/************************************************************* 
        Simplest OpenGL Program 

        H. Masterman  19 September 2000
		modified every year since then, and in class
************************************************************/


#include <glut.h>  // automatically includes GL.h and glu.h
#include <freeglut_ext.h>  // added to include some extensions in freeglut
#include <iostream>  // so we can do some output to the console
using namespace std;  //so we can use cout function

void myinit(void)
{
 
/* Set up attributes */

glClearColor(0.0, 0.0, 0.0, 0.0); /* black background */

/* set up viewing projection*/
/* 500 x 500 window with origin lower left */

glMatrixMode(GL_PROJECTION);  //set up camera for parallel (orthographic) projection
glLoadIdentity();
glOrtho(0.0, 500.0, 0.0, 500.0,0.0, 500.0);  // set up 500 x 500 coordinate system
glMatrixMode(GL_MODELVIEW);  //restore matrix pointer to MODELVIEW

}

void display( void ) 

{

glClear(GL_COLOR_BUFFER_BIT);  //clear the window 

//set attributes

glColor3f(1.0, 0.0, 0.0); // set color
glLineWidth(1.0);
glPointSize(4.0);

//draw a polygon in immediate mode
glBegin(GL_POLYGON);

        glVertex2f(250, 250);  
        glVertex2f(100,100);
		glVertex2f(375, 56);

glEnd();
  
//print some text information to the console

	cout<<"executing display()"<<endl; //just to show when display() is being called
	cout<<"The version is: "<<glGetString(GL_VERSION)<<endl;
	cout<<"The vendor is: "<<glGetString(GL_VENDOR)<<endl;
	cout<<"The renderer is: "<<glGetString(GL_RENDERER)<<endl;


 glFlush(); 
 }

void main(int argc, char** argv)
{

/* Standard GLUT initialization */

    glutInit(&argc,argv); //initialize GLUT
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); /* default, not needed */
    glutInitWindowSize(700,700); /* 500 x 500 pixel window */
    //glutInitWindowPosition(0,0); /* place window top left on display */
	//glutInitContextVersion (3,3);
	glutInitContextFlags(GLUT_CORE_PROFILE);
	glutCreateWindow("Hello World OpenGL Program"); /* window title */
    glutDisplayFunc(display); /* display callback invoked when window opened */
	
    myinit(); /* set attributes, viewing parameters */

    glutMainLoop(); /* enter event loop */
}