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use crate::ray::Ray;
use crate::util::degrees_to_radians;
use crate::vec3::{Point3, Vec3};
pub struct Camera {
origin: Point3,
lower_left_corner: Point3,
horizontal: Vec3,
vertical: Vec3,
w: Vec3,
u: Vec3,
v: Vec3,
lens_radius: f64,
time_start: f64,
time_end: f64,
}
impl Camera {
pub fn new(
lookfrom: Point3,
lookat: Point3,
vup: Vec3,
vfov: f64,
aspect_ratio: f64,
aperture: f64,
focus_dist: f64,
time_start: f64,
time_end: f64,
) -> Camera {
let theta = degrees_to_radians(vfov);
let h = (theta / 2.0).tan();
let viewport_height = 2.0 * h;
let viewport_width = aspect_ratio * viewport_height;
let w = (&lookfrom - &lookat).unit_vector();
let u = vup.cross(&w).unit_vector();
let v = w.cross(&u);
let origin = lookfrom;
let horizontal = focus_dist * viewport_width * &u;
let vertical = focus_dist * viewport_height * &v;
Camera {
lower_left_corner: &origin - &horizontal / 2.0 - &vertical / 2.0 - focus_dist * &w,
origin,
horizontal,
vertical,
w,
u,
v,
lens_radius: aperture / 2.0,
time_start,
time_end,
}
}
pub fn get_ray(&self, s: f64, t: f64) -> Ray {
let rd = self.lens_radius * Vec3::random_in_unit_disk();
let offset = &self.u * rd.x + &self.v * rd.y;
Ray {
origin: &self.origin + &offset,
direction: &self.lower_left_corner + s * &self.horizontal + t * &self.vertical
- &self.origin
- &offset,
time: self.time_start + (self.time_end - self.time_start) * rand::random::<f64>(),
}
}
}
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