/*
* [3]
*/
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Vec3 {
    pub x: f32,
    pub y: f32,
    pub z: f32,
}
pub type Point = Vec3;
pub type Color = Vec3;

/*
fn: P(t) = t*b
*/
#[derive(Debug)]
pub struct Ray {
    pub point: Point,
    pub direction: Vec3
}

pub struct HitRecord {
    pub t: f32,
    pub p: Vec3,
    pub normal: Vec3,
}


/*
/////////////
// for test
/////////////
*/
pub struct Sphere {
    pub center: Point,
    pub radius: f32,
}