OpenSiv3DのTransitonで滑らかにトランジションさせるミニプログラム

TransitonSunMoon.cpp

//Created by Akira Koizumi 2018.
//http://movement.hatenablog.jp/entry/siv3dtransiton
//
//this code is licensed under cc0.
# include <Siv3D.hpp> //OpenSiv3D Ver0.2.0
void Main()
{
    const Texture sun(Emoji(U"🌞"), TextureDesc::Mipped);
    const Texture moon(Emoji(U"🌝"), TextureDesc::Mipped);
    const Texture tree(Emoji(U"🌳"), TextureDesc::Mipped);
    
    Transition transition(0.3s, 0.301s);

    while (System::Update())
    {
        transition.update(MouseL.pressed());

        //空
        Rect(0, 0, Window::Size()).draw(ColorF(U"#41A7FF").setA(transition.value()));
        Rect(0, 0, Window::Size()).draw(ColorF(U"#181991").setA(1.0-transition.value()));

        //大地
        Rect(0, 300, Window::Size()).draw(ColorF(U"#95EB00").setA(transition.easeIn(Easing::Sine)));
        Rect(0, 300, Window::Size()).draw(ColorF(U"#207720").setA(1.0 - transition.easeIn(Easing::Sine)));

        //木
        tree.drawAt(200, 300, ColorF(transition.value()*0.6+0.4));

        //月と太陽
        sun.drawAt(100, 100, AlphaF(transition.value()));
        moon.drawAt(Window::Width() - 100, 100, AlphaF(1.0-transition.value()));
    }
}