ドットお絵かき - Siv3D/Reference-JP GitHub Wiki

# include <Siv3D.hpp>

void Main()
{
    Graphics::SetBackground(Palette::White);

    const int32 dotSize = 40;

    Grid<int32> dots(Window::Width() / dotSize, Window::Height() / dotSize);

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

            if (rect.leftClicked)
            {
                ++dots[p.y][p.x] %= 4;
            }

            const Color color(240 - dots[p.y][p.x] * 70);

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