methods called with std::async does not behave correctly

I have a method that inits my program state and to speed up the whole process I'm trying to add multi threading to my app (first time using this - still learning). The problem is, when I'm calling it normally everything is fine, but with std::future and std::async I'm experiencing some problems (like gl_invalid_operation when copying SFML texture or sometimes some of the letters in wstring are incorrect).

I've never touched multi threading before, but according to many tutorials, everything should be fine.

my code:

SettingsState.cpp

void SettingsState::InitState()
{

#define ASYNC 1
#if ASYNC

    // Weird behavior
    std::future<void> gen_gui_init =  std::async(std::launch::async, &SettingsState::InitGenSetGUI, this);
    std::future<void> win_sett_init = std::async(std::launch::async, &SettingsState::InitWindowSettings, this);
    std::future<void> aud_sett_init = std::async(std::launch::async, &SettingsState::InitAudioSettings, this);
    std::future<void> sim_sett_init = std::async(std::launch::async, &SettingsState::InitSimulationSettings, this);
    std::future<void> key_sett_init = std::async(std::launch::async, &SettingsState::InitKeybindsSettings, this);

#else

    // Everything is fine
    this->InitGenSetGUI();
    this->InitWindowSettings();
    this->InitAudioSettings();
    this->InitSimulationSettings();
    this->InitKeybindsSettings();

#endif

}

SettingsState.hpp

class SettingsState :
    public State
{
public:
    // constructors

    void InitState();

    void InitGenSetGUI();
    void InitWindowSettings();
    void InitAudioSettings();
    void InitSimulationSettings();
    void InitKeybindsSettings();

    // other methods and members
};

I think something is wrong with std::future, but as I said, I've just touched it and cannot find the answer. Thanks in advance

Other Inits:

void SettingsState::InitGenSetGUI()
{
    const int types_number = 4;
    //const int wSettingsColorsCount = 26;

    sf::Event fake_event;

    m_stateBackground.create(winSize, { 0, 0 }, ke::Origin::LEFT_TOP, "Textures/earth_view2.png");
    m_backgroundMask.create(winSize, { 0, 0 }, ke::Origin::LEFT_TOP, L"", 0, {}, sf::Color(0, 0, 0, 255.f - 255.f * AppSettings::BackgroundBrightness() * 0.01f));
    m_stateMask.create(winSize, { 0, 0 }, ke::Origin::LEFT_TOP, {}, {}, {}, sf::Color(0, 0, 0, 0));


    // SETTINGS GUI


    // window settings types

    m_settings_types.reserve(types_number);

    m_settings_types.emplace_back(std::make_unique<ke::Rectangle>(winSize / 9.f, sf::Vector2f(1 * winSize.x / 9, winSize.y / 18), ke::Origin::LEFT_TOP, L"Window", winSize.y / 32.f, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 255)));
    m_settings_types.emplace_back(std::make_unique<ke::Rectangle>(winSize / 9.f, sf::Vector2f(3 * winSize.x / 9, winSize.y / 18), ke::Origin::LEFT_TOP, L"Audio", winSize.y / 32.f, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 128)));
    m_settings_types.emplace_back(std::make_unique<ke::Rectangle>(winSize / 9.f, sf::Vector2f(5 * winSize.x / 9, winSize.y / 18), ke::Origin::LEFT_TOP, L"Simulation", winSize.y / 32.f, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 128)));
    m_settings_types.emplace_back(std::make_unique<ke::Rectangle>(winSize / 9.f, sf::Vector2f(7 * winSize.x / 9, winSize.y / 18), ke::Origin::LEFT_TOP, L"Keybinds", winSize.y / 32.f, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 128)));

    m_selected_type_itr = m_settings_types.begin();

    for (auto& itr : m_settings_types)
        itr->update({ 0, 0 }, fake_event, sf::Mouse::Left, nullptr);


    // separation bar

    m_separation_bar.create({ winSize.x, winSize.y / 576 }, { 0, winSize.y / 4.5f }, ke::Origin::LEFT_MIDDLE, {}, {}, {}, sf::Color(255, 255, 255, 160));


    // slider

    m_slider.create({ winSize.x / 100, winSize.y - winSize.y / 4.5f }, { winSize.x, winSize.y / 4.5f }, viewSize.y * 1.1f, ke::Origin::RIGHT_TOP, nullptr, nullptr, sf::Color(192, 192, 192, 128), sf::Color(128, 128, 128, 128));


    // apply and restore defaults button

    m_apply_button.create({ winSize.x * 0.1f, winSize.y * 0.05f }, { winSize.x / 6.f, 0.95f * winSize.y }, ke::RIGHT_TOP, L"Apply", winSize.y / 32.f, ke::Origin::MIDDLE_MIDDLE, sf::Color(128, 128, 128, 64), sf::Color(192, 192, 192, 192));
    m_restore_def_buttoon.create({ winSize.x * 0.1f, winSize.y * 0.05f }, { winSize.x / 6.f, 0.95f * winSize.y }, ke::LEFT_TOP, L"Restore defaults", winSize.y / 48.f, ke::Origin::MIDDLE_MIDDLE, sf::Color(128, 128, 128, 128), sf::Color(192, 192, 192, 255));
}




