//
//  triangle_fwd.h
//  Cozmo
//
//  Created by Andrew Stein on 5/28/14.
//
//  NOTE: This header "forward declares" templated definitions.
//        To get the implementations, you must include triangle.h.
//

#ifndef CORETECH_ENGINE_MATH_TRIANGLE_H
#define CORETECH_ENGINE_MATH_TRIANGLE_H

#include "coretech/common/shared/math/point_fwd.h"
#include "coretech/common/shared/types.h"

namespace Anki {
  
// A class for storing 2D triangles
template<typename T>
class Triangle : public std::array<Point<2,T>, 3>
{
public:
  
  Triangle() { }
  
  Triangle(const Point2<T>& point1,
           const Point2<T>& point2,
           const Point2<T>& point3);
  
  Triangle(std::initializer_list<Point2<T> >& points);
  
  bool Contains(const Point<2,T>& point) const;
  
  T GetArea() const;
  
  // Calculates centroid of the triangle (barycenter), which always divides each median in a 2:1 ratio, or in
  // other words, it's always 2/3 away from each vertex
  Point<2, T> GetCentroid() const;
  
}; // class Triangle


// Each method returns true if the given point is within the given triangle,
// and false otherwise.  The only difference is whether the triangle is
// given as three 2D Points or three _pointers_ to 2D points.

template<typename T>
bool IsPointWithinTriangle(const Point<2,T>&                      point,
                           const std::array<const Point<2,T>*,3>& triangle);


template<typename T>
bool IsPointWithinTriangle(const Point<2,T>&                point,
                           const std::array<Point<2,T>, 3>& triangle);


// common typedefs
using Triangle2f = Triangle<f32>;

} // namespace Anki


#endif // CORETECH_ENGINE_MATH_TRIANGLE_H