#include "SceneEntity.h"
#include "Geometry.h"
#include "Material.h"
#include "RenderState.h"
#include "Shape.h"
#include "Transform3.h"
#include "Camera.h"

#include "glInterface.h"
#include <Cg/cg.h>
#include <Cg/cgGL.h>


using namespace std;


namespace CHCDemoEngine 
{

bool SceneEntity::sUseLODs = true;


SceneEntity::SceneEntity(Transform3 *trafo): 
mTransform(trafo), mCurrentLODLevel(0), mLODLastUpdated(-1)
{
	mBox.Initialize();
}


SceneEntity::~SceneEntity()
{
}


void SceneEntity::UpdateLODs(const Vector3 &viewPoint)
{
	mCurrentLODLevel = 0;

	if (!sUseLODs) return;

	const Vector3 pos = GetCenter();

	const float dist = SqrDistance(pos, viewPoint);

	// note: we assume that lods are ordered from smallest distance to largest
	const int l = (int)mLODLevels.size();

	for (int i = 0; i < l; ++ i)
	{
		LODLevel *lod = mLODLevels[i];

		if (lod->GetSquaredDistance() > dist)
			break;

		mCurrentLODLevel = i;
	}
}


int SceneEntity::GetCurrentLODLevel()
{
	if (mLODLastUpdated != LODLevel::sFrameId)
	{
		mLODLastUpdated = LODLevel::sFrameId;
		UpdateLODs(LODLevel::sViewPoint);
	}

	return mCurrentLODLevel;
}


void SceneEntity::GetCurrentLODLevel(ShapeContainer::iterator &start, 
									 ShapeContainer::iterator &end)
{
	if (mLODLastUpdated != LODLevel::sFrameId)
	{
		mLODLastUpdated = LODLevel::sFrameId;
		UpdateLODs(LODLevel::sViewPoint);
	}

	start = mLODLevels[mCurrentLODLevel]->GetShapes().begin(); 
	end   = mLODLevels[mCurrentLODLevel]->GetShapes().end();
}


void SceneEntity::GetLODLevel(int level, 
							  ShapeContainer::iterator &start, 
							  ShapeContainer::iterator &end)
{
	LODLevel *lod = mLODLevels[level];

	start = lod->GetShapes().begin();
	end = lod->GetShapes().end();
}


void SceneEntity::Render(RenderState *state)
{
	ShapeContainer::iterator sit, sit_end;

	GetCurrentLODLevel(sit, sit_end);

	for (; sit != sit_end; ++ sit)
	{
		(*sit)->Render(state);
	}
}


void SceneEntity::AddShape(Shape *shape)
{
	mShapes.push_back(shape);
	mBox.Include(shape->GetBoundingBox());

	mCenter = mBox.Center();
}


void SceneEntity::SetTransform(Transform3 *trafo)
{
	mTransform = trafo;
}


void SceneEntity::SetLastRendered(int lastRendered)
{
	mLastRendered = lastRendered;
}


int SceneEntity::GetLastRendered() const
{
	return mLastRendered;
}


int SceneEntity::CountNumTriangles(int lodLevel)
{
	int numTriangles = 0;
	
	ShapeContainer::iterator sit, sit_end;

	if (lodLevel == -1)
	{
		lodLevel = GetCurrentLODLevel();
	}

	return mLODLevels[lodLevel]->GetNumTriangles();
}


AxisAlignedBox3 SceneEntity::GetTransformedBoundingBox() const
{
	Matrix4x4 *mat = mTransform->GetMatrix();

	if (!mat)
		return mBox;

	return Transform(mBox, *mat);
}


AxisAlignedBox3 SceneEntity::GetBoundingBox() const
{
	return mBox;
}


Vector3 SceneEntity::GetCenter() const
{
	Matrix4x4 *mat = mTransform->GetMatrix();

	if (!mat) return mCenter;

	return (*mat) * mCenter;
}


}