From 24e7663c5caccf0772a3115fad3c5ee0bfaf44f1 Mon Sep 17 00:00:00 2001
From: Sam Hocevar <sam@hocevar.net>
Date: Fri, 21 Nov 2014 13:52:05 +0000
Subject: [PATCH] simplex: fix confusion between interpolated types and
 coordinate types.

---
 src/lol/math/simplex_interpolator.h | 26 +++++++++++++-------------
 src/t/math/simplex_interpolator.cpp | 12 +++++++++++-
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/src/lol/math/simplex_interpolator.h b/src/lol/math/simplex_interpolator.h
index 41a3f139..97825107 100644
--- a/src/lol/math/simplex_interpolator.h
+++ b/src/lol/math/simplex_interpolator.h
@@ -33,14 +33,14 @@ public:
     }
 
     // Single interpolation
-    inline T Interp(vec_t<T, N> position) const
+    inline T Interp(vec_t<float, N> position) const
     {
         // Computing position in simplex referential
-        vec_t<T, N> simplex_position = m_base_inverse * position;
+        vec_t<float, N> simplex_position = m_base_inverse * position;
 
         // Retrieving the closest floor point and decimals
         vec_t<int, N> floor_point;
-        vec_t<T, N> decimal_point;
+        vec_t<float, N> decimal_point;
 
         this->ExtractFloorDecimal(simplex_position, floor_point, decimal_point);
 
@@ -55,12 +55,12 @@ public:
 protected:
 
     inline T LastInterp(vec_t<int, N> const & floor_point,
-                        vec_t<T, N> const & decimal_point,
+                        vec_t<float, N> const & decimal_point,
                         int const & sign) const
     {
-        T result = 0;
-        T floor_coeff = 0;
-        T divider = 0;
+        T result(0);
+        float floor_coeff = 0;
+        float divider = 0;
 
         for (int i = 0 ; i < N ; ++i)
         {
@@ -72,7 +72,7 @@ protected:
             divider += decimal_point[i];
         }
 
-        T sqr_norm = N;
+        float sqr_norm = N;
 
         result += (1 - 2 * floor_coeff / sqr_norm) * this->m_samples[floor_point];
         divider += (1 - 2 * floor_coeff / sqr_norm);
@@ -87,12 +87,12 @@ protected:
         return ret >= 0 ? ret : ret + dim;
     }
 
-    inline void GetReference(vec_t<int, N> & floor_point, vec_t<T, N> & decimal_point, int & sign) const
+    inline void GetReference(vec_t<int, N> & floor_point, vec_t<float, N> & decimal_point, int & sign) const
     {
         // Choosing the reference point which determines in which simplex we are working
         // ie. (0, 0, 0, …) and upper or (1, 1, 1, …) and lower
 
-        T cumul = 0;
+        float cumul = 0;
         for (int i = 0 ; i < N ; ++i)
             cumul += decimal_point[i];
 
@@ -102,12 +102,12 @@ protected:
         {
             sign = -1;
 
-            decimal_point = vec_t<T, N>(1) - decimal_point;
+            decimal_point = vec_t<float, N>(1) - decimal_point;
             floor_point = floor_point + vec_t<int, N>(1);
         }
     }
 
-    inline void ExtractFloorDecimal(vec_t<T, N> const & simplex_position, vec_t<int, N> & floor_point, vec_t<T, N> & decimal_point) const
+    inline void ExtractFloorDecimal(vec_t<float, N> const & simplex_position, vec_t<int, N> & floor_point, vec_t<float, N> & decimal_point) const
     {
         // Finding floor point index
         for (int i = 0 ; i < N ; ++i)
@@ -140,7 +140,7 @@ protected:
         }
     }
 
-    mat_t<T, N, N> m_base, m_base_inverse;
+    mat_t<float, N, N> m_base, m_base_inverse;
     arraynd<N, T> m_samples;
 };
 
diff --git a/src/t/math/simplex_interpolator.cpp b/src/t/math/simplex_interpolator.cpp
index c97cee0c..818c00f4 100644
--- a/src/t/math/simplex_interpolator.cpp
+++ b/src/t/math/simplex_interpolator.cpp
@@ -23,7 +23,7 @@ lolunit_declare_fixture(SimplexInterpolatorTest)
 
     void TearDown() {}
 
-    lolunit_declare_test(GridPoints2D1x1)
+    lolunit_declare_test(FloatGridPoints2D1x1)
     {
         simplex_interpolator<2> s({{1.f}});
         float val;
@@ -48,6 +48,16 @@ lolunit_declare_fixture(SimplexInterpolatorTest)
         lolunit_assert_doubles_equal(1.f, val, 1e-5f);
     }
 
+    lolunit_declare_test(VectorGridPoints2D1x1)
+    {
+        simplex_interpolator<2, vec3> s({{vec3(1.f, 2.f, 3.f)}});
+
+        vec3 val = s.Interp(GridPoint2D(-1, 0));
+        lolunit_assert_doubles_equal(1.f, val.x, 1e-5f);
+        lolunit_assert_doubles_equal(2.f, val.y, 1e-5f);
+        lolunit_assert_doubles_equal(3.f, val.z, 1e-5f);
+    }
+
     lolunit_declare_test(GridPoints2D2x2)
     {
         simplex_interpolator<2> s({{1.f, 1.f}, {1.f, 2.f}});