Confused about how to use paint()

Question

Hi, I have been working really hard to try to get the following program to work but I am really confused on how to use paint(). I do not have anyone to ask so I thought this forum could help. Anyways, here is my problem...
I am trying to recursively figure out the Sierpinski fractal. I cannot figure out if my math works or not because I do not know how to call the paint() recursively to draw my triangles.
Please have a look at the following code. Thank you!
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
public class DrawTriangle extends Frame {
  Point a = new Point(20,480),
        b = new Point(350,40),
        c = new Point(680,480),
        halfB,
        halfC,
        halfB2,
        halfC2,
        halfC3;
  int width;
  public DrawTriangle() {
    super("Sierpinski Fractal");
    addWindowListener( new WindowAdapter() {
      public void windowClosing( WindowEvent we ) {
        dispose();
        System.exit( 0 );
    setBackground( Color.white );
    setSize(700, 500);
    setVisible(true);
  public void paint(Graphics g, Point a, Point b, Point c) {
    width = c.x - a.x;
    if (width < 6){return;}
    g.setColor( Color.GREEN );
    g.drawPolygon( new int[] { a.x, b.x, c.x }, new int[] { a.y, b.y, c.y }, 3 );
    halfC.x = c.x/2;
    halfC.y = c.y;
    halfB.y = b.y/2;
    halfB.x = b.x;
    halfB2.y = halfB.y + a.y;
    halfB2.x = a.x;
    halfC2.x = halfC.x + a.x;
    halfC2.y = a.y;
    halfC3.x = halfC.x/2 + a.x;
    halfC3.y = halfB2.y;
    paint(g, a, halfC, halfB);
    paint(g, halfC3, halfC, halfB);
    paint(g, halfC2, halfC, halfB);
  public static void main(String[] args) {
     new DrawTriangle();

Answer 1

thanks jsalonen, your tip let me start working on the math to correct it.
I have a new problem now. My math is correct but I am having problems with the recursion. I can draw only the top , left , or right triangles. I cannot get them all to work together. See code and comments below.
Any ideas why I cant call all three of the paint()s toegther and have them work?
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
public class DrawTriangle extends Frame {
  Point a = new Point(20,480),
        b = new Point(350,40),
        c = new Point(680,480),
        halfA,
        halfB,
        halfC;
  int width;
  public DrawTriangle() {
    super("Sierpinski Fractal");
    addWindowListener( new WindowAdapter() {
      public void windowClosing( WindowEvent we ) {
        dispose();
        System.exit( 0 );
    setBackground( Color.white );
    setSize(700, 500);
    setVisible(true);
  public void paint(Graphics g)
  paint(g, a, b, c);
  public void paint(Graphics g, Point a, Point b, Point c) {
    width = c.x - a.x;
    if (width < 6){return;}
    halfA = new Point((a.x+b.x)/2, (a.y+b.y)/2);
    halfB = new Point((a.x+c.x)/2, (a.y+c.y)/2);
    halfC = new Point((b.x+c.x)/2, (b.y+c.y)/2);
    g.setColor( Color.GREEN ); //draw left triangle in green
    g.drawPolygon( new int[] { a.x, halfA.x, halfB.x }, new int[] { a.y, halfA.y, halfB.y }, 3 );
    g.setColor( Color.RED ); //draw top triangle in red
    g.drawPolygon( new int[] { b.x, halfA.x, halfC.x }, new int[] { b.y, halfA.y, halfC.y }, 3 );
    g.setColor( Color.BLUE ); //draw right triangle in blue
    g.drawPolygon( new int[] { c.x, halfB.x, halfC.x }, new int[] { c.y, halfB.y, halfC.y }, 3 );
    /*If you were to comment our two of these paint() calls the one will work correctly alone.
     *But my problem is that they do not work together! */
    //g, left point, top point, right point
    paint(g, halfA, b, halfC); //top triangle
    paint(g, halfC, halfB, c); //right triangle
    paint(g, a, halfA, halfB); //left triangle
  public static void main(String[] args) {
     new DrawTriangle();
}