#pragma once

#include <QOpenGLTexture>
#include <QOpenGLContext>
#include <QTextCodec>
#include <algorithm>
#include <QVector4D>
#include <iostream>
#include <memory>
#include <vector>
#include <cmath>

using std::tr1::shared_ptr;

struct BvhTreeData {
	QVector4D bound;
	GLuint leftSon, rightSon;
	void show() {
		printf("Bvh: (%lf, %lf) (%lf, %lf): %d %d\n",
			bound.x(), bound.y(), bound.z(), bound.w(),
			leftSon, rightSon);
	}
	BvhTreeData()
		: leftSon(0), rightSon(0) {}
	~BvhTreeData() {}
};
// BvhTree 节点
struct BvhNode {	
	GLuint lab;
	bool isLeaf;
	QVector4D bound;
	shared_ptr<BvhNode> child[2];
	static bool x_compare(BvhTreeData a, BvhTreeData b) {
		return a.bound.x() < b.bound.x();
	}
	static bool y_compare(BvhTreeData a, BvhTreeData b) {
		return a.bound.y() < b.bound.y();
	}
	GLuint getLeftSon(int k) {
		if (isLeaf) {
			return 0x80000000+child[0]->lab;
		}
		return child[0]->lab;
	}
	GLuint getRightSon(int k) {
		if (isLeaf) {
			return child[1]->lab;
		}
		return child[1]->lab;
	}
	BvhNode() {
		child[0] = child[1] = NULL;
		isLeaf = false;
		lab = 0;
	}
	int maximumBound() {
		return (std::fabs(bound.x() - bound.w()) < std::fabs(bound.y() - bound.z()));
	}
	~BvhNode() {}
};

typedef std::tr1::shared_ptr<BvhNode> BvhPtr;

class BvhTree
{
	
private:
	GLuint tot;
	BvhPtr root;
	static QVector4D calcBound(BvhTreeData initBound[], int l, int r);
	static QVector4D Union(QVector4D a, QVector4D b);
	BvhPtr subBvhTree(BvhTreeData initBound[], int l, int r);
	void traverseBvhTree(BvhPtr now, std::vector<GLuint>& children, std::vector<QVector4D>& bounds);
public:
	BvhTree() {
		tot = 0;
		root = NULL;
	}
	// 根据底层包围盒生成bvh树
	void buildBvhTree(BvhTreeData initBound[], int len);
	// 获得 Bvh （rootBvh部分）的 children 数组，包围盒数组 vector 传输
	void getBvhArray(std::vector<GLuint>& children, std::vector<QVector4D>& bounds);
	// 获得 BvhTree 中节点总数
	GLuint getBvhNodeNum();
};