/// <summary>
/// Determines if the specified polygon at the specified position and rotation contains the specified point
/// </summary>
/// <param name="poly">The polygon</param>
/// <param name="pos">Origin of the polygon</param>
/// <param name="rot">Rotation of the polygon</param>
/// <param name="point">Point to check</param>
/// <param name="strict">True if the edges do not count as inside</param>
/// <returns>If the polygon at pos with rotation rot about its center contains point</returns>
public static bool Contains(Polygon2 poly, Vector2 pos, Rotation2 rot, Vector2 point, bool strict)
{
if (!Rect2.Contains(poly.AABB, pos, point, strict))
{
return(false);
}
// Calculate the area of the triangles constructed by the lines of the polygon. If it
// matches the area of the polygon, we're inside the polygon.
float myArea = 0;
var center = poly.Center + pos;
var last = Math2.Rotate(poly.Vertices[poly.Vertices.Length - 1], poly.Center, rot) + pos;
for (int i = 0; i < poly.Vertices.Length; i++)
{
var curr = Math2.Rotate(poly.Vertices[i], poly.Center, rot) + pos;
myArea += Math2.AreaOfTriangle(center, last, curr);
last = curr;
}
return(Math2.Approximately(myArea, poly.Area, poly.Area / 1000));
}
/// <summary>
/// Determines if the specified circle an rectangle intersect at their given positions.
/// </summary>
/// <param name="circle">The circle</param>
/// <param name="rect">The rectangle</param>
/// <param name="pos1">The top-left of the circles bounding box</param>
/// <param name="pos2">The origin of the rectangle</param>
/// <param name="strict">If overlap is required for intersection</param>
/// <returns>If circle at pos1 intersects rect at pos2</returns>
public static bool Intersects(Circle2 circle, Rect2 rect, Vector2 pos1, Vector2 pos2, bool strict)
{
var circleCenter = new Vector2(pos1.X + circle.Radius, pos1.Y + circle.Radius);
return(CircleIntersectsHorizontalLine(circle, new Line2(rect.Min + pos2, rect.UpperRight + pos2), circleCenter, strict) ||
CircleIntersectsHorizontalLine(circle, new Line2(rect.LowerLeft + pos2, rect.Max + pos2), circleCenter, strict) ||
CircleIntersectsVerticalLine(circle, new Line2(rect.Min + pos2, rect.LowerLeft + pos2), circleCenter, strict) ||
CircleIntersectsVerticalLine(circle, new Line2(rect.UpperRight + pos2, rect.Max + pos2), circleCenter, strict) ||
Rect2.Contains(rect, pos2, new Vector2(pos1.X + circle.Radius, pos1.Y + circle.Radius), strict));
}
