// This is the main project file for VC++ application project 
// generated using an Application Wizard.

#include "stdafx.h"

#using <mscorlib.dll>

using namespace System;

/* The program opens a window, clears it to black,
then draws a box at the location of the mouse each time the
left button is clicked and dragged. The right button exits the program

The program also reacts correctly when the window is
moved or resized by clearing the new window to black*/

#include <math.h>
#include <glut.h>


/* globals */

GLsizei wh = 500, ww = 500; /* initial window size in integers*/
GLfloat size = 3.0;   /* half side length of square */


void drawSquare(int x, int y)
{

	  y=wh-y;
	  glColor3ub( (char) rand()%256, (char) rand()%256, (char) rand()%256);
	  glBegin(GL_POLYGON);
	 	   glVertex2f(x+size, y+size);
		    glVertex2f(x-size, y+size);
	 	   glVertex2f(x-size, y-size);
	    	glVertex2f(x+size, y-size);
	  glEnd();
	  glFlush();
}


/* rehaping routine called whenever window is resized
or moved */

void myReshape(int w, int h)
{

/* adjust viewport and clear */

	glViewport(0,0,w,h);
    glClearColor (0.0, 0.0, 0.0, 1.0);
   	glClear(GL_COLOR_BUFFER_BIT);
 	glFlush();
/* adjust clipping box */

   	glMatrixMode(GL_PROJECTION);
   	glLoadIdentity(); 
   	glOrtho(0.0, (GLdouble)w, 0.0, (GLdouble)h, -1.0, 1.0);
   	glMatrixMode(GL_MODELVIEW);
   	glLoadIdentity(); 
 
/* set global size for use by drawing routine */

	ww = w;
   	wh = h; 
}

void myinit(void)
{

   	glViewport(0,0,ww,wh);

/* Pick 2D clipping window to match size of screen window 
This choice avoids having to scale object coordinates
each time window is resized */

   	glMatrixMode(GL_PROJECTION);
   	glLoadIdentity(); 
   	glOrtho(0.0, (GLdouble) ww , 0.0, (GLdouble) wh , -1.0, 1.0);

/* set clear color to black and clear window */

   	glClearColor (0.0, 0.0, 0.0, 1.0);
	glClear(GL_COLOR_BUFFER_BIT);
	glFlush();

}

void mouse(int btn, int state, int x, int y)
{
    if(btn==GLUT_RIGHT_BUTTON && state==GLUT_DOWN)   exit(0);
	if(btn==GLUT_LEFT_BUTTON && state==GLUT_DOWN) glutPostRedisplay;
}

/* display callback required by GLUT 3.0 */

void display(void)
{}

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

   	glutInit(&argc,argv);
	glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
	glutCreateWindow("square");
   	myinit ();
   	glutReshapeFunc (myReshape);
   	glutMouseFunc (mouse);
   	glutMotionFunc(drawSquare);
	glutDisplayFunc(display);

   	glutMainLoop();

}