import processing.opengl.*;
import anar.*;





/*
 * Example for Anar library by Guillaume LaBelle + Julien Nembrini
 * http://anar.ch
 */


Obj myObj;

void setup(){
    size(800,400,OPENGL);
  Anar.init(this);
  Anar.drawAxis();

  initForm();
}

void initForm(){
  myObj = new Obj();

  Face triangle = new Face();

  triangle.add(Anar.PtRnd(100,100));
  triangle.add(Anar.PtRnd(100,100));
  triangle.add(Anar.PtRnd(100,100));
  
  myObj.add(triangle);

  Pt center = new PtBary(triangle);
  center.fill(255,0,0);
  myObj.add(center);

  Anar.camTarget(myObj);

  Pt circumcenter = circumCenter(triangle);
  circumcenter.fill(0,0,255);
  myObj.add(circumcenter);

  Face circle = new Circle(circumcenter,circumRadius(triangle),100);
  myObj.add(circle);

}

// http://en.wikipedia.org/wiki/Circumcircle
Pt circumCenter(Face f){

  Vertex p1 = new Vertex(f.pt(0));
  Vertex p2 = new Vertex(f.pt(1));
  Vertex p3 = new Vertex(f.pt(2));

  float aLen = p2.lengthSq(p3);
  float bLen = p1.lengthSq(p3);
  float cLen = p1.lengthSq(p2);

  float sub = 2*Vertex.cross(p1.minus(p2),p2.minus(p3)).lengthSq();

  float a = aLen*Vertex.dot(p1.minus(p2),p1.minus(p3))/sub;
  float b = bLen*Vertex.dot(p2.minus(p1),p2.minus(p3))/sub;
  float c = cLen*Vertex.dot(p3.minus(p1),p3.minus(p2))/sub;

  Vertex result = (Vertex)p1.multiply(a).plus(p2.multiply(b)).plus(p3.multiply(c));

  return Anar.Pt(result);
}

// http://en.wikipedia.org/wiki/Circumcircle
float circumRadius(Face f){

  float totalLength;

  // Isit general for polyfgons?
  totalLength = f.pt(0).length(f.pt(1));
  totalLength *= f.pt(1).length(f.pt(2));
  totalLength *= f.pt(2).length(f.pt(0));

  float area = f.area();

  println(area);

  println(totalLength);

  return totalLength/ (4*area);
}


void draw(){
  background(155);
  myObj.draw();
}

void keyPressed(){
  if(key==' ')
    initForm();
}