vector: add homogenous converter

added for symmetry with point classes

Makefile.am

@@ -246,6 +246,7 @@ UTIL_FILES   =			\
     variadic.ipp		\
     vector.cpp			\
     vector.hpp			\
+    vector.ipp			\
     version.cpp			\
     version.hpp			\
     view.cpp			\

vector.hpp

@@ -11,7 +11,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
- * Copyright 2011 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2011-2015 Danny Robson <danny@nerdcruft.net>
  */
 
 #ifndef __UTIL_VECTOR_HPP
@@ -45,6 +45,9 @@ namespace util {
         vector<S,T>& normalise  (void);
         vector<S,T>  normalised [[gnu::warn_unused_result]] (void) const;
 
+        // representations
+        template <size_t D> vector<D,T> homog (void) const;
+
         // constants
         static const vector<S,T> UNIT;
         static const vector<S,T> ZERO;
@@ -83,5 +86,7 @@ namespace util {
     typedef vector<3,double> vector4d;
 }
 
+#include "vector.ipp"
+
 #endif
 

vector.ipp

@@ -0,0 +1,33 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2011-2015 Danny Robson <danny@nerdcruft.net>
+ */
+
+#if defined(__UTIL_VECTOR_IPP)
+#error
+#else
+#define __UTIL_VECTOR_IPP
+#endif
+
+
+namespace util {
+    template <size_t S, typename T>
+    template <size_t D>
+    vector<D,T>
+    vector<S,T>::homog (void) const
+    {
+        static_assert (D > S, "reducing size loses data");
+        return (*this).template redim<D> (0.f);
+    }
+}