NurbsIntersection/include/bvh.hpp

/*
 * @File Created: 2022-11-24, 20:13:58
 * @Last Modified: 2022-11-26, 18:45:16
 * @Author: forty-twoo
 * Copyright (c) 2022, Caiyue Li (li_caiyue@zju.edu.cn), All rights reserved.
 */
#ifndef BVH_H_
#define BVH_H_

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

class BVH_AABB;

//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);
    }
    void ShowAABB()
    {

        std::cout << "min_point (" << Bmin.x << ", " << Bmin.y << ", " << Bmin.z << ") , max_point (" << Bmax.x << ", "
                  << Bmax.y << ", " << Bmax.z << ")\n";
    }
} 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 *myBVH;                              //指向自己的BVH结构
} 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]
    tinynurbs::RationalCurve<double> *NurbsCurvePtr = NULL;     //指向该BVH对应的NurbsCurve的指针针
    tinynurbs::RationalSurface<double> *NurbsSurfacePtr = NULL; //指向该BVH对应的NurbsSurface的指针针
    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_, tinynurbs::RationalCurve<double> NurbsCurve_) : Hlevel(Hlevel_), BranchNum(BranchNum_), sampleNum(sampleNum_)
    {
        bvh_aabb_node = new BVH_AABB_Node;
        NurbsCurvePtr = new tinynurbs::RationalCurve<double>(NurbsCurve_);
        std::cout << "BVH_AABB constructed correct, this is a bvh of NurbsCurve!\n";
    };
    BVH_AABB(unsigned int Hlevel_, unsigned int BranchNum_, double sampleNum_, tinynurbs::RationalSurface<double> NurbsSurface_) : Hlevel(Hlevel_), BranchNum(BranchNum_), sampleNum(sampleNum_)
    {
        bvh_aabb_node = new BVH_AABB_Node;
        NurbsSurfacePtr = new tinynurbs::RationalSurface<double>(NurbsSurface_);
        std::cout << "BVH_AABB constructed correct, this is a bvh of NurbsSurface!\n";
    };
    BVH_AABB_Node *GetNode() const
    {
        return bvh_aabb_node;
    };
    AABB UnionBound(const AABB &a, const AABB &b);
    AABB UpdateBound(const AABB &bound, const glm::vec3 &p);
    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);
};

#endif // !BVH_H_