[MrDeath537]

Here's my code, you can change the Z value in SetPlayerVelocity to make it better or worst.

pawn Код:

public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
    if (!IsPlayerInAnyVehicle(playerid))
    {
        if (newkeys & KEY_JUMP)
        {
            new
                Float: fVehX,
                Float: fVehY,
                Float: fVehZ
                ;

            GetPlayerVelocity(playerid, fVehX, fVehY, fVehZ);
            if (fVehZ == 0.0)
            {
                SetPlayerVelocity(playerid, fVehX, fVehY, 0.5);
            }
        }
    }

    return 1;
}