From 204db1dfb803a97481f2a8b3bbaf6e20be6e0980 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 20 May 2013 19:12:24 +0300
Subject: [PATCH] Give Vector constructors from one higher/lower dimension

These replace the augment/reduce_vector functions, which were in a rather
odd place.
---
 source/geometry/affinetransformation.h | 34 ++------------------------
 source/linal/vector.h                  | 21 ++++++++++++++++
 2 files changed, 23 insertions(+), 32 deletions(-)

diff --git a/source/geometry/affinetransformation.h b/source/geometry/affinetransformation.h
index 430619e..0e377ba 100644
--- a/source/geometry/affinetransformation.h
+++ b/source/geometry/affinetransformation.h
@@ -168,46 +168,16 @@ inline AffineTransformation<T, D> invert(const AffineTransformation<T, D> &at)
 	return r.invert();
 }
 
-
-template<typename T, unsigned N>
-inline LinAl::Vector<T, N+1> augment_vector(const LinAl::Vector<T, N> &v, T s)
-{
-	LinAl::Vector<T, N+1> r;
-	for(unsigned i=0; i<N; ++i)
-		r[i] = v[i];
-	r[N] = s;
-	return r;
-}
-
-template<typename T, unsigned N>
-inline LinAl::Vector<T, N-1> reduce_vector(const LinAl::Vector<T, N> &v)
-{
-	LinAl::Vector<T, N-1> r;
-	for(unsigned i=0; i<N-1; ++i)
-		r[i] = v[i];
-	return r;
-}
-
-template<typename T, unsigned N>
-inline LinAl::Vector<T, N-1> divide_vector(const LinAl::Vector<T, N> &v)
-{
-	LinAl::Vector<T, N-1> r;
-	for(unsigned i=0; i<N-1; ++i)
-		r[i] = v[i]/v[N-1];
-	return r;
-}
-
-
 template<typename T, unsigned D>
 inline LinAl::Vector<T, D> AffineTransformation<T, D>::transform(const LinAl::Vector<T, D> &v) const
 {
-	return reduce_vector(matrix*augment_vector(v, T(1)));
+	return LinAl::Vector<T, D>(matrix*LinAl::Vector<T, D+1>(v, T(1)));
 }
 
 template<typename T, unsigned D>
 inline LinAl::Vector<T, D> AffineTransformation<T, D>::transform_linear(const LinAl::Vector<T, D> &v) const
 {
-	return reduce_vector(matrix*augment_vector(v, T(0)));
+	return LinAl::Vector<T, D>(matrix*LinAl::Vector<T, D+1>(v, T(0)));
 }
 
 } // namespace Geometry
diff --git a/source/linal/vector.h b/source/linal/vector.h
index 369e3ff..a5c9a26 100644
--- a/source/linal/vector.h
+++ b/source/linal/vector.h
@@ -81,6 +81,10 @@ public:
 	Vector(T, T, T, T);
 	template<typename U>
 	Vector(const Vector<U, N> &);
+	template<typename U>
+	Vector(const Vector<U, N-1> &, U);
+	template<typename U>
+	explicit Vector(const Vector<U, N+1> &);
 
 	Vector &operator*=(T);
 	Vector &operator/=(T);
@@ -140,6 +144,23 @@ inline Vector<T, N>::Vector(const Vector<U, N> &v)
 		(*this)[i] = v[i];
 }
 
+template<typename T, unsigned N>
+template<typename U>
+inline Vector<T, N>::Vector(const Vector<U, N-1> &v, U s)
+{
+	for(unsigned i=0; i<N-1; ++i)
+		(*this)[i] = v[i];
+	(*this)[N-1] = s;
+}
+
+template<typename T, unsigned N>
+template<typename U>
+inline Vector<T, N>::Vector(const Vector<U, N+1> &v)
+{
+	for(unsigned i=0; i<N; ++i)
+		(*this)[i] = v[i];
+}
+
 template<typename T, unsigned N>
 inline Vector<T, N> &Vector<T, N>::operator*=(T s)
 {
-- 
2.43.0