import pbox2d.*;
import org.jbox2d.common.*;
import org.jbox2d.dynamics.joints.*;
import org.jbox2d.collision.shapes.*;
import org.jbox2d.collision.shapes.Shape;
import org.jbox2d.common.*;
import org.jbox2d.dynamics.*;
import org.jbox2d.dynamics.contacts.*;

ArrayList<Box> boxes;
PBox2D box2d;
Boundary bord1;
Boundary bord2;
Boundary bord3;
Boundary bord4;
Box b1;
Box b2;
Box b3;
void setup() {
  size(400, 300);
  smooth();
  // Create ArrayLists	
  boxes = new ArrayList<Box>();
  box2d = new PBox2D(this);
  box2d.createWorld();
  bord1 = new Boundary(width/2, height-10, width, 10);
  bord2 = new Boundary(width/2, 0, width, 10);
   bord3 = new Boundary(0, height/2, 10, height);
      bord4 = new Boundary(width, height/2, 10, height);
  // We are setting a custom gravity
  box2d.setGravity(0, -20);
  b1 = new Box(100, 50, 1);
  b2 = new Box(200, 50, 50);
  b3 = new Box(300, 50, 100);
}

void draw() {
  background(255);
  box2d.step();
  bord1.display();
  bord2.display();
  bord3.display();
  // When the mouse is clicked, add a new Box object

  b1.display();
  b2.display();
  b3.display();
  if (mousePressed) {
    box2d.setGravity(0, map(mouseY, 0, height, 50, -50));
  }
  /* if (mousePressed) {
   Box p = new Box(mouseX,mouseY);
   boxes.add(p);
   }
   
   // Display all the boxes
   for (Box b: boxes) {
   b.display();
   }*/
}

// A rectangular box
class Box  {
 
  // We need to keep track of a Body and a width and height
  Body body;
 
  float w;
  float h;
  Box(float x, float y,float poids) {
 
    w = random(4,16);
    h = random(4,16);
 
    // Define a polygon (this is what we use for a rectangle)
    PolygonDef sd = new PolygonDef();
    float box2dW = box2d.scalarPixelsToWorld(w/2);
    float box2dH = box2d.scalarPixelsToWorld(h/2);
    sd.setAsBox(box2dW, box2dH);
 
    // Parameters that affect physics
    sd.density = poids;
    sd.friction = 0.3;
    sd.restitution = 0.5;
 
    // Define the body and make it from the shape
    BodyDef bd = new BodyDef();
    Vec2 center = new Vec2(x,y);
    bd.position.set(box2d.coordPixelsToWorld(center));
 
    body = box2d.createBody(bd);
    body.createShape(sd);
    body.setMassFromShapes();
 
    // Give it some initial random velocity
    body.setLinearVelocity(new Vec2(random(-5,5),random(2,5)));
    body.setAngularVelocity(random(-5,5));
 }
  void display() {
    // We look at each body and get its screen position
    Vec2 pos = box2d.getBodyPixelCoord(body);
    // Get its angle of rotation
    float a = body.getAngle();
 
    rectMode(CENTER);
    pushMatrix();
    translate(pos.x,pos.y);
    rotate(-a);
    fill(175);
    stroke(0);
    rect(0,0,w,h);
    popMatrix();
  }
}

// The Nature of Code
// <http://www.shiffman.net/teaching/nature>
// Spring 2010
// PBox2D example

// A fixed boundary class

class Boundary {

  // A boundary is a simple rectangle with x,y,width,and height
  float x;
  float y;
  float w;
  float h;
  // But we also have to make a body for box2d to know about it
  Body b;

  Boundary(float x_,float y_, float w_, float h_) {
    x = x_;
    y = y_;
    w = w_;
    h = h_;

    // Figure out the box2d coordinates
    float box2dW = box2d.scalarPixelsToWorld(w/2);
    float box2dH = box2d.scalarPixelsToWorld(h/2);
    Vec2 center = new Vec2(x,y);

    // Define the polygon
    PolygonDef sd = new PolygonDef();
    sd.setAsBox(box2dW, box2dH);
    sd.density = 0;    // No density means it won't move!
    sd.friction = 0.1;

    // Create the body
    BodyDef bd = new BodyDef();
    bd.position.set(box2d.coordPixelsToWorld(center));
    b = box2d.createBody(bd);
    b.createShape(sd);
  }

  // Draw the boundary, if it were at an angle we'd have to do something fancier
  void display() {
    fill(0);
    stroke(0);
    rectMode(CENTER);
    rect(x,y,w,h);
  }

}