////////////////////////////////////////////////////////////////



void SettingsState::InitWindowSettings()
{
    // WINDOW SETTINGS

    sf::Event fake_event;
    auto color_itr = m_windowSettings_colors.begin();


    // FPS bars

    m_maxMenuFPS_bar.create({ winSize.x / 6, winSize.y / 24 }, { 0.6f * winSize.x, 4 * winSize.y * 0.1f }, nullptr, AppSettings::MaxMenuFPS(), 30, 240, ke::Origin::LEFT_MIDDLE, sf::Color::Black, sf::Color(255, 255, 255, 160), winSize.y / 450, 0, sf::Color(255, 255, 255, 160), sf::Color::Transparent);;
    m_maxSimFPS_bar.create({ winSize.x / 6, winSize.y / 24 }, { 0.6f * winSize.x, 5 * winSize.y * 0.1f }, nullptr, AppSettings::MaxSimulationFPS(), 120, 960, ke::Origin::LEFT_MIDDLE, sf::Color::Black, sf::Color(255, 255, 255, 160), winSize.y / 450, 0, sf::Color(255, 255, 255, 160), sf::Color::Transparent);;


    // FPS bars accessories

    m_WS_accessories.reserve(11);

    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.y / 24.f, winSize.y / 24.f), sf::Vector2f(0.6f * winSize.x, 4 * winSize.y * 0.1f), ke::Origin::RIGHT_MIDDLE, "Textures/left_arrow2.png"));
    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.y / 24.f, winSize.y / 24.f), sf::Vector2f(23.f * winSize.x / 30, 4 * winSize.y * 0.1f), ke::Origin::LEFT_MIDDLE, "Textures/right_arrow2.png"));
    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.x / 6.f, winSize.y / 24.f), sf::Vector2f(0.4f * winSize.x, 4 * winSize.y * 0.1f), ke::Origin::RIGHT_MIDDLE, L"Menu FPS limit", winSize.y / 32, ke::Origin::RIGHT_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 160)));
    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.y / 24.f, winSize.y / 24.f), sf::Vector2f(0.6f * winSize.x, 4 * winSize.y * 0.1f), ke::Origin::LEFT_MIDDLE, std::to_wstring(AppSettings::MaxMenuFPS()), winSize.y / 48, ke::Origin::LEFT_MIDDLE, sf::Color::Transparent, sf::Color::Black, 0, sf::Color::Transparent, 0, sf::Text::Regular, sf::Vector2f(2 * winSize.y / 450, 0)));

    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.y / 24.f, winSize.y / 24.f), sf::Vector2f(0.6f * winSize.x, 5 * winSize.y * 0.1f), ke::Origin::RIGHT_MIDDLE, "Textures/left_arrow2.png"));
    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.y / 24.f, winSize.y / 24.f), sf::Vector2f(23.f * winSize.x / 30, 5 * winSize.y * 0.1f), ke::Origin::LEFT_MIDDLE, "Textures/right_arrow2.png"));
    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.x / 6.f, winSize.y / 24.f), sf::Vector2f(0.4f * winSize.x, 5 * winSize.y * 0.1f), ke::Origin::RIGHT_MIDDLE, L"Simulation FPS limit", winSize.y / 32, ke::Origin::RIGHT_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 160)));
    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.y / 24.f, winSize.y / 24.f), sf::Vector2f(0.6f * winSize.x, 5 * winSize.y * 0.1f), ke::Origin::LEFT_MIDDLE, std::to_wstring(AppSettings::MaxSimulationFPS()), winSize.y / 48, ke::Origin::LEFT_MIDDLE, sf::Color::Transparent, sf::Color::Black, 0, sf::Color::Transparent, 0, sf::Text::Regular, sf::Vector2f(2 * winSize.y / 450, 0)));

    if (m_maxSimFPS_bar.getPointCount() >= 960)
        m_WS_accessories.at(7)->setText(L"Unlimited");

