Sphere.cpp

//
// Created by mtakagi on 2024/02/19.
//

#include "Sphere.h"
#include "Isect.h"
#include "Ray.h"
#include <cmath>

namespace aobench {
    const Isect Sphere::rayIntersect(const Isect &isect, const Ray &ray) const noexcept {
        auto rs = ray.org() - center_;
        auto B = rs.dot(ray.dir());
        auto C = rs.dot(rs) - radius_ * radius_;
        auto D = B * B - C;

        if (D > 0) {
            auto t = -B - sqrt(D);

            if (t > 0.0 && (t < isect.t())) {
                auto p = ray.org() + ray.dir() * t;
                auto n = p - center_;

                return Isect(t, p, n.normalize(), true);
            }
        }

        return isect;
    }
} // aobench