check_version.cpp

#include <GL\glew.h>        // the opengl library wrapped by extended features
#include <GL\freeglut.h>    // library cross-platform toolkit windows and managing input operations

#include <iostream>
#include <sstream>

using namespace std;

/**
* analyse the version
*/
string makeMeString (GLint versionRaw) {
    stringstream ss;
    ss << versionRaw; // transfers versionRaw value into 'ss'
    return ss.str ();
}

/**
 * Format the string as expected
 */
void formatMe (string *text) {
    string dot = ".";
    
    text->insert (1, dot); // transforms 30000 into 3.0000
    text->insert (4, dot); // transforms 3.0000 into 3.00.00
}

/**
 * Message
 */
void consoleMessage () {
    char *versionGL;
    /* there is some error when checking glut version.
     * so I commented it for now.
     */
    // GLint versionFreeGlutInt;
    
    versionGL = (char*) (glGetString (GL_VERSION));
    // versionFreeGlutInt = (glutGet (GLUT_VERSION));
    
    // string versionFreeGlutString = makeMeString (versionFreeGlutInt);
    // formatMe (&versionFreeGlutString);
    
    cout << endl;
    cout << "OpenGL version: " << versionGL << endl << endl;
    // cout << "FreeGLUT version: " << versionFreeGlutString << endl << endl;
    
    cout << "GLEW version: "
         << GLEW_VERSION << "."
         << GLEW_VERSION_MAJOR << "."
         << GLEW_VERSION_MINOR << "."
         << GLEW_VERSION_MICRO << endl;
}

/**
 * Manager error
 */
void managerError () {
    if (glewInit ()) { // checks if glewInit() is activated
        cerr << "Unable to initialize GLEW." << endl;
        while (1); // let's use this infinite loop to check the error message before closing the window
        exit (EXIT_FAILURE);
    }
    // FreeConsole();
}

/**
 * Manage display (to be implemented)
 */
void managerDisplay ()
{
    glClear (GL_COLOR_BUFFER_BIT); // clear the screen
    glutSwapBuffers ();
}


/**
 * Initialize FREEGLUT
 */
void initFreeGlut (int ac, char *av[]) {
    // A. init
    glutInit (&ac, av);                            // 1. inits glut with arguments from the shell
    glutInitDisplayString ("");                    // 2a. sets display parameters with a string (obsolete)
    glutInitDisplayMode (GLUT_SINGLE);             // 2b. sets display parameters with defines
    glutInitWindowSize (600, 600);                 // 3. window size
    
    /* these lines produce error */
    // glutInitContextVersion (3, 3);              // 4. sets the version 3.3 as current version (so some functions of 1.x and 2.x could not work properly)
    // glutInitContextProfile (GLUT_CORE_PROFILE); // 5. sets the version 3.3 for the profile core
    glutInitWindowPosition (500, 500);             // 6. distance from the top-left screen
    
    // B. create window
    glutCreateWindow ("BadproG - Hello world :D"); // 7. message displayed on top bar window
}

/**
 * Manage keyboard
 */
void managerKeyboard (unsigned char key, int x, int y) {
    if (key == 27) // 27 = ESC key
        exit(0);
}

/**
 * Main, what else?
 */
int main (int argc, char** argv) {
    initFreeGlut (argc, argv); // inits freeglut
    managerError (); // manages errors
    consoleMessage (); // displays message on the console
    
    // C. register the display callback function
    glutDisplayFunc (managerDisplay); // 8. callback function
    glutKeyboardFunc (managerKeyboard);
    
    // D. main loop
    glutMainLoop (); // 9. infinite loop
    return 0;
}