The cubic_hermite_def function is a bit fucked as impossible to use.

Cargo.toml

@@ -23,9 +23,11 @@ maintenance = { status = "actively-developed" }
 default = ["std"]
 serialization = ["serde", "serde_derive"]
 std = ["num-traits/std"]
+impl-cgmath = ["cgmath"]
 impl-nalgebra = ["nalgebra"]
 
 [dependencies]
+cgmath = { version = "0.17", optional = true }
 nalgebra = { version = ">=0.14, <0.19", optional = true }
 num-traits = { version = "0.2", default-features = false }
 serde =  { version = "1", optional = true }

src/cgmath.rs

@@ -0,0 +1,26 @@
+use cgmath::{BaseNum, InnerSpace, Quaternion, VectorSpace, Vector2, Vector3, Vector4};
+use num_traits::Float;
+
+use crate::interpolate::{Interpolate, cubic_hermite_def};
+
+macro_rules! impl_interpolate_vec {
+  ($t:ty, $($q:tt)*) => {
+    impl Interpolate<$t> for $($q)*<$t> {
+      fn lerp(a: Self, b: Self, t: $t) -> Self {
+        a.lerp(b, t)
+      }
+
+      fn cubic_hermite(x: (Self, $t), a: (Self, $t), b: (Self, $t), y: (Self, $t), t: $t) -> Self {
+        cubic_hermite_def(x, a, b, y, t)
+      }
+    }
+  }
+}
+
+impl_interpolate_vec!(f32, Vector2);
+
+//impl Interpolate for Quaternion<f32> {
+//  fn lerp(a: Self, b: Self, t: f32) -> Self {
+//    a.nlerp(b, t)
+//  }
+//}

src/lib.rs

@@ -81,6 +81,9 @@
 //!     + This feature implements both the `Serialize` and `Deserialize` traits from `serde` for all
 //!       types exported by this crate.
 //!     + Enable with the `"serialization"` feature.
+//!   - **[cgmath](https://crates.io/crates/cgmath) implementors.**
+//!     + Adds some useful implementations of `Interpolate` for some cgmath types.
+//!     + Enable with the `"impl-cgmath"` feature.
 //!   - **[nalgebra](https://crates.io/crates/nalgebra) implementors.**
 //!     + Adds some useful implementations of `Interpolate` for some nalgebra types.
 //!     + Enable with the `"impl-nalgebra"` feature.
@@ -94,6 +97,7 @@
 #![cfg_attr(not(feature = "std"), feature(alloc))]
 #![cfg_attr(not(feature = "std"), feature(core_intrinsics))]
 
+#[cfg(feature = "impl-cgmath")] mod cgmath;
 pub mod interpolate;
 pub mod interpolation;
 pub mod iter;