Package com.google.common.geometry

Class S2Polygon.S2LoopSequenceIndex

java.lang.Object

com.google.common.geometry.S2EdgeIndex

com.google.common.geometry.S2Polygon.S2LoopSequenceIndex

Direct Known Subclasses:

S2Polygon.S2PolygonIndex

Enclosing class:

S2Polygon

private abstract static class S2Polygon.S2LoopSequenceIndex
extends S2EdgeIndex

Indexing structure to efficiently S2EdgeIndex.clipEdge(com.google.common.geometry.S2Point, com.google.common.geometry.S2Point, boolean, java.util.Collection<com.google.common.geometry.ParametrizedS2Point>) of a polygon. This is an abstract class because we need to use if for both polygons (for S2Polygon.initToIntersection(com.google.common.geometry.S2Polygon, com.google.common.geometry.S2Polygon) and friends) and for sets of lists of points (for initToSimplified() future?).

Usage: In your subclass, create an array of vertex counts for each loop in the loop sequence and pass it to this constructor. Overwrite edgeFromTo(int), calling decodeIndex(int) and use the resulting two indices to access your vertices.

Nested Class Summary

Nested classes/interfaces inherited from class com.google.common.geometry.S2EdgeIndex

S2EdgeIndex.DataEdgeIterator

Field Summary

Fields

Modifier and Type	Field	Description
private int[]	indexToLoop	Map from the uni-dimensional edge index to the loop this edge belongs to.
private int[]	loopToFirstIndex	Reverse of indexToLoop: maps a loop index to the uni-dimensional index of the first edge in the loop.

Constructor Summary

Constructors

Constructor	Description
S2LoopSequenceIndex(int[] numVertices)	Must be called by each subclass with the array of vertices per loop.

Method Summary

Modifier and Type	Method	Description
S2Polygon.LoopVertexIndexPair	decodeIndex(int index)
S2Point	edgeFrom(int index)	Returns the starting vertex of the edge at offset index.
abstract S2Edge	edgeFromTo(int index)	Mark the edgeFromTo(int) method abstract again, so children of this class must implement it without using edgeFrom(int) and edgeTo(int).
S2Point	edgeTo(int index)	Returns the ending vertex of the edge at offset index.
int	getNumEdges()	Returns the number of edges in this index.

Methods inherited from class com.google.common.geometry.S2EdgeIndex

clipEdge, computeIndex, findCandidateCrossings, incrementQueryCount, isIndexComputed, predictAdditionalCalls, reset

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

indexToLoop

private final int[] indexToLoop

Map from the uni-dimensional edge index to the loop this edge belongs to.

loopToFirstIndex

private final int[] loopToFirstIndex

Reverse of indexToLoop: maps a loop index to the uni-dimensional index of the first edge in the loop.

Constructor Detail

S2LoopSequenceIndex

public S2LoopSequenceIndex(int[] numVertices)

Must be called by each subclass with the array of vertices per loop. The length of the array is the number of loops, and the i ^th loop's vertex count is in the i ^th index of the array.

Method Detail

decodeIndex

public final S2Polygon.LoopVertexIndexPair decodeIndex(int index)

getNumEdges

public final int getNumEdges()

Description copied from class: S2EdgeIndex

Returns the number of edges in this index.

Specified by:

getNumEdges in class S2EdgeIndex

edgeFromTo

public abstract S2Edge edgeFromTo(int index)

Mark the edgeFromTo(int) method abstract again, so children of this class must implement it without using edgeFrom(int) and edgeTo(int).

Overrides:

edgeFromTo in class S2EdgeIndex

edgeFrom

public S2Point edgeFrom(int index)

Description copied from class: S2EdgeIndex

Returns the starting vertex of the edge at offset index.

Specified by:

edgeFrom in class S2EdgeIndex

edgeTo

public S2Point edgeTo(int index)

Description copied from class: S2EdgeIndex

Returns the ending vertex of the edge at offset index.

Specified by:

edgeTo in class S2EdgeIndex