Sierpiinski Triangle / Gasket

SierpiinskiTriangle.java 

import java.awt.*;

import java.applet.*;

/*

<applet code=SierpiinskiTriangle height=300 width=500>

</applet>

*/

public class SierpiinskiTriangle extends Applet 

{

public SierpiinskiTriangle(){

}

public void paint(Graphics g){

super.paint(g);

int x[] = { 50 ,0,100}; 

int y[] = {  0 ,100,100};

g.setColor(Color.black);

g.fillPolygon (x, y, 3);

for(int i=0;i<5;i++){

int x1[] = { 150+(i*100) ,100+(i*100),200+(i*100)}; 

int y1[] = { 0 ,100,100};

g.setColor(Color.black);

g.fillPolygon (x1, y1, 3);

g.setColor(Color.white);

makeTriangle(g, x1[0],y1[0], x1[1], y1[1], x1[2], y1[2], i);

}

 

}

public void makeTriangle(Graphics g, int x1, int y1, int x2, int y2, int x3, int y3, int level) {

      // Compute the points

      int[] xPoints = new int[3];

      int[] yPoints = new int[3];

      int xMid12;

      int xMid23;

      int xMid31;

      int yMid12;

      int yMid23;

      int yMid31;

      // Compute midpoints of triangle sides

      xMid12 = (x1 + x2) / 2;

      xMid23 = (x2 + x3) / 2;

      xMid31 = (x3 + x1) / 2;

      yMid12 = (y1 + y2) / 2;

      yMid23 = (y2 + y3) / 2;

      yMid31 = (y3 + y1) / 2;

      xPoints[0] = xMid12;

      xPoints[1] = xMid23;

      xPoints[2] = xMid31;

      yPoints[0] = yMid12;

      yPoints[1] = yMid23;

      yPoints[2] = yMid31;

      // Fill the triangle

      g.fillPolygon(xPoints, yPoints, 3);

      // Recursively draw three smaller triangles if level > 0

      if (level > 0) {

        g.setColor(Color.white);

        makeTriangle(g, x1, y1, xMid12, yMid12, xMid31, yMid31, level - 1);

        makeTriangle(g, xMid12, yMid12, x2, y2, xMid23, yMid23, level - 1);

        makeTriangle(g, xMid31, yMid31, xMid23, yMid23, x3, y3, level - 1);

      }

}

}