hittablelist.rs

use cgmath::Vector3;
use crate::{ray::Ray, material::Material};

pub struct HitRecord <'a> {
    pub p: Vector3<f64>,
    pub normal: Vector3<f64>,
    pub t: f64,
    pub front_face: bool,
    pub material: &'a dyn Material
}

impl <'a> HitRecord <'a> {
    pub fn set_face_normal(&mut self, r: &Ray, outward_normal: Vector3<f64>) {
        self.front_face = cgmath::dot(r.direction, outward_normal) < 0.0;
        self.normal = match self.front_face {
            true => outward_normal,
            false => -outward_normal,
        }
    }
}

pub trait Hittable {
    fn hit(&self, r: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord>;
}

#[derive(Default)]
pub struct HittableList {
    objects: Vec<Box<dyn Hittable + Send + Sync>>,
}

impl HittableList {
    pub fn add(&mut self, obj: impl Hittable + Send + Sync + 'static) {
        self.objects.push(Box::new(obj));
    }
}

impl Hittable for HittableList {
    fn hit(&self, r: &Ray, t_min: f64, t_max: f64) -> Option<HitRecord> {
        let mut closest_so_far = t_max;
        let mut rec: Option<HitRecord> = None;
        for obj in &self.objects {
            match obj.hit(r, t_min, closest_so_far) {
                Some(r) => {
                    closest_so_far = r.t;
                    rec = Some(r);
                }
                None => (),
            }
        }
        rec
    }
}