Fix feature documentation in both README and lib.rs.

CHANGELOG.md

@@ -1,3 +1,17 @@
+# 0.2.1
+
+> Thu 20th September 2018
+
+  - Enhance the features documentation.
+
+# 0.2
+
+> Thu 6th September 2018
+
+  - Add the `"std"` feature gate, that can be used to compile with the standard library.
+  - Add the `"impl-cgmath"` in order to make it optional, if wanted, the `cgmath` dependency.
+  - Enhance the documentation.
+
 ## 0.1.1
 
 > Wed 8th August 2018

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "splines"
-version = "0.1.1"
+version = "0.2.1"
 license = "BSD-3-Clause"
 authors = ["Dimitri Sabadie <dimitri.sabadie@gmail.com>"]
 description = "Spline interpolation made easy"
@@ -18,12 +18,14 @@ is-it-maintained-open-issues = { repository = "phaazon/splines" }
 maintenance = { status = "actively-developed" }
 
 [features]
-default = ["std"]
+default = ["std", "impl-cgmath"]
 serialization = ["serde", "serde_derive"]
 std = []
+impl-cgmath = ["cgmath"]
 
-[dependencies]
-cgmath = "0.16"
+[dependencies.cgmath]
+version = "0.16"
+optional = true
 
 [dependencies.serde]
 version = "1"

README.md

@@ -12,7 +12,10 @@ This crate has features! Here’s a comprehensive list of what you can enable:
   - **Serialization / deserialization.**
     + This feature implements both the `Serialize` and `Deserialize` traits from `serde`.
     + Enable with the `"serialization"` feature.
-  - **Standard library / no stdandard library**
+  - **[cgmath](https://crates.io/crates/cgmath) implementors**
+    + Adds some usefull implementations of `Interpolate` for some cgmath types.
+    + Enable with the `"impl-cgmath"` feature.
+  - **Standard library / no stdandard library.**
     + It’s possible to compile against the standard library or go on your own without it.
     + Compiling with the standard library is enabled by default.
     + Use `defaut-features = []` in your `Cargo.toml` to disable.

src/lib.rs

@@ -77,9 +77,13 @@
 //! So here’s a list of currently supported features and how to enable them:
 //!
 //!   - **Serialization / deserialization.**
-//!     + This feature implements both the `Serialize` and `Deserialize` traits from `serde`.
+//!     + This feature implements both the `Serialize` and `Deserialize` traits from `serde` for all
+//!       types exported by this crate.
 //!     + Enable with the `"serialization"` feature.
-//!   - **Standard library / no stdandard library**
+//!   - **[cgmath](https://crates.io/crates/cgmath) implementors.**
+//!     + Adds some usefull implementations of `Interpolate` for some cgmath types.
+//!     + Enable with the `"impl-cgmath"` feature.
+//!   - **Standard library / no stdandard library.**
 //!     + It’s possible to compile against the standard library or go on your own without it.
 //!     + Compiling with the standard library is enabled by default.
 //!     + Use `defaut-features = []` in your `Cargo.toml` to disable.
@@ -87,16 +91,17 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 #![cfg_attr(not(feature = "std"), feature(alloc))]
+#![cfg_attr(not(feature = "std"), feature(core_intrinsics))]
 
 // on no_std, we also need the alloc crate for Vec
 #[cfg(not(feature = "std"))] extern crate alloc;
 
-extern crate cgmath;
+#[cfg(feature = "impl-cgmath")] extern crate cgmath;
 
 #[cfg(feature = "serialization")] extern crate serde;
 #[cfg(feature = "serialization")] #[macro_use] extern crate serde_derive;
 
-use cgmath::{InnerSpace, Quaternion, Vector2, Vector3, Vector4};
+#[cfg(feature = "impl-cgmath")] use cgmath::{InnerSpace, Quaternion, Vector2, Vector3, Vector4};
 
 #[cfg(feature = "std")] use std::cmp::Ordering;
 #[cfg(feature = "std")] use std::f32::consts;
@@ -227,7 +232,18 @@ impl<T> Spline<T> {
       Interpolation::Cosine => {
         let cp1 = &keys[i+1];
         let nt = normalize_time(t, cp0, cp1);
-        let cos_nt = (1. - f32::cos(nt * consts::PI)) * 0.5;
+        let cos_nt = {
+          #[cfg(feature = "std")]
+          {
+            (1. - f32::cos(nt * consts::PI)) * 0.5
+          }
+
+          #[cfg(not(feature = "std"))]
+          {
+            use core::intrinsics::cosf32;
+            unsafe { (1. - cosf32(nt * consts::PI)) * 0.5 }
+          }
+        };
 
         Some(Interpolate::lerp(cp0.value, cp1.value, cos_nt))
       },
@@ -329,6 +345,7 @@ impl Interpolate for f32 {
   }
 }
 
+#[cfg(feature = "impl-cgmath")]
 impl Interpolate for Vector2<f32> {
   fn lerp(a: Self, b: Self, t: f32) -> Self {
     a.lerp(b, t)
@@ -339,6 +356,7 @@ impl Interpolate for Vector2<f32> {
   }
 }
 
+#[cfg(feature = "impl-cgmath")]
 impl Interpolate for Vector3<f32> {
   fn lerp(a: Self, b: Self, t: f32) -> Self {
     a.lerp(b, t)
@@ -349,6 +367,7 @@ impl Interpolate for Vector3<f32> {
   }
 }
 
+#[cfg(feature = "impl-cgmath")]
 impl Interpolate for Vector4<f32> {
   fn lerp(a: Self, b: Self, t: f32) -> Self {
     a.lerp(b, t)
@@ -359,6 +378,7 @@ impl Interpolate for Vector4<f32> {
   }
 }
 
+#[cfg(feature = "impl-cgmath")]
 impl Interpolate for Quaternion<f32> {
   fn lerp(a: Self, b: Self, t: f32) -> Self {
     a.nlerp(b, t)