Struct HexEdgeCoord

Represents a canonical edge in a hexagonal grid, identified by the anchor hex coordinate and the edge direction (E, NE, or NW).

Implements

IEquatable<HexEdgeCoord>

Inherited Members

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Scylla.Core.Structures

Assembly: ScyllaCore.dll

Syntax

public readonly struct HexEdgeCoord : IEquatable<HexEdgeCoord>

Remarks

Every interior edge of a hex grid is shared by two hexes. The canonical form avoids duplication by always expressing the edge in terms of the three outward-facing directions of a chosen anchor hex (E, NE, NW). The other three directions (W, SW, SE) are represented as the E, NE, or NW edge of a neighboring cell respectively. See HexEdgeDirection for the exact equivalences.

Use GetCellsNonAlloc(HexEdgeCoord, Span<HexCoord>) to retrieve the two hexes that share this edge, GetCornersNonAlloc(HexEdgeCoord, Span<HexCornerCoord>) to retrieve the two corner vertices at either end, and GetEdgesOfCellNonAlloc(HexCoord, Span<HexEdgeCoord>) to enumerate all six edges of a given cell.

HexEdgeCoord is a value type safe for use as a dictionary key. Use HexEdgeMap<TData> for per-edge data storage.

Constructors

HexEdgeCoord(int, int, HexEdgeDirection)

Creates a new hex edge coordinate from an anchor hex and a canonical edge direction.

Declaration

public HexEdgeCoord(int q, int r, HexEdgeDirection direction)

Parameters

Type	Name	Description
int	q	The Q axis value of the anchor hex.
int	r	The R axis value of the anchor hex.
HexEdgeDirection	direction	The edge direction relative to the anchor hex. Should be one of E, NE, or NW to be in canonical form; other values are accepted but may break uniqueness guarantees.

Fields

Direction

The edge direction relative to the anchor hex. Always one of E, NE, or NW; never W, SW, or SE (those are represented as the canonical edge of a neighboring cell).

Declaration

public readonly HexEdgeDirection Direction

Field Value

Type	Description
HexEdgeDirection

Q

The Q axis value of the anchor hex that owns this edge in the canonical representation.

Declaration

public readonly int Q

Field Value

Type	Description
int

R

The R axis value of the anchor hex that owns this edge in the canonical representation.

Declaration

public readonly int R

Field Value

Type	Description
int

Methods

Equals(HexEdgeCoord)

Determines whether this edge coordinate equals another edge coordinate.

Declaration

public bool Equals(HexEdgeCoord other)

Parameters

Type	Name	Description
HexEdgeCoord	other	The edge coordinate to compare with.

Returns

Type	Description
bool	True if all fields are equal.

Equals(object)

Determines whether this edge coordinate equals another object.

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
object	obj	The object to compare with.

Returns

Type	Description
bool	True if the object is a HexEdgeCoord with equal values.

Overrides

ValueType.Equals(object)

GetCellsNonAlloc(HexEdgeCoord, Span<HexCoord>)

Writes the two hex cells that share this edge into the provided buffer.

Declaration

public static int GetCellsNonAlloc(HexEdgeCoord edge, Span<HexCoord> buffer)

Parameters

Type	Name	Description
HexEdgeCoord	edge	The canonical edge coordinate.
Span<HexCoord>	buffer	A span of at least 2 elements to receive the cell coordinates. buffer[0] is always the anchor hex; buffer[1] is the neighbor.

Returns

Type	Description
int	The number of cells written: 2 if the buffer is large enough, 0 otherwise.

Remarks

The two cells for each direction are:

• E edge of (q, r): cells (q, r) and (q+1, r).
• NE edge of (q, r): cells (q, r) and (q+1, r-1).
• NW edge of (q, r): cells (q, r) and (q, r-1).

If buffer has fewer than 2 elements, no data is written.

GetCornersNonAlloc(HexEdgeCoord, Span<HexCornerCoord>)

Writes the two HexCornerCoord vertices that form the endpoints of this edge into the provided buffer.

Declaration

public static int GetCornersNonAlloc(HexEdgeCoord edge, Span<HexCornerCoord> buffer)

Parameters

Type	Name	Description
HexEdgeCoord	edge	The canonical edge coordinate.
Span<HexCornerCoord>	buffer	A span of at least 2 elements to receive the corner coordinates.

Returns

Type	Description
int	The number of corners written: 2 if the buffer is large enough, 0 otherwise.

Remarks

The corner-to-edge mapping for each canonical direction is:

• (q, r, E): corners (q+1, r-1, S) and (q, r+1, N).
• (q, r, NE): corners (q, r, N) and (q+1, r-1, S).
• (q, r, NW): corners (q, r, N) and (q, r-1, S).

If buffer has fewer than 2 elements, no data is written.

GetEdgesOfCellNonAlloc(HexCoord, Span<HexEdgeCoord>)

Writes the six canonical HexEdgeCoord values for all edges of the given hex cell into the provided buffer. Each of the six edges is returned in its canonical form (anchor hex with an E, NE, or NW direction).

Declaration

public static int GetEdgesOfCellNonAlloc(HexCoord cell, Span<HexEdgeCoord> buffer)

Parameters

Type	Name	Description
HexCoord	cell	The hex cell whose edges to enumerate.
Span<HexEdgeCoord>	buffer	A span of at least 6 elements to receive the edge coordinates.

Returns

Type	Description
int	The number of edges written: 6 if the buffer is large enough, 0 otherwise.

Remarks

The six canonical edges of cell (q, r) are:

• (q, r, E) - east edge.
• (q, r, NE) - northeast edge.
• (q, r, NW) - northwest edge.
• (q-1, r, E) - west edge (E of western neighbor).
• (q-1, r+1, NE) - southwest edge (NE of SW neighbor).
• (q, r+1, NW) - southeast edge (NW of SE neighbor).

If buffer has fewer than 6 elements, no data is written.

GetHashCode()

Returns a hash code for this edge coordinate.

Declaration

public override int GetHashCode()

Returns

Type	Description
int	A hash code based on Q, R, and direction.

Overrides

ValueType.GetHashCode()

ToString()

Returns a string representation of this edge coordinate.

Declaration

public override string ToString()

Returns

Type	Description
string	A string in the format "(Q, R, Direction)".

Overrides

ValueType.ToString()

Operators

operator ==(HexEdgeCoord, HexEdgeCoord)

Returns true if left and right have equal Q, R, and Direction values.

Declaration

public static bool operator ==(HexEdgeCoord left, HexEdgeCoord right)

Parameters

Type	Name	Description
HexEdgeCoord	left	The left operand.
HexEdgeCoord	right	The right operand.

Returns

Type	Description
bool

operator !=(HexEdgeCoord, HexEdgeCoord)

Returns true if left and right differ in Q, R, or Direction.

Declaration

public static bool operator !=(HexEdgeCoord left, HexEdgeCoord right)

Parameters

Type	Name	Description
HexEdgeCoord	left	The left operand.
HexEdgeCoord	right	The right operand.

Returns

Type	Description
bool

Implements

IEquatable<T>