/**

 * @file  kdtree.h

 * @brief KdTree class

 *

 * This file is part of Pyrit Ray Tracer.

 *

 * Copyright 2006, 2007, 2008  Radek Brich

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#ifndef KDTREE_H

#define KDTREE_H

#include <iostream>

#include <fstream>

#include <assert.h>

#include "common.h"

#include "vector.h"

#include "scene.h"

#include "container.h"

#include "mempool.h"

using namespace std;

/**

 * a node of kd-tree

 */

class KdNode

{

	Float split;

	union {

		KdNode *children;

		ShapeList *shapes;

		int flags; /* 0,1,2 => x,y,z; 3 => leaf */

	};

public:

	KdNode() { shapes = new ShapeList(); assert((flags & 3) == 0); setLeaf(); };

	~KdNode();

	/** mark this node as leaf */

	void setLeaf() { flags |= 3; };

	bool isLeaf() const { return (flags & 3) == 3; };

	/** set split axis (this removes leaf flag) */

	void setAxis(int aAxis) { flags &= ~3; flags |= aAxis; };

	int getAxis() const { return flags & 3; };

	/** set split position (leaf) */

	void setSplit(Float aSplit) { split = aSplit; };

	const Float& getSplit() const { return split; };

	/** set children (non-leaf) */

	void setChildren(KdNode *node) { children = node; assert((flags & 3) == 0); };

	KdNode* getLeftChild() const { return (KdNode*)((size_t)children & ~3); };

	KdNode* getRightChild() const { return (KdNode*)(((size_t)children & ~3) + 16); };

	/** get shape list of the leaf node*/

	ShapeList* getShapes() const { return (ShapeList*)((size_t)shapes & ~3); };

	/** add shape to shape list */

	void addShape(const Shape* aShape) { getShapes()->push_back(aShape); };

};

/**

 * kd-tree

 */

class KdTree: public Container

{

	MemoryPool<KdNode> mempool;

	KdNode *root;

	bool built;

	void recursive_build(KdNode *node, const BBox &bbox, int maxdepth);

	void recursive_load(istream &st, KdNode *node);

public:

	~KdTree() { if (root) delete root; };

	/** add shape pointer to the container */

	void addShape(const Shape* aShape) { Container::addShape(aShape); built = false; };

	const Shape *nearest_intersection(const Shape *origin_shape, const Ray &ray,

		Float &nearest_distance);

#ifndef NO_SIMD

	void packet_intersection(const Shape* const* origin_shapes, const RayPacket &rays,

		Float *nearest_distances, const Shape **nearest_shapes);

#endif

	void optimize() { build(); };

	/** build the tree (alias for 'optimize') */

	void build();

	bool isBuilt() const { return built; };

	KdNode *getRootNode() const { return root; };

	ostream & dump(ostream &st) const;

	istream & load(istream &st, Material *mat);

};

#endif