From 70d6cf20813a8cb0e373b2427a9e7b4ee5328fd2 Mon Sep 17 00:00:00 2001
From: Dimitri Sabadie <dimitri.sabadie@gmail.com>
Date: Sun, 21 Apr 2019 18:11:06 +0200
Subject: [PATCH] Implement impl-cgmath.

---
 Cargo.toml         |  2 +-
 src/cgmath.rs      | 52 ++++++++++++++++++++++++++++++++++------------
 src/interpolate.rs |  4 ----
 src/spline.rs      | 10 ++++++---
 tests/mod.rs       | 18 ++++++++++++++--
 5 files changed, 63 insertions(+), 23 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 9b6f6aa..2f72b35 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,7 +28,7 @@ std = []
 
 [dependencies]
 alga = { version = "0.9", optional = true }
-cgmath = { version = "0.17", optional = true }
+cgmath = { version = "0.16", optional = true }
 nalgebra = { version = ">=0.14, <0.19", optional = true }
 num-traits = { version = "0.2", optional = true }
 serde =  { version = "1", optional = true }
diff --git a/src/cgmath.rs b/src/cgmath.rs
index 9cdd459..c1f05c7 100644
--- a/src/cgmath.rs
+++ b/src/cgmath.rs
@@ -1,26 +1,52 @@
-use cgmath::{BaseNum, InnerSpace, Quaternion, VectorSpace, Vector2, Vector3, Vector4};
-use num_traits::Float;
+use cgmath::{BaseFloat, BaseNum, InnerSpace, Quaternion, VectorSpace, Vector1, Vector2, Vector3, Vector4};
 
-use crate::interpolate::{Interpolate, cubic_hermite_def};
+use crate::interpolate::{Additive, Interpolate, Linear, One, 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: $t) -> Self {
+  ($($t:tt)*) => {
+    impl<T> Linear<T> for $($t)*<T> where T: BaseNum {
+      fn outer_mul(self, t: T) -> Self {
+        self * t
+      }
+
+      fn outer_div(self, t: T) -> Self {
+        self / t
+      }
+    }
+
+    impl<T> Interpolate<T> for $($t)*<T> where Self: InnerSpace<Scalar = T>, T: Additive + BaseFloat + One {
+      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 {
+      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_vec!(Vector1);
+impl_interpolate_vec!(Vector2);
+impl_interpolate_vec!(Vector3);
+impl_interpolate_vec!(Vector4);
 
-//impl Interpolate for Quaternion<f32> {
-//  fn lerp(a: Self, b: Self, t: f32) -> Self {
-//    a.nlerp(b, t)
-//  }
-//}
+impl<T> Linear<T> for Quaternion<T> where T: BaseFloat {
+  fn outer_mul(self, t: T) -> Self {
+    self * t
+  }
+
+  fn outer_div(self, t: T) -> Self {
+    self / t
+  }
+}
+
+impl<T> Interpolate<T> for Quaternion<T> where Self: InnerSpace<Scalar = T>, T: Additive + BaseFloat + One {
+  fn lerp(a: Self, b: Self, t: T) -> Self {
+    a.nlerp(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)
+  }
+}
diff --git a/src/interpolate.rs b/src/interpolate.rs
index 314f37c..d4c5460 100644
--- a/src/interpolate.rs
+++ b/src/interpolate.rs
@@ -27,16 +27,12 @@ pub trait Interpolate<T>: Sized + Copy {
 /// A trait for anything that supports additions, subtraction, multiplication and division.
 pub trait Additive:
   Copy +
-  PartialEq +
-  PartialOrd +
   Add<Self, Output = Self> +
   Sub<Self, Output = Self> {
 }
 
 impl<T> Additive for T
 where T: Copy +
-         PartialEq +
-         PartialOrd +
          Add<Self, Output = Self> +
          Sub<Self, Output = Self> {
 }
diff --git a/src/spline.rs b/src/spline.rs
index f4e7f16..fa096c4 100644
--- a/src/spline.rs
+++ b/src/spline.rs
@@ -53,7 +53,9 @@ impl<T, V> Spline<T, V> {
   /// sampling impossible. For instance, `Interpolate::CatmullRom` requires *four* keys. If you’re
   /// near the beginning of the spline or its end, ensure you have enough keys around to make the
   /// sampling.
-  pub fn sample(&self, t: T) -> Option<V> where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T>, V: Interpolate<T> {
+  pub fn sample(&self, t: T) -> Option<V>
+  where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T> + PartialOrd,
+        V: Interpolate<T> {
     let keys = &self.0;
     let i = search_lower_cp(keys, t)?;
     let cp0 = &keys[i];
@@ -108,7 +110,9 @@ impl<T, V> Spline<T, V> {
   /// # Error
   ///
   /// This function returns `None` if you have no key.
-  pub fn clamped_sample(&self, t: T) -> Option<V> where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T>, V: Interpolate<T> {
+  pub fn clamped_sample(&self, t: T) -> Option<V>
+  where T: Additive + One + Trigo + Mul<T, Output = T> + Div<T, Output = T> + PartialOrd,
+        V: Interpolate<T> {
     if self.0.is_empty() {
       return None;
     }
@@ -136,7 +140,7 @@ pub(crate) fn normalize_time<T, V>(
   t: T,
   cp: &Key<T, V>,
   cp1: &Key<T, V>
-) -> T where T: Additive + Div<T, Output = T> {
+) -> T where T: Additive + Div<T, Output = T> + PartialEq {
   assert!(cp1.t != cp.t, "overlapping keys");
   (t - cp.t) / (cp1.t - cp.t)
 }
diff --git a/tests/mod.rs b/tests/mod.rs
index 216bb7d..a73b18b 100644
--- a/tests/mod.rs
+++ b/tests/mod.rs
@@ -1,7 +1,7 @@
 use splines::{Interpolation, Key, Spline};
 
-#[cfg(feature = "impl-nalgebra")]
-use nalgebra as na;
+#[cfg(feature = "impl-cgmath")] use cgmath as cg;
+#[cfg(feature = "impl-nalgebra")] use nalgebra as na;
 
 #[test]
 fn step_interpolation_f32() {
@@ -145,6 +145,20 @@ fn several_interpolations_several_keys() {
   assert_eq!(spline.clamped_sample(11.), Some(4.));
 }
 
+#[cfg(feature = "impl-cgmath")]
+#[test]
+fn cgmath_vector_interpolation() {
+  use splines::Interpolate;
+
+  let start = cg::Vector2::new(0.0, 0.0);
+  let mid = cg::Vector2::new(0.5, 0.5);
+  let end = cg::Vector2::new(1.0, 1.0);
+
+  assert_eq!(Interpolate::lerp(start, end, 0.0), start);
+  assert_eq!(Interpolate::lerp(start, end, 1.0), end);
+  assert_eq!(Interpolate::lerp(start, end, 0.5), mid);
+}
+
 #[cfg(feature = "impl-nalgebra")]
 #[test]
 fn nalgebra_vector_interpolation() {