ddf.minim.ugens

Class Wavetable

java.lang.Object

ddf.minim.ugens.Wavetable

All Implemented Interfaces:

Waveform

public class Wavetable
extends java.lang.Object
implements Waveform

Wavetable wraps a float array of any size and lets you sample the array using a normalized value [0,1]. This means that if you have an array that is 2048 samples long, then value(0.5) will give you the 1024th sample. You will most often use Wavetables as the Waveform in an Oscil, but other uses are also possible. Additionally, Wavetable provides a set of methods for transforming the samples it contains.

Author:

Mark Godfrey <mark.godfrey@gatech.edu>

Constructor Summary

Constructors

Constructor and Description
Wavetable(float[] waveform) Construct a Wavetable that will use waveform as the float array to sample from.
Wavetable(int size) Construct a Wavetable that contains size entries.
Wavetable(Wavetable wavetable) Make a new Wavetable that has the same waveform values as wavetable.

Method Summary

Modifier and Type	Method and Description
void	addNoise(float sigma) Adds Gaussian noise to the waveform.
void	flip(float in) Flip the values in the table around a particular value.
float	get(int i) Returns the value of the ith entry in this Wavetable's waveform.
float[]	getWaveform() Returns the underlying waveform, not a copy of it.
void	invert() Flips the table around 0.
void	normalize() Normalizes the Wavetable by finding the largest amplitude in the table and scaling the table by the inverse of that amount.
void	offset(float amount) Apply a DC offset to this Wavetable.
void	rectify() Inverts all values in the table that are less than zero.
void	scale(float scale) Multiplies each value of the underlying waveform by scale.
void	set(int i, float value) Sets the ith entry of the underlying waveform to value.
void	setWaveform(float[] waveform) Sets this Wavetable's waveform to the one provided.
int	size() Returns the length of the underlying waveform.
void	smooth(int windowLength) Smooth out the values in the table by using a moving average window.
float	value(float at) Sample the Wavetable using a value in the range [0,1].
void	warp(float warpPoint, float warpTarget) Warping works by choosing a point in the waveform, the warpPoint, and then specifying where it should move to, the warpTarget.

Methods inherited from class java.lang.Object

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

Constructor Detail

Wavetable

public Wavetable(int size)

Construct a Wavetable that contains size entries.

Parameters:

size - int: the number of samples the Wavetable should contain

Wavetable

public Wavetable(float[] waveform)

Construct a Wavetable that will use waveform as the float array to sample from. This will not copy waveform, it will use it directly.

Parameters:

waveform - float[]: the float array this Wavetable will sample

Wavetable

public Wavetable(Wavetable wavetable)

Make a new Wavetable that has the same waveform values as wavetable. This will copy the values from the provided Wavetable into this Wavetable's waveform.

Parameters:

wavetable - Wavetable: the Wavetable to copy

Method Detail

setWaveform

public void setWaveform(float[] waveform)

Sets this Wavetable's waveform to the one provided. This will not copy the values from the provided waveform, it will use the waveform directly.

Parameters:

waveform - float[]: the new sample data

get

public float get(int i)

Returns the value of the i^th entry in this Wavetable's waveform. This is equivalent to getWaveform()[i].

Parameters:

i - int: the index of the sample to return

Returns:

float: the value of the sample at i

value

public float value(float at)

Sample the Wavetable using a value in the range [0,1]. For instance, if the Wavetable has 1024 values in its float array, then calling value(0.5) will return the 512th value in the array. If the result is that it needs say the 456.65th value, this will interpolate between the surrounding values.

Specified by:

value in interface Waveform

Parameters:

at - float: a value in the range [0, 1]

Returns:

float: this Wavetable sampled at the requested interval

getWaveform

public float[] getWaveform()

Returns the underlying waveform, not a copy of it.

Returns:

float[]: the float array managed by this Wavetable

set

public void set(int i,
                float value)

Sets the i^th entry of the underlying waveform to value. This is equivalent to:

getWaveform()[i] = value;

Parameters:

i - int: the index of the sample to set

value - float: the new sample value

size

public int size()

Returns the length of the underlying waveform. This is equivalent to:

getWaveform().length

Returns:

int: the length of the underlying float array

scale

public void scale(float scale)

Multiplies each value of the underlying waveform by scale.

Parameters:

scale - float: the amount to scale the Wavetable with

offset

public void offset(float amount)

Apply a DC offset to this Wavetable. In other words, add amount to every sample.

Parameters:

amount - float: the amount to add to every sample in the table

normalize

public void normalize()

Normalizes the Wavetable by finding the largest amplitude in the table and scaling the table by the inverse of that amount. The result is that the largest value in the table will now have an amplitude of 1 and everything else is scaled proportionally.

invert

public void invert()

Flips the table around 0. Equivalent to flip(0).

See Also:

flip(float)

flip

public void flip(float in)

Flip the values in the table around a particular value. For example, if you flip around 2, values greater than 2 will become less than two by the same amount and values less than 2 will become greater than 2 by the same amount. 3 -> 1, 0 -> 4, etc.

Parameters:

in - float: the value to flip the table around

addNoise

public void addNoise(float sigma)

Adds Gaussian noise to the waveform.

Parameters:

sigma - float: the amount to scale the random values by, in effect how "loud" the added noise will be.

rectify

public void rectify()

Inverts all values in the table that are less than zero. -1 -> 1, -0.2 -> 0.2, etc.

smooth

public void smooth(int windowLength)

Smooth out the values in the table by using a moving average window.

Parameters:

windowLength - int: how many samples large the window should be

warp

public void warp(float warpPoint,
                 float warpTarget)

Warping works by choosing a point in the waveform, the warpPoint, and then specifying where it should move to, the warpTarget. Both values should be normalized (i.e. in the range [0,1]). What will happen is that the waveform data in front of and behind the warpPoint will be squashed or stretch to fill the space defined by where the warpTarget is. For instance, if you took Waves.SQUARE and called warp( 0.5, 0.2 ), you would wind up with a square wave with a 20 percent duty cycle, the same as using Waves.square( 0.2 ). This is because the crossover point of a square wave is halfway through and warping it such that the crossover is moved to 20% through the waveform is equivalent to changing the duty cycle. Or course, much more interesting things happen when warping a more complex waveform, such as one returned by the Waves.randomNHarms method, especially if it is warped more than once.

Parameters:

warpPoint - float: the point in the wave for to be moved, expressed as a normalized value.

warpTarget - float: the point in the wave to move the warpPoint to, expressed as a normalized value.