问CPU光线跟踪器对象已扭曲

EN

fn canvas_to_viewport(x: u32, y: u32, scene: &Scene) -> Point {
    let x: f64 = x as f64 - (scene.width as f64 / 2.) ;
    let y: f64 = y as f64 - (scene.width as f64 / 2.) ;

    // x * viewport width / camera width
    // y * viewport height / camera height
    Point {
        x: x  * 1.,
        y: y  * 1.,
        z: 10.
    }
}

fn trace_ray(camera: Point, viewport: Point, t_min: f64, _t_max: f64, spheres: &Vec<Sphere>) -> Color {
    let mut closest_t = 1000.;
    let mut closest_sphere_color = Color (255,255,255);

    for sphere in spheres {
        let (t1, t2) = intersect_ray_sphere(camera, viewport, &sphere);
        if t1 > t_min && t1 < closest_t {
            closest_t = t1;
            closest_sphere_color = sphere.color;
        };
        if t2 > t_min && t2 < closest_t {
            closest_t = t2;
            closest_sphere_color = sphere.color;
        };
    }
       closest_sphere_color
}

fn intersect_ray_sphere(o: Point,  d: Point, sphere: &Sphere) -> (f64, f64) {
    let r = sphere.radius;

    let co = Point { 
        x: o.x - sphere.center.x, 
        y: o.y - sphere.center.y,
        z: o.z - sphere.center.z
    };

    let a = dot_product(&d, &d);
    let b = 2. * dot_product(&co, &d);
    let c = dot_product(&co, &co) - r*r;

    let discriminant = b*b - 4.*a*c;
    if discriminant < 0. {
        return (1000., 1000.);
    };

    let t1 = (-b + discriminant.sqrt()) / (2.*a);
    let t2 = (-b - discriminant.sqrt()) / (2.*a);
    return (t1, t2)
}