/// <summary>
/// Perform a line query on this index. This will return all entries in the index that are intersecting with the
/// specified query line.
/// </summary>
/// <param name="start">The start point.</param>
/// <param name="end">The end point.</param>
/// <param name="t">The fraction along the line to consider.</param>
/// <param name="results">The list to put the results into.</param>
/// <returns></returns>
public void Find(TPoint start, TPoint end, float t, ISet <T> results)
{
foreach (var cell in ComputeCells(IntersectionExtensions.BoundsFor(start, end, t)))
{
if (_cells.ContainsKey(cell.Item1))
{
// Convert the query to the tree's local coordinate space.
// ReSharper disable RedundantCast Necessary for FarCollections.
var relativeStart = (Vector2)(start + cell.Item2);
var relativeEnd = (Vector2)(end + cell.Item2);
// ReSharper restore RedundantCast
// And do the query.
_cells[cell.Item1].Find(relativeStart, relativeEnd, t, results);
}
}
}
/// <summary>
/// Perform a circular query on this index. This will return all entries in the index that are in the specified range
/// of the specified point, using the euclidean distance function (i.e. <c>sqrt(x*x+y*y)</c>).
/// </summary>
/// <param name="center">The query point near which to get entries.</param>
/// <param name="radius">The maximum distance an entry may be away from the query point to be returned.</param>
/// <param name="results"> </param>
/// <remarks>
/// This checks for intersections of the query circle and the bounds of the entries in the index. Intersections
/// (i.e. bounds not fully contained in the circle) will be returned, too.
/// </remarks>
public void Find(TPoint center, float radius, ISet <T> results)
{
// Compute the area bounds for that query to get the involved trees.
var queryBounds = IntersectionExtensions.BoundsFor(center, radius);
foreach (var cell in ComputeCells(queryBounds))
{
// Only if the cell exists.
if (_cells.ContainsKey(cell.Item1))
{
// Convert the query to the tree's local coordinate space.
// ReSharper disable RedundantCast Necessary for FarCollections.
var relativePoint = (Vector2)(center + cell.Item2);
// ReSharper restore RedundantCast
// And do the query.
_cells[cell.Item1].Find(relativePoint, radius, results);
}
}
}
/// <summary>
/// Perform a line query on this index. This will return all entries in the index that are intersecting with the
/// specified query line.
/// <para>
/// Note that the callback will be passed the fraction along the line that the hit occurred at, and may return
/// the new maximum fraction up to which the search will run. If the returned fraction is exactly zero the search
/// will be stopped. If the returned fraction is negative the hit will be ignored, that is the max fraction will
/// not change.
/// </para>
/// </summary>
/// <param name="start">The start of the line.</param>
/// <param name="end">The end of the line.</param>
/// <param name="t">The fraction along the line to consider.</param>
/// <param name="callback">The method to call for each found hit.</param>
/// <returns></returns>
public bool Find(TPoint start, TPoint end, float t, LineQueryCallback <T> callback)
{
// HashSet we might use for filtering duplicate results. We initialize it lazily.
HashSet <T> filter = null;
foreach (var cell in ComputeCells(IntersectionExtensions.BoundsFor(start, end, t)))
{
if (_cells.ContainsKey(cell.Item1))
{
// Convert the query to the tree's local coordinate space.
// ReSharper disable RedundantCast Necessary for FarCollections.
var relativeStart = (Vector2)(start + cell.Item2);
var relativeEnd = (Vector2)(end + cell.Item2);
// ReSharper restore RedundantCast
// And do the query.
if (!_cells[cell.Item1].Find(
relativeStart,
relativeEnd,
t,
(value, fraction) =>
{
if (!Filter(value, ref filter))
{
return(-1f);
}
return(t = callback(value, fraction));
}))
{
return(false);
}
}
}
return(true);
}
