ft: 12: movable camera + camera init overhaul

src/vec3.rs

@@ -6,7 +6,7 @@ use std::{
     ops::{Add, AddAssign, Div, DivAssign, Mul, MulAssign, Neg, Sub, SubAssign},
 };
 
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub struct Vec3 {
     r: f32,
     g: f32,