#include "IntersectableWrapper.h"
#include "Mesh.h"
#include "Triangle3.h"
#include "KdTree.h"
#include "BvHierarchy.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) {
		if (ray.GetType() == Ray::LOCAL_RAY && !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(0.0f, 1.0f);
	float b = RandomValue(0.0f, 1.0f);
	float c = RandomValue(0.0f, 1.0f);
	
	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::GetRandomSurfacePoint(const float u,
											 const float v,
											 Vector3 &point,
											 Vector3 &normal)
{
  // random barycentric coordinates
  float a = u;
  float b = v;
  float c = 1.0f - u - v;
  
  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);
}


int TriangleIntersectable::GetRandomEdgePoint(Vector3 &point,
											  Vector3 &normal)
{
	const int edge = Random(3);

	const Vector3 a = mItem.mVertices[edge];
	const Vector3 b = mItem.mVertices[(edge + 1) % 3];

	const float factor = RandomValue(0.0f, 1.0f);

	point = a * factor + b * factor;
	normal = mItem.GetNormal();

	return edge;
}


KdIntersectable::KdIntersectable(KdNode *item, const AxisAlignedBox3 &box)  :
  IntersectableWrapper<KdNode *>(item)
{
	mBox = box;
}
}