Delegate NeighborWriter<TCoord>

Delegate for writing the neighbors of a coordinate into a caller-supplied span buffer. Required because Span<T> is a ref struct and therefore cannot be used as a generic type argument in Func<T, TResult> or similar delegates.

Namespace: Scylla.Core.Structures
Assembly: ScyllaCore.dll
Syntax
public delegate int NeighborWriter<TCoord>(TCoord coord, Span<TCoord> buffer) where TCoord : struct, IEquatable<TCoord>
Parameters
Type Name Description
TCoord coord

The coordinate whose neighbors are to be written into buffer.
Span<TCoord> buffer

A caller-provided span to receive the neighbor coordinates. The delegate writes up to buffer.Length neighbors and must never write beyond the end of the span. The caller is responsible for ensuring the buffer is large enough to hold the maximum possible neighbor count (e.g. 4 for Von Neumann square adjacency, 6 for hexagonal, 8 for Moore square adjacency, 3 for triangular edge neighbors).
Returns
Type Description
int

The number of neighbor coordinates actually written into buffer. May be less than the theoretical maximum if the coordinate is near a grid boundary or if buffer is smaller than the neighbor count.
Type Parameters
Name Description
TCoord

The coordinate type. Must be a value type that implements IEquatable<T>. Typical values are SquareCoord, HexCoord, and TriCoord.
Remarks

Pass an instance of this delegate to generic algorithms such as FloodFill<TCoord>(TCoord, Func<TCoord, bool>, NeighborWriter<TCoord>, TCoord[], HashSet<TCoord>, Queue<TCoord>) to decouple grid topology from the algorithm. Typical implementations are obtained from the concrete grid's GetNeighborsNonAlloc method or from GetEdgeNeighbors(TriCoord, Span<TriCoord>).

Extension Methods

See Also

FloodFill<TCoord>(TCoord, Func<TCoord, bool>, NeighborWriter<TCoord>, TCoord[], HashSet<TCoord>, Queue<TCoord>)