68 lines
1.5 KiB
C++
68 lines
1.5 KiB
C++
#ifndef SPHERE_H
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#define SPHERE_H
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#include "hittable.hpp"
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#include "vec3.hpp"
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struct sphere : hittable {
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/* Attributes */
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point3 center;
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double radius;
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std::shared_ptr<material> mat_ptr;
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/* Contructor */
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sphere(point3 c, double r, std::shared_ptr<material> m)
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{
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center = c;
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radius = r;
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mat_ptr = m;
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}
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/* Virtual methods declaration */
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virtual bool hit(const ray& r, double t_min, double t_max, hit_record& rec) const override;
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};
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/* Virtual method implementations */
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bool sphere::hit(const ray& r, double t_min, double t_max, hit_record& rec) const
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{
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rmt_ScopedCPUSample(Sphere_Hit, RMTSF_Aggregate);
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// Part 1
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vec3 oc = r.origin - center;
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double a = r.direction.length_squared();
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double half_b = dot(oc, r.direction);
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double c = oc.length_squared() - radius*radius;
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// Part 2
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double discriminant = half_b*half_b - a*c;
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if (discriminant < 0)
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return false;
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double sqrtd = sqrt(discriminant);
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// Find the nearest root that lies in the acceptable range
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// Part 3
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double root = (-half_b - sqrtd) / a;
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if (root < t_min || t_max < root)
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{
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root = (-half_b + sqrtd) / a;
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if (root < t_min || t_max < root)
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return false;
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}
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// Part 4
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rec.t = root;
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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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rec.mat_ptr = mat_ptr;
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return true;
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}
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#endif
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