Struct TriCornerCoord

Immutable coordinate for a corner vertex in a triangular grid, expressed in three-axis lane coordinates on the dual vertex sublattice.

Implements

IEquatable<TriCornerCoord>

Inherited Members

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Scylla.Core.Structures

Assembly: ScyllaCore.dll

Syntax

public readonly struct TriCornerCoord : IEquatable<TriCornerCoord>

Remarks

In a triangular tiling each geometric vertex is shared by six triangles - three downward and three upward. The dual sublattice represents vertices using the same three-axis coordinate scheme as TriCoord, but the valid sum values differ:

• Type I (A + B + C = 0): the vertex is adjacent to three downward triangles. Check with IsTypeI.
• Type II (A + B + C = 1): the vertex is adjacent to three upward triangles. Check with IsTypeII.

Because a single geometric vertex is reachable from both sublattice representations, callers that need the full six-triangle neighbourhood around a vertex must query both the Type I and Type II coordinates for that geometric point.

Use GetTrianglesNonAlloc(TriCornerCoord, Span<TriCoord>) to find the three triangles adjacent to a given corner, and GetCornersOfCellNonAlloc(TriCoord, Span<TriCornerCoord>) to find all three corners of a triangle cell. Per-corner data can be stored in a TriCornerMap<TData>.

Constructors

TriCornerCoord(int, int, int)

Creates a new triangle corner coordinate with the specified dual-sublattice lane values.

Declaration

public TriCornerCoord(int a, int b, int c)

Parameters

Type	Name	Description
int	a	The A lane value for the new corner coordinate.
int	b	The B lane value for the new corner coordinate.
int	c	The C lane value for the new corner coordinate. For a valid vertex, a + b + c should equal 0 (Type I) or 1 (Type II).

Fields

A

The A lane value on the vertex dual sublattice.

Declaration

public readonly int A

Field Value

Type	Description
int

B

The B lane value on the vertex dual sublattice.

Declaration

public readonly int B

Field Value

Type	Description
int

C

The C lane value on the vertex dual sublattice. For a valid corner, A + B + C equals 0 (Type I) or 1 (Type II).

Declaration

public readonly int C

Field Value

Type	Description
int

Properties

IsTypeI

Gets a value indicating whether this is a Type I corner (A + B + C = 0), which is adjacent to three downward triangles.

Declaration

public bool IsTypeI { get; }

Property Value

Type	Description
bool	true when the sum of all lane values is 0; false otherwise.

IsTypeII

Gets a value indicating whether this is a Type II corner (A + B + C = 1), which is adjacent to three upward triangles.

Declaration

public bool IsTypeII { get; }

Property Value

Type	Description
bool	true when the sum of all lane values is 1; false otherwise.

IsValid

Gets a value indicating whether this corner coordinate has a valid lane sum, meaning it represents a real vertex in the triangular tiling.

Declaration

public bool IsValid { get; }

Property Value

Type	Description
bool	true when A + B + C equals 0 (Type I) or 1 (Type II); false for any other sum.

Methods

Equals(TriCornerCoord)

Determines whether this corner coordinate equals another corner coordinate.

Declaration

public bool Equals(TriCornerCoord other)

Parameters

Type	Name	Description
TriCornerCoord	other	The corner coordinate to compare with.

Returns

Type	Description
bool	True if all three lane values are equal.

Equals(object)

Determines whether this corner 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 TriCornerCoord with equal values.

Overrides

ValueType.Equals(object)

GetCornersOfCellNonAlloc(TriCoord, Span<TriCornerCoord>)

Writes the three corner vertices of a triangle cell into the provided buffer without allocating.

Declaration

public static int GetCornersOfCellNonAlloc(TriCoord cell, Span<TriCornerCoord> buffer)

Parameters

Type	Name	Description
TriCoord	cell	The triangle coordinate whose corners are requested.
Span<TriCornerCoord>	buffer	A span of at least 3 elements to receive the three TriCornerCoord values.

Returns

Type	Description
int	The number of corners written - 3 when buffer is large enough and cell is a valid triangle; 0 otherwise.

Remarks

The formula is the same regardless of triangle orientation: the three corners are (a-1, b, c), (a, b-1, c), and (a, b, c-1).

• For a downward triangle (A + B + C = 1), each decremented coordinate yields sum 0, so all three corners are Type I.
• For an upward triangle (A + B + C = 2), each decremented coordinate yields sum 1, so all three corners are Type II.

Returns 0 if cell has an invalid sum (neither 1 nor 2).

GetHashCode()

Returns a hash code for this corner coordinate.

Declaration

public override int GetHashCode()

Returns

Type	Description
int	A hash code based on A, B, and C.

Overrides

ValueType.GetHashCode()

GetTrianglesNonAlloc(TriCornerCoord, Span<TriCoord>)

Writes the three triangle cells directly adjacent to the specified corner vertex into the provided buffer without allocating.

Declaration

public static int GetTrianglesNonAlloc(TriCornerCoord corner, Span<TriCoord> buffer)

Parameters

Type	Name	Description
TriCornerCoord	corner	The corner coordinate whose adjacent triangles are requested.
Span<TriCoord>	buffer	A span of at least 3 elements to receive the three adjacent TriCoord values.

Returns

Type	Description
int	The number of triangles written - 3 when buffer is large enough and corner is valid; 0 otherwise.

Remarks

The formula for the adjacent triangles is the same for both corner types: (a+1, b, c), (a, b+1, c), (a, b, c+1).

• Type I (A + B + C = 0): the three adjacent triangles are all downward (each incremented coordinate gives sum 1).
• Type II (A + B + C = 1): the three adjacent triangles are all upward (each incremented coordinate gives sum 2).

For the full six-triangle ring around a geometric vertex, call this method on both the Type I and Type II forms of the same vertex.

Returns 0 if corner has an invalid sum (neither 0 nor 1).

ToString()

Returns a human-readable string representation of this corner coordinate.

Declaration

public override string ToString()

Returns

Type	Description
string	A string in the format (A, B, C), for example (0, 0, 0) for the origin Type I corner.

Overrides

ValueType.ToString()

Operators

operator ==(TriCornerCoord, TriCornerCoord)

Returns true when left and right have identical A, B, and C lane values.

Declaration

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

Parameters

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

Returns

Type	Description
bool	true if both corner coordinates are equal; otherwise false.

operator !=(TriCornerCoord, TriCornerCoord)

Returns true when left and right differ in at least one lane value.

Declaration

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

Parameters

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

Returns

Type	Description
bool	true if the corner coordinates are not equal; otherwise false.

Implements

IEquatable<T>

See Also

TriCoord

TriEdgeCoord

TriCornerMap<TData>