Missing GL version

To obtain the version of OpenGL (GL) in C++, you can use the following steps:

1. Include the necessary headers:

#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>

These headers provide the necessary functions and definitions for working with OpenGL.

1. Initialize the OpenGL context:

glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
glutInitWindowSize(800, 600);
glutCreateWindow("OpenGL Version Example");

The glutInit function initializes the GLUT library and passes the command-line arguments to it. The glutInitDisplayMode function sets the display mode for the window, specifying things like double buffering and depth buffering. The glutInitWindowSize function sets the initial size of the window. Finally, glutCreateWindow creates the window with the specified title.

1. Print the OpenGL version:

const GLubyte* version = glGetString(GL_VERSION);
std::cout << "OpenGL version: " << version << std::endl;

The glGetString function retrieves a string that describes the version of OpenGL supported by the current context. In this case, we are interested in the GL_VERSION parameter. The returned value is a const pointer to a string, which can be printed using std::cout.

1. Set up the display function:

void display()
{
    // Clear the color and depth buffers
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Set up the view and projection matrices
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45, 1, 1, 10);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(0, 0, 5, 0, 0, 0, 0, 1, 0);

    // Render your scene here

    // Swap the front and back buffers
    glutSwapBuffers();
}

This function is responsible for rendering the scene. It first clears the color and depth buffers using glClear. Then, it sets up the view and projection matrices using glMatrixMode, glLoadIdentity, gluPerspective, and gluLookAt. Finally, it renders the scene and swaps the front and back buffers using glutSwapBuffers.

1. Set up the main function:

int main(int argc, char argv)
{
    // Initialize GLUT and create the window
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(800, 600);
    glutCreateWindow("OpenGL Version Example");

    // Register the display function
    glutDisplayFunc(display);

    // Enter the main loop
    glutMainLoop();

    return 0;
}

The main function initializes GLUT, creates the window, registers the display function, and enters the main loop using glutMainLoop.

This is a basic outline of how to obtain the version of OpenGL in C++. You can customize the rendering and other aspects of the code to suit your needs.