void init_circles() {
  for (int i=0; i<numcircles; i++) {
    circles[i] = new Circle(20, (i+1)*0.8, (i+1)*20);
  }
}

void complete_graph_between_circles() {
  Circle c1=circles[0], c2;
  PVector p1, p2;
  for (int c=1; c<numcircles; c++) { // per tutti i cerchi prendine due
    c1 = circles[c-1];
    c2 = circles[c];

    for (int i=0; i<c1.numpoints; i++) {
      for (int j=0; j<c2.numpoints; j++) { // per tutti i punti di questi confronta quelli del primo con quelli del secondo
        p1 = c1.points[i];
        p2 = c2.points[j];
        //p2 = c2.points[i];

        float distance = PVector.dist(p1, p2);
        stroke(0, 0, 0, map(distance, 0, height, 50, 0));

        line(p1.x, p1.y, p1.z, p2.x, p2.y, p2.z);
      } // j
    } // i
  } // c
}

class Circle {
  float radius = 0;
  int numpoints = 20;
  
  float height = 50;
  float velocity = 2;

  PVector center = new PVector();
  PVector points[] = new PVector[numpoints];

  Circle(int numpoints, float velocity, float radius) {
    this.velocity = velocity;
    this.radius = radius;
    this.numpoints = numpoints;

    points = new PVector[this.numpoints];
    for (int i=0; i<this.numpoints; i++) {
      points[i] = new PVector();
    }
  }

  void update() {
    center.y = sin(theta+velocity) * this.height;
  }

  void draw() {

    float a = 0;
    float delta = TWO_PI/(numpoints-1);
    float x, y, z;
    beginShape();
    for (int i=0; i<numpoints; i++) {
      x = cos(a)*radius + center.x;
      y = center.y;
      z = sin(a)*radius + center.z;

      points[i].x = x;
      points[i].y = y;
      points[i].z = z;

      vertex( x, y, z );
      a += delta;
    }
    endShape();
  }
}

import processing.opengl.*;
import javax.media.opengl.GL;

import peasy.*;
import controlP5.*;

ControlP5 controlP5;
PMatrix3D currCameraMatrix;
PGraphics3D g3; 
PeasyCam cam;
GL gl;

int numcircles = 25;
Circle[] circles = new Circle[numcircles];
float theta = 0, dt = 0.1;
float ripples = 0.2, height_ripples = 2;

void setup() {
  size(800, 600, OPENGL);
  init_circles();
  init_gl();
  
  g3 = (PGraphics3D)g;
  cam = new PeasyCam(this, 1200);
  controlP5 = new ControlP5(this);
  controlP5.setAutoDraw(false);
  
  controlP5.addSlider("dt",            0, 0.6,0.1, 10,10, 100,30);
  controlP5.addSlider("ripples",       0, 1,  0.1, 10,40, 100,30);
  controlP5.addSlider("height_ripples",0, 20, 2,   10,70, 100,30);
}

void init_gl() {
  // init gl for alpha lines rendering
  // see http://www.opengl.org/resources/code/samples/sig99/advanced99/notes/node120.html    
  
  gl=((PGraphicsOpenGL)g).gl;

  hint(DISABLE_DEPTH_TEST);
  gl.glDisable(GL.GL_DEPTH_TEST);
  gl.glClear(GL.GL_DEPTH_BUFFER_BIT);

  gl.glEnable(GL.GL_LINE_SMOOTH);
  gl.glHint(GL.GL_LINE_SMOOTH_HINT, GL.GL_NICEST);
  gl.glBlendFunc(GL.GL_SRC_ALPHA, GL.GL_ONE_MINUS_SRC_ALPHA);
  //gl.glDepthMask(false);
}

void keyPressed() {
  //saveFrame(frameCount+".png");
}

void draw() {
  
  // don't use peasycam when moving controlP5 slider
  if (controlP5.window(this).isMouseOver()) {
    cam.setActive(false);
  } else {
    cam.setActive(true);
  }
  
  background(255);
  translate(0,-circles[numcircles-1].center.y, 0);

  noFill();
  stroke(0, 100);

  for (int i=0; i<numcircles; i++) {
    circles[i].velocity = (i+1)*ripples;
    circles[i].height = (numcircles-i)*height_ripples;
    if (!keyPressed) circles[i].update();
    circles[i].draw();
  }

  complete_graph_between_circles();
  
  gui();
  theta += dt; //map(mouseY, 0, height, 0, 0.4);
}

void gui() {
   currCameraMatrix = new PMatrix3D(g3.camera);
   camera();
   controlP5.draw();
   g3.camera = currCameraMatrix;
}