Static and Buzzing when Generating and Playing Sine Waves with SFML - c++

Question

I am writing a program that needs to play a lot of synthesized sine waves in rapid succession. I am using C++ and SFML to write this program. I have created a class to represent a synthesizer. It is responsible for generating the sine wave and playing it down a single audio stream. However, whenever I use the app, I get a lot of crackling and popping sounds that get intermixed in. I am not sure if this is a library issue or I am generating and feeding in the sine wave wrong. Here is my code:
synth.h
#pragma once
#include <SFML/Audio.hpp>
#include <vector>
#include <mutex>
class Synth : public sf::SoundStream {
std::vector<sf::Int16> m_AudioData;
std::mutex m_Lock;
bool m_ClearData, m_Loaded, m_Started;
int m_Amplitude;
const float TAU = 6.28318;
public:
Synth(int);
Synth(const Synth&);
~Synth();
bool onGetData(sf::SoundStream::Chunk&) override;
void onSeek(sf::Time) override;
void makeSound(float, int);
bool busy();
};
synth.cpp
#include "synth.h"
Synth::Synth(int amplitude)
: m_Amplitude(amplitude)
, m_Loaded(false)
, m_ClearData(false)
, m_Started(false)
{
initialize(1, 44100);
}
Synth::Synth(const Synth& other)
: m_Amplitude(other.m_Amplitude)
, m_Loaded(false)
, m_ClearData(false)
, m_Started(false)
{
initialize(1, 44100);
}
Synth::~Synth() {
stop();
}
bool Synth::onGetData(Chunk &chunk) {
static const sf::Int16 empty[10] = { 0 };
m_Lock.lock();
if (m_Loaded) {
chunk.sampleCount = m_AudioData.size();
chunk.samples = m_AudioData.data();
m_ClearData = true;
m_Loaded = false;
}
else {
if (m_ClearData) {
m_AudioData.clear();
m_ClearData = false;
}
chunk.sampleCount = 10;
chunk.samples = empty;
}
m_Lock.unlock();
return true;
}
void Synth::onSeek(sf::Time) {}
void Synth::makeSound(float freq, int duration) {
m_Lock.lock();
m_ClearData = false;
m_Loaded = true;
m_AudioData.clear();
int sampleCount = duration * 44;
int amplitude = m_Amplitude;
for (int i = 0; i < sampleCount; i++) {
if (i < sampleCount / 5)
amplitude = floor(m_Amplitude * (i / (double)sampleCount) * 5);
else if (i > sampleCount / 2)
amplitude = floor(m_Amplitude * ((sampleCount - i) / (double)sampleCount));
else
amplitude = m_Amplitude;
m_AudioData.push_back(amplitude * sin(TAU * (freq / 44100) * i));
}
m_Lock.unlock();
if (!m_Started) {
play();
m_Started = true;
}
}
bool Synth::busy() {
bool isBusy = false;
if (m_Lock.try_lock()) {
isBusy = m_Loaded || m_ClearData;
m_Lock.unlock();
}
return isBusy;
}
For context, these synthesizers are stored in a vector owned by a parent class. They are used to represent available channels for playing audio. There are 50 stored in the parent class in total, however the number can vary. I doubt that this has any relevance to my problem, but I wanted to inform everyone to the best of my ability.
Thanks a million, open to any other side criticisms of my code.