modal

#include <imgui.h>
#include <imgui_impl_glfw.h>
#include <imgui_impl_opengl3.h>

#include <GLFW/glfw3.h>

#include <cstdio>

int main()
{
    const GLFWerrorfun glfwErrorFun = [](int error, const char* description)
        {
            fprintf(stderr, "Glfw Error %d: %s\n", error, description);
        };
    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
    // Setup
    glfwSetErrorCallback(glfwErrorFun);
    if (!glfwInit()) {
        return 1;
    }

    const char* glsl_version = "#version 130";
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);

    GLFWwindow* window = glfwCreateWindow(640, 480, "Dear ImGui test", nullptr, nullptr);
    if (window == nullptr) {
        puts("Cannot create window. Exiting.");
        return 1;
    }

    glfwMakeContextCurrent(window);
    glfwSwapInterval(1); // Enable Vsync

    // Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    auto& io = ImGui::GetIO();

    ImGui::StyleColorsDark();

    ImGui_ImplGlfw_InitForOpenGL(window, true);
    ImGui_ImplOpenGL3_Init(glsl_version);

    while(!glfwWindowShouldClose(window)) {
        glfwPollEvents();

        // Start new DearImGui frame
        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

        ImGui::Begin("Modal test"); {
            ImGui::TextUnformatted("Click button to open modal");
            if (ImGui::Button("Here")) {
                ImGui::OpenPopup("Open modal");
            }
        }

        static bool theBooleans = false;
        if (ImGui::BeginPopupModal("Open modal", nullptr, ImGuiWindowFlags_AlwaysAutoResize)) {
            ImGui::TextUnformatted("wow");
            ImGui::MenuItem("outside BeginMenu", nullptr, false);
            if (ImGui::BeginMenu("options...")) {
                ImGui::MenuItem("(options)", nullptr, false, false);
                if (ImGui::MenuItem("inside BeginMenu", nullptr, theBooleans)) {
                    theBooleans = !theBooleans;
                }
                ImGui::MenuItem("Inside BeginMenu 1", nullptr, false);
                ImGui::EndMenu();
            }
            ImGui::EndPopup();
        }

        ImGui::End();
        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();
    }
}