From 124ec71c50b8a5dd8e2ebd3590e067367d1040a5 Mon Sep 17 00:00:00 2001
From: Benoit Jacob <jacob.benoit.1@gmail.com>
Date: Sun, 24 Aug 2008 21:25:04 +0000
Subject: [PATCH] allow constructing Transform from small-matrix (like
 fromPosOrientScale but with trivial Pos and Scale)

---
 Eigen/src/Geometry/Transform.h | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Eigen/src/Geometry/Transform.h b/Eigen/src/Geometry/Transform.h
index 1b68a37e5..65d52b51d 100644
--- a/Eigen/src/Geometry/Transform.h
+++ b/Eigen/src/Geometry/Transform.h
@@ -89,10 +89,19 @@ public:
   inline Transform& operator=(const Transform& other)
   { m_matrix = other.m_matrix; return *this; }
 
-  /** Constructs and initializes a transformation from a (Dim+1)^2 matrix. */
+  /** Constructs and initializes a transformation from a Dim^2 or a (Dim+1)^2 matrix. */
   template<typename OtherDerived>
   inline explicit Transform(const MatrixBase<OtherDerived>& other)
-  { m_matrix = other; }
+  {
+    if(OtherDerived::RowsAtCompileTime == Dim)
+    {
+      linear() = other;
+      translation().setZero();
+      m_matrix(Dim,Dim) = Scalar(1);
+      m_matrix.template block<1,Dim>(Dim,0).setZero();
+    }
+    else m_matrix = other;
+  }
 
   /** Set \c *this from a (Dim+1)^2 matrix. */
   template<typename OtherDerived>