1 /*
2 * Copyright 2018 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
17 #include "SoundGenerator.h"
18
SoundGenerator(int32_t sampleRate,int32_t channelCount)19 SoundGenerator::SoundGenerator(int32_t sampleRate, int32_t channelCount) :
20 TappableAudioSource(sampleRate, channelCount)
21 , mOscillators(std::make_unique<Oscillator[]>(channelCount)){
22
23 double frequency = 440.0;
24 constexpr double interval = 110.0;
25 constexpr float amplitude = 1.0;
26
27 // Set up the oscillators
28 for (int i = 0; i < mChannelCount; ++i) {
29 mOscillators[i].setFrequency(frequency);
30 mOscillators[i].setSampleRate(mSampleRate);
31 mOscillators[i].setAmplitude(amplitude);
32 frequency += interval;
33 }
34 }
35
renderAudio(float * audioData,int32_t numFrames)36 void SoundGenerator::renderAudio(float *audioData, int32_t numFrames) {
37 // Render each oscillator into its own channel
38 std::fill_n(mBuffer.get(), kSharedBufferSize, 0);
39 for (int i = 0; i < mChannelCount; ++i) {
40 mOscillators[i].renderAudio(mBuffer.get(), numFrames);
41 for (int j = 0; j < numFrames; ++j) {
42 audioData[(j * mChannelCount) + i] = mBuffer[j];
43 }
44 }
45 }
46
tap(bool isOn)47 void SoundGenerator::tap(bool isOn) {
48 for (int i = 0; i < mChannelCount; ++i) {
49 mOscillators[i].setWaveOn(isOn);
50 }
51 }
52