1 /*
2  * Copyright 2021 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package org.hyphonate.megaaudio.player.sources;
17 
18 import org.hyphonate.megaaudio.player.AudioSource;
19 
20 import java.util.Random;
21 
22 /**
23  * A source of white noise audio
24  */
25 public class NoiseAudioSource extends AudioSource {
26     private Random mRandom = new Random();
27 
28     /**
29      * Fills the specified buffer with Random Data (more-or-less White Noise).
30      *
31      * @param buffer The buffer to be filled.
32      * @param numFrames The number of frames of audio to provide.
33      * @param numChans The number of channels (in the buffer) required by the player.
34      * @return  The number of samples generated. Since we are generating a continuous periodic
35      * signal, this will always be <code>numFrames</code>.
36      */
37     @Override
pull(float[] buffer, int numFrames, int numChans)38     public int pull(float[] buffer, int numFrames, int numChans) {
39         for (int index = 0; index < numFrames * numChans; index++) {
40             buffer[index] = (mRandom.nextFloat() * 2.0f) - 1.0f;
41         }
42 
43         return numFrames;
44     }
45 }
46