#include "IntersectableWrapper.h"
#include "Mesh.h"
#include "Triangle3.h"


namespace GtpVisibilityPreprocessor {


AxisAlignedBox3 TriangleIntersectable::GetBox() const
{	
	return mItem.GetBoundingBox();
}


int TriangleIntersectable::CastRay(Ray &ray)
{	
	float nearestT = MAX_FLOAT;
	float t;
	Vector3 nearestNormal;

	if (ray.GetType() == Ray::LOCAL_RAY && !ray.intersections.empty())
		nearestT = ray.intersections[0].mT;

	const int hitCode = mItem.CastRay(ray, t, nearestT, nearestNormal);

	nearestT = t;

	if ((hitCode == Ray::INTERSECTION) && (ray.GetType() == Ray::LOCAL_RAY))
	{
		if (!ray.intersections.empty())
		{
			ray.intersections[0] = Ray::Intersection(nearestT, nearestNormal, this, 0);
		}
		else
		{
			ray.intersections.push_back(Ray::Intersection(nearestT, nearestNormal, this, 0));
		}
		
		return 1;
	}

	return 0;
}
	

int TriangleIntersectable::NumberOfFaces() const
{
	return 1;
}


Vector3 TriangleIntersectable::GetNormal(const int idx) const
{
	return mItem.GetNormal();
}

int
TriangleIntersectable::GetRandomSurfacePoint(Vector3 &point, Vector3 &normal)
{
	// random barycentric coordinates
	float a = RandomValue(0,1);
	float b = RandomValue(0,1);
	float c = RandomValue(0,1);
	
	const float sum = a + b + c;

	// scale so we get vaccumated value of 1
	if (sum)
	{
		a /= sum;
		b /= sum;
		c /= sum;
	}

	//cout << "a: " << a << " b: " << b << " c: " << c << " sum: " << sum << endl;
	point = mItem.mVertices[0] * a + mItem.mVertices[1] * b + mItem.mVertices[2] * c;
	normal = mItem.GetNormal();

	return 0;
}


int TriangleIntersectable::GetRandomVisibleSurfacePoint(Vector3 &point,
														Vector3 &normal,
														const Vector3 &viewpoint,
														const int maxTries)
{
	return GetRandomSurfacePoint(point, normal);
}
 
}