Hello Open GL

main.c

//
//  main.c
//  HelloOpenGL
//
//  Created by Andri Setiawan on 2/13/12.
//  Copyright 2012 Institut Teknologi Bandung. All rights reserved.
//


#include <stdlib.h>
#include <GLUT/glut.h>

int lastFrameTime = 0;

float boxX = 0.0f;

void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    if (lastFrameTime == 0)
    {
        lastFrameTime = glutGet(GLUT_ELAPSED_TIME);
    }
    
    int now = glutGet(GLUT_ELAPSED_TIME);
    int elapsedMilliseconds = now - lastFrameTime;
    float elapsedTime = elapsedMilliseconds / 1000.0f;
    lastFrameTime = now;
    
    int windowWidth = glutGet(GLUT_WINDOW_WIDTH);
    
    boxX += 512.0f * elapsedTime;
    if (boxX > windowWidth)
    {
        boxX -= windowWidth;
    }
    
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    glPushMatrix();
    glTranslatef(boxX, 0.0f, 0.0f);
    
    glBegin(GL_QUADS);
    glVertex2f(  0.0f,   0.0f);
    glVertex2f(128.0f,   0.0f);
    glVertex2f(128.0f, 128.0f);
    glVertex2f(  0.0f, 128.0f);
    glEnd();
    glPopMatrix();    
    
    glutSwapBuffers();
}

void reshape(int width, int height)
{
    glViewport(0, 0, width, height);
    
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluOrtho2D(0, width, 0, height);
    glMatrixMode(GL_MODELVIEW);
}

void idle(void)
{
    glutPostRedisplay();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    
    glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(640, 480);
    
    glutCreateWindow("GLUT Program");
    
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutIdleFunc(idle);
    
    glutMainLoop();
    return EXIT_SUCCESS;
}