From 97ccb1d641176dabd83d92be2d3a2a7056615db1 Mon Sep 17 00:00:00 2001
From: Hans-Christian Ebke <ebke@cs.rwth-aachen.de>
Date: Mon, 9 Nov 2015 18:46:39 +0100
Subject: [PATCH] Modernized VectorT constructors in C++11 branch.

* Less redundancy.
* We can now make some of the VectorT constructors constexpr which is
useful for other features.
---
 src/OpenMesh/Core/Geometry/VectorT.hh     | 48 +++++++++++++++++------
 src/OpenMesh/Core/Geometry/VectorT_inc.hh | 13 +++++-
 src/Unittests/unittests_vector_type.cc    | 28 +++++++++++++
 3 files changed, 77 insertions(+), 12 deletions(-)

diff --git a/src/OpenMesh/Core/Geometry/VectorT.hh b/src/OpenMesh/Core/Geometry/VectorT.hh
index 5b552072..9c3db706 100644
--- a/src/OpenMesh/Core/Geometry/VectorT.hh
+++ b/src/OpenMesh/Core/Geometry/VectorT.hh
@@ -67,7 +67,6 @@
 
 //== INCLUDES =================================================================
 
-
 #include <OpenMesh/Core/System/config.h>
 #include <ostream>
 #include <cmath>
@@ -78,6 +77,10 @@
 #include <xmmintrin.h>
 #endif
 
+#ifdef CPP11_ENABLED
+#include <array>
+#include <initializer_list>
+#endif
 
 //== NAMESPACES ===============================================================
 
@@ -98,22 +101,45 @@ namespace OpenMesh {
     aligned, so that aligned SSE instructions can be used on these
     vectors.
 */
-template <typename Scalar,int N> struct VectorDataT
-{
-  Scalar values_[N];
+template<typename Scalar, int N> class VectorDataT {
+    public:
+#ifdef CPP11_ENABLED
+        VectorDataT() {}
+
+        template<typename... T>
+        constexpr VectorDataT(T... vs) : values_ {vs...} {
+            static_assert(sizeof...(vs) == N,
+                    "Incorrect number of vector components supplied.");
+        }
+        std::array<Scalar, N> values_;
+#else
+        Scalar values_[N];
+#endif
 };
 
 
 #if defined(__GNUC__) && defined(__SSE__)
 
 /// This specialization enables us to use aligned SSE instructions.
-template <> struct VectorDataT<float, 4>
-{
-  union 
-  {
-    __m128  m128;
-    float   values_[4];
-  };
+template<> class VectorDataT<float, 4> {
+    public:
+#ifdef CPP11_ENABLED
+        VectorDataT() {}
+
+        template<typename... T>
+        constexpr VectorDataT(T... vs) : values_ {vs...} {
+            static_assert(sizeof...(vs) == 4,
+                    "Incorrect number of vector components supplied.");
+        }
+#endif
+        union {
+            __m128 m128;
+#ifdef CPP11_ENABLED
+            std::array<float, 4> values_;
+#else
+            float values_[4];
+#endif
+        };
 };
 
 #endif
diff --git a/src/OpenMesh/Core/Geometry/VectorT_inc.hh b/src/OpenMesh/Core/Geometry/VectorT_inc.hh
index e76ca544..b0c682e8 100644
--- a/src/OpenMesh/Core/Geometry/VectorT_inc.hh
+++ b/src/OpenMesh/Core/Geometry/VectorT_inc.hh
@@ -97,6 +97,15 @@ public:
   /// default constructor creates uninitialized values.
   inline VectorT() {}
 
+#ifdef CPP11_ENABLED
+  explicit inline VectorT(const Scalar& v) {
+      vectorize(v);
+  }
+
+  template<typename... T>
+  constexpr VectorT(T... vs) : Base {vs...}
+  { }
+#else
   /// special constructor for 1D vectors
   explicit inline VectorT(const Scalar& v) {
 //     assert(DIM==1);
@@ -124,6 +133,8 @@ public:
      const Scalar v2, const Scalar v3) {
     Base::values_[0]=v0; Base::values_[1]=v1; Base::values_[2]=v2; Base::values_[3]=v3;
   }
+
+  VectorT homogenized() { return VectorT(Base::values_[0]/Base::values_[3], Base::values_[1]/Base::values_[3], Base::values_[2]/Base::values_[3], 1); }
 #endif
 
 #if DIM == 5
@@ -142,7 +153,7 @@ public:
     Base::values_[3]=v3; Base::values_[4]=v4; Base::values_[5]=v5;
   }
 #endif
-
+#endif
   /// construct from a value array (explicit)
   explicit inline VectorT(const Scalar _values[DIM]) {
     memcpy(Base::values_, _values, DIM*sizeof(Scalar));
diff --git a/src/Unittests/unittests_vector_type.cc b/src/Unittests/unittests_vector_type.cc
index 240eab07..0d157766 100644
--- a/src/Unittests/unittests_vector_type.cc
+++ b/src/Unittests/unittests_vector_type.cc
@@ -83,6 +83,34 @@ TEST_F(OpenMeshVectorTest, VectorCasting) {
 
 }
 
+#ifdef CPP11_ENABLED
+TEST_F(OpenMeshVectorTest, cpp11_constructors) {
+    OpenMesh::Vec3d vec1 { 1.2, 2.0, 3.0 };
 
+    EXPECT_EQ(1.2, vec1[0]);
+    EXPECT_EQ(2.0, vec1[1]);
+    EXPECT_EQ(3.0, vec1[2]);
+
+    OpenMesh::Vec4f vec2 { 1.2f, 3.5f, 1.0f, 0.0f };
+
+    EXPECT_EQ(1.2f, vec2[0]);
+    EXPECT_EQ(3.5f, vec2[1]);
+    EXPECT_EQ(1.0f, vec2[2]);
+    EXPECT_EQ(0.0f, vec2[3]);
+
+    OpenMesh::Vec4f vec2b { vec2 };
+
+    EXPECT_EQ(1.2f, vec2b[0]);
+    EXPECT_EQ(3.5f, vec2b[1]);
+    EXPECT_EQ(1.0f, vec2b[2]);
+    EXPECT_EQ(0.0f, vec2b[3]);
+
+    OpenMesh::Vec4d vec4d { 1.23 };
+    EXPECT_EQ(1.23, vec4d[0]);
+    EXPECT_EQ(1.23, vec4d[1]);
+    EXPECT_EQ(1.23, vec4d[2]);
+    EXPECT_EQ(1.23, vec4d[3]);
+}
+#endif
 
 }