KochSnowflake.java

/**
 * Koch Snowflake implementation.
 */
public class KochSnowflake {
    private static final int ORDER = 6;

    public static void koch(double x1, double y1, double x2, double y2, int n) {
        if (n == 0) {
            StdDraw.line(x1, y1, x2, y2);
            return;
        }

        double dx = (x2 - x1) / 3.0;
        double dy = (y2 - y1) / 3.0;

        double xA = x1 + dx;
        double yA = y1 + dy;

        double xB = x1 + 2 * dx;
        double yB = y1 + 2 * dy;

        double xPeak = xA + (dx - Math.sqrt(3) * dy) / 2.0;
        double yPeak = yA + (dy + Math.sqrt(3) * dx) / 2.0;

        koch(x1, y1, xA, yA, n - 1);
        koch(xA, yA, xPeak, yPeak, n - 1);
        koch(xPeak, yPeak, xB, yB, n - 1);
        koch(xB, yB, x2, y2, n - 1);
    }

    public static void main(String[] args) {
        StdDraw.setCanvasSize(800, 800);
        StdDraw.setXscale(-0.1, 1.1);
        StdDraw.setYscale(-0.1, 1.1);

        // Equilateral triangle
        double x1 = 0.1, y1 = 0.2;
        double x2 = 0.9, y2 = 0.2;
        double x3 = 0.5, y3 = 0.2 + Math.sqrt(3) / 2 * 0.8;

        koch(x1, y1, x2, y2, ORDER);
        koch(x2, y2, x3, y3, ORDER);
        koch(x3, y3, x1, y1, ORDER);
    }
}