OpenGL Test

//The headers
#include "SDL.h"
#include "SDL_opengl.h"

//Screen attributes
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;

//Event handler
SDL_Event event;

//The timer
class Timer
{
    private:
    //The clock time when the timer started
    int startTicks;

    //The ticks stored when the timer was paused
    int pausedTicks;

    //The timer status
    bool paused;
    bool started;

    public:
    //Initializes variables
    Timer();

    //The various clock actions
    void start();
    void stop();
    void pause();
    void unpause();

    //Gets the timer's time
    int get_ticks();

    //Checks the status of the timer
    bool is_started();
    bool is_paused();
};

bool init_GL()
{
    //Set clear color
    glClearColor(0, 0, 0, 0);

    //Set projection
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0, SCREEN_WIDTH, SCREEN_HEIGHT, 0, -1, 1);

    //Initialize modelview matrix
    glMatrixMode(GL_MODELVIEW);
    glEnable(GL_TEXTURE_2D);
    glLoadIdentity();

    //If there was any errors
    if (glGetError() != GL_NO_ERROR)
    {
        return false;
    }

    //If everything initialized
    return true;
}

bool init()
{
    //Initialize SDL
    if (SDL_Init(SDL_INIT_EVERYTHING) < 0)
    {
        return false;
    }

    //Create Window
    if (SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, 32, SDL_HWSURFACE | SDL_GL_DOUBLEBUFFER | SDL_OPENGL) == NULL)
    {
        return false;
    }

    //Initialize OpenGL
    if (init_GL() == false)
    {
        return false;
    }

    //Set caption
    SDL_WM_SetCaption("OpenGL Test", NULL);

    return true;
}

Timer::Timer()
{
    //Initialize the variables
    startTicks = 0;
}

void Timer::start()
{
    //Get the current clock time
    startTicks = SDL_GetTicks();
}

int Timer::get_ticks()
{
    //Return the current time minus the start time
    return SDL_GetTicks() - startTicks;
}

int main (int argc, char *argv[])
{
    //Quit flag
    bool quit = false;

    //Initialize
    if (init() == false)
    {
        return 1;
    }

    //The frame rate regulator
    Timer fps;

    //Wait for user exit
    while (quit == false)
    {
        //Start the frame timer
        fps.start();

        //While there are events to handle
        while (SDL_PollEvent(&event))
        {
            if (event.type == SDL_QUIT)
            {
                quit = true;
            }
        }

        //Clear the screen
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        //Render single quad on screen
        glLoadIdentity();
        glBegin(GL_QUADS);
            glVertex3f(0, 0, 0);
            glVertex3f(SCREEN_WIDTH, 0, 0);
            glVertex3f(SCREEN_WIDTH, SCREEN_HEIGHT, 0);
            glVertex3f(0, SCREEN_HEIGHT, 0);
        glEnd();

        //Update screen
        SDL_GL_SwapBuffers();

        //Cap the frame rate
        if (fps.get_ticks() < 1000 / 60)
        {
            SDL_Delay((1000 / 60) - fps.get_ticks());
        }
    }

    //Clean up
    SDL_Quit();

    return 0;
}