// Tree.java
// Robert Sedgewick and Kevin Wayne
// Slightly reformatted by Andrew Davison, Nov. 2022

// https://introcs.cs.princeton.edu/java/23recursion/Tree.java.html

/* Plot angle tree fractal.

   Usage:
     > compile Tree.java
     > run Tree n
   e.g.
     > run Tree 6
*/


public class Tree
{
  private static final double BEND_ANGLE   = Math.toRadians(15);
  private static final double BRANCH_ANGLE = Math.toRadians(37);
  private static final double BRANCH_RATIO = 0.65;


  public static void main(String[] args)
  {
    if (args.length != 1) {
      System.out.println("Usage: java Tree <int>");
      return;
    }

    int n = Integer.parseInt(args[0]);
    tree(n, 0.5, 0, Math.PI/2, 0.3);
  } /* main */


  public static void tree(int n, double x, double y,
                          double angle, double branchRadius)
  {
    double cx = x + Math.cos(angle) * branchRadius;
    double cy = y + Math.sin(angle) * branchRadius;
    StdDraw.setPenRadius(0.001 * Math.pow(n, 1.2));
    StdDraw.line(x, y, cx, cy);

    if (n == 0) 
      return;

    tree(n-1, cx, cy, angle+BEND_ANGLE - BRANCH_ANGLE, 
                                branchRadius * BRANCH_RATIO);
    tree(n-1, cx, cy, angle+BEND_ANGLE + BRANCH_ANGLE, 
                                branchRadius * BRANCH_RATIO);
    tree(n-1, cx, cy, angle+BEND_ANGLE, 
                                branchRadius * (1 - BRANCH_RATIO));
  } /* tree */


}  // end of Tree class