49 lines
1.7 KiB
C++
49 lines
1.7 KiB
C++
#include "moving_sphere.h"
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#include "sphere.h"
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Point3 Moving_sphere::center(double time) const {
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return center0 + ((time - time0) / (time1 - time0)) * (center1 - center0);
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}
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bool Moving_sphere::hit(const Ray& r, double tmin, double tmax, hit_record& rec) const {
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compute_sphere_uv((rec.p - center(r.time()))/radius, rec.u, rec.v);
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Vec3 oc = r.origin() - center(r.time());
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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(r.time())) / 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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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(r.time())) / 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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}
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return false;
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}
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bool Moving_sphere::bounding_box(double t0, double t1, Aabb& output_box) const {
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Aabb box0(
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center(t0) - Vec3(radius, radius, radius),
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center(t0) + Vec3(radius, radius, radius));
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Aabb box1(
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center(t1) - Vec3(radius, radius, radius),
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center(t1) + Vec3(radius, radius, radius));
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output_box = surrounding_box(box0, box1);
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return true;
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}
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