Add CheckerTexture.

rtiow/src/scenes/test.rs

@@ -5,10 +5,10 @@ use hitable::Hit;
 use hitable_list::HitableList;
 use kdtree::KDTree;
 use material::Lambertian;
-use material::Metal;
 use renderer::Opt;
 use renderer::Scene;
 use sphere::Sphere;
+use texture::CheckerTexture;
 use texture::ConstantTexture;
 use vec3::Vec3;
 
@@ -33,7 +33,10 @@ pub fn new(opt: &Opt) -> Scene {
     let mut objects: Vec<Box<Hit>> = vec![Box::new(Sphere::new(
         Vec3::new(0., 0., 0.),
         5.,
-        Box::new(Metal::new(Vec3::new(0.5, 0.5, 0.5), 0.)),
+        Box::new(Lambertian::new(Box::new(CheckerTexture::new(
+            Box::new(ConstantTexture::new(Vec3::new(0., 0., 0.))),
+            Box::new(ConstantTexture::new(Vec3::new(1., 1., 1.))),
+        )))),
     ))];
     let num_spheres = 6;
     let radius = 7.;

rtiow/src/texture.rs

@@ -19,3 +19,25 @@ impl Texture for ConstantTexture {
         self.color
     }
 }
+
+pub struct CheckerTexture {
+    odd: Box<Texture>,
+    even: Box<Texture>,
+}
+
+impl CheckerTexture {
+    pub fn new(odd: Box<Texture>, even: Box<Texture>) -> CheckerTexture {
+        CheckerTexture { odd, even }
+    }
+}
+
+impl Texture for CheckerTexture {
+    fn value(&self, u: f32, v: f32, p: Vec3) -> Vec3 {
+        let sines = (10. * p.x).sin() * (10. * p.y).sin() * (10. * p.z).sin();
+        if sines < 0. {
+            self.odd.value(u, v, p)
+        } else {
+            self.even.value(u, v, p)
+        }
+    }
+}