SIERPINSKI TRIANGLE

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package st;

import java.awt.Color;
import java.awt.Polygon;
import java.util.Scanner;
import javax.swing.JFrame;

/**
 *
 * @author aginta geniusa
 */

public class MAIN extends Sierpinski {
public static void main (String[] args)
    {
        // make the base triangle based on the window size
        //point 1 -- top
        int p1x = WINDOWSIZE/2;
        int p1y = WINDOWSIZE/20;
        //point 2 -- bottom right
        int p2x = WINDOWSIZE-p1y;
        int p2y = WINDOWSIZE-p1y;
        //point 3 -- bottom left
        int p3x = WINDOWSIZE/20;
        int p3y = WINDOWSIZE-p1y;

        // ask user berapa bagian ?
        Scanner keyboard = new Scanner(System.in);
        System.out.print("berapa bagian ? ");
        int splits = keyboard.nextInt();
        polyList = new Polygon[(int)Math.pow(3,splits-1)];


        // new window
        JFrame f = new JFrame("Sierpinski");
        f.setSize(WINDOWSIZE,WINDOWSIZE);
        f.setBackground(Color.white);
        f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        f.setVisible(true);

        drawTriangles(splits,p1x,p1y,p2x,p2y,p3x,p3y);

        Sierpinski s = new Sierpinski();
        f.add(s);
    }
}


--------------------------------------------------------------------------------------------------------
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package st;

/**
 *
 * @author aginta geniusa
 */
import java.awt.*;
import javax.swing.*;

public class Sierpinski extends JPanel{
    // set window size here
    // set window size here
    public static final int WINDOWSIZE = 500;

    // some static variables
    static Polygon[] polyList;
    static int count = 0;

    public static void drawTriangles(int splits, int ax, int ay, int bx, int by, int cx, int cy)
    {
        int[] p1 = {ax,ay};
        int[] p2 = {bx,by};
        int[] p3 = {cx,cy};

        if(splits == 1){
            //create basic triangle
            int[]xs={ax,bx,cx};
            int[]ys={ay,by,cy};
            Polygon p = new Polygon(xs,ys,xs.length);

            polyList[count] = p;
            count++;
        }
        else
        {
            //get midpoints for each side
            int[] p4 = getMidpoint(ax, ay, bx, by);
            int[] p5 = getMidpoint(bx, by, cx, cy);
            int[] p6 = getMidpoint(ax, ay, cx, cy);

            // 3 new triangles
            drawTriangles(splits - 1,p1[0],p1[1],p4[0],p4[1],p6[0],p6[1]);
            drawTriangles(splits - 1,p4[0],p4[1],p2[0],p2[1],p5[0],p5[1]);
            drawTriangles(splits - 1,p6[0],p6[1],p5[0],p5[1],p3[0],p3[1]);
        }
    }

    // returns the midpoint as an array [x,y] of any line given the coordinates
    public static int[] getMidpoint(int ax, int ay, int bx, int by)
    {
        int[] mid = new int[2];

        mid[0] = (ax + bx)/2;
        mid[1] = (ay + by)/2;

        return mid;
    }

    @Override
    public void paint(Graphics g)
    {
        for(int i = 0; i < polyList.length; i++)
        {
            g.fillPolygon(polyList[i]);
                        g.setColor(Color.red);
    }

    }
}