// https://forum.processing.org/topic/
// controlling-the-length-of-line-from-x-y-to-a-point-which-is-randomly-chosen

final PVector p = new PVector(), n = new PVector();
final static int DIM = 5, LEN = 30;

void setup() {
  size(1200, 800);
  stroke(-1);
  fill(-1);

  mousePressed();
}

void draw() {
  if ((frameCount & 0xF) == 0)   filter(BLUR);

  PVector.random2D(n).mult(LEN);
  n.add(p);

  line(p.x, p.y, n.x, n.y);
  ellipse(n.x, n.y, DIM, DIM);

  p.set(n);

  frame.setTitle("FPS: " + round(frameRate));
}

void mousePressed() {
  background(0);
  p.set(width>>1, height>>1);
}

/** 
 * Brownian Motion (v2.11)
 * by Ammon.Owed (2013/Aug)
 * mod GoToLoop
 * 
 * http://forum.processing.org/topic/
 * controlling-the-length-of-line-from-x-y-to-a-point-which-is-randomly-chosen
 */

import java.util.Deque;
import java.util.ArrayDeque;

final static int DIM = 100, MAX = 03000, DETAIL = 1000, DEPTH = 2000;
final static int HUE = 0x200, FPS = 60, TOLERANCE = 40, ALIASING = 2;
final static boolean HAS_MAX_LIMIT = true;

final Deque<PVector> points = new ArrayDeque(MAX);
final PVector cam = new PVector(), lp = new PVector();

float canvasRatio;

void setup() {
  size(1000, 700, P3D);
  frameRate(FPS);
  smooth(ALIASING);
  colorMode(HSB, HUE, 1, 1);
  strokeWeight(1.5);
  noFill();

  canvasRatio = (float) width/height;

  points.add(new PVector());

  frameRate = TOLERANCE<<1;
}

void draw() {
  // auxiliary local variables
  final int fc = frameCount, fr = round(frameRate);
  final PVector tmp = new PVector();

  // interpolated rotating camera aimed at last point
  lp.set(points.getLast());
  cam.mult(.99);
  cam.add(PVector.mult(lp, .01, tmp));

  background(0);
  perspective(THIRD_PI, canvasRatio, 1, 1e6);

  camera(cam.x + sin(fc*.01)*DETAIL, cam.y + cos(10 + fc*8e-3)*DETAIL, 
  cam.z - DEPTH, cam.x, cam.y, cam.z, 0, 1, 0);

  // colored curved lines
  int idx = 0;
  beginShape();

  for (PVector p: points) {
    stroke(fc + idx++ & HUE - 1, 1, 1);
    curveVertex(p.x, p.y, p.z);
  }

  endShape();

  if (HAS_MAX_LIMIT) {
    if (fc >= MAX)       points.remove();
  }

  else {
    if (fr < TOLERANCE)  points.remove();
  }

  // new point at specified range
  PVector.random3D(tmp).mult(DIM);
  tmp.add(lp);
  points.add(tmp);


  frame.setTitle("Brownian Motion\t\tFPS: " +fr+ "\t\tSize: " +points.size());
}