60 lines
1.6 KiB
Rust
60 lines
1.6 KiB
Rust
use std::ops::Deref;
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use crate::hittable::*;
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use crate::material::Material;
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use crate::vec3::*;
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use crate::Ray;
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pub struct Sphere {
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center: Point3,
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radius: f64,
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material: Box<dyn Material>,
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}
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impl Sphere {
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pub fn new<T: Material + 'static>(center: Point3, radius: f64, material: Box<T>) -> Self {
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Sphere {center, radius, material}
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}
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}
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impl Hittable for Sphere {
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fn hit(&self, r: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord<'_>> {
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let oc = r.origin() - self.center;
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let a = r.direction().length_squared();
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let half_b = oc.dot(&r.direction());
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let c = oc.length_squared() - self.radius * self.radius;
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let discriminant = half_b * half_b - a * c;
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if discriminant < 0.0 {
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return None;
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}
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let sqrtd = discriminant.sqrt();
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// Find the nearest root that lies in the acceptable range
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let mut root = (-half_b - sqrtd) / a;
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if root < t_min || t_max < root {
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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 None;
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}
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}
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let p = r.at(root);
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let outward_normal = (p - self.center) / self.radius;
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let front_face = r.direction().dot(&outward_normal) < 0.0;
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let outward_normal = if front_face {
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outward_normal
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} else {
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outward_normal * -1.0
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};
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Some(HitRecord {
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t: root,
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p: p,
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normal: outward_normal,
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front_face,
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material: self.material.deref(),
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})
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}
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} |