// Tree growth sim

class Pt {
  float x, y, z;
  Pt(float nx, float ny) {
    x = nx; y = ny;
  }
}

class Branch {

  float squigBias;
  float lengthBias;
  float direction;
  float fade;

  Pt points[];
  Branch branches[];

  Branch(Branch parent, int limit) {

    createBranch(parent);

    if (limit < 8)
    createSubBranches(limit);

  }

  void createBranch(Branch parent) {

    points = new Pt[3];
    float dirChange;

    // Create new branch

    if (parent != null) {
      squigBias = random(parent.squigBias * .75, parent.squigBias * 1.1);
      lengthBias = random(parent.lengthBias * .45, parent.lengthBias*.90);

      dirChange = random(-squigBias, squigBias);

      direction = parent.direction + dirChange;

      points[0] = parent.points[points.length-1];

      fade = random(parent.fade*.6, parent.fade);
    } else {
      squigBias = 55;
      lengthBias = 160;
      direction = -90.0f;
      dirChange = 0;
      points[0] = new Pt(width/2, height);
      fade = 1.0f;
    }

    float tX = (lengthBias * cos(radians(direction))) + points[0].x;
    float tY = (lengthBias * sin(radians(direction))) + points[0].y;

    // end
    points[points.length-1] = new Pt(tX, tY);

    // mid 1
    float dX = (points[0].x + points[points.length-1].x) / 2;
    float dY = (points[0].y + points[points.length-1].y) / 2;

    points[1] = new Pt(dX + random(lengthBias * .2) - lengthBias * .1, dY + random(lengthBias * .2) - lengthBias * .1);

    // mid 2

    //points[2] = new Pt(points[0].x + dX*.6, points[0].y + dY*.6 + random(5));

    //b print ("Creating new branch: " + lengthBias + " " + direction + " " + dirChange + " tx: " + tX + "ty: " + tY + "\n");

  }

  void createSubBranches(int limit) {

    branches = new Branch[4];

    for (int i=0; i < branches.length; i++) {
      branches[i] = new Branch(this, limit+1);
    }

  }

  void drawBranch(float magnitude) {

    push();
    translate(points[0].x, points[0].y);
    //rotateZ(magnitude);

    stroke(255 - 255*fade);
    /*
    for (int i=0; i < points.length-1; i++) {
      float scale = float(i)/points.length-2;
      stroke(255 * scale, 255 * scale, 255 * scale);
      line(points[i].x, points[i].y, points[i+1].x, points[i+1].y);
    }*/

    beginShape(LINE_STRIP);
    //bezierVertex(points[0].x, points[0].y);
    bezierVertex(0, 0);
    bezierVertex(points[1].x- points[0].x, points[1].y- points[0].y);
    bezierVertex(points[2].x- points[0].x, points[2].y- points[0].y);
    bezierVertex(points[2].x- points[0].x, points[2].y- points[0].y);

    //curveVertex(0, 0);
    endShape();

    //line(0, 0, points[points.length-1].x - points[0].x, points[points.length-1].y - points[0].y);
    pop();

    if (branches != null) {
      for (int i=0; i < branches.length; i++) {
        branches[i].drawBranch(magnitude*.5);
      }
    } else {
      //print("No sub: " + points[0].x + " " + points[0].y + " " + points[2].x + " " + points[2].y);
    }
  }
}

Branch root;
float sway = 0.0f;
BFont metaBold;

void setup() {

  ellipseMode(CENTER_DIAMETER);
  push();
  size (1000, 1000);
  root = new Branch(null, 0);
}

void loop() {

  Branch current = root;

  background(255);

  sway += PI/360;

  push();
  current.drawBranch(cos(sway));
  pop();

  delay(1);

}

void mousePressed() {
  root = new Branch(null, 0);
}