Class Trapezoid

Implements the trapezoid primitive for reconfiguration. See https://doi.org/10.4230/LIPIcs.SAND.2026.11.
The constant-time reconfiguration of a trapezoid where only the shorter base and the legs are occupied, and a starting point (a node on the longer base) to a configuration where the base of the trapezoid and a path between the bases from the starting point are occupied.

The algorithm consists of three phases: the first phase splits the trapezoid into a triangle and parallelogram so that the starting point is in the triangle. Then the parallelogram primitive is applied on the parallelogram to partially occupy the longer base. The second phase has two cases: the starting point is in a corner of the triangle, then we apply the triangle primitive on the triangle so that the occupied leg starts at the starting point. Then the algorithm is finished. Otherwise, we split the triangle into two triangles and a parallelogram, so that the starting point is a corner of the lower triangle and parallelogram. Then we apply the triangle primitive to the upper triangle. The lower triangle and parallelogram form a trapezoid with an attached leg. The third phase is repeating the first and second phase with the leg attached. This time the algorithm finishes.

The algorithm also has the ability to flip the created arm at the end of the algorithm with the flipArm parameter.

Inheritance

object

Suboracle<Trapezoid>

Trapezoid

Namespace: AS2.Suboracles.Reconfiguration

Assembly: .dll

Syntax

public class Trapezoid : Suboracle<Trapezoid>

Constructors

Trapezoid(Particle)

Declaration

public Trapezoid(Particle rep)

Parameters

Type	Name	Description
Particle	rep

Fields

allMembers

Declaration

private List<ParticleAlgorithm> allMembers

Field Value

Type	Description
List<ParticleAlgorithm>

allMembersBonds

Declaration

private List<ParticleAlgorithm> allMembersBonds

Field Value

Type	Description
List<ParticleAlgorithm>

anchor

Declaration

private ParticleAlgorithm anchor

Field Value

Type	Description
ParticleAlgorithm

anchor2

Declaration

private ParticleAlgorithm anchor2

Field Value

Type	Description
ParticleAlgorithm

caseInfo

Declaration

private int[] caseInfo

Field Value

Type	Description
int[]

flipArm

Declaration

private ParticleAttribute<bool> flipArm

Field Value

Type	Description
ParticleAttribute<bool>

ignoreCornerCase

Declaration

private ParticleAttribute<bool> ignoreCornerCase

Field Value

Type	Description
ParticleAttribute<bool>

ignoreFlipArm

Declaration

private ParticleAttribute<bool> ignoreFlipArm

Field Value

Type	Description
ParticleAttribute<bool>

line

Declaration

private List<ParticleAlgorithm> line

Field Value

Type	Description
List<ParticleAlgorithm>

line2

Declaration

private List<ParticleAlgorithm> line2

Field Value

Type	Description
List<ParticleAlgorithm>

line3

Declaration

private List<ParticleAlgorithm> line3

Field Value

Type	Description
List<ParticleAlgorithm>

lineDir

Declaration

private Direction lineDir

Field Value

Type	Description
Direction

markers

Declaration

private List<Vector2Int> markers

Field Value

Type	Description
List<Vector2Int>

memberParticles

Declaration

private (List<Trapezoid>, List<Vector2Int>) memberParticles

Field Value

Type	Description
(List<Trapezoid>, List<Vector2Int>)

parallelogram

Declaration

private Parallelogram parallelogram

Field Value

Type	Description
Parallelogram

phase

Declaration

private ParticleAttribute<Trapezoid.Phase> phase

Field Value

Type	Description
ParticleAttribute<Trapezoid.Phase>

round

Declaration

private ParticleAttribute<int> round

Field Value

Type	Description
ParticleAttribute<int>

startPoint

Declaration

public Vector2Int startPoint

Field Value

Type	Description
Vector2Int

startPointParticle

Declaration

private ParticleAlgorithm startPointParticle

Field Value

Type	Description
ParticleAlgorithm

triangle

Declaration

private Triangle triangle

Field Value

Type	Description
Triangle

Methods

FindCase()

Determines which case of the algorithm should be used based on the position of the given start point and stores this information in the caseInfo array for later. caseInfo{ left corner of right triangle, right corner of right triangle, on the left side, x and y coordinate of calculated point }

Declaration

private void FindCase()

GetParticleAt(ParticleAlgorithm)

Declaration

private Vector2Int GetParticleAt(ParticleAlgorithm p)

Parameters

Type	Name	Description
ParticleAlgorithm	p

Returns

Type	Description
Vector2Int

GetParticleAt(Vector2Int)

Helper function to get the particle algorithm based on the position

Declaration

private ParticleAlgorithm GetParticleAt(Vector2Int pos)

Parameters

Type	Name	Description
Vector2Int	pos	position to convert to particle algorithm

Returns

Type	Description
ParticleAlgorithm	the particle algorithm at the specified position, or null if not found

HandleInitPhase()

Handles the initialization of the algorithm, detecting the legs and the base of the trapezoid and detecting which case of the algorithm should be used

Declaration

private void HandleInitPhase()

HandlePhaseOne()

Handles the first phase of the algorithm, executing the parallelogram suboracle based on the start point

Declaration

private void HandlePhaseOne()

HandlePhaseThree()

Handles the third phase of the algorithm, executing another parallelogram suboracle and triangle suboracle and optional flipping of the created arm

Declaration

private void HandlePhaseThree()

HandlePhaseTwo()

Handles the second phase of the algorithm, executing the triangle suboracle with the calculated point or start point as representative based on the case

Declaration

private void HandlePhaseTwo()

HandlePhaseZero()

Declaration

private void HandlePhaseZero()

Init(List<Trapezoid>, List<Vector2Int>, Direction, string, bool, bool, bool, bool)

Initializes the trapezoid suboracle with the given parameters, setting up the member particles

Declaration

public void Init(List<Trapezoid> members, List<Vector2Int> positions, Direction startDir = Direction.NONE, string startPoint = "", bool markers = true, bool ignoreCornerCase = true, bool flipArm = false, bool ignoreFlipArm = false)

Parameters

Type	Name	Description
List<Trapezoid>	members	list of particles that are members of the trapezoid
List<Vector2Int>	positions	list of positions for the member particles
Direction	startDir	the direction of the "left" leg of the trapezoid
string	startPoint	the starting point for the primitive
bool	markers	whether to mark the starting point and calculated point
bool	ignoreCornerCase	whether to ignore the corner case
bool	flipArm	whether to flip the created arm at the end
bool	ignoreFlipArm	whether to ignore the flip for one case

OnActivate()

Activates the trapezoid suboracle, performing one step of the algorithm based on the current phase and round.

Declaration

protected override bool OnActivate()

Returns

Type	Description
bool	true if the algorithm is finished, false otherwise

Overrides

Suboracle<Trapezoid>.OnActivate()

ShowMarker(List<Vector2Int>)

Helper function to mark the given positions with a green border

Declaration

public static void ShowMarker(List<Vector2Int> positions)

Parameters

Type	Name	Description
List<Vector2Int>	positions	list of positions to mark

removeBonds()

Removes bonds from members (except for the connection points) to non-member particles

Declaration

private void removeBonds()