cdx
Class Reducer

java.lang.Object
  cdx.Reducer

public class Reducer
extends java.lang.Object

Reduces the set of collisions to be tested using a voxel hashing algorithm.

Field Summary

Vector2d	horizontal The horizontal side of a voxel.
Vector2d	vertical The vertical side of a voxel.
float	voxel_size The voxel size.

Constructor Summary

Reducer(float voxel_size)
Initialise the reducer with a voxel size.

Method Summary

protected void	dfsVoxelHashRecurse(Motion motion, Vector2d next_voxel, HashMap voxel_map, HashMap graph_colors) Recursive method to check which voxels overlap with a motion
protected boolean	isInVoxel(Vector2d voxel, Motion motion) Given a voxel and a Motion, determines if they overlap.
protected void	performVoxelHashing(Motion motion, HashMap voxel_map, HashMap graph_colors) Colours all of the voxels that overlap with the Motion.
protected void	putIntoMap(HashMap voxel_map, Vector2d voxel, Motion motion) Puts a Motion object into the voxel map at a voxel.
LinkedList	reduceCollisionSet(LinkedList motions) Takes a List of Motions and returns an List of Lists of Motions, where the inner lists implement RandomAccess.
protected void	voxelHash(Vector3d position, Vector2d voxel) Creates a Vector2d that represents a voxel.

Methods inherited from class java.lang.Object

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

Field Detail

voxel_size

public final float voxel_size

The voxel size. Each voxel is a square, so this is the length of a side.

horizontal

public final Vector2d horizontal

The horizontal side of a voxel.

vertical

public final Vector2d vertical

The vertical side of a voxel.

Constructor Detail

Reducer

public Reducer(float voxel_size)

Initialise the reducer with a voxel size.

Parameters:

voxel_size - the size of a voxel

Method Detail

voxelHash

protected void voxelHash(Vector3d position,
                         Vector2d voxel)

Creates a Vector2d that represents a voxel.

Parameters:

position - a aircraft 3D position

voxel - a 2D voxel

putIntoMap

protected void putIntoMap(HashMap voxel_map,
                          Vector2d voxel,
                          Motion motion)

Puts a Motion object into the voxel map at a voxel.

Parameters:

voxel_map - a voxel hashmap

voxel - a voxel

motion - a motion to be hashed in the map

isInVoxel

protected boolean isInVoxel(Vector2d voxel,
                            Motion motion)

Given a voxel and a Motion, determines if they overlap.

Parameters:

voxel - a voxel to be checked

motion - a motion to be checked in the voxel

Returns:

false if no overlapping

dfsVoxelHashRecurse

protected void dfsVoxelHashRecurse(Motion motion,
                                   Vector2d next_voxel,
                                   HashMap voxel_map,
                                   HashMap graph_colors)

Recursive method to check which voxels overlap with a motion

Parameters:

motion - a motion to be checked with voxels

next_voxel - the next voxel in the map

voxel_map - the hashmap for all voxels

graph_colors - the hashmap who colors the voxels that overlap with the motion

performVoxelHashing

protected void performVoxelHashing(Motion motion,
                                   HashMap voxel_map,
                                   HashMap graph_colors)

Colours all of the voxels that overlap with the Motion.

Parameters:

motion - the checked motion

voxel_map - the hashmap of all voxels

graph_colors - the haspmap where coloured voxels overlap with this motion

reduceCollisionSet

public LinkedList reduceCollisionSet(LinkedList motions)

Takes a List of Motions and returns an List of Lists of Motions, where the inner lists implement RandomAccess. Each Vector of Motions that is returned represents a set of Motions that might have collisions.

Parameters:

motions - a lisit of motions that are to be checked with voxels

Returns:

a list of sets of motions that might have collisions