//#include <windows.h>   // use as needed for your system
#include <GL/gl.h>
#include <GLUT/glut.h>

class GLintPoint{
public: 
		GLint x, y;
};
int counter=0;
const int screenWidth = 640;	   // width of screen window in pixels 
const int screenHeight = 480;	   // height of screen window in pixels

//<<<<<<<<<<<<<<<<<<<<<<< myInit >>>>>>>>>>>>>>>>>>>>
 void myInit(void)
 {
    glClearColor(1.0,1.0,1.0,0.0);       // set white background color
    glColor3f(0.0f, 0.0f, 0.0f);          // set the drawing color 
 	glPointSize(4.0);		       // a ‘dot’ is 4 by 4 pixels
	glMatrixMode(GL_PROJECTION); 
	glLoadIdentity();
	gluOrtho2D(0.0, 640.0, 0.0, 480.0);
}
//<<<<<<<<<<<<<<<<<<<<<<<< myDisplay >>>>>>>>>>>>>>>>>
void myDisplay(void)
{
	glClear(GL_COLOR_BUFFER_BIT);     // clear the screen 
	glFlush();		                 // send all output to display 
}
void myMouse(int button, int state, int x, int y)
{
     static GLintPoint corner[2];
    static int numCorners = 0;		         // initial value is 0
    if(button == GLUT_LEFT_BUTTON && state == GLUT_DOWN)
	 {
		  corner[numCorners].x = x;
			 corner[numCorners].y = screenHeight - y;    // flip y coordinate
		  numCorners++;		                     // have another point
		  if(numCorners == 2)
		  {

		    glRecti(corner[0].x, corner[0].y, corner[1].x, corner[1].y);
			    numCorners = 0;				   // back to 0 corners
		  }
	 }
	 else if(button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN)
	glClear(GL_COLOR_BUFFER_BIT);	         // clear the window
	 glFlush();
}



//<<<<<<<<<<<<<<<<<<<<<<<< main >>>>>>>>>>>>>>>>>>>>>>
int main(int argc, char** argv)
{
	glutInit(&argc, argv);          // initialize the toolkit
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display mode
	glutInitWindowSize(640,480);     // set window size
	glutInitWindowPosition(100, 150); // set window position on screen
	glutCreateWindow("mouse interaction"); // open the screen window
	glutMouseFunc(myMouse);     // register redraw function
	glutDisplayFunc(myDisplay);     // register redraw function
	myInit();                   
	glutMainLoop(); 		     // go into a perpetual loop
	return 0;
}