/*******************************************************************************
* Catroid: An on-device visual programming system for Android devices
* Copyright (C) 2010-2013 The Catrobat Team
* (<http://developer.catrobat.org/credits>)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* An additional term exception under section 7 of the GNU Affero
* General Public License, version 3, is available at
* http://www.catroid.org/catroid/licenseadditionalterm
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
******************************************************************************/
package org.catrobat.musicdroid.metronom;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
public class AudioGenerator {
private int sampleRate;
private AudioTrack audioTrack;
public AudioGenerator(int sampleRate) {
this.sampleRate = sampleRate;
}
public double[] getSineWave(int samples, int sampleRate, double frequencyOfTone) {
double[] sample = new double[samples];
for (int i = 0; i < samples; i++) {
sample[i] = Math.sin(2 * Math.PI * i / (sampleRate / frequencyOfTone));
}
return sample;
}
public byte[] get16BitPcm(double[] samples) {
byte[] generatedSound = new byte[2 * samples.length];
int index = 0;
for (double sample : samples) {
short maxSample = (short) ((sample * Short.MAX_VALUE));
generatedSound[index++] = (byte) (maxSample & 0x00ff);
generatedSound[index++] = (byte) ((maxSample & 0xff00) >>> 8);
}
return generatedSound;
}
public void createPlayer() {
audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, sampleRate, AudioFormat.CHANNEL_OUT_MONO,
AudioFormat.ENCODING_PCM_16BIT, sampleRate, AudioTrack.MODE_STREAM);
audioTrack.play();
}
public void writeSound(double[] samples) {
byte[] generatedSnd = get16BitPcm(samples);
audioTrack.write(generatedSnd, 0, generatedSnd.length);
}
public void destroyAudioTrack() {
audioTrack.stop();
audioTrack.release();
}
}