com.brackeen.javagamebook.util
Class TimeSmoothie

java.lang.Object
  com.brackeen.javagamebook.util.TimeSmoothie

public class TimeSmoothie
extends java.lang.Object

Smoothes out the jumps in time do to poor timer accuracy. This is a simple algorithm that is slightly inaccurate (the smoothed time may be slightly ahead of real time) but gives better-looking results.

Field Summary

protected static long	AVERAGE_PERIOD Take the average of the last few samples during the last 100ms
protected int	firstIndex
protected static long	FRAME_RATE_RECALC_PERIOD How often to recalc the frame rate
protected float	frameRate
protected static long	MAX_ELAPSED_TIME Don't allow the elapsed time between frames to be more than 100 ms
protected static int	NUM_SAMPLES
protected static int	NUM_SAMPLES_BITS
protected static int	NUM_SAMPLES_MASK
protected int	numFrames
protected int	numSamples
protected long[]	samples
protected long	startTime

Constructor Summary

TimeSmoothie()

Method Summary

void	addSample(long elapsedTime) Adds a time sample.
long	getAverage() Gets the average of the recorded time samples.
float	getFrameRate() Gets the frame rate (number of calls to getTime() or addSample() in real time).
long	getTime(long elapsedTime) Adds the specified time sample and returns the average of all the recorded time samples.

Methods inherited from class java.lang.Object

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

Field Detail

FRAME_RATE_RECALC_PERIOD

protected static final long FRAME_RATE_RECALC_PERIOD

How often to recalc the frame rate

See Also:

Constant Field Values

MAX_ELAPSED_TIME

protected static final long MAX_ELAPSED_TIME

Don't allow the elapsed time between frames to be more than 100 ms

See Also:

Constant Field Values

AVERAGE_PERIOD

protected static final long AVERAGE_PERIOD

Take the average of the last few samples during the last 100ms

See Also:

Constant Field Values

NUM_SAMPLES_BITS

protected static final int NUM_SAMPLES_BITS

See Also:

Constant Field Values

NUM_SAMPLES

protected static final int NUM_SAMPLES

See Also:

Constant Field Values

NUM_SAMPLES_MASK

protected static final int NUM_SAMPLES_MASK

See Also:

Constant Field Values

samples

protected long[] samples

numSamples

protected int numSamples

firstIndex

protected int firstIndex

numFrames

protected int numFrames

startTime

protected long startTime

frameRate

protected float frameRate

Constructor Detail

TimeSmoothie

public TimeSmoothie()

Method Detail

getTime

public long getTime(long elapsedTime)

Adds the specified time sample and returns the average of all the recorded time samples.

addSample

public void addSample(long elapsedTime)

Adds a time sample.

getAverage

public long getAverage()

Gets the average of the recorded time samples.

getFrameRate

public float getFrameRate()

Gets the frame rate (number of calls to getTime() or addSample() in real time). The frame rate is recalculated every 500ms.