public static bool IsNeighbour(LevelRect a, LevelRect b)
{
/// # DESCRIPTION
/// Determine whether rectangles a and b are neighbors
/// by projecting them onto both axes and comparing their
/// combined projections ("one-dimensional shadows") to
/// their actual sizes.
/// If a projection:
/// - is smaller than both rectangles' width/height,
/// then the rectangles overlap on the x/ y - axis.
/// - is equivalent to both rectangles' width/height,
/// then the rectangles are touching on the x / y - axis.
/// - is greater than both rectangles' width/height,
/// then the rectangles can not be neighbors.
///
/// Return true iff the overlap on one axis is greater than zero
/// while the overlap on the other axis is equal to zero.
/// (If both overlaps were greater than zero, the rectangles
/// would be overlapping. If both overlaps were equal to zero,
/// the rectangles would be touching on a corner only.)
int xProjection = Math.Max(a.x2, b.x2) - Math.Min(a.x1, b.x1);
int xOverlap = a.Width + b.Width - xProjection;
int yProjection = Math.Max(a.y2, b.y2) - Math.Min(a.y1, b.y1);
int yOverlap = a.Height + b.Height - yProjection;
return(xOverlap > 0 && yOverlap == 0 ||
xOverlap == 0 && yOverlap > 0);
}
public bool Intersects(LevelRect other)
{
return(x1 <= other.x2 && x2 >= other.x1 &&
y1 <= other.y2 && y2 >= other.y1);
}
