#include <stdlib.h>

#include <GL/glut.h>

void display(void)
{
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    glBegin(GL_QUADS);
    glVertex2f(  0.0f,   0.0f);
    glVertex2f(128.0f,   0.0f);
    glVertex2f(128.0f, 128.0f);
    glVertex2f(  0.0f, 128.0f);
    glEnd();
	    
    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;
}