box.h

// This file contains the class for the geometric object box, which is a cube
// Refer to the documentation for technical and mathematical details

#ifndef BOX_H
#define BOX_H

#include "aarect.h"
#include "hitable_list.h"

class box: public hitable  {
public:
    box() {}
    box(const vec3& p0, const vec3& p1, material *ptr);
    virtual bool hit(const ray& r, float t0, float t1, hit_record& rec) const;
    virtual bool bounding_box(float t0, float t1, aabb& box) const {
        box =  aabb(pmin, pmax);
        return true; }
    vec3 pmin, pmax;
    hitable *list_ptr;
};

// constructor. p0 is the bottom back front vertex, p1 is the top front right vertex.
box::box(const vec3& p0, const vec3& p1, material *ptr) {
    pmin = p0;
    pmax = p1;
    hitable **list = new hitable*[6];
    list[0] = new xy_rect(p0.x(), p1.x(), p0.y(), p1.y(), p1.z(), ptr);
    list[1] = new flip_normals(new xy_rect(p0.x(), p1.x(), p0.y(), p1.y(), p0.z(), ptr));
    list[2] = new xz_rect(p0.x(), p1.x(), p0.z(), p1.z(), p1.y(), ptr);
    list[3] = new flip_normals(new xz_rect(p0.x(), p1.x(), p0.z(), p1.z(), p0.y(), ptr));
    list[4] = new yz_rect(p0.y(), p1.y(), p0.z(), p1.z(), p1.x(), ptr);
    list[5] = new flip_normals(new yz_rect(p0.y(), p1.y(), p0.z(), p1.z(), p0.x(), ptr));
    list_ptr = new hitable_list(list,6);
}

// compute if a ray hits the box
bool box::hit(const ray& r, float t0, float t1, hit_record& rec) const {
    return list_ptr->hit(r, t0, t1, rec);
}

#endif //BOX_H