com.threerings.opengl.effect
Class PositionHistory

java.lang.Object
  com.threerings.opengl.effect.PositionHistory

public final class PositionHistory
extends Object

Stores all of the positions occupied by a particle up to a maximum interval and provides a means of retrieving an interpolated historical position.

Nested Class Summary

protected static class

PositionHistory.Entry An entry in the history.

Field Summary

protected ArrayList<PositionHistory.Entry>	_entries The entries in the history.
protected float	_length The current length.
protected ArrayList<PositionHistory.Entry>	_pool The pool of entries to reuse.
protected float	_time The last time value recorded.
protected Transform3D	_transform The transform to apply to new entries.

Constructor Summary

PositionHistory()

Method Summary

protected void	addEntry(Vector3f position, float time) Adds an entry for the specified values, fetching one from the pool if possible.
Vector3f	get(float t, Vector3f result) Computes the position at some point in the past.
void	init(Vector3f initial, Transform3D transform) (Re)initializes the history.
void	record(Vector3f position, float elapsed, float length) Records a position occupied by the particle.

Methods inherited from class java.lang.Object

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

Field Detail

_time

protected float _time

The last time value recorded.

_length

protected float _length

The current length.

_transform

protected Transform3D _transform

The transform to apply to new entries.

_entries

protected ArrayList<PositionHistory.Entry> _entries

The entries in the history.

_pool

protected ArrayList<PositionHistory.Entry> _pool

The pool of entries to reuse.

Constructor Detail

PositionHistory

public PositionHistory()

Method Detail

init

public void init(Vector3f initial,
                 Transform3D transform)

(Re)initializes the history.

Parameters:

initial - the initial position.

transform - the transform to apply to new entries, or null for none.

record

public void record(Vector3f position,
                   float elapsed,
                   float length)

Records a position occupied by the particle.

get

public Vector3f get(float t,
                    Vector3f result)

Computes the position at some point in the past.

Parameters:

t - the time parameter: zero for the oldest location, one for the newest.

addEntry

protected void addEntry(Vector3f position,
                        float time)

Adds an entry for the specified values, fetching one from the pool if possible.