Renderer/src/vec3.rs

use std::ops::*;
use super::utility;

#[derive(Clone, Copy, Debug)]
pub struct Vec3 {
    pub e: [f64; 3],
}

pub type Color = Vec3;
pub type Point3 = Vec3;

impl Vec3 {
    pub fn new(x: f64, y: f64, z: f64) -> Self {
        Vec3 { e: [x, y, z] }
    }

    pub fn length(&self) -> f64 {
        self.length_squared().sqrt()
    }

    pub fn length_squared(&self) -> f64 {
        self.e[0] * self.e[0] + self.e[1] * self.e[1] + self.e[2] * self.e[2]
    }

    pub fn cross(a: Vec3, b: Vec3) -> Vec3 {
        Vec3::new(
            a.y() * b.z() - a.z() * b.y(),
            a.z() * b.x() - a.x() * b.z(),
            a.x() * b.y() - a.y() * b.x(),
        )
    }

    pub fn dot(a: Vec3, b: Vec3) -> f64 {
        a.x() * b.x() + a.y() * b.y() + a.z() * b.z()
    }

    pub fn unit_vector(a: Vec3) -> Vec3 {
        a / a.length()
    }

    pub fn random_f64() -> Vec3 {
        Vec3::new(utility::random_f64(),utility::random_f64(),utility::random_f64())
    }

    pub fn random_rng(min: f64, max: f64) -> Self {
        Self::new(utility::random_rng(min,max), utility::random_rng(min,max), utility::random_rng(min,max))
    }

    pub fn random_in_unit_sphere() -> Self {
        loop {
            let p = Vec3::random_rng(-1.0, 1.0);
            if p.length_squared() >= 1.0 { continue };
            return p;
        }
    }

    pub fn random_unit_vector() -> Self {
        Self::unit_vector(Self::random_in_unit_sphere())
    }

    pub fn random_in_hemisphere(&self) -> Self {
        let in_unit_sphere = Self::random_in_unit_sphere();
        if Self::dot(in_unit_sphere, *self) > 0.0 {
            return in_unit_sphere;
        } else {
            return -1.0*in_unit_sphere;
        }
    }

    pub fn x(&self) -> f64 {
        self.e[0]
    }
    pub fn y(&self) -> f64 {
        self.e[1]
    }
    pub fn z(&self) -> f64 {
        self.e[2]
    }
}

impl Add for Vec3 {
    type Output = Vec3;

    fn add(self, rhs: Self) -> Vec3 {
        Vec3::new(self.x() + rhs.x(), self.y() + rhs.y(), self.z() + rhs.z())
    }
}

impl AddAssign for Vec3 {
    fn add_assign(&mut self, rhs: Self) {
        self.e[0] += rhs.x();
        self.e[1] += rhs.y();
        self.e[2] += rhs.z();
    }
}

impl Sub for Vec3 {
    type Output = Vec3;

    fn sub(self, rhs: Self) -> Vec3 {
        Vec3::new(self.x() - rhs.x(), self.y() - rhs.y(), self.z() - rhs.z())
    }
}

impl SubAssign for Vec3 {
    fn sub_assign(&mut self, rhs: Self) {
        self.e[0] -= rhs.x();
        self.e[1] -= rhs.y();
        self.e[2] -= rhs.z();
    }
}

impl Mul<Vec3> for f64 {
    type Output = Vec3;

    fn mul(self, rhs: Vec3) -> Vec3 {
        Vec3::new(self * rhs.x(), self * rhs.y(), self * rhs.z())
    }
}

impl MulAssign<f64> for Vec3 {
    fn mul_assign(&mut self, rhs: f64) {
        self.e[0] *= rhs;
        self.e[1] *= rhs;
        self.e[2] *= rhs;
    }
}

impl DivAssign<f64> for Vec3 {
    fn div_assign(&mut self, rhs: f64) {
        self.e[0] /= rhs;
        self.e[1] /= rhs;
        self.e[2] /= rhs;
    }
}

impl Div<f64> for Vec3 {
    type Output = Vec3;

    fn div(self, rhs: f64) -> Vec3 {
        Vec3::new(self.x() / rhs, self.y() / rhs, self.z() / rhs)
    }
}