changing polygon class into shapes

edited January 2016 in Kinect

hey guys, I just started coding in processing and want to know if it is it possible to change a code i found. The code I want to use is the CAN kinect physics code.

It uses the custom shapes class to create different shapes. would it be possible to change the code in such a way that i can change te shapes into images, i.e leaves or snow flakes? and if so, would anyone be so kind to help me in the right direction?

This is the CustomShape class that creates a shape and interacts with the shape of my body.

import java.util.List;
import java.util.Arrays;

class CustomShape {
  // to hold the box2d body
  Body body;
  // to hold the Toxiclibs polygon shape
  Polygon2D toxiPoly;
  // custom color for each shape
  color col;
  // radius (also used to distinguish between circles and polygons in this combi-class
  float r;

  CustomShape(float x, float y, float r, BodyType type) {
    this.r = r;
    // create a body (polygon or circle based on the r)
    makeBody(x, y, type);
    // get a random color
    col = getRandomColor();

  void makeBody(float x, float y, BodyType type) 
    // define a dynamic body positioned at xy in box2d world coordinates,
    // create it and set the initial values for this box2d body's speed and angle
    BodyDef bd = new BodyDef();
    bd.type = type;
    bd.position.set(box2d.coordPixelsToWorld(new Vec2(x, y)));
    body = box2d.createBody(bd);
    body.setLinearVelocity(new Vec2(random(-8, 8), random(2, 8)));
    body.setAngularVelocity(random(-5, 5));

    // box2d polygon shape
    //PolygonShape sd = new PolygonShape();
    /* toxiPoly = new Polygon2D(Arrays.asList(new Vec2D(-r, r*1.5), 
     new Vec2D(r, r*1.5), 
     new Vec2D(r, -r*1.5), 
     new Vec2D(-r, -r*1.5)));*/

    if (r == -1) 
      // box2d polygon shape
      PolygonShape sd = new PolygonShape();
      // toxiclibs polygon creator (triangle, square, etc)
      toxiPoly = new Circle(random(5, 20)).toPolygon2D(int(random(3, 6)));
      // place the toxiclibs polygon's vertices into a vec2d array
      Vec2[] vertices = new Vec2[toxiPoly.getNumPoints()];

      for (int i=0; i<vertices.length; i++) 
        Vec2D v = toxiPoly.vertices.get(i);
        vertices[i] = box2d.vectorPixelsToWorld(new Vec2(v.x, v.y));
      // put the vertices into the box2d shape
      sd.set(vertices, vertices.length);
      // create the fixture from the shape (deflect things based on the actual polygon shape)
      body.createFixture(sd, 1);

      // box2d circle shape of radius r
      CircleShape cs = new CircleShape();
      cs.m_radius = box2d.scalarPixelsToWorld(r);
      // tweak the circle's fixture def a little bit
      FixtureDef fd = new FixtureDef();
      fd.shape = cs;
      fd.density = 1;
      fd.friction = 0.01;
      fd.restitution = 0.3;
      // create the fixture from the shape's fixture def (deflect things based on the actual circle shape)

  // method to loosely move shapes outside a person's polygon
  // (alternatively you could allow or remove shapes inside a person's polygon)
  void update() 
    // get the screen position from this shape (circle of polygon)
    Vec2 posScreen = box2d.getBodyPixelCoord(body);
    // turn it into a toxiclibs Vec2D
    Vec2D toxiScreen = new Vec2D(posScreen.x, posScreen.y);
    // check if this shape's position is inside the person's polygon
    boolean inBody = poly.containsPoint(toxiScreen);
    // if a shape is inside the person
    if (inBody) {
      // find the closest point on the polygon to the current position
      Vec2D closestPoint = toxiScreen;
      float closestDistance = 9999999;
      for (Vec2D v : poly.vertices) 
        float distance = v.distanceTo(toxiScreen);
        if (distance < closestDistance) 
          closestDistance = distance;
          closestPoint = v;
      // create a box2d position from the closest point on the polygon
      Vec2 contourPos = new Vec2(closestPoint.x, closestPoint.y);
      Vec2 posWorld = box2d.coordPixelsToWorld(contourPos);
      float angle = body.getAngle();
      // set the box2d body's position of this CustomShape to the new position (use the current angle)
      body.setTransform(posWorld, angle);

  // display the customShape
  void display() {
    // get the pixel coordinates of the body
    Vec2 pos = box2d.getBodyPixelCoord(body);
    // translate to the position
    translate(pos.x, pos.y);
    // use the shape's custom color

    if (r == -1) {
      // rotate by the body's angle
      float a = body.getAngle();
      rotate(-a); // minus!
    else {
      ellipse(0, 0, r*2, r*2);


  // if the shape moves off-screen, destroy the box2d body (important!)
  // and return true (which will lead to the removal of this CustomShape object)
  boolean done() {
    Vec2 posScreen = box2d.getBodyPixelCoord(body);
    boolean offscreen = posScreen.y > height;
    if (offscreen) {
      return true;
    return false;


Thanks in advance


  • Please format the code. Select it, hit Ctrl-o.

  • oh snap, will do

  • Well, this is all for a box2d. You can certainly use image to display anything you like, however, you'll need to fit the body object to it, so it can interact with box2d physics correctly. You can just use .setAsBox() method of PolygonShape to create a box around your image, but it won't be precise of course.

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