/**
 * Broeltorens: 
 * klik en schuif met de postkaarten doorheen het beeldvlak.</p><p><em>Achtergrond: Broeltorens en omgeving. 
 * Schilderij van Jan Baptist Daveloose, 1847.</em>
 * </p><p><a href="http://www.kortrijksetaferelen.net">Keer terug</a>
*/

PImage img;
PImage img2;

Spring2D s1, s2, s3,s4;

float gravity = 6.0;
float mass = 1.0;

void setup() 
{
  size(944,674);
  img2 = loadImage("schilderij.jpg");
  image(img2,0,0);
  smooth();
  fill(0);
  
  s1 = new Spring2D(0.0, width/2, mass, gravity);
  s2 = new Spring2D(0.0, width/2, mass, gravity);
  s3 = new Spring2D(0.0, width/2, mass, gravity);
  s4 = new Spring2D(0.0, width/2, mass, gravity);
 
}

void draw() 
{
  background(204,5);
  img2 = loadImage("schilderij.jpg");
  image(img2,0,0);
  s1.update(mouseX, mouseY);
  s1.display(mouseX, mouseY);
  s2.update(s1.x, s1.y);
  s2.display(s1.x, s1.y);
  s3.update(s2.x, s2.y);
  s3.display(s2.x, s2.y);
  s4.update(s3.x, s3.y);
  s4.display(s3.x, s3.y);
 
}

class Spring2D {
  float vx, vy; 
  float x, y; 
  float gravity;
  float mass;
  float radius = 20;
  float stiffness = 0.2;
  float damping = 0.7;
  
  Spring2D(float xpos, float ypos, float m, float g) {
    x = xpos;
    y = ypos;
    mass = m;
    gravity = g;
  }
  
  void update(float targetX, float targetY) {
    float forceX = (targetX - x) * stiffness;
    float ax = forceX / mass;
    vx = damping * (vx + ax);
    x += vx;
    float forceY = (targetY - y) * stiffness;
    forceY += gravity;
    float ay = forceY / mass;
    vy = damping * (vy + ay);
    y += vy;
  }
  
  void display(float nx, float ny) {
    
    img = loadImage("ic1.jpg");
    image(img,x,y);
    fill(255,102,0);
    rect(0,0,x,y);
    
  }
}