hello world gl

CMakeLists.txt

cmake_minimum_required(VERSION 3.10)

# Set the project name
project(HelloWorldOpenGL)

# Find the required packages
find_package(OpenGL REQUIRED)
find_package(GLU REQUIRED)
find_package(GLEW REQUIRED)
find_package(PkgConfig REQUIRED)
pkg_search_module(GLFW REQUIRED glfw3)

# Add the executable
add_executable(hello_world_opengl hello_world_opengl.c)

# Link the libraries
target_link_libraries(hello_world_opengl PRIVATE OpenGL::GLU GLEW::GLEW ${GLFW_LIBRARIES})
target_include_directories(hello_world_opengl PRIVATE ${GLFW_INCLUDE_DIRS})
target_link_directories(hello_world_opengl PRIVATE ${GLFW_LIBRARY_DIRS})

hello_world_opengl.c

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

// Error callback function for GLFW
void error_callback(int error, const char* description)
{
    std::cerr << "Error: " << description << std::endl;
}

// Key callback function for GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GLFW_TRUE);
}

int main()
{
    // Initialize the library
    if (!glfwInit())
    {
        std::cerr << "Failed to initialize GLFW" << std::endl;
        return -1;
    }

    // Set the error callback
    glfwSetErrorCallback(error_callback);

    // Create a windowed mode window and its OpenGL context
    GLFWwindow* window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
    if (!window)
    {
        std::cerr << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }

    // Make the window's context current
    glfwMakeContextCurrent(window);

    // Initialize GLEW
    GLenum err = glewInit();
    if (GLEW_OK != err)
    {
        std::cerr << "Error: " << glewGetErrorString(err) << std::endl;
        glfwTerminate();
        return -1;
    }

    // Set the key callback
    glfwSetKeyCallback(window, key_callback);

    // Loop until the user closes the window
    while (!glfwWindowShouldClose(window))
    {
        // Render here
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // Set up the model-view matrix
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();

        // Apply transformations
        gluLookAt(0.0, 0.0, 5.0,  // Eye position
                  0.0, 0.0, 0.0,  // Center position
                  0.0, 1.0, 0.0); // Up vector

        // Render a simple triangle
        glBegin(GL_TRIANGLES);
        glColor3f(1.0f, 0.0f, 0.0f);
        glVertex3f(-0.5f, -0.5f, 0.0f);
        glColor3f(0.0f, 1.0f, 0.0f);
        glVertex3f(0.5f, -0.5f, 0.0f);
        glColor3f(0.0f, 0.0f, 1.0f);
        glVertex3f(0.0f, 0.5f, 0.0f);
        glEnd();

        // Swap front and back buffers
        glfwSwapBuffers(window);

        // Poll for and process events
        glfwPollEvents();
    }

    glfwDestroyWindow(window);
    glfwTerminate();
    return 0;
}