78 lines
2.2 KiB
Rust
78 lines
2.2 KiB
Rust
use std::f32::consts::PI;
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use aabb::AABB;
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use hitable::Hit;
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use hitable::HitRecord;
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use material::Material;
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use ray::Ray;
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use vec3::dot;
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use vec3::Vec3;
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pub struct Sphere {
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center: Vec3,
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radius: f32,
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material: Box<Material>,
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}
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pub fn get_sphere_uv(p: Vec3) -> (f32, f32) {
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let phi = p.z.atan2(p.x);
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let theta = p.y.asin();
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let u = 1. - (phi + PI) / (2. * PI);
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let v = (theta + PI / 2.) / PI;
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(u, v)
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}
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impl Sphere {
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pub fn new(center: Vec3, radius: f32, material: Box<Material>) -> Sphere {
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Sphere {
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center,
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radius,
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material,
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}
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}
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}
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impl Hit for Sphere {
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fn hit(&self, r: Ray, t_min: f32, t_max: f32) -> Option<HitRecord> {
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let oc = r.origin - self.center;
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let a = dot(r.direction, r.direction);
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let b = dot(oc, r.direction);
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let c = dot(oc, oc) - self.radius * self.radius;
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let discriminant = b * b - a * c;
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if discriminant > 0. {
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let temp = (-b - (b * b - a * c).sqrt()) / a;
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if temp < t_max && temp > t_min {
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let point = r.point_at_parameter(temp);
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let uv = get_sphere_uv((point - self.center) / self.radius);
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return Some(HitRecord {
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t: temp,
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uv,
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p: point,
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normal: (point - self.center) / self.radius,
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material: &*self.material,
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});
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}
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let temp = (-b + (b * b - a * c).sqrt()) / a;
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if temp < t_max && temp > t_min {
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let point = r.point_at_parameter(temp);
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let uv = get_sphere_uv((point - self.center) / self.radius);
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return Some(HitRecord {
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t: temp,
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uv,
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p: point,
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normal: (point - self.center) / self.radius,
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material: &*self.material,
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});
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}
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}
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None
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}
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fn bounding_box(&self, _t_min: f32, _t_max: f32) -> Option<AABB> {
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Some(AABB::new(
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self.center - Vec3::new(self.radius, self.radius, self.radius),
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self.center + Vec3::new(self.radius, self.radius, self.radius),
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))
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}
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}
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