Add solid and checker texture

src/hittable.rs

@@ -1,14 +1,18 @@
 use crate::{Point3, Ray, Vec3};
 use crate::material::{Material};
 use crate::aabb::Aabb;
+use std::f64::consts::PI;
 
 pub type HittableList = Vec<Box<dyn Hittable + Sync>>;
 
-#[derive(Debug, Clone, Copy)]
+//#[derive(Debug, Clone, Copy)]
+#[derive(Clone, Copy)]
 pub struct HitRecord<'material> {
     pub point: Point3,
     pub normal: Vec3,
     pub t: f64,
+    pub u: f64,
+    pub v: f64,
     pub front_face: bool,
     pub material: &'material Material
 }
@@ -18,7 +22,7 @@ pub trait Hittable {
     fn bounding_box(&self, time0: f64, time1: f64) -> Option<Aabb>;
 }
 
-#[derive(Clone)]
+//#[derive(Clone)]
 pub struct Sphere {
     pub center: Point3,
     pub radius: f64,
@@ -28,6 +32,19 @@ impl Sphere {
     pub fn new(center: Point3, radius: f64, material: Material) -> Sphere {
         Sphere { center, radius, material }
     }
+    pub fn uv(point: &Point3) -> (f64, f64) {
+        // p: a given point on the sphere of radius one, centered at the origin.
+        // u: returned value [0,1] of angle around the Y axis from X=-1.
+        // v: returned value [0,1] of angle from Y=-1 to Y=+1.
+        //     <1 0 0> yields <0.50 0.50>       <-1  0  0> yields <0.00 0.50>
+        //     <0 1 0> yields <0.50 1.00>       < 0 -1  0> yields <0.50 0.00>
+        //     <0 0 1> yields <0.25 0.50>       < 0  0 -1> yields <0.75 0.50>
+
+        let theta = -(point.y()).acos();
+        let phi = -(point.z()).atan2(point.x()) + PI;
+
+        (phi / (2.0 * PI), theta / PI)
+    }
 }
 impl Default for Sphere {
     fn default() -> Self {
@@ -57,11 +74,14 @@ impl Hittable for Sphere {
         let normal = (point - self.center) / self.radius;
         let dot = ray.direction().dot(&normal);
         let front_face = dot < 0.0;
+        let (u, v) = Sphere::uv(&normal);
         let normal = if front_face { normal } else { -normal };
         Some(HitRecord {
             point,
             normal,
             t: root,
+            u,
+            v,
             front_face,
             material: &self.material
         })
@@ -75,7 +95,7 @@ impl Hittable for Sphere {
     }
 }
 
-#[derive(Clone)]
+//#[derive(Clone)]
 pub struct MovableSphere {
     pub center0: Point3,
     pub center1: Point3,
@@ -130,13 +150,16 @@ impl Hittable for MovableSphere {
         let normal = (point - self.center(ray.time())) / self.radius;
         let dot = ray.direction().dot(&normal);
         let front_face = dot < 0.0;
+        let (u, v) = Sphere::uv(&normal);
         let normal = if front_face { normal } else { -normal };
         Some(HitRecord {
             point,
             normal,
             t: root,
+            u,
+            v,
             front_face,
-            material: &self.material
+            material: &self.material,
         })
     }
     fn bounding_box(&self, time0: f64, time1: f64) -> Option<Aabb> {