// Poligon.cpp: implementation of the CPoligon class.
//
//////////////////////////////////////////////////////////////////////

#include "Poligon.h"
#include <math.h>

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CPoligon::CPoligon()
{

}

CPoligon::~CPoligon()
{
  int i;
 
  //for (i=0;i<n;i++)
  //{
	 // ~p_point[i];
	 //delete [] &p_point[i];
  //}
  delete [] p_point;
}

CPoligon::CPoligon(int n_sides)
{
	p_point=new CPoint[n_sides];
	n=n_sides;
}

bool CPoligon::ifSquare()
{
	bool result;
	int i;

	this->sides(); // computing the sides of the square.

	result=false;
	if(n==4)
	{
      for(i=0;i<n;i++)
	  {
		  if(angle_values[i]!=90) 
		  {
			  result=false;
			  break;
		  }
			result=true; // Rectangle
	  }
	  result = result &&  (side_length[0]==side_length[1]);
	}
	return result;
}

CPoligon::sides()
// Computes the sides of the poligon.
{
	int i;
	int i1;

	double t1,t2;

	for(i=0;i<n;i++)
	{
		i1=i+1;
		if(i==n) i1=0;
		t1=p_point[i1].x-p_point[i].x;
		t2=pow(t1,2.0);
		side_length[i]=sqrt(
			pow( p_point[i1].x-p_point[i].x,2.0)+
			pow( p_point[i1].y-p_point[i].y,2.0)
			);
	}

}


CPoligon::angles()
// Computes the angles of the poligon.
{
	int i,i1,i2;  // indices.


	double A1,B1,C1; // first line Ax+By+C=0
	double A2,B2,C2;
	// (y2-y1)x-(x2-x1)y-(y2-y1)x1+(x2-x1)y1=0

	double t1,t2;
	double phi;
	double pi; // 3.14

	pi=4*atan(1.0);

	for(i=0;i<n;i++)
	{
		i1=i+1;
		i2=i1+1;
		if(i==(n-1)) 
		{
		  i1=0;
		  i2=1;
		}

		if(i==(n-2))
		{
			i1=n-1;
			i2=0;
		}
	

		// Ax+By+C=0;

		A1=(p_point[i2].y - p_point[i1].y);
		B1=-(p_point[i2].x - p_point[i1].x);
		C1=-A1*p_point[i1].x + B1*p_point[i1].y;

		A2=(p_point[i1].y - p_point[i].y);
		B2=-(p_point[i1].x - p_point[i].x);
		C2=-A2*p_point[i].x + B2*p_point[i].y;


        // An angle between two lines:
		// 
		//            A1*B2 - A2*B1
		// tan(phi)= -----------------
        //            A1*A2 + B1*B2
		//
		t1=A1*B2 - A2*B1;
		t2=A1*A2 + B1*B2;
		phi=atan(t1/t2);
		angle_values[i]=(double)fabs(phi/pi*(double)180);
		//angle_values[i]=(double)abs((float)180.0);
	}

}
//