C# - 随机旋转多边形

Question

我正在尝试使用计时器随机旋转多边形。我必须绘制正多边形并将其旋转到一个方向。但我不确定如何使用角度或计时器间隔将多边形旋转到随机方向。

我的代码如下:

int sides = 5;
Graphics g = e.Graphics;
nPoints = CalculateVertices(sides, radius, angle, center);

g.DrawPolygon(navypen, nPoints);
g.FillPolygon(BlueBrush, nPoints);
Point center = new Point(ClientSize.Width / 2, ClientSize.Height / 2);

for(int i = 0; i < sides; i++) {
     g.DrawLine(new Pen(Color.Navy), center.X, center.Y, nPoints[i].X, nPoints[i].Y);

}

private PointF[] CalculateVertices(int sides, int radius, float startingAngle, Point center)
{
    if (sides < 3) {
        sides = 3;
    }

    List<PointF> points = new List<PointF>();
    float step = 360.0f / sides;

    float angle = startingAngle; //starting angle
    for (double i = startingAngle; i < startingAngle + 360.0; i += step) //go in a circle
    {
        points.Add(DegreesToXY(angle, radius, center));
        angle += step;
    }

    return points.ToArray();
}

private PointF DegreesToXY(float degrees, float radius, Point origin)
{
    PointF xy = new PointF();
    double radians = degrees * Math.PI / 180.0;

    xy.X = (int)(Math.Cos(radians) * radius + origin.X);
    xy.Y = (int)(Math.Sin(-radians) * radius + origin.Y);

    return xy;
}

private void timer2_Tick(object sender, EventArgs e){
    angle += 1;
    angle_tri -= 1;
    Invalidate();
}

Answer 1

这是绘制以不同速度(角度和时间)旋转的点列表的示例......:

首先是一些变量:

Random rnd = new Random();
float angle = 0f;
List<Point> points = new List<Point>();

然后以不同的速度和不同的角度进行Tick:

private void timer1_Tick(object sender, EventArgs e)
{
    angle += rnd.Next(0, 33)/ 10f;
    timer1.Interval = rnd.Next(100) + 15;
    pictureBox5.Invalidate();
}

这里是PictureBox的Paint事件，它是DoubleBuffered，所以不会闪烁..:

private void pictureBox5_Paint(object sender, PaintEventArgs e)
{
    if (points.Count > 1)
    {
        Point center = new Point(
            (points.Select(x => x.X).Max() + points.Select(x => x.X).Min()) / 2,
            (points.Select(x => x.Y).Max() + points.Select(x => x.Y).Min()) / 2);

        e.Graphics.TranslateTransform(center.X, center.Y);
        e.Graphics.RotateTransform(angle);
        e.Graphics.TranslateTransform(-center.X, -center.Y);
        e.Graphics.DrawPolygon(Pens.DarkGreen, points.ToArray());
    }
}

请注意，由于奇怪的速度变化，这绝不是平滑的；你必须为它们找到比单纯的随机性更好的算法..