Question

import gpdraw.*;
import javax.swing.*;
import java.lang.Math;


public class Koch2 extends JFrame {

SketchPad paper;
DrawingTool pen;

public Koch2() {

    paper = new SketchPad(600, 600);
    pen = new DrawingTool(paper);

}


public void drawKoch(double sL, int level, double length) {

int x = level - 1;
double y = length / 3;

double z = -1.5 * sL;


if (level < 1) {
    pen.up();
    pen.move(z, 0);
    pen.down();
    pen.setDirection(0);
    pen.forward(sL);
}
else {
    pen.up();
    pen.move(z, 0);
    pen.down();
    pen.setDirection(0);
    pen.forward(length / (Math.pow(3, length)));
    pen.setDirection(60);
    pen.forward(length / (Math.pow(3, length)));
    pen.turnRight(120);
    pen.forward(length / (Math.pow(3, length)));
    pen.turnLeft(60);
    pen.forward(length / (Math.pow(3, length)));
    pen.setDirection(60);
    pen.forward(length / (Math.pow(3, length)));
    pen.turnRight(120);
    pen.forward(length / (Math.pow(3, length)));
    pen.turnRight(120);
    pen.forward(length / (Math.pow(3, length)));
    pen.setDirection(60);
    pen.forward(length / (Math.pow(3, length)));
    pen.turnRight(120);
    pen.forward(length / (Math.pow(3, length)));
    pen.turnLeft(60);
    pen.forward(length / (Math.pow(3, length)));
    pen.setDirection(60);
    pen.forward(length / (Math.pow(3, length)));
    pen.turnRight(120);
    pen.forward(length / (Math.pow(3, length)));


    /*pen.setDirection(0);
    pen.forward(length / (Math.pow(3, length)));
    */

    drawKoch((sL), (x) , (y));

}



}

public static void main(String[] args) {

    new Koch2().drawKoch(300, 6, 300);
}
}

Which sections of this code are faulty? I am trying to figure out how to generate a single template curve and then repeat that many times to make the actual curve. I don’t need to make the actual snowflake just yet, that can wait until after I figure the curve out.

Answer 1

Assuming pen.forward(length / (Math.pow(3, length))); draws a straight line :

The formation of a Koch curve is recursive. To draw a level n Koch curve, you’ll need to draw four level (n-1) curves. The pseudo code for drawing Koch curves is like this:

drawKochCurve (length, level):
    if level = 0:
        drawStraightLine(length)
    else:
        drawKochCurve(length / 3, level - 1)
        turnLeft(60)
        drawKochCurve(length / 3, level - 1)
        turnRight(120)
        drawKochCurve(length / 3, level - 1)
        turnLeft(60)
        drawKochCurve(length / 3, level - 1)

In your code, I see there’s one recursive call. Instead of drawing straight lines, you need to draw smaller Koch curves. Draw Straight lines only at the base cases.