text: // Dear ImGui: standalone example application for GLFW + OpenGL 3, using programmable pipeline
  // (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan/Metal graphics context creation, etc.)
  // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
  // Read online: https://github.com/ocornut/imgui/tree/master/docs
  
  #include "imgui.h"
  #include "imgui_impl_glfw.h"
  #include "imgui_impl_opengl3.h"
  #include <stdio.h>
  #if defined(IMGUI_IMPL_OPENGL_ES2)
  #include <GLES2/gl2.h>
  #endif
  #include <GLFW/glfw3.h> // Will drag system OpenGL headers
  
  // [Win32] Our example includes a copy of glfw3.lib pre-compiled with VS2010 to maximize ease of testing and compatibility with old VS compilers.
  // To link with VS2010-era libraries, VS2015+ requires linking with legacy_stdio_definitions.lib, which we do using this pragma.
  // Your own project should not be affected, as you are likely to link with a newer binary of GLFW that is adequate for your version of Visual Studio.
  #if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
  #pragma comment(lib, "legacy_stdio_definitions")
  #endif
  
  static void glfw_error_callback(int error, const char* description)
  {
      fprintf(stderr, "Glfw Error %d: %s\n", error, description);
  }
  
  int main(int, char**)
  {
      // Setup window
      glfwSetErrorCallback(glfw_error_callback);
      if (!glfwInit())
          return 1;
  
      // Decide GL+GLSL versions
  #if defined(IMGUI_IMPL_OPENGL_ES2)
      // GL ES 2.0 + GLSL 100
      const char* glsl_version = "#version 100";
      glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
      glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
      glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
  #elif defined(__APPLE__)
      // GL 3.2 + GLSL 150
      const char* glsl_version = "#version 150";
      glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
      glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
      glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
      glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // Required on Mac
  #else
      // GL 3.0 + GLSL 130
      const char* glsl_version = "#version 130";
      glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
      glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
      //glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);  // 3.2+ only
      //glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);            // 3.0+ only
  #endif
  
      // Create window with graphics context
      GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+OpenGL3 example", NULL, NULL);
      if (window == NULL)
          return 1;
      glfwMakeContextCurrent(window);
      glfwSwapInterval(1); // Enable vsync
  
      // Setup Dear ImGui context
      IMGUI_CHECKVERSION();
      ImGui::CreateContext();
      ImGuiIO& io = ImGui::GetIO(); (void)io;
      //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
      //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
  
      // Setup Dear ImGui style
      ImGui::StyleColorsDark();
      //ImGui::StyleColorsClassic();
  
      // Setup Platform/Renderer backends
      ImGui_ImplGlfw_InitForOpenGL(window, true);
      ImGui_ImplOpenGL3_Init(glsl_version);
  
      // Load Fonts
      // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them.
      // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple.
      // - If the file cannot be loaded, the function will return NULL. Please handle those errors in your application (e.g. use an assertion, or display an error and quit).
      // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call.
      // - Read 'docs/FONTS.md' for more instructions and details.
      // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ !
      //io.Fonts->AddFontDefault();
      //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf"/*, 16.0f*/);
      //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf"/*, 15.0f*/);
      //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf"/*, 16.0f*/);
      //io.Fonts->AddFontFromFileTTF("../../misc/fonts/ProggyTiny.ttf"/*, 10.0f*/);
      //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, NULL, io.Fonts->GetGlyphRangesJapanese());
      //IM_ASSERT(font != NULL);
      
      // Our state
      bool show_demo_window = true;
      bool show_another_window = false;
      ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
  
      // Main loop
      while (!glfwWindowShouldClose(window))
      {
          // Poll and handle events (inputs, window resize, etc.)
          // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
          // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
          // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
          // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
          glfwPollEvents();
  
          // Start the Dear ImGui frame
          ImGui_ImplOpenGL3_NewFrame();
          ImGui_ImplGlfw_NewFrame();
          ImGui::NewFrame();
  
          // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
          if (show_demo_window)
              ImGui::ShowDemoWindow(&show_demo_window);
  
          // 2. Show a simple window that we create ourselves. We use a Begin/End pair to created a named window.
          {
              static float f = 0.0f;
              static int counter = 0;
  
              ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.
  
              ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)
              ImGui::Checkbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
              ImGui::Checkbox("Another Window", &show_another_window);
  
              ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
              ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color
  
              if (ImGui::Button("Button"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
                  counter++;
              ImGui::SameLine();
              ImGui::Text("counter = %d", counter);
  
              ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
              ImGui::End();
          }
  
          // 3. Show another simple window.
          if (show_another_window)
          {
              ImGui::Begin("Another Window", &show_another_window);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
              ImGui::Text("Hello from another window!");
              if (ImGui::Button("Close Me"))
                  show_another_window = false;
              ImGui::End();
          }
  
          // Rendering
          ImGui::Render();
          int display_w, display_h;
          glfwGetFramebufferSize(window, &display_w, &display_h);
          glViewport(0, 0, display_w, display_h);
          glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w);
          glClear(GL_COLOR_BUFFER_BIT);
          ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
  
          glfwSwapBuffers(window);
      }
  
      // Cleanup
      ImGui_ImplOpenGL3_Shutdown();
      ImGui_ImplGlfw_Shutdown();
      ImGui::DestroyContext();
  
      glfwDestroyWindow(window);
      glfwTerminate();
  
      return 0;
  }
  