added impl-nalgebra feature

Cargo.toml

@@ -22,6 +22,11 @@ default = ["std", "impl-cgmath"]
 serialization = ["serde", "serde_derive"]
 std = []
 impl-cgmath = ["cgmath"]
+impl-nalgebra = ["nalgebra"]
+
+[dependencies.nalgebra]
+version = "0.16"
+optional = true
 
 [dependencies.cgmath]
 version = "0.16"

src/lib.rs

@@ -98,11 +98,15 @@
 
 #[cfg(feature = "impl-cgmath")] extern crate cgmath;
 
+#[cfg(feature = "impl-nalgebra")] extern crate nalgebra;
+
 #[cfg(feature = "serialization")] extern crate serde;
 #[cfg(feature = "serialization")] #[macro_use] extern crate serde_derive;
 
 #[cfg(feature = "impl-cgmath")] use cgmath::{InnerSpace, Quaternion, Vector2, Vector3, Vector4};
 
+#[cfg(feature = "impl-nalgera")] use nalgera::{Point, Vector};
+
 #[cfg(feature = "std")] use std::cmp::Ordering;
 #[cfg(feature = "std")] use std::f32::consts;
 #[cfg(feature = "std")] use std::ops::{Add, Div, Mul, Sub};
@@ -385,6 +389,20 @@ impl Interpolate for Quaternion<f32> {
   }
 }
 
+#[cfg(feature = "impl-nalgebra")]
+impl<T : Interpolate > Interpolate for Point<T> {
+    fn lerp(a: Self, b: Self, t: f32) -> Self {
+        a.lerp(b, t)
+    }
+}
+
+#[cfg(feature = "impl-nalgebra")]
+impl<T : Interpolate > Interpolate for Vector<T> {
+    fn lerp(a: Self, b: Self, t: f32) -> Self {
+        a.lerp(b, t)
+    }
+}
+
 // Default implementation of Interpolate::cubic_hermit.
 pub(crate) fn cubic_hermite<T>(x: (T, f32), a: (T, f32), b: (T, f32), y: (T, f32), t: f32) -> T
     where T: Copy + Add<Output = T> + Sub<Output = T> + Mul<f32, Output = T> + Div<f32, Output = T> {