#include "SimpleTri.h"


using namespace std;


SimpleTri::SimpleTri(const SimpleVec &a, const SimpleVec &b, const SimpleVec &c) 
{
	Init(a, b, c);
}


void SimpleTri::Init(const SimpleVec &a, const SimpleVec &b, const SimpleVec &c) 
{
	mVertices[0] = a;
	mVertices[1] = b;
	mVertices[2] = c;
}


SimpleVec SimpleTri::GetNormal() const 
{
	const SimpleVec v1 = mVertices[0] - mVertices[1];
	const SimpleVec v2 = mVertices[2] - mVertices[1];

	return Normalize(CrossProd(v2, v1));
}


SimpleVec SimpleTri::GetWorldCenter() const 
{
	return (mVertices[0] + mVertices[1] + mVertices[2]) / 3.0f;
}


float SimpleTri::GetArea() const 
{
	SimpleVec v1 = mVertices[0] - mVertices[1], v2=mVertices[2] - mVertices[1];
	return 0.5f * Magnitude(CrossProd(v2, v1));
}