ddf.minim.ugens

Class WavetableGenerator

java.lang.Object

ddf.minim.ugens.WavetableGenerator

public class WavetableGenerator
extends java.lang.Object

WavetableGenerator is a helper class for generating Wavetables. The method names come from CSound. Generally speaking, it will often be easier to use the static methods in the Waves class, but the methods in this class provide more flexibility.

Author:

Mark Godfrey <mark.godfrey@gatech.edu>

Method Summary

Modifier and Type	Method and Description
static Wavetable	gen10(int size, float[] amp) Generate a Wavetable given a list of amplitudes for successive partials (harmonics).
static Wavetable	gen7(int size, float[] val, int[] dist) Generate a piecewise linear waveform given an array of sample values and the distances between them.
static Wavetable	gen9(int size, float[] partial, float[] amp, float[] phase) Generates a Wavetable from a list of partials with matching amplitudes and phases.

Methods inherited from class java.lang.Object

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

Method Detail

gen7

public static Wavetable gen7(int size,
                             float[] val,
                             int[] dist)

Generate a piecewise linear waveform given an array of sample values and the distances between them. The dist array should contain one value less than the val array. The values in the dist array should also add up to size. For instance, a call like this:

Wavetable table = WavetableGenerator.gen7( 4096, new float[] { 1.0, -1.0, 1.0 }, new int[] { 2048, 2048 } );

Would generate a Wavetable that was 4096 samples long and the values of those samples would start at 1.0, linearly decrease to -1.0 over 2048 samples, and then increase to 1.0 over the next 2048 samples.

If you wanted to generate a triangle wavetable with 4096 samples, you'd do this:

Wavetable table = WavetableGenerator.gen7( 4069, new float[] { 0.0, 1.0, 0.0, -1.0, 0.0 }, new int[] { 1024, 1024, 1024, 1024 } );

Parameters:

size - int: the size of the Wavetable that you want generate

val - float[]: the sample values used as control points for generating the waveform

dist - int[]: the sample distances between control points in val

Returns:

a Wavetable

gen9

public static Wavetable gen9(int size,
                             float[] partial,
                             float[] amp,
                             float[] phase)

Generates a Wavetable from a list of partials with matching amplitudes and phases. Partial, here, refers to a particular sine wave in the harmonic series (see: Harmonic vs. partial). If you want to generate a single sine wave, suitable for playing a single tone of a particular frequency in an Oscil, you could use this code:

Wavetable sine = WavetableGenerator.gen9(4096, new float[] { 1 }, new float[] { 1 }, new float[] { 0 });

But what this method lets you do, is create a Wavetable that contains several different partials, each with a particular amplitude or phase shift. For instance, you could create a Wavetable that plays two pitches an octave apart like this:

Wavetable octave = WavetableGenerator.gen9(4096, new float[] { 1, 2 }, new float[] { 1, 1 }, new float[] { 0, 0 });

If this is something you want a particular instrument you write to do, then creating a Wavetable that already contains the octave and using that in an Oscil will be less computationally expensive than creating two Oscils and setting their frequencies an octave apart.

Parameters:

size - int: how many samples the Wavetable should contain

partial - float[]: a list of partials to generate

amp - float[]: the amplitude of each partial

phase - float[]: the phase of each partial

Returns:

a Wavetable

gen10

public static Wavetable gen10(int size,
                              float[] amp)

Generate a Wavetable given a list of amplitudes for successive partials (harmonics). These two method calls are equivalent:

Wavetable table = WavetableGenerator.gen9(4096, new float[] { 1, 2, 3 }, new float[] { 1, 0.5, 0.2 }, new float[] { 0, 0, 0 });

Wavetable table = WavetableGenerator.gen10(4096, new float[] { 1, 0.5, 0.2 });

Parameters:

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

amp - float[]: the amplitude of each successive partial, beginning with partial 1.

Returns:

a Wavetable

See Also:

gen9(int, float[], float[], float[])