MIDIシーケンサー

# include <Siv3D.hpp>

void Main()
{
    Window::Resize(480, 480);
    Graphics::SetBackground(Palette::White);
    Midi::SendMessage(MidiMessage::SetInstrument(0, GMInstrument::MusicBox));

    const Array<uint8> midis{ 86, 84, 83, 81, 79, 77, 76, 74, 72, 71, 69, 67, 65, 64, 62, 60 };
    const int32 dotSize = 30;

    Grid<bool> dots(16, 16);
    int32 previousLine = 0;

    while (System::Update())
    {
        const int32 currentLine = Time::MillisecSince1601() / 160 % 16;

        if (currentLine != previousLine)
        {
            for (auto i : step(dots.height))
            {
                Midi::SendMessage(dots[i][currentLine] ?
                    MidiMessage::NoteOn(0, midis[i]) : MidiMessage::NoteOff(0, midis[i]));
            }

            previousLine = currentLine;
        }

        for (auto p : step({ dots.width, dots.height }))
        {
            Rect rect(p * dotSize, dotSize, dotSize);

            if (rect.leftClicked)
            {
                dots[p.y][p.x] = !dots[p.y][p.x];
            }

            const Color color = HSV(40, 0.2 + dots[p.y][p.x] * 0.8 - (p.x == currentLine) * 0.2, 0.9 + dots[p.y][p.x] * 0.1);

            rect.stretched(-1).draw(color);
        }
    }
}