From 57a3b0fd1e0af0eb032bb426655a3af037cf5f01 Mon Sep 17 00:00:00 2001
From: Mathias Froehlich <Mathias.Froehlich@web.de>
Date: Sat, 3 Mar 2012 11:56:40 +0100
Subject: [PATCH] math: Move lerp function into SGMisc.

---
 simgear/math/CMakeLists.txt |  1 -
 simgear/math/Math.hxx       | 23 -----------------------
 simgear/math/SGMisc.hxx     |  5 +++++
 simgear/scene/sky/dome.cxx  | 10 +++++-----
 4 files changed, 10 insertions(+), 29 deletions(-)
 delete mode 100644 simgear/math/Math.hxx

diff --git a/simgear/math/CMakeLists.txt b/simgear/math/CMakeLists.txt
index b01f9259..ef71ed50 100644
--- a/simgear/math/CMakeLists.txt
+++ b/simgear/math/CMakeLists.txt
@@ -2,7 +2,6 @@ include (SimGearComponent)
 
 
 set(HEADERS 
-    Math.hxx
     SGBox.hxx
     SGCMath.hxx
     SGGeoc.hxx
diff --git a/simgear/math/Math.hxx b/simgear/math/Math.hxx
deleted file mode 100644
index 427923ec..00000000
--- a/simgear/math/Math.hxx
+++ /dev/null
@@ -1,23 +0,0 @@
-#ifndef SIMGEAR_MATH_MATH_HXX
-#define SIMGEAR_MATH_MATH_HXX 1
-namespace simgear
-{
-namespace math
-{
-/** Linear interpolation between two values.
- */
-template<typename T>
-inline T lerp(const T& x, const T& y, double alpha)
-{
-    return x * (1.0 - alpha) + y * alpha;
-}
-
-template<typename T>
-inline T lerp(const T& x, const T& y, float alpha)
-{
-    return x * (1.0f - alpha) + y * alpha;
-}
-
-}
-}
-#endif
diff --git a/simgear/math/SGMisc.hxx b/simgear/math/SGMisc.hxx
index 89417cb3..5e69077e 100644
--- a/simgear/math/SGMisc.hxx
+++ b/simgear/math/SGMisc.hxx
@@ -87,6 +87,11 @@ public:
   static int roundToInt(const T& v)
   { return int(round(v)); }
 
+  // Linear interpolation between two arbitrary typed values
+  template<typename S>
+  static S lerp(const S& val0, const S& val1, const T& t)
+  { return val0*(T(1) - t) + val1*t; }
+
 #ifndef NDEBUG
   /// Returns true if v is a NaN value
   /// Use with care: allways code that you do not need to use that!
diff --git a/simgear/scene/sky/dome.cxx b/simgear/scene/sky/dome.cxx
index 5cd40cb4..53018f02 100644
--- a/simgear/scene/sky/dome.cxx
+++ b/simgear/scene/sky/dome.cxx
@@ -40,7 +40,7 @@
 #include <osg/CullFace>
 
 #include <simgear/debug/logstream.hxx>
-#include <simgear/math/Math.hxx>
+#include <simgear/math/SGMath.hxx>
 #include <simgear/scene/util/VectorArrayAdapter.hxx>
 #include <simgear/scene/material/Effect.hxx>
 #include <simgear/scene/material/EffectGeode.hxx>
@@ -234,7 +234,7 @@ static void fade_to_black(osg::Vec3 sky_color[], float asl, int count) {
         sky_color[i] *= d;
 }
 
-inline void clampColor(osg::Vec3& color)
+static inline void clampColor(osg::Vec3& color)
 {
     color.x() = osg::clampTo(color.x(), 0.0f, 1.0f);
     color.y() = osg::clampTo(color.y(), 0.0f, 1.0f);
@@ -310,17 +310,17 @@ SGSkyDome::repaint( const SGVec3f& sun_color, const SGVec3f& sky_color,
         int j=0;
         // Color top half by linear interpolation (90...60 degrees)
         for (; j < upperRings; j++)
-            colors(j, i) = simgear::math::lerp(toOsg(sky_color), colors(upperRings, i), j / (float)upperRings);
+            colors(j, i) = SGMiscf::lerp(toOsg(sky_color), colors(upperRings, i), j / (float)upperRings);
 
         j++; // Skip the 60 deg ring
         // From 60 to ~85 degrees
         for (int l = 0; j < upperRings + middleRings + 1; j++, l++)
-            colors(j, i) = simgear::math::lerp(colors(upperRings, i),
+            colors(j, i) = SGMiscf::lerp(colors(upperRings, i),
                        toOsg(sky_color - middleVisFactor * diff + middle_amt), l / (float)middleRings);
 
         // 85 to 90 degrees
         for (int l = 0; j < halfRings; j++, l++)
-            colors(j, i) = simgear::math::lerp(colors(upperRings + middleRings, i), toOsg(fog_color + outer_amt),
+            colors(j, i) = SGMiscf::lerp(colors(upperRings + middleRings, i), toOsg(fog_color + outer_amt),
                         l / (float)(halfRings - upperRings - middleRings));
 
         // Original colors