/// <summary>
/// Returns a polygon shape with 3 to 12 corners.
/// </summary>
/// <param name="r"></param>
/// <param name="xSize"></param>
/// <param name="ySize"></param>
/// <param name="centerX"></param>
/// <param name="centerY"></param>
/// <param name="shapeSize"></param>
/// <returns></returns>
public static OutlineShape Random(Random r, int xSize, int ySize, double centerX, double centerY, double shapeSize)
{
// We build polygons with up to 12 corners.
int corners = 3 + r.Next(10);
int windings;
double slant = 0;
// For high number of corners, we prefer star shapes.
// 5 corners: 50% / 12 corners: 99%
if (corners > 4 && r.Next(100) < 50 + (corners - 5) * 7)
{
// Build a star shaped polygon.
windings = 2 + r.Next((corners - 3) / 2);
}
else
{
// Build a regular polygon.
windings = 1;
}
// Apply a random rotation of the whole shape.
// 3 corners: 55% / 12 corners: 10%
if (r.Next(100) < 70 - corners * 5)
{
slant = 2.0 * Math.PI * r.NextDouble();
}
else
{
// Rotate by half the rotation symmetry angle.
// This brings a corner (instead of an edge) to the south; applies to all shapes.
if (r.Next(100) < 50)
{
slant = 2.0 * Math.PI / corners / 2;
}
// Rotate by 90 degrees.
// This has no effect when corners is a multiple of four.
// For an even number of corners, the effect is the same as the previous rotation, i.e. neutral.
// For an odd number of corners, the edge is rotated from south/north to east/west.
if (r.Next(100) < 50)
{
slant += Math.PI / 4.0;
}
}
PolygonOutlineShape result = new PolygonOutlineShape(corners, windings, slant, xSize, ySize, centerX, centerY, shapeSize);
return(result);
}
/// <summary>
/// Create an outline shape.
/// </summary>
/// <param name="r">a source of random numbers</param>
/// <param name="xSize">width of the created shape</param>
/// <param name="ySize">height of the created shape</param>
/// <param name="centerX">X coordinate, relative to total width; 0.0 = top, 1.0 = bottom</param>
/// <param name="centerY">Y coordinate, relative to total height; 0.0 = left, 1.0 = right</param>
/// <param name="shapeSize">size, relative to distance of center from the border; 1.0 will touch the border </param>
/// <returns></returns>
public static OutlineShape Polygon(Random r, int xSize, int ySize, double centerX, double centerY, double shapeSize)
{
return(PolygonOutlineShape.Random(r, xSize, ySize, centerX, centerY, shapeSize));
}
