From bd9f129b3a6bc15d71698f5116f14b6d6b6b626f Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Tue, 3 Sep 2013 18:03:18 +1000
Subject: [PATCH] Add Mat2::from_angle constructor

---
 src/cgmath/matrix.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/cgmath/matrix.rs b/src/cgmath/matrix.rs
index 6a2096f..c5d2cdb 100644
--- a/src/cgmath/matrix.rs
+++ b/src/cgmath/matrix.rs
@@ -15,7 +15,7 @@
 
 //! Column major, square matrix types and traits.
 
-use std::num::{one, zero};
+use std::num::{one, zero, sin, cos};
 
 use array::*;
 use quaternion::{Quat, ToQuat};
@@ -69,6 +69,17 @@ impl<S: Clone + Num> Mat2<S> {
     }
 }
 
+impl<S: Clone + Float> Mat2<S> {
+    #[inline]
+    pub fn from_angle(radians: S) -> Mat2<S> {
+        let cos_theta = cos(radians.clone());
+        let sin_theta = sin(radians.clone());
+
+        Mat2::new(cos_theta.clone(),  -sin_theta.clone(),
+                  sin_theta.clone(),  cos_theta.clone())
+    }
+}
+
 impl<S: Clone + Num> Mat3<S> {
     #[inline]
     pub fn new(c0r0:S, c0r1:S, c0r2:S,