From 1b3c412102ec7d36b6eed980eb3dc3a6f4e27f68 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Wed, 21 Oct 2020 22:26:12 +0300
Subject: [PATCH] Fix orthographic transform applied to vectors & points

---
 libs/geom/include/psemek/geom/homogeneous.hpp | 20 +++++++++++++++++++
 .../geom/include/psemek/geom/orthographic.hpp |  4 ++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/libs/geom/include/psemek/geom/homogeneous.hpp b/libs/geom/include/psemek/geom/homogeneous.hpp
index 137576f3..cce0b495 100644
--- a/libs/geom/include/psemek/geom/homogeneous.hpp
+++ b/libs/geom/include/psemek/geom/homogeneous.hpp
@@ -42,4 +42,24 @@ namespace psemek::geom
 		return result;
 	}
 
+	template <typename T, std::size_t D>
+	vector<T, D - 1> as_vector(vector<T, D> const & v)
+	{
+		static_assert(D > 1);
+		vector<T, D - 1> result;
+		for (std::size_t i = 0; i < D - 1; ++i)
+			result[i] = v[i];
+		return result;
+	}
+
+	template <typename T, std::size_t D>
+	point<T, D - 1> as_point(vector<T, D> const & v)
+	{
+		static_assert(D > 1);
+		point<T, D - 1> result;
+		for (std::size_t i = 0; i < D - 1; ++i)
+			result[i] = v[i] / v[D - 1];
+		return result;
+	}
+
 }
diff --git a/libs/geom/include/psemek/geom/orthographic.hpp b/libs/geom/include/psemek/geom/orthographic.hpp
index b3cd224b..0748008c 100644
--- a/libs/geom/include/psemek/geom/orthographic.hpp
+++ b/libs/geom/include/psemek/geom/orthographic.hpp
@@ -64,13 +64,13 @@ namespace psemek::geom
 	template <typename T, std::size_t D>
 	vector<T, D> orthographic<T, D>::operator() (vector<T, D> v) const
 	{
-		return homogeneous_matrix() * homogeneous(v);
+		return as_vector(homogeneous_matrix() * homogeneous(v));
 	}
 
 	template <typename T, std::size_t D>
 	point<T, D> orthographic<T, D>::operator() (point<T, D> p) const
 	{
-		return homogeneous_matrix() * homogeneous(p);
+		return as_point(homogeneous_matrix() * homogeneous(p));
 	}
 
 	template <typename T, std::size_t D>