Added ToComponents. Moved from_value into .

src/cgmath.rs

@@ -15,7 +15,7 @@
 
 #![crate_type = "rlib"]
 #![crate_type = "dylib"]
-#![feature(old_impl_check, plugin, core, hash, std_misc)]
+#![feature(old_impl_check, plugin, core, std_misc)]
 #![plugin(rand_macros)]
 
 //! Computer graphics-centric math.

src/transform.rs

@@ -16,7 +16,7 @@
 use std::fmt;
 
 use approx::ApproxEq;
-use matrix::{Matrix, Matrix4, ToMatrix4};
+use matrix::{Matrix, ToMatrix3, Matrix4, ToMatrix4};
 use num::{BaseNum, BaseFloat, zero, one};
 use point::{Point, Point3};
 use ray::Ray;
@@ -84,7 +84,12 @@ pub struct Decomposed<S, V, R> {
     pub disp: V,
 }
 
-impl<S: BaseFloat, V: Vector<S>, P: Point<S, V>, R: Rotation<S, V, P>> Transform<S, V, P> for Decomposed<S, V, R> {
+impl<
+    S: BaseFloat,
+    V: Vector<S>,
+    P: Point<S, V>,
+    R: Rotation<S, V, P>
+> Transform<S, V, P> for Decomposed<S, V, R> {
     #[inline]
     fn identity() -> Decomposed<S, V, R> {
         Decomposed {
@@ -142,7 +147,10 @@ impl<S: BaseFloat, V: Vector<S>, P: Point<S, V>, R: Rotation<S, V, P>> Transform
 
 pub trait Transform3<S>: Transform<S, Vector3<S>, Point3<S>> + ToMatrix4<S> {}
 
-impl<S: BaseFloat + 'static, R: Rotation3<S>> ToMatrix4<S> for Decomposed<S, Vector3<S>, R> {
+impl<
+    S: BaseFloat + 'static,
+    R: Rotation3<S>
+> ToMatrix4<S> for Decomposed<S, Vector3<S>, R> {
     fn to_matrix4(&self) -> Matrix4<S> {
         let mut m = self.rot.to_matrix3().mul_s(self.scale.clone()).to_matrix4();
         m.w = self.disp.extend(one());
@@ -150,9 +158,15 @@ impl<S: BaseFloat + 'static, R: Rotation3<S>> ToMatrix4<S> for Decomposed<S, Vec
     }
 }
 
-impl<S: BaseFloat, R: Rotation3<S>> Transform3<S> for Decomposed<S,Vector3<S>,R> where S: 'static {}
+impl<
+    S: BaseFloat + 'static,
+    R: Rotation3<S>
+> Transform3<S> for Decomposed<S, Vector3<S>, R> {}
 
-impl<S: BaseFloat, R: fmt::Debug + Rotation3<S>> fmt::Debug for Decomposed<S,Vector3<S>,R> {
+impl<
+    S: BaseFloat,
+    R: fmt::Debug + Rotation3<S>
+> fmt::Debug for Decomposed<S, Vector3<S>, R> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "(scale({:?}), rot({:?}), disp{:?})",
             self.scale, self.rot, self.disp)
@@ -202,3 +216,40 @@ impl<S: BaseNum> ToMatrix4<S> for AffineMatrix3<S> {
 }
 
 impl<S: BaseFloat> Transform3<S> for AffineMatrix3<S> where S: 'static {}
+
+/// A trait that allows extracting components (rotation, translation, scale)
+/// from an arbitrary transformation/
+pub trait ToComponents<S, V: Vector<S>, P: Point<S, V>> {
+    /// Associated rotation type
+    type Rotation;
+    /// Extract translation component
+    fn to_translation(&self) -> V;
+    /// Extract rotation component
+    fn to_rotation(&self) -> Self::Rotation;
+    /// Extract scale component
+    fn to_scale(&self) -> V;
+}
+
+impl<
+    S: BaseFloat,
+    V: Vector<S> + Clone,
+    P: Point<S, V>,
+    R: Rotation<S, V, P> + Clone,
+> ToComponents<S, V, P> for Decomposed<S, V, R> {
+    type Rotation = R;
+    
+    fn to_translation(&self) -> V {
+        self.disp.clone()
+    }
+
+    fn to_rotation(&self) -> R {
+        self.rot.clone()
+    }
+
+    fn to_scale(&self) -> V {
+        Vector::from_value(self.scale)
+    }
+}
+
+pub trait ToComponents3<S>: ToComponents<S, Vector3<S>, Point3<S>>
+    where Self::Rotation: ToMatrix3<S> {}

