What Is OpenGL?

OpenGL is a Graphics rendering API which is operating system independent, window system independent and has high-quality color images composed of geometric and image primitives. OpenGL APIs can use following -

1. GL
   • OpenGL API implementation (http://www.opengl.org)
2. GLU
   • OpenGL Utility
3. Glut
   • GLUT (OpenGL Utility Toolkit) – Glut is portable windowing API and it is not officially part of OpenGL.
   • OpenGL Utility Toolkit (http://www.opengl.org/resources/libraries/glut/)
4. FLTK
   • FlashLight ToolKit (http://www.fltk.org/)
5. GLEW

Now lets see how to install OpenGL in Ubuntu.

Now because GLUT (OpenGL Utility Toolkit) depends upon OpenGL and a number of other related libraries, if we install GLUT then OpenGL will be automatically be installed.

First update the repository using the given command

$ sudo apt-get update

Run the following command to install OpenGL.

$ sudo apt-get install libglu1-mesa-dev freeglut3-dev mesa-common-dev

Now to test if OpenGL libraries are working fine on our Linux machine, we will create a C++ program and test it.

So create a following C++ Program.

#include <GL/glut.h>

void displayMe(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glBegin(GL_POLYGON);
        glVertex3f(0.5, 0.0, 0.5);
        glVertex3f(0.5, 0.0, 0.0);
        glVertex3f(0.0, 0.5, 0.0);
        glVertex3f(0.0, 0.0, 0.5);
    glEnd();
    glFlush();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE);
    glutInitWindowSize(400, 300);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Hello world!");
    glutDisplayFunc(displayMe);
    glutMainLoop();
    return 0;
}

Now give the command below to compile your code.

$ g++ main.cpp -o firstOpenGlApp -lglut -lGLU -lGL

Now run your OpenGl program with following command

$ ./firstOpenGlApp

You will see something like this on your screen if everythings went well.