First Samplle for OpenCV with ImGui

CMakeLists.txt

main.cpp

#include <iostream>
#include <opencv2/opencv.hpp>

#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl3.h"
#include <GL/gl3w.h>
#include <GLFW/glfw3.h>

int main( int argc, char* argv[] )
{
    cv::Mat image = cv::imread( "../lena.jpg", cv::IMREAD_COLOR );
    if( image.empty() ){
        return -1;
    }
    cv::cvtColor( image, image, cv::COLOR_BGR2RGBA );

    if( !glfwInit() ){
        return -1;
    }

    GLFWwindow* window = glfwCreateWindow( 800, 600, "glfw window", nullptr, nullptr );
    glfwSetWindowCloseCallback( window, []( GLFWwindow* window ){ glfwSetWindowShouldClose( window, GL_FALSE ); } );
    glfwMakeContextCurrent( window );
    glfwSwapInterval( 1 );
    gl3wInit();

    IMGUI_CHECKVERSION();
    ImGui::CreateContext();

    ImGui_ImplGlfw_InitForOpenGL( window, true );
    ImGui_ImplOpenGL3_Init( "#version 330" );

    bool is_show = true;
    while( is_show ){
        glfwPollEvents();
        glClearColor( 0.0f, 0.0f, 0.0f, 1.0f );
        glClear( GL_COLOR_BUFFER_BIT );

        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

        ImGui::Begin( "imgui image", &is_show );
        GLuint texture;
        glGenTextures( 1, &texture );
        glBindTexture( GL_TEXTURE_2D, texture );
        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
        glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
        glPixelStorei( GL_UNPACK_ROW_LENGTH, 0 );
        glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, image.cols, image.rows, 0, GL_RGBA, GL_UNSIGNED_BYTE, image.data );
        ImGui::Image( reinterpret_cast<void*>( static_cast<intptr_t>( texture ) ), ImVec2( image.cols, image.rows ) );
        ImGui::End();

        ImGui::Render();
        ImGui_ImplOpenGL3_RenderDrawData( ImGui::GetDrawData() );

        glfwSwapBuffers( window );
    }

    ImGui_ImplGlfw_Shutdown();
    ImGui_ImplOpenGL3_Shutdown();
    ImGui::DestroyContext();
    glfwTerminate();

    return 0;
}