imgui cannot show utf-8 chinese character correctly，how to solve

[aliule2020]

//#include <SFML/Graphics.hpp>
//
//int main()
//{
//    sf::RenderWindow window(sf::VideoMode(sf::Vector2u{200,200}), "SFML works!");
//    sf::CircleShape shape(100.f);
//    shape.setFillColor(sf::Color::Green);
//
//    while (window.isOpen())
//    {
//        sf::Event event;
//        while (window.pollEvent(event))
//        {
//            if (event.type == sf::Event::Closed)
//                window.close();
//        }
//
//        window.clear();
//        window.draw(shape);
//        window.display();
//    }
//
//    return 0;
//}


#include <string>
using namespace std;


#include "imgui.h" // necessary for ImGui::*, imgui-SFML.h doesn't include imgui.h

#include "imgui-SFML.h" // for ImGui::SFML::* functions and SFML-specific overloads

#include <SFML/Graphics.hpp>
#include <SFML/Graphics/CircleShape.hpp>
#include <SFML/Graphics/RenderWindow.hpp>
#include <SFML/System/Clock.hpp>
#include <SFML/Window/Event.hpp>

int main() {
    sf::RenderWindow window(sf::VideoMode(sf::Vector2u{ 1024,768 }), "SFML works!");
    window.setFramerateLimit(60);
    ImGui::SFML::Init(window);

   


    sf::CircleShape shape(100.f);
    shape.setFillColor(sf::Color::Green);

    sf::Text tx;
    tx.setString( sf::String(L"你好") );   //here is ok
    sf::Font font;
    font.loadFromFile("C:\\Windows\\Fonts\\stsong.ttf");
    tx.setFont(font);
    tx.setCharacterSize(36);
    tx.setFillColor(sf::Color::Red);
    tx.setPosition(sf::Vector2f{ 400, 400 });
    

    sf::Clock deltaClock;
    while (window.isOpen()) {
        sf::Event event;
        while (window.pollEvent(event)) {
            ImGui::SFML::ProcessEvent(window, event);

            if (event.type == sf::Event::Closed) {
                window.close();
            }
        }

        ImGui::SFML::Update(window, deltaClock.restart());   

        ImGui::BeginMainMenuBar();
        ImGui::SetWindowFontScale(1);

        if (ImGui::BeginMenu("File"))
        {
            
            if (ImGui::MenuItem("Open..", "Ctrl+O")) { /* Do stuff */ }
            if (ImGui::MenuItem("Save", "Ctrl+S")) { /* Do stuff */ }
            if (ImGui::MenuItem("Close", "Ctrl+W")) {  }
            ImGui::EndMenu();
        }
        ImGui::EndMainMenuBar();

        ImGui::ShowDemoWindow();


        ImGuiIO& io = ImGui::GetIO();
        //io.Fonts->Clear();
        io.Fonts->AddFontFromFileTTF("C:\\Windows\\Fonts\\stsong.ttf", 13.0f, NULL, io.Fonts->GetGlyphRangesChineseFull());
        io.Fonts->AddFontFromFileTTF("C:\\Windows\\Fonts\\simhei.ttf", 13.0f, NULL, io.Fonts->GetGlyphRangesChineseFull());
        //ImGui::PushFont(ImGui::GetIO().Fonts->Fonts[0]);
        ImGui::SFML::UpdateFontTexture();
       
        ImGui::Begin("hello");
        ImGui::SetWindowFontScale(4);
        ImGui::SetWindowPos("hello", ImVec2{ 50,50 });
        ImGui::SetWindowSize("hello", ImVec2{ 200,200 });
        ImGui::Button((char*)u8"中文测试");      //here is failed
        ImGui::End();

        window.clear(sf::Color::White);
        window.draw(shape);
        
        ImGui::SFML::Render(window);

        window.draw(tx);
        window.display();
    }

    ImGui::SFML::Shutdown();

    return 0;
}