    // vertical sync status buttons

    m_vSyncOn.create({ winSize.x / 12.f, winSize.y / 24.f }, { 41.f * winSize.x / 60.f, 6.f * winSize.y * 0.1f }, ke::Origin::RIGHT_MIDDLE, L"ON", winSize.y / 48, ke::Origin::MIDDLE_MIDDLE, sf::Color(160, 160, 160, 128), sf::Color::Black);
    m_vSyncOff.create({ winSize.x / 12.f, winSize.y / 24.f }, { 41.f * winSize.x / 60.f, 6.f * winSize.y * 0.1f }, ke::Origin::LEFT_MIDDLE, L"OFF", winSize.y / 48, ke::Origin::MIDDLE_MIDDLE, sf::Color(160, 160, 160, 128), sf::Color::Black);

    if (m_vSyncStatus)
    {
        m_vSyncOn.setFillColor(sf::Color(255, 255, 255, 192));
        m_vSyncOn.setTextStyle(sf::Text::Bold);
    }
    else
    {
        m_vSyncOff.setFillColor(sf::Color(255, 255, 255, 192));
        m_vSyncOff.setTextStyle(sf::Text::Bold);
    }


    // vertical sync buttons accessories

    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.x / 6, winSize.y / 24), sf::Vector2f(0.4f * winSize.x, 6 * winSize.y * 0.1f), ke::Origin::RIGHT_MIDDLE, L"Vertical Synchronization", winSize.y / 32, ke::Origin::RIGHT_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 160)));



    // bright level bar

    m_bright_lvl.create({ winSize.x / 6.f, winSize.y / 24.f }, winSize.y / 49, { 41.f * winSize.x / 60.f, 7.f * winSize.y * 0.1f }, ke::Origin::MIDDLE_MIDDLE, nullptr, nullptr, sf::Color(160, 160, 160, 255), sf::Color(96, 96, 96, 255));
    m_bright_lvl.setPercent(AppSettings::BackgroundBrightness());


    // bright level accessories 

    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.x / 6, winSize.y / 24), sf::Vector2f(0.4f * winSize.x, 7 * winSize.y * 0.1f), ke::Origin::RIGHT_MIDDLE, L"Background brightness", winSize.y / 32, ke::Origin::RIGHT_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 160)));



    // window size dropdown list

    m_windowSize_drl.create({ winSize.x / 6.f, winSize.y / 24.f }, { 41.f * winSize.x / 60.f, 8.f * winSize.y * 0.1f }, "Textures/earth_view2.png", L"Something went wrong :(",
        winSize.y / 48, ke::Origin::MIDDLE_MIDDLE, sf::Color::Black, sf::Color(255, 255, 255, 192), winSize.y / 450, sf::Color(255, 255, 255, 192), sf::Text::Bold);
    m_windowSize_drl.addMember(nullptr, L"1024 \u00D7 576", winSize.y / 56, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(160, 160, 160, 255));
    m_windowSize_drl.addMember(nullptr, L"1280 \u00D7 720", winSize.y / 56, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(160, 160, 160, 255));
    m_windowSize_drl.addMember(nullptr, L"1366 \u00D7 768", winSize.y / 56, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(160, 160, 160, 255));
    m_windowSize_drl.addMember(nullptr, L"1600 \u00D7 900", winSize.y / 56, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(160, 160, 160, 255));
    m_windowSize_drl.addMember(nullptr, L"1920 \u00D7 1080", winSize.y / 56, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(160, 160, 160, 255));
    m_windowSize_drl.addMember(nullptr, L"1920 \u00D7 1080 Fullscreen", winSize.y / 56, ke::Origin::MIDDLE_MIDDLE, sf::Color::Transparent, sf::Color(160, 160, 160, 255));

    for (auto& itr : *m_windowSize_drl.getMembers())
        itr->update({ 0, 0 }, fake_event, sf::Mouse::Left, nullptr);


    if (AppSettings::DefaultWindowSize() == sf::Vector2f(1024, 576)) m_windowSize_drl.setMemberAsActive(0);
    if (AppSettings::DefaultWindowSize() == sf::Vector2f(1280, 720)) m_windowSize_drl.setMemberAsActive(1);
    if (AppSettings::DefaultWindowSize() == sf::Vector2f(1366, 768)) m_windowSize_drl.setMemberAsActive(2);
    if (AppSettings::DefaultWindowSize() == sf::Vector2f(1600, 900)) m_windowSize_drl.setMemberAsActive(3);
    if (AppSettings::DefaultWindowSize() == sf::Vector2f(1920, 1080)) m_windowSize_drl.setMemberAsActive(4);
    if (AppSettings::DefaultWindowSize() == sf::Vector2f(1920, 1080)) m_windowSize_drl.setMemberAsActive(5);


    m_start_window_size = m_windowSize_drl.getSelectedID();
    m_current_window_size = m_windowSize_drl.getSelectedID();


    // window size dropdown list accessories

    m_WS_accessories.emplace_back(std::make_unique<ke::Rectangle>(sf::Vector2f(winSize.x / 6, winSize.y / 24), sf::Vector2f(0.4f * winSize.x, 8 * winSize.y * 0.1f), ke::Origin::RIGHT_MIDDLE, L"Window Resolution", winSize.y / 32, ke::Origin::RIGHT_MIDDLE, sf::Color::Transparent, sf::Color(255, 255, 255, 160)));
}