diff --git a/projects/kiwano/kiwano.vcxproj b/projects/kiwano/kiwano.vcxproj
index aee8098b..56a87356 100644
--- a/projects/kiwano/kiwano.vcxproj
+++ b/projects/kiwano/kiwano.vcxproj
@@ -70,6 +70,7 @@
+
diff --git a/projects/kiwano/kiwano.vcxproj.filters b/projects/kiwano/kiwano.vcxproj.filters
index f22d5eea..5e622aef 100644
--- a/projects/kiwano/kiwano.vcxproj.filters
+++ b/projects/kiwano/kiwano.vcxproj.filters
@@ -405,6 +405,9 @@
event\listener
+
+ math
+
diff --git a/src/kiwano/2d/animation/TweenAnimation.cpp b/src/kiwano/2d/animation/TweenAnimation.cpp
index d3498b80..306a4a4e 100644
--- a/src/kiwano/2d/animation/TweenAnimation.cpp
+++ b/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;
diff --git a/src/kiwano/kiwano.h b/src/kiwano/kiwano.h
index 9af44c4c..5958bad6 100644
--- a/src/kiwano/kiwano.h
+++ b/src/kiwano/kiwano.h
@@ -38,6 +38,7 @@
#include
#include
#include
+#include
//
// core
diff --git a/src/kiwano/math/Interpolator.h b/src/kiwano/math/Interpolator.h
new file mode 100644
index 00000000..05e7cd65
--- /dev/null
+++ b/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
+#include
+#include
+#include
+
+namespace kiwano
+{
+namespace math
+{
+
+
+template
+struct InterpolateMethod;
+
+template <>
+struct InterpolateMethod
+{
+ inline float operator()(float frac) const noexcept
+ {
+ return frac;
+ }
+};
+
+template <>
+struct InterpolateMethod
+{
+ 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 method;
+
+ InterpolateMethod(const Function& method) noexcept
+ : method(method)
+ {
+ }
+
+ inline float operator()(float frac) const noexcept
+ {
+ if (method)
+ return method(frac);
+ return frac;
+ }
+};
+
+template
+class Interpolator;
+
+template
+class Interpolator
+{
+public:
+ template
+ 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(end - start) * method(frac));
+ }
+};
+
+template
+class Interpolator>
+{
+public:
+ template
+ 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
+class Interpolator>
+{
+public:
+ template
+ inline RectT<_Ty> Interpolate(const RectT<_Ty>& start, const RectT<_Ty>& end, float frac,
+ const InterpolateMethod<_Method>& method = {})
+ {
+ if (frac >= 1)
+ return end;
+
+ Interpolator> 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
+class Interpolator>
+{
+public:
+ template
+ 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> 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