From cb9e4bce1903ef60e67f4f20ba85931f61fb7547 Mon Sep 17 00:00:00 2001
From: King_DuckZ <king_duckz@gmx.com>
Date: Sun, 16 Aug 2015 20:32:58 +0200
Subject: [PATCH] Add to_index() function to convert coords to scalar.

---
 include/doorkeeper/components/tilecoords.hpp |  6 +++++
 include/doorkeeper/implem/tilecoords.inl     | 26 +++++++++++++++++++
 test/unit/tilecoords.cpp                     | 27 ++++++++++++++++++++
 3 files changed, 59 insertions(+)

diff --git a/include/doorkeeper/components/tilecoords.hpp b/include/doorkeeper/components/tilecoords.hpp
index 1126f50..b5f87a2 100644
--- a/include/doorkeeper/components/tilecoords.hpp
+++ b/include/doorkeeper/components/tilecoords.hpp
@@ -48,6 +48,12 @@ namespace dk {
 		CoordinateScalarType sub_mod ( CoordinateScalarType parA, CoordinateScalarType parB, CoordinateScalarType parDiv ) a_pure;
 		CoordinateScalarType sub_div ( CoordinateScalarType parA, CoordinateScalarType parB, CoordinateScalarType parDiv ) a_pure;
 	} //namespace implem
+
+	template <uint32_t D>
+	CoordinateDistType to_index ( const Vector<D>& parPos, const Vector<D>& parUpper ) a_pure;
+
+	template <uint32_t D>
+	CoordinateDistType to_index ( const TileCoords<D>& parTC ) a_pure;
 } //namespace dk
 
 #include "doorkeeper/implem/tilecoords.inl"
diff --git a/include/doorkeeper/implem/tilecoords.inl b/include/doorkeeper/implem/tilecoords.inl
index 6b19bef..214634e 100644
--- a/include/doorkeeper/implem/tilecoords.inl
+++ b/include/doorkeeper/implem/tilecoords.inl
@@ -40,6 +40,32 @@ namespace dk {
 		}
 	} //namespace implem
 
+	template <uint32_t D>
+	inline CoordinateDistType to_index (const Vector<D>& parPos, const Vector<D>& parUpper) {
+		CoordinateDistType index = 0;
+		for (CoordinateDistType d = 0; d < D; ++d) {
+			auto pos = static_cast<CoordinateDistType>(parPos[D - 1 - d]);
+			for (CoordinateDistType p = 0; p < D - 1 - d; ++p) {
+				pos *= static_cast<CoordinateDistType>(parUpper[p] + 1);
+			}
+
+			index += pos;
+		}
+		return index;
+	}
+
+#if defined(NDEBUG)
+	template <>
+	inline CoordinateDistType to_index<2> (const Vector<2>& parPos, const Vector<2>& parUpper) {
+		return parPos.y() * (parUpper.x() + 1) + parPos.x();
+	}
+#endif
+
+	template <uint32_t D>
+	inline CoordinateDistType to_index (const TileCoords<D>& parTC) {
+		return to_index<D>(parTC.position(), parTC.upper());
+	}
+
 	template <uint32_t D>
 	TileCoords<D>::TileCoords (const coords& parSize) :
 		m_pos(CoordinateScalarType(0)),
diff --git a/test/unit/tilecoords.cpp b/test/unit/tilecoords.cpp
index 55c94ea..c496da3 100644
--- a/test/unit/tilecoords.cpp
+++ b/test/unit/tilecoords.cpp
@@ -140,3 +140,30 @@ TEST(back_forward, tilecoords) {
 		EXPECT_EQ(coords4(69, 1934, 3, 0), test.position());
 	}
 }
+
+TEST(to_index, tilecoords) {
+	typedef dk::TileCoords<2> tcoords2;
+	typedef dk::TileCoords<2>::coords coords2;
+
+	{
+		const coords2 max_coords(1000);
+		tcoords2 test(max_coords);
+
+		EXPECT_EQ(0, dk::to_index(test));
+
+		++test;
+		EXPECT_EQ(1, dk::to_index(test));
+
+		--test;
+		EXPECT_EQ(0, dk::to_index(test));
+
+		test += 1;
+		EXPECT_EQ(1, dk::to_index(test));
+
+		test += 1;
+		EXPECT_EQ(2, dk::to_index(test));
+
+		test += 1501;
+		EXPECT_EQ(1503, dk::to_index(test));
+	}
+}