Bare bones GLFW + Dear Imgui

main.cpp

#include <GL/glew.h>
#include <GLFW/glfw3.h>

#include "dear imgui/imgui.h"
#include "dear imgui/imgui_impl_glfw.h"
#include "dear imgui/imgui_impl_opengl3.h"

// Automatically link in the GLFW and GLEW libraries if compiling on MSVC++
#ifdef _MSC_VER
#pragma comment(lib, "glew32")
#pragma comment(lib, "glfw3") // https://github.com/glfw/glfw/releases/download/3.3.2/glfw-3.3.2.bin.WIN64.zip
#endif

#include <stdio.h>

#if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
#pragma comment(lib, "legacy_stdio_definitions")
#endif

GLFWwindow* main_window;

bool lmb_down = false;
bool mmb_down = false;
bool rmb_down = false;
GLuint mouse_x = 0;
GLuint mouse_y = 0;

static void glfw_error_callback(int error, const char* description)
{
    fprintf(stderr, "Glfw Error %d: %s\n", error, description);
}


void cursor_position_callback(GLFWwindow* window, double xpos, double ypos)
{
    int prev_mouse_x = mouse_x;
    int prev_mouse_y = mouse_y;

    mouse_x = xpos;
    mouse_y = ypos;

    if (ImGui::IsAnyWindowHovered())
        return;

    int mouse_delta_x = mouse_x - prev_mouse_x;
    int mouse_delta_y = prev_mouse_y - mouse_y;

    if (true == lmb_down && (0 != mouse_delta_x || 0 != mouse_delta_y))
    {
    }
    else if (true == rmb_down && (0 != mouse_delta_y))
    {
    }
}

void mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
{
    if (ImGui::IsAnyWindowHovered())
        return;

    if (GLFW_MOUSE_BUTTON_LEFT == button)
    {
        if (action == GLFW_PRESS)
            lmb_down = true;
        else
            lmb_down = false;
    }
    else if (GLFW_MOUSE_BUTTON_MIDDLE == button)
    {
        if (action == GLFW_PRESS)
            mmb_down = true;
        else
            mmb_down = false;
    }
    else if (GLFW_MOUSE_BUTTON_RIGHT == button)
    {
        if (action == GLFW_PRESS)
            rmb_down = true;
        else
            rmb_down = false;
    }
}




void generate_cancel_button_func(void)
{
}



int main(int, char**)
{
    // Setup window
    glfwSetErrorCallback(glfw_error_callback);
    if (!glfwInit())
        return 1;

    // Decide GL+GLSL versions

    // GL 3.0 + GLSL 130
    const char* glsl_version = "#version 430 core";
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);

    GLFWmonitor* monitor = glfwGetPrimaryMonitor();
    const GLFWvidmode* mode = glfwGetVideoMode(monitor);

    // Create window with graphics context
    main_window = glfwCreateWindow(mode->width, mode->height, "Julia 4D 3 Multithreaded", NULL, NULL);
    if (main_window == NULL)
        return 1;

    glfwMakeContextCurrent(main_window);
    glfwSwapInterval(1); // Enable vsync

    bool err = glewInit() != GLEW_OK;

    if (err)
    {
        fprintf(stderr, "Failed to initialize OpenGL loader!\n");
        return 1;
    }


    // Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableSetMousePos;     // Enable Keyboard Controls
    //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls
    io.WantCaptureMouse = true;

    glfwSetCursorPosCallback(main_window, cursor_position_callback);
    glfwSetMouseButtonCallback(main_window, mouse_button_callback);

    // Setup Dear ImGui style
    ImGui::StyleColorsDark();
    //ImGui::StyleColorsClassic();

    // Setup Platform/Renderer bindings
    ImGui_ImplGlfw_InitForOpenGL(main_window, true);
    ImGui_ImplOpenGL3_Init(glsl_version);

    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

    // Main loop
    while (!glfwWindowShouldClose(main_window))
    {        
        glfwPollEvents();

        // Start the Dear ImGui frame
        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

		{
			ImGui::SetNextWindowSize(ImVec2(400,500));

			ImGui::Begin("Controls");                          // Create a window called "Hello, world!" and append into it.

            if (ImGui::Button("Generate mesh"))                            // Buttons return true when clicked (most widgets return true when edited/activated)
				generate_cancel_button_func();

            ImGui::End();
        }

        // Rendering
        ImGui::Render();
        int display_w, display_h;
        glfwGetFramebufferSize(main_window, &display_w, &display_h);
        glViewport(0, 0, display_w, display_h);

 
        glClearColor(1, 0.5f, 0, 1);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glDisable(GL_BLEND);

        const GLfloat black[] = { 0.0f, 0.0f, 0.0f, 0.0f };
        static const GLfloat one = 1.0f;
        static const GLenum draw_buffers[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 };

        glViewport(0, 0, display_w, display_h);

		ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

        glfwSwapBuffers(main_window);
    }

    // Cleanup
    ImGui_ImplOpenGL3_Shutdown();
    ImGui_ImplGlfw_Shutdown();
    ImGui::DestroyContext();

    glfwDestroyWindow(main_window);
    glfwTerminate();

    return 0;
}