need help drawing Sierpinski triangles using recursion

[dalearyous]

ok i understand the overall idea but i am having trouble finding the vertices (midpoints of each line) of a triangle. basically i am going to have the program draw a triangle then draw another triangle inside that one with the three midpoints (only upside down). once that one is created ill have 3 triangles around it that are also sierpinski triangles. if i can find each of the 3 triangles vertices then i can just repeat process because each time i draw a new triangle i have 3 more sierpinski triangles. if you post suggestions keep in mind im kinda noob with java.

[dalearyous]

// this program draws Sierpinski triangles every time you click the screen


import java.applet.*;
import java.awt.*;

public class Sierpinski extends Applet
{

    Graphics g;
    Point a1,b1,c1, a2,b2,c2, a3,b3,c3;

    int depth = 0;

    public void init()
    {
        setBackground(new Color(255,255,255));
        setBackground( Color.black );
    }

// this handles the mouse operations, every time you left click it steps up one depth
// every time you right click it steps down one depth
    public boolean mouseDown(Event click, int x, int y)
    {
        if (!click.metaDown()) depth += 1;
        else if (depth>0) depth -= 1;
        repaint();
        return true;
    }

// draws first triangle
    public void paint(Graphics tri)
    {
        tri.setColor( Color.YELLOW );
        // tri.setColor(new Color(-16777216));
        int xCoords[] = {10, 390, 200};
        int yCoords[] = {390, 390, 10};
        tri.drawPolygon(xCoords, yCoords, 3);

        drawTriangle(tri, new Point(10,390),new Point(390,390),new Point(200,10), depth);
    }

    public void fillPolygon()
    {

    }

// i know the coordinates were supposed to be passed in as an array but here is the draw method
    public void drawTriangle(Graphics g, Point a, Point b, Point c, int depth)
    {
        if (depth==0) return;

        depth -= 1;

// did the array here because i couldn't get it to work if i initialize it at beginning
        int xCoords[] = {c.x, (c.x+b.x)/2, (a.x+c.x)/2};
        int yCoords[] = {b.y, (c.y+a.y)/2, (c.y+a.y)/2};

        g.drawPolygon(xCoords, yCoords, 3);

        a1 = a;
        b1 = new Point(c.x, b.y);
        c1 = new Point((a.x+c.x)/2, (c.y+a.y)/2);
        drawTriangle(g, a1, b1, c1, depth);

        a2 = new Point(c.x, b.y);
        b2 = b;
        c2 = new Point((c.x+b.x)/2, (c.y+a.y)/2);
        drawTriangle(g, a2, b2, c2, depth);

        a3 = new Point((a.x+c.x)/2, (c.y+a.y)/2);
        b3 = new Point((c.x+b.x)/2, (c.y+a.y)/2);
        c3 = c;
        drawTriangle(g, a3, b3, c3, depth);
    }
}

ok i finished it. that does exactly what i want except, i want each triangle to be a random color. any help?

[dalearyous]

nevermind i got it

[John]

Can you post your final code?