From 038b20033843cdfe3938d93d98e2fff5377d0be7 Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Sat, 7 Sep 2013 15:04:33 +1000
Subject: [PATCH] Implement matrix to matrix conversions

---
 src/cgmath/matrix.rs | 42 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/cgmath/matrix.rs b/src/cgmath/matrix.rs
index 63e719a..0d12d46 100644
--- a/src/cgmath/matrix.rs
+++ b/src/cgmath/matrix.rs
@@ -39,11 +39,6 @@ approx_eq!(impl<S> Mat2<S>)
 approx_eq!(impl<S> Mat3<S>)
 approx_eq!(impl<S> Mat4<S>)
 
-// Conversion traits
-pub trait ToMat2<S: Clone + Num + Ord> { fn to_mat2(&self) -> Mat2<S>; }
-pub trait ToMat3<S: Clone + Num + Ord> { fn to_mat3(&self) -> Mat3<S>; }
-pub trait ToMat4<S: Clone + Num + Ord> { fn to_mat4(&self) -> Mat4<S>; }
-
 impl<S: Clone + Num + Ord> Mat2<S> {
     #[inline]
     pub fn new(c0r0: S, c0r1: S,
@@ -571,6 +566,43 @@ for Mat4<S>
     }
 }
 
+// Conversion traits
+pub trait ToMat2<S: Clone + Num + Ord> { fn to_mat2(&self) -> Mat2<S>; }
+pub trait ToMat3<S: Clone + Num + Ord> { fn to_mat3(&self) -> Mat3<S>; }
+pub trait ToMat4<S: Clone + Num + Ord> { fn to_mat4(&self) -> Mat4<S>; }
+
+impl<S: Clone + Float> ToMat3<S> for Mat2<S> {
+    /// Clone the elements of a 2-dimensional matrix into the top corner of a
+    /// 3-dimensional identity matrix.
+    fn to_mat3(&self) -> Mat3<S> {
+        Mat3::new(self.cr(0, 0).clone(), self.cr(0, 1).clone(), zero(),
+                  self.cr(1, 0).clone(), self.cr(1, 1).clone(), zero(),
+                  zero(), zero(), one())
+    }
+}
+
+impl<S: Clone + Float> ToMat4<S> for Mat2<S> {
+    /// Clone the elements of a 2-dimensional matrix into the top corner of a
+    /// 4-dimensional identity matrix.
+    fn to_mat4(&self) -> Mat4<S> {
+        Mat4::new(self.cr(0, 0).clone(), self.cr(0, 1).clone(), zero(), zero(),
+                  self.cr(1, 0).clone(), self.cr(1, 1).clone(), zero(), zero(),
+                  zero(), zero(), one(), zero(),
+                  zero(), zero(), zero(), one())
+    }
+}
+
+impl<S: Clone + Float> ToMat4<S> for Mat3<S> {
+    /// Clone the elements of a 3-dimensional matrix into the top corner of a
+    /// 4-dimensional identity matrix.
+    fn to_mat4(&self) -> Mat4<S> {
+        Mat4::new(self.cr(0, 0).clone(), self.cr(0, 1).clone(), self.cr(0, 2).clone(), zero(),
+                  self.cr(1, 0).clone(), self.cr(1, 1).clone(), self.cr(1, 2).clone(), zero(),
+                  self.cr(2, 0).clone(), self.cr(2, 1).clone(), self.cr(2, 2).clone(), zero(),
+                  zero(), zero(), zero(), one())
+    }
+}
+
 impl<S:Clone + Float> ToQuat<S> for Mat3<S> {
     /// Convert the matrix to a quaternion
     fn to_quat(&self) -> Quat<S> {