math: Interp class for frame-independent interpolation.

src/Makefile.am

@@ -37,7 +37,7 @@ liblolcore_headers = \
     \
     lol/math/math.h \
     lol/math/functions.h lol/math/vector.h lol/math/half.h lol/math/real.h \
-    lol/math/remez.h lol/math/math.h lol/math/geometry.h \
+    lol/math/remez.h lol/math/math.h lol/math/geometry.h lol/math/interp.h \
     \
     lol/sys/sys.h \
     lol/sys/init.h lol/sys/file.h lol/sys/thread.h lol/sys/atomic.h \

src/lol/math/interp.h

@@ -0,0 +1,88 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2013 Sam Hocevar <sam@hocevar.net>
+//   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.
+//
+
+//
+// Interpolator classes
+// --------------------
+//
+
+#if !defined __LOL_MATH_INTERP_H__
+#define __LOL_MATH_INTERP_H__
+
+namespace lol
+{
+
+template<typename T, int N = 16> class Interp
+{
+public:
+    inline Interp() : m_pos(-N) {}
+    inline ~Interp() {}
+
+    void Set(float key, T const &val)
+    {
+        if (m_pos < 0)
+        {
+            m_key[m_pos + N] = key;
+            m_val[m_pos + N] = val;
+            ++m_pos;
+        }
+        else
+        {
+            m_key[m_pos] = key;
+            m_val[m_pos] = val;
+            m_pos = (m_pos + 1) % N;
+        }
+    }
+
+    T Get(float key)
+    {
+        if (m_pos == -N)
+            return T();
+        if (m_pos == 1 - N)
+            return m_val[0];
+
+        int start = max(0, m_pos);
+        int a = 0;
+        int b = min(m_pos + N, N);
+
+        while (a + 1 < b)
+        {
+            int c = (a + b) / 2;
+            if (m_key[(start + c) % N] >= key)
+                b = c;
+            else
+                a = c;
+        }
+
+        float ka = m_key[(start + a) % N];
+        float kb = m_key[(start + b) % N];
+        float u = (key - ka) / (kb - ka);
+
+        return (1.f - u) * m_val[(start + a) % N] + u * m_val[(start + b) % N];
+    }
+
+    inline void Reset()
+    {
+        m_pos = -N;
+    }
+
+private:
+    float m_key[N];
+    T m_val[N];
+
+    /* If m_pos < 0, the value indicates how many free slots
+     * there are. */
+    int m_pos;
+};
+
+} /* namespace lol */
+
+#endif // __LOL_MATH_INTERP_H__
+

src/lol/math/math.h

@@ -16,6 +16,7 @@
 #include <lol/math/real.h>
 #include <lol/math/vector.h>
 #include <lol/math/geometry.h>
+#include <lol/math/interp.h>
 
 #endif // __LOL_MATH_MATH_H__
 

src/lolcore.vcxproj

@@ -214,6 +214,7 @@
     <ClInclude Include="lol\math\functions.h" />
     <ClInclude Include="lol\math\geometry.h" />
     <ClInclude Include="lol\math\half.h" />
+    <ClInclude Include="lol\math\interp.h" />
     <ClInclude Include="lol\math\math.h" />
     <ClInclude Include="lol\math\real.h" />
     <ClInclude Include="lol\math\remez.h" />
@@ -280,4 +281,4 @@
   <ImportGroup Label="ExtensionTargets">
     <Import Project="$(SolutionDir)\Lol.Fx.targets" />
   </ImportGroup>
-</Project>
+</Project>

src/lolcore.vcxproj.filters

@@ -512,6 +512,9 @@
     <ClInclude Include="lol\math\geometry.h">
       <Filter>lol\math</Filter>
     </ClInclude>
+    <ClInclude Include="lol\math\interp.h">
+      <Filter>lol\math</Filter>
+    </ClInclude>
     <ClInclude Include="easymesh\csgbsp.h">
       <Filter>easymesh</Filter>
     </ClInclude>

test/Makefile.am

@@ -21,7 +21,7 @@ testsuite_SOURCES = testsuite.cpp \
     unit/vector.cpp unit/matrix.cpp unit/half.cpp unit/trig.cpp \
     unit/build.cpp unit/real.cpp unit/image.cpp unit/quat.cpp unit/cmplx.cpp \
     unit/array.cpp unit/rotation.cpp unit/string.cpp unit/map.cpp \
-    unit/color.cpp unit/atomic.cpp
+    unit/color.cpp unit/atomic.cpp unit/interp.cpp
 testsuite_CPPFLAGS = $(AM_CPPFLAGS)
 testsuite_DEPENDENCIES = @LOL_DEPENDENCIES@
 

test/testsuite.vcxproj

@@ -42,6 +42,7 @@
     <ClCompile Include="unit\color.cpp" />
     <ClCompile Include="unit\half.cpp" />
     <ClCompile Include="unit\image.cpp" />
+    <ClCompile Include="unit\interp.cpp" />
     <ClCompile Include="unit\map.cpp" />
     <ClCompile Include="unit\matrix.cpp" />
     <ClCompile Include="unit\quat.cpp" />

test/unit/color.cpp

@@ -84,7 +84,7 @@ LOLUNIT_FIXTURE(ColorTest)
             LOLUNIT_SET_CONTEXT(n / 7);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(d1, d2, 0.0001);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(d2, d3, 0.0001);
-            LOLUNIT_UNSET_CONTEXT();
+            LOLUNIT_UNSET_CONTEXT(n / 7);
         }
     }
 
@@ -106,7 +106,7 @@ LOLUNIT_FIXTURE(ColorTest)
             LOLUNIT_ASSERT_DOUBLES_EQUAL(v1.g, v3.g, 0.0001);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(v1.b, v3.b, 0.0001);
 
-            LOLUNIT_UNSET_CONTEXT();
+            LOLUNIT_UNSET_CONTEXT(&rgb[0]);
         }
     }
 
@@ -128,7 +128,7 @@ LOLUNIT_FIXTURE(ColorTest)
             LOLUNIT_ASSERT_DOUBLES_EQUAL(v2.y, v3.y, 0.0001);
             LOLUNIT_ASSERT_DOUBLES_EQUAL(v2.z, v3.z, 0.0001);
 
-            LOLUNIT_UNSET_CONTEXT();
+            LOLUNIT_UNSET_CONTEXT(&rgb[0]);
         }
     }
 };

test/unit/interp.cpp

@@ -0,0 +1,41 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2013 Sam Hocevar <sam@hocevar.net>
+//   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.
+//
+
+#if defined HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include "core.h"
+#include "lol/unit.h"
+
+namespace lol
+{
+
+LOLUNIT_FIXTURE(InterpTest)
+{
+    void SetUp() {}
+
+    void TearDown() {}
+
+    LOLUNIT_TEST(FloatInterp)
+    {
+        Interp<float> interp;
+
+        interp.Set(1.f, 100.f);
+        interp.Set(2.f, 150.f);
+
+        LOLUNIT_ASSERT_DOUBLES_EQUAL(75.f, interp.Get(0.5f), 1.e-5f);
+        LOLUNIT_ASSERT_DOUBLES_EQUAL(125.f, interp.Get(1.5f), 1.e-5f);
+        LOLUNIT_ASSERT_DOUBLES_EQUAL(175.f, interp.Get(2.5f), 1.e-5f);
+    }
+};
+
+} /* namespace lol */
+