//#include <windows.h> // use proper includes for your system
#include <math.h>
#include <GL/gl.h>
#include <GLUT/glut.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.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
GLdouble A, B, C, D;  // values used for scaling and shifting
//<<<<<<<<<<<<<<<<<<<<<<< myInit >>>>>>>>>>>>>>>>>>>>
 void myInit(void)
 {
    glClearColor(1.0,1.0,1.0,0.0);       // background color is white
    glColor3f(0.0f, 0.0f, 0.0f);         // drawing color is black 
 	  glPointSize(2.0);		          // a 'dot' is 2 by 2 pixels
	  glMatrixMode(GL_PROJECTION); 	   // set "camera shape"
	  glDrawBuffer(GL_BACK);
	  glLoadIdentity();
	  gluOrtho2D(0.0, (GLdouble)screenWidth, 0.0, (GLdouble)screenHeight);
		 A = screenWidth / 4.0; // set values used for scaling and shifting
		 B = 0.0;
		 C = D = screenHeight / 2.0;
}


int random(int m)
{
 return rand()%m;
}

void drawDot(GLint x, GLint y)
{
     glVertex2d(x, y);
}
void Sierpinski(void) 
{
	GLintPoint T[3]= {{10,10},{300,30},{200, 300}};
	
	int index = random(3);         // 0, 1, or 2 equally likely 
	GLintPoint point = T[index]; 	 // initial point 
	drawDot(point.x, point.y);     // draw initial point 
	for(int i = 0; i < 4000; i++)  // draw 4000 dots
	{
		 index = random(3); 	
		 point.x = (point.x + T[index].x) / 2;
		 point.y = (point.y + T[index].y) / 2;
		 drawDot(point.x,point.y);  
	glFlush(); 	
	} 

}
//<<<<<<<<<<<<<<<<<<<<<<<< myDisplay >>>>>>>>>>>>>>>>>
void myDisplay(void)
{
	glClear(GL_COLOR_BUFFER_BIT);     // clear the screen 
	glBegin(GL_POINTS);
	Sierpinski(); 
	glEnd();	
	glFlush();		   // send all output to display 
}
//<<<<<<<<<<<<<<<<<<<<<<<< main >>>>>>>>>>>>>>>>>>>>>>
int main(int argc, char** argv)
{
	glutInit(&argc, argv);          // initialize the toolkit
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display mode
	glutInitWindowSize(screenWidth, screenHeight); // set window size
	glutInitWindowPosition(100, 150); // set window position on screen
	glutCreateWindow("Sierpinski"); // open the screen window
	glutDisplayFunc(myDisplay);     // register redraw function
	myInit();                   
	glutMainLoop(); 		     // go into a perpetual loop
	return 0;
}