/*
1. Compile and run this code.  

2. Reshape your window.  What happens?  Does the entire polygon get rendered?  Is 
it still square?

3. Create (and enable the use of) a reshape function which:
	- adjusts the pixel rectangle for drawing to be the entire new window, this
	  is your  glViewport  call.
	- adjusts the clipping volume so the lower-left corner is 0,0, and the
	  upper right is w,h , this is your call to  gluOrtho2D  .
So, your new reshape should preserve the aspect ratio of the polygon (it stays
square), but the polygon might might get clipped if the new window is smaller than 200
pixels wide and 200 pixels tall.

4. Finally, modify the projection (what you do with gluOrtho2D) in your reshape
function so it preserves the aspect ratio of the original polygon, and renders
the entire polygon to the new window.

5. Update your code from #4 above so that the polygon is always centered in the
resized window.
*/

#include <GL/glut.h>
#include <iostream>
using namespace std;

#define WINDOW 400

void myInit()
{
	glClearColor(1.0,1.0,1.0,0.0);
	glColor3f(0.0,0.0,0.0);

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0,400,0,400);
	glMatrixMode(GL_MODELVIEW);
}

void reshape (GLint w, GLint h)
{
	
}

void display()
{
	glClear(GL_COLOR_BUFFER_BIT);

	glBegin(GL_POLYGON);
		glVertex2f(100,100);
		glVertex2f(300,100);
		glVertex2f(300,300);
		glVertex2f(100,300);
	glEnd();


	glFlush();
}


int main (int argc , char **argv)
{
	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowSize(WINDOW,WINDOW);
	glutInitWindowPosition(100.0,100.0);
	glutCreateWindow("Reshape");
	glutDisplayFunc(display);
//	glutReshapeFunc(reshape);
	myInit();
	glutMainLoop();

	return 0;
}