Add turbulence

src/noise.rs

@@ -9,8 +9,6 @@ pub struct NoiseTexture {
 
 impl Texture for NoiseTexture {
     fn value(&self, _u: f64, _v: f64, point: &Point3) -> Color {
-        Color::new(1.0, 1.0, 1.0)
-            * 0.5
-            * (1.0 + self.noise.noise(&(*point * self.scale)))
+        Color::new(1.0, 1.0, 1.0) * self.noise.default_turbulence(&(*point * self.scale))
     }
 }

src/perlin.rs

@@ -22,6 +22,22 @@ impl Perlin {
         }
     }
 
+    pub fn default_turbulence(&self, point: &Point3) -> f64 {
+       self.turbulence(point, 7)
+    }
+
+    pub fn turbulence(&self, point: &Point3, depth: i32) -> f64 {
+        let mut accum = 0.0;
+        let mut temp_p = point.clone();
+        let mut weight = 1.0;
+        for _i in 0..depth {
+            accum += weight * self.noise(&temp_p);
+            weight *= 0.5;
+            temp_p *= 2.0;
+        }
+        accum.abs()
+    }
+
     pub fn noise(&self, point: &Point3) -> f64 {
         let u = point.x() - point.x().floor();
         let v = point.y() - point.y().floor();

src/vec3.rs

@@ -1,5 +1,5 @@
 use std::fmt::{Display, Formatter};
-use std::ops::{Add, AddAssign, Div, Mul, Neg, Sub, Index};
+use std::ops::{Add, AddAssign, Div, Mul, Neg, Sub, Index, MulAssign};
 use rand::distributions::{Distribution, Uniform};
 
 #[derive(Debug, Clone, Copy)]
@@ -228,6 +228,32 @@ impl Mul<Vec3> for f64 {
     }
 }
 
+impl Mul<f64> for &Vec3 {
+    type Output = Vec3;
+
+    fn mul(self, other: f64) -> Vec3 {
+        Vec3 {
+            x: self.x * other,
+            y: self.y * other,
+            z: self.z * other,
+        }
+    }
+}
+
+impl Mul<&Vec3> for f64 {
+    type Output = Vec3;
+
+    fn mul(self, other: &Vec3) -> Vec3 {
+        other * self
+    }
+}
+
+impl MulAssign<f64> for Vec3 {
+    fn mul_assign(&mut self, rhs: f64) {
+        *self = *self * rhs;
+    }
+}
+
 impl Div<Vec3> for Vec3 {
     type Output = Vec3;