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

/* the viewport is 500x500 with the origin at (0,0) */
int Vx_min=0, Vx_max=500, Vy_min=0, Vy_max=500, Vz_min=0, Vz_max=0;


void init(void) 
{
   glClearColor (0.0, 0.0, 0.0, 0.0);
}

void display(void)
{
	glClear (GL_COLOR_BUFFER_BIT);   
	glColor3f(1.0,1.0,1.0);

	glBegin(GL_LINES);
	glVertex2d(100.0, 100.0);
	glVertex2d(400.0, 100.0);

	glVertex2d(400.0, 100.0);
	glVertex2d(400.0, 400.0);
	
	glVertex2d(400.0, 400.0);
	glVertex2d(100.0, 400.0);
	
	glVertex2d(100.0, 400.0);
	glVertex2d(100.0, 100.0);
	
	glEnd();

	glFlush ();
}

void reshape (int w, int h)
{
   glViewport (0, 0, (GLsizei) w, (GLsizei) h); 
   glMatrixMode (GL_PROJECTION);
   glLoadIdentity ();
   gluOrtho2D(Vx_min, Vx_max, Vy_min, Vy_max);
   glMatrixMode (GL_MODELVIEW);

}
void mouse(int button, int state, int x, int y)
{

   switch (button) {
      case GLUT_LEFT_BUTTON:
		  if (state == GLUT_DOWN) {
			printf("left mouse click\n");
			glutPostRedisplay();
		  }
         break;
      default:
         break;
   }
}

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
   glutInitWindowSize (Vx_max-Vx_min, Vy_max-Vy_min); 
   glutInitWindowPosition (100, 100);
   glutCreateWindow (argv[0]);
   
   init ();

   glutDisplayFunc(display); 
   glutReshapeFunc(reshape);
   glutMouseFunc(mouse);
   glutMainLoop();
   return 0;
}