simplex_interpolator: adding interpolator skeleton

src/lol/math/simplex_interpolator.h

@@ -0,0 +1,76 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2014 Sam Hocevar <sam@hocevar.net>
+//            (c) 2013-2014 Benjamin "Touky" Huet <huet.benjamin@gmail.com>
+//            (c) 2013-2014 Guillaume Bittoun <guillaume.bittoun@gmail.com>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+#pragma once
+
+template<int N /* Dimension of the space */, typename T = float /* floating type used for interpolation */>
+class simplex_interpolator
+{
+public:
+
+    simplex_interpolator()
+    {
+        this->InitBase();
+    }
+
+    inline arraynd<N, T> & GetSamples()
+    {
+        return this->samples;
+    }
+
+    // Single interpolation
+    inline T interp(vec_t<T, N> position)
+    {
+        vec_t<T, N> simplex_position = this->ToSimplexRef(position);
+
+        // TODO
+
+        return 0;
+    }
+
+protected:
+
+    inline void InitBase()
+    {
+        base.SetSize(vec_t<int, 2>(N, N));
+        base_inverse.SetSize(vec_t<int, 2>(N, N));
+
+        for (int i = 0 ; i < N ; ++i)
+        {
+            for (int j = i ; j < N ; ++j)
+            {
+                base[i][j] = sqrt((i+2)/(2*i + 2)) / (j > i ? i + 2 : 1);
+                base_inverse[i][j] = sqrt((2*j + 2)/(j+2)) * (j > i ? (1 / (float)j) : 1);
+            }
+        }
+    }
+
+    inline vec_t<T, N> ToSimplexRef(vec_t<T, N> const & position)
+    {
+        vec_t<T, N> result;
+
+        for (int i = 0 ; i < N ; ++i)
+        {
+            for (int j = i ; j < N ; ++j)
+            {
+                result[i] += base_inverse[i][j] * position[j];
+            }
+        }
+
+        return result;
+    }
+
+    arraynd<2, T> base;
+    arraynd<2, T> base_inverse;
+
+    arraynd<N, T> samples;
+};