src/vector.rs

@@ -22,11 +22,11 @@
 //! vector are also provided:
 //!
 //! ```rust
-//! use cgmath::{Vector2, Vector3, Vector4, one, zero, vec3};
+//! use cgmath::{Vector, Vector2, Vector3, Vector4, zero, vec2, vec3};
 //!
 //! assert_eq!(Vector2::new(1.0f64, 0.0f64), Vector2::unit_x());
 //! assert_eq!(vec3(0.0f64, 0.0f64, 0.0f64), zero());
-//! assert_eq!(Vector4::from_value(1.0f64), one());
+//! assert_eq!(Vector::from_value(1.0f64), vec2(1.0, 1.0));
 //! ```
 //!
 //! Vectors can be manipulated with typical mathematical operations (addition,
@@ -76,7 +76,7 @@
 //!
 //! // Scalar multiplication can return a new object, or be done in place
 //! // to avoid an allocation:
-//! let mut c: Vector4<f64> = Vector4::from_value(3.0);
+//! let mut c: Vector4<f64> = Vector::from_value(3.0);
 //! let d: Vector4<f64> = c.mul_s(2.0);
 //! c.mul_self_s(2.0);
 //! assert_eq!(c, d);
@@ -110,6 +110,8 @@ use num::{BaseNum, BaseFloat, Zero, One, zero, one};
 /// of these make sense from a linear algebra point of view, but are included
 /// for pragmatic reasons.
 pub trait Vector<S: BaseNum>: Array1<S> + Zero + One + Neg<Output=Self> {
+    /// Construct a vector from a single value, replicating it.
+    fn from_value(s: S) -> Self;
     /// Add a scalar to this vector, returning a new vector.
     #[must_use]
     fn add_s(&self, s: S) -> Self;
@@ -206,14 +208,6 @@ macro_rules! vec(
             $Self_::new($($field),+)
         }
 
-        impl<$S: Copy> $Self_<$S> {
-            /// Construct a vector from a single value, replicating it.
-            #[inline]
-            pub fn from_value(value: $S) -> $Self_<$S> {
-                $Self_ { $($field: value),+ }
-            }
-        }
-
         impl<$S: Zero> Zero for $Self_<$S> {
             #[inline]
             fn zero() -> $Self_<S> { $Self_ { $($field: zero()),+ } }
@@ -292,6 +286,7 @@ macro_rules! vec(
         }
 
         impl<S: BaseNum> Vector<S> for $Self_<S> {
+            #[inline] fn from_value(s: S) -> $Self_<S> { $Self_ { $($field: s),+ } }
             #[inline] fn add_s(&self, s: S) -> $Self_<S> { $Self_::new($(self.$field + s),+) }
             #[inline] fn sub_s(&self, s: S) -> $Self_<S> { $Self_::new($(self.$field - s),+) }
             #[inline] fn mul_s(&self, s: S) -> $Self_<S> { $Self_::new($(self.$field * s),+) }

tests/vector.rs

@@ -31,9 +31,9 @@ fn test_constructor() {
 
 #[test]
 fn test_from_value() {
-    assert_eq!(Vector2::from_value(102is), Vector2::new(102is, 102is));
+    assert_eq!(Vector::from_value(102is), Vector2::new(102is, 102is));
-    assert_eq!(Vector3::from_value(22is), Vector3::new(22is, 22is, 22is));
+    assert_eq!(Vector::from_value(22is), Vector3::new(22is, 22is, 22is));
-    assert_eq!(Vector4::from_value(76.5f64), Vector4::new(76.5f64, 76.5f64, 76.5f64, 76.5f64));
+    assert_eq!(Vector::from_value(76.5f64), Vector4::new(76.5f64, 76.5f64, 76.5f64, 76.5f64));
 }
 
 #[test]