add Interpolator

projects/kiwano/kiwano.vcxproj

@@ -70,6 +70,7 @@
     <ClInclude Include="..\..\src\kiwano\core\RefBasePtr.hpp" />
     <ClInclude Include="..\..\src\kiwano\math\Constants.h" />
     <ClInclude Include="..\..\src\kiwano\math\EaseFunctions.h" />
+    <ClInclude Include="..\..\src\kiwano\math\Interpolator.h" />
     <ClInclude Include="..\..\src\kiwano\math\Math.h" />
     <ClInclude Include="..\..\src\kiwano\math\Matrix.hpp" />
     <ClInclude Include="..\..\src\kiwano\math\Random.h" />

projects/kiwano/kiwano.vcxproj.filters

@@ -405,6 +405,9 @@
     <ClInclude Include="..\..\src\kiwano\event\listener\KeyEventListener.h">
       <Filter>event\listener</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\src\kiwano\math\Interpolator.h">
+      <Filter>math</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\..\src\kiwano\2d\Canvas.cpp">

src/kiwano/2d/animation/TweenAnimation.cpp

@@ -42,6 +42,8 @@ TweenAnimation::TweenAnimation(Duration duration)
 
 float TweenAnimation::Interpolate(float frac)
 {
+    if (frac == 1)
+        return 1;
     if (ease_func_)
         frac = ease_func_(frac);
     return frac;

src/kiwano/kiwano.h

@@ -38,6 +38,7 @@
 #include <kiwano/math/EaseFunctions.h>
 #include <kiwano/math/Random.h>
 #include <kiwano/math/Scalar.h>
+#include <kiwano/math/Interpolator.h>
 
 //
 // core

src/kiwano/math/Interpolator.h

@@ -0,0 +1,159 @@
+// Copyright (c) 2016-2018 Kiwano - Nomango
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#pragma once
+#include <kiwano/core/Function.h>
+#include <kiwano/math/Vec2.hpp>
+#include <kiwano/math/Rect.hpp>
+#include <kiwano/math/Transform.hpp>
+
+namespace kiwano
+{
+namespace math
+{
+
+
+template <typename _Method = void>
+struct InterpolateMethod;
+
+template <>
+struct InterpolateMethod<void>
+{
+    inline float operator()(float frac) const noexcept
+    {
+        return frac;
+    }
+};
+
+template <>
+struct InterpolateMethod<float (*)(float)>
+{
+    float (*method)(float);
+
+    InterpolateMethod(float (*method)(float)) noexcept
+        : method(method)
+    {
+    }
+
+    inline float operator()(float frac) const noexcept
+    {
+        if (method)
+            return method(frac);
+        return frac;
+    }
+};
+
+template <>
+struct InterpolateMethod<Function<float(float)>>
+{
+    Function<float(float)> method;
+
+    InterpolateMethod(const Function<float(float)>& method) noexcept
+        : method(method)
+    {
+    }
+
+    inline float operator()(float frac) const noexcept
+    {
+        if (method)
+            return method(frac);
+        return frac;
+    }
+};
+
+template <typename _Ty>
+class Interpolator;
+
+template <typename _Ty>
+class Interpolator
+{
+public:
+    template <typename _Method = void>
+    inline _Ty Interpolate(_Ty start, _Ty end, float frac, const InterpolateMethod<_Method>& method = {})
+    {
+        if (frac >= 1)
+            return end;
+        return start + static_cast<_Ty>(static_cast<float>(end - start) * method(frac));
+    }
+};
+
+template <typename _Ty>
+class Interpolator<Vec2T<_Ty>>
+{
+public:
+    template <typename _Method = void>
+    inline Vec2T<_Ty> Interpolate(const Vec2T<_Ty>& start, const Vec2T<_Ty>& end, float frac,
+                                  const InterpolateMethod<_Method>& method = {})
+    {
+        if (frac >= 1)
+            return end;
+
+        Interpolator<_Ty> fi;
+        return Vec2T<_Ty>{
+            fi.Interpolate(start.x, end.x, frac, method),
+            fi.Interpolate(start.y, end.y, frac, method)
+        };
+    }
+};
+
+template <typename _Ty>
+class Interpolator<RectT<_Ty>>
+{
+public:
+    template <typename _Method = void>
+    inline RectT<_Ty> Interpolate(const RectT<_Ty>& start, const RectT<_Ty>& end, float frac,
+                                  const InterpolateMethod<_Method>& method = {})
+    {
+        if (frac >= 1)
+            return end;
+
+        Interpolator<Vec2T<_Ty>> vi;
+        return RectT<_Ty>{
+            vi.Interpolate(start.left_top, end.left_top, frac, method),
+            vi.Interpolate(start.right_bottom, end.right_bottom, frac, method)
+        };
+    }
+};
+
+template <typename _Ty>
+class Interpolator<TransformT<_Ty>>
+{
+public:
+    template <typename _Method = void>
+    inline TransformT<_Ty> Interpolate(const TransformT<_Ty>& start, const TransformT<_Ty>& end, float frac,
+                                       const InterpolateMethod<_Method>& method = {})
+    {
+        if (frac >= 1)
+            return end;
+
+        Interpolator<_Ty>        fi;
+        Interpolator<Vec2T<_Ty>> vi;
+
+        TransformT<_Ty> transform;
+        transform.rotation = fi.Interpolate(start.rotation, end.rotation, frac, method);
+        transform.position = vi.Interpolate(start.position, end.position, frac, method);
+        transform.scale    = vi.Interpolate(start.scale, end.scale, frac, method);
+        transform.skew     = vi.Interpolate(start.skew, end.skew, frac, method);
+        return transform;
+    }
+};
+
+}  // namespace math
+}  // namespace kiwano