51 lines
1.3 KiB
C++
51 lines
1.3 KiB
C++
#ifndef SPHERE_H
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#define SPHERE_H
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#include <cmath>
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#include "hittable.h"
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#include "vec3.h"
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class Sphere : public Hittable {
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public:
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Sphere() {}
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Sphere(Point3 cen, double r) : center(cen), radius(r) {}
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virtual bool hit(const Ray& r, double tmin, double tmax, hit_record& rec) const;
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private:
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Point3 center;
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double radius;
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};
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bool Sphere::hit(const Ray& r, double tmin, double tmax, hit_record& rec) const {
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Vec3 oc = r.origin() - center;
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auto a = r.direction().length_squared();
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auto half_b = dot(oc, r.direction());
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auto c = oc.length_squared() - radius * radius;
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auto discriminant = half_b*half_b - a*c;
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if (discriminant > 0) {
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auto root = std::sqrt(discriminant);
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auto temp = (-half_b - root) / a;
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if (temp < tmax && temp > tmin) {
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rec.t = temp;
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rec.p = r.at(rec.t);
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Vec3 outward_normal = (rec.p - center) / radius;
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rec.set_face_normal(r, outward_normal);
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return true;
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}
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temp = (-half_b + root) / a;
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if (temp < tmax && temp > tmin) {
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rec.t = temp;
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rec.p = r.at(rec.t);
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Vec3 outward_normal = (rec.p - center) / radius;
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rec.set_face_normal(r, outward_normal);
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return true;
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}
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}
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return false;
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}
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#endif // SPHERE_H
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