テンポとピッチの変更 - Siv3D/Reference-JP GitHub Wiki

# include <Siv3D.hpp>

void Main()
{
    const Sound sound = Dialog::OpenSound();

    if (!sound)
    {
        return;
    }

    sound.play();

    while (System::Update())
    {
        Line(0, 240, 640, 240).drawArrow(4, { 20, 20 });
        Line(320, 480, 320, 0).drawArrow(4, { 20, 20 });

        const Point pos = Mouse::Pos();
        Circle(pos, 20).draw(Palette::Orange);

        const double tempo = Exp2((pos.x - 320) / 240.0);
        const double pitch = -(pos.y - 240) / 80.0;

        sound.changeTempo(tempo);
        sound.changePitchSemitones(pitch);

        PutText(L"tempo: {}\npitch: {}"_fmt, tempo, pitch).from(20, 20);
    }
}