleVelocity(vehicleid, x, y, z);
    return SpeedCheck(x, y, z, 100.0, get3d);
}

public OnPlayerUpdate(playerid)
{
    new string[128];
    GearLimit[playerid] = Gear[GetPlayerVehicleID(playerid)] * VEHICLE_GEAR_SPEED;
    if(Gear[GetPlayerVehicleID(playerid)] == -1)
    {
        GearLimit[playerid] = 0;
    }
    if(GetPlayerState(playerid) == PLAYER_STATE_DRIVER)
    {
        new a, b, c;
        GetPlayerKeys(playerid, a, b ,c);
        if(IsVehicleDrivingBackwards(GetPlayerVehicleID(playerid)))
        {
            if(Gear[GetPlayerVehicleID(playerid)] == -1)
            {
                return 1;
            }
            else
            {
                ModifyVehicleSpeed(GetPlayerVehicleID(playerid), - GetVehicleSpeed(GetPlayerVehicleID(playerid), 0));
            }
        }
        if(a == 8 && GetVehicleSpeed(GetPlayerVehicleID(playerid), 0) > GearLimit[playerid])
        {
            if(IsVehicleDrivingBackwards(GetPlayerVehicleID(playerid)))
            {
                if(Gear[GetPlayerVehicleID(playerid)] != -1) return ModifyVehicleSpeed(GetPlayerVehicleID(playerid), - GetVehicleSpeed(GetPlayerVehicleID(playerid), 0));
            }
            if(!IsVehicleDrivingBackwards(GetPlayerVehicleID(playerid)))
            {
                if(Gear[GetPlayerVehicleID(playerid)] == -1) return ModifyVehicleSpeed(GetPlayerVehicleID(playerid), - GetVehicleSpeed(GetPlayerVehicleID(playerid), 0));
            }
            new newspeed = GetVehicleSpeed(GetPlayerVehicleID(playerid), 0) - GearLimit[playerid];
            ModifyVehicleSpeed(GetPlayerVehicleID(playerid), -newspeed);
        }
        if(GetVehicleModel(GetPlayerVehicleID(playerid)) != 481 || GetVehicleModel(GetPlayerVehicleID(playerid)) != 509 || GetVehicleModel(GetPlayerVehicleID(playerid)) != 510)
        {
            if(IsPlayerConnected(playerid) && IsPlayerInAnyVehicle(playerid))
            {
                TextDrawShowForPlayer(playerid,Geartxd[playerid]);
                format(string,sizeof(string),"Gear: %d",Gear[GetPlayerVehicleID(playerid)]);
                if(Gear[GetPlayerVehicleID(playerid)] == -1)
                {
                    format(string,sizeof(string),"Gear: R");
                }
                TextDrawSetString(Geartxd[playerid],string);
            }
        }
        else if(GetVehicleModel(GetPlayerVehicleID(playerid)) == 481 || GetVehicleModel(GetPlayerVehicleID(playerid)) == 509 || GetVehicleModel(GetPlayerVehicleID(playerid)) == 510)
        {
            GearLimit[playerid] = 999;
        }
        return 1;
    }
    if(!IsPlayerInAnyVehicle(playerid))
    {
        TextDrawHideForPlayer(playerid,Geartxd[playerid]);
    }
    return 1;
}