NurbsIntersection/include/bvh.hpp

#ifndef BVH_H_
#define BVH_H_

#include <iostream>
#include <tinynurbs/tinynurbs.h>

//包围盒结构，存储盒子对角的两个点
typedef struct AABB
{
    glm::vec3 Bmin, Bmax;
    AABB()
    {
        double minNum = std::numeric_limits<double>::lowest();
        double maxNum = std::numeric_limits<double>::max();
        Bmax = glm::vec3(minNum, minNum, minNum);
        Bmin = glm::vec3(maxNum, maxNum, maxNum);
    }
} AABB;

// AABB包围盒的结点
typedef struct BVH_AABB_Node
{
    AABB bound;                                   //包围盒边界
    std::vector<std::pair<double, double>> param; //此包围盒对应的每个参数的范围
    std::vector<struct BVH_AABB_Node *> childPtr; //把每个孩子结点指针存储到容器里
} BVH_AABB_Node, *BVH_AABB_NodePtr;

class BVH_AABB
{
public:
    unsigned int Hlevel;                   //递归层数
    unsigned int BranchNum;                //每个结点的分支数 [BranchNum=2:曲线 || BranchNum=4:曲面]
    double sampleNum;                      //采样点数--越大包围盒构造越准确
    BVH_AABB_NodePtr bvh_aabb_node = NULL; // bvh树的根指针

public:
    BVH_AABB(unsigned int Hlevel_, unsigned int BranchNum_, double sampleNum_) : Hlevel(Hlevel_), BranchNum(BranchNum_), sampleNum(sampleNum_)
    {
        bvh_aabb_node = new BVH_AABB_Node;
        std::cout << "BVH_AABB constructed correct!\n";
    };
    BVH_AABB_Node *GetNode() const
    {
        return bvh_aabb_node;
    };
    BVH_AABB_NodePtr Build_NurbsCurve(tinynurbs::RationalCurve<double> &curve, BVH_AABB_NodePtr &curNode, int curLevel, double t, double tstep);
    BVH_AABB_NodePtr Build_NurbsSurface(tinynurbs::RationalSurface<double> &surface, BVH_AABB_NodePtr &curNode, int curLevel, double u, double v, double ustep, double vstep);
    AABB &UnionBound(const AABB &a, const AABB &b);
    AABB &UpdateBound(const AABB &bound, const glm::vec3 &p);
};

#endif // !BVH_H_