Sierpinski's Triangle

Code for Sierpinski's Triangle

// appropriate includes here
#include <GL.h>
#include <glut.h>
#include <stdlib.h>



class GLintPoint{
public:
	GLint x, y;
};

// function prototypes
void myInit(void);
void myDisplay(void);
void Sierpinski(void);
void drawDot(void);
int random(int);


int x, y ;


//<<<<<<<<<<<<<<< myinit >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
void myInit(void)
{
	glClearColor(1.0, 1.0, 1.0, 0.0) ; // set white background color
	glColor3f(1.0f, 0.0f, 0.5f) ; // set the drawing color
	glPointSize(2.0) ; // a dot is 2 by 2 pixels
	glMatrixMode (GL_PROJECTION) ;
	glLoadIdentity () ;
	gluOrtho2D(0.0, 640.0, 0.0, 480.0) ;
}



//<<<<<<<<<<<<<<< drawDot >>>>>>>>>>>>>>>>>>>>>>>>>>>>
void drawDot()
{
	glBegin(GL_POINTS) ;
	
		glVertex2i(x, y) ; //draw  point
	glEnd() ;
	glFlush() ; //send all output to displau
}

//<<<<<<<<<<<<<<< random >>>>>>>>>>>>>>>>>>>>>>>>>>>>
int random(int m)
{
	return rand()%m;
}


//<<<<<<<<<<<<<<< Sierpinski >>>>>>>>>>>>>>>>>>>>>>>>>>>>

void Sierpinski(void) 
{
	GLintPoint T[3]= {{50,50},{600,50},{600, 400}};
	//int x, y ;	
	int index = random(3);         // 0, 1, or 2 equally likely 
	GLintPoint point = T[index]; 	 // initial point
	//x = point.x;
	//y = point.y;
	
	drawDot();     // draw initial point 
	for(int i = 0; i < 10000; i++)  // draw 1000 dots
	{
		 index = random(3); 	
		 point.x = (point.x + T[index].x) / 2;
		 point.y = (point.y + T[index].y) / 2;
		 x = point.x;
		 y = point.y;
		 drawDot();  
	} 
	glFlush(); 	
}


//<<<<<<<<<<<<<< main >>>>>>>>>>>>>>>>>>>>>>>>>>>>
void main(int argc, char** argv)
{

	glutInit(&argc, argv) ; //initializes the toolkit
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB) ; //set the display mode
	glutInitWindowSize(640, 480) ; //  setwindow size
	glutCreateWindow("my first attempt"); // open the screen window 
	glutDisplayFunc(drawDot) ; // register the redraw functions

	
	myInit(); //additional initializations as necessary
	glClear(GL_COLOR_BUFFER_BIT) ; //clear the screen
	
	Sierpinski();
	glutMainLoop() ; // go into a perpetual loop
	

}