Lecture #1
==========

This lecture gives a basic introduction to configuring the `Arduino <https://www.arduino.cc/>`_ board on Linux,
as well as programming and uploading sketches on it.
We also study our very first OpenGL
example that opens a window when the program is run. The window closes upon
pressing the ``ESC`` key. All OpenGL examples dicussed in CS 428 have been
inspired by this `source <https://learnopengl.com/>`_.

| **Scribe Notes by Ryan Goldstein:** `Source1 <../scribe_notes/lecture1_notes_Ryan_Goldstein.md>`_ `PDF1 <../scribe_notes/lecture1_notes_Ryan_Goldstein.pdf>`_
| **Scribe Notes by Tavel Findlater:** `Source2 <../scribe_notes/lecture1_notes_Tavel_Findlater.docx>`_ `PDF2 <../scribe_notes/lecture1_notes_Tavel_Findlater.pdf>`_

::

    #include <GL/glew.h>
    #include <GLFW/glfw3.h>
    #include <iostream>
    
    void key_callback(GLFWwindow* window,int key,int scancode,int action,int mode)
    {
        if(key==GLFW_KEY_ESCAPE && action==GLFW_PRESS)
            glfwSetWindowShouldClose(window,GL_TRUE);
    }
    
    int main()
    {
        glfwInit();
    #if __APPLE__
        glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT,GL_TRUE);
    #endif
        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR,3);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR,3);
        glfwWindowHint(GLFW_OPENGL_PROFILE,GLFW_OPENGL_CORE_PROFILE);
        glfwWindowHint(GLFW_RESIZABLE,GL_FALSE);
    
        GLFWwindow *window=glfwCreateWindow(800,600,"Learn OpenGL",nullptr,nullptr);
        if(window==nullptr)
        {
            std::cout<<"Failed to create GLFW window!"<<std::endl;
            glfwTerminate();
            return -1;
        }
        glfwMakeContextCurrent(window);
    
        glewExperimental=GL_TRUE;
        if(glewInit()!=GLEW_OK)
        {
            std::cout<<"Failed to initialize GLEW!"<<std::endl;
            return -1;
        }
    
        int width,height;
        glfwGetFramebufferSize(window,&width,&height);
        glViewport(0,0,width,height);
    
        glfwSetKeyCallback(window,key_callback);
    
        while(!glfwWindowShouldClose(window))
        {
            glfwPollEvents();
    
            glClearColor(.2f,.3f,.3f,1.f);
            glClear(GL_COLOR_BUFFER_BIT);
    
            glfwSwapBuffers(window);
        }
        glfwTerminate();
    
        return 0;
    }

Save this file as ``main.cpp``. To compile the code, run the following command: ::

    g++ -O3 main.cpp -o window -lGLEW -lglfw -lGL -lX11 -lpthread -lXrandr -ldl -lXxf86vm -lXinerama -lXcursor -lrt -lm -std=c++11

This will create a binary ``window``, and now if you execute the following command: ::

    ./window

then you should see a new window (like the one shown below) pop-up on your screen:


.. image:: ../images/window.png
    :width: 32%
    :align: center

Execute the following command to run this code on Mac OS: ::

    g++ -O3 main.cpp -o window -lGLEW -lglfw -framework OpenGL -ldl -lm -std=c++11

If you're running this command for the very first time, you'll need to install some libraries. The following command may help on Linux: ::

    sudo apt-get install libglu1-mesa-dev libglew-dev libglfw3-dev libxrandr-dev libxxf86vm-dev libxinerama-dev libxcursor-dev

The following command may help on Mac OS: ::

    brew install glm freetype glfw3 glew pkg-config