make basic audio engine parameters configurable

src/ConfigInterface.cpp

@@ -11,39 +11,34 @@ namespace fs = std::filesystem;
 
 ConfigInterface::ConfigInterface() {
     
-    std::string audioConfig = configRoot + "/" + filename;
-
-    std::cout << "CWD: " << fs::current_path() << std::endl;
-    std::cout << "Audio config: " << fs::absolute(audioConfig).string() << std::endl;
-
-    // opening the file myself because YAML::LoadFile didn't seem to work on windows
-    std::ifstream file(fs::absolute(audioConfig).string());
-    if(file.good()) {
-        std::cout << "File exists" << std::endl;
-    } else {
-        std::cout << "File does not exist" << std::endl;
-    }
-
-    //YAML::Node config;
-    /*
-    try {
-        YAML::Node config = YAML::Load("{sampleRate: 44100}");
-        std::cout << "Loaded config file" << std::endl;
-
-        std::cout << "Type enum: " << static_cast<int>(config.Type()) << std::endl;
-
-        if(config["sampleRate"]) {
-            //int sampleRate = config["sampleRate"].as<int>();
-            //std::cout << sampleRate << std::endl;
-        } else {
-            std::cout << "Key does not exist" << std::endl;
-        }
-    } catch(const std::exception& e) {
-        std::cerr << e.what() << '\n';
-    }
-    */
-
-    YAML::Node n = YAML::Load("{sampleRate: 44100}");
-    std::cout << n["sampleRate"].as<int>() << "\n";    
+    //std::cout << "Config constructor" << std::endl;
+
+}
+
+int ConfigInterface::getValue(ConfigFile file, std::string key, int defaultVal) {
+
+    // assemble filepath
+    std::string filepath = configRoot + "/" + filePaths[static_cast<int>(file)];
+    filepath = fs::absolute(filepath).string();
+    
+    // attempt to open file
+    YAML::Node config;
+    try {
+        YAML::Node config = YAML::LoadFile(filepath);
+
+        // read key if it exists
+        if(config[key]) {
+            return config[key].as<int>(defaultVal);
+        } else {
+            return -1; // key does not exist
+        }
+
+    } catch(const std::exception& e) {
+        std::cerr << e.what() << std::endl;
+        return -1;
+    }
+
+    // unreachable
+    return -1;
 
 }

src/ConfigInterface.h

@@ -2,6 +2,17 @@
 #pragma once
 
 #include <string>
+#include <vector>
+
+enum class ConfigFile {
+    Audio = 0
+    // other files here
+};
+
+// might have a config file for specifying paths to other config files instead of this
+const std::vector<std::string> filePaths = {
+    "audio.yaml"
+};
 
 class ConfigInterface {
 
@@ -10,9 +21,10 @@ public:
     ConfigInterface();
     ~ConfigInterface() = default;
 
+    int getValue(ConfigFile file, std::string key, int defaultVal);
+
 private:
 
     const std::string configRoot = "config";
-    const std::string filename = "audio.yaml";
 
 };

src/main.cpp

@@ -9,9 +9,7 @@
 int main(int argc, char *argv[]) {
 
     // std::cout << "Main()" << std::endl;
-
-    ConfigInterface config = ConfigInterface();
-
+    
     QApplication app(argc, argv);
 
     MainWindow window; // entry point goes to MainWindow::MainWindow()

src/synth/AudioEngine.cpp

@@ -3,14 +3,11 @@
 
 #include <iostream>
 
-AudioEngine::AudioEngine() : synth_(params_) {
+AudioEngine::AudioEngine(ConfigInterface* config) : synth_(params_), config_(config) {
     if(audio_.getDeviceCount() < 1) {
         throw std::runtime_error("No audio devices found");
     }
 
-    // TODO: get audio configurations
-    synth_.setSampleRate(sampleRate_);
-
     synth_.setScopeBuffer(&scope_);
 
 }
@@ -21,6 +18,13 @@ AudioEngine::~AudioEngine() {
 
 bool AudioEngine::start() {
 
+    // get config values
+    sampleRate_ = config_->getValue(ConfigFile::Audio, "sampleRate", sampleRate_);
+    bufferFrames_ = config_->getValue(ConfigFile::Audio, "bufferSize", bufferFrames_);
+    channels_ = config_->getValue(ConfigFile::Audio, "channels", channels_);
+
+    synth_.setSampleRate(sampleRate_);
+
     // initialize the audio engine
     RtAudio::StreamParameters params;
     params.deviceId = audio_.getDefaultOutputDevice();

src/synth/AudioEngine.h

@@ -7,6 +7,7 @@
 
 #include "Synth.h"
 #include "../KeyboardController.h"
+#include "../ConfigInterface.h"
 
 #if defined(_WIN32)
     #define AUDIO_API RtAudio::WINDOWS_WASAPI
@@ -17,7 +18,7 @@
 class AudioEngine {
 
 public:
-    AudioEngine();
+    AudioEngine(ConfigInterface* config);
     ~AudioEngine();
 
     // starts the audio stream. returns true on success and false on failure
@@ -43,6 +44,7 @@ private:
     NoteQueue noteQueue_; // stores note events for passing between threads
     Synth synth_; // generates audio
     ScopeBuffer scope_ { 1024 }; // stores audio samples for visualization
+    ConfigInterface* config_; // access to config files
 
     RtAudio audio_{AUDIO_API}; // audio device
     // TODO: id like a yml config file or something for these

src/synth/ScopeBuffer.cpp

@@ -11,11 +11,12 @@ void ScopeBuffer::push(float sample) {
     buffer_[w % buffer_.size()] = sample;
 }
 
-// TODO: needs a mutex to prevent flickering
+// TODO: needs a mutex/spinlock to prevent flickering
 // outputs value from the scope buffer, called by the scope widget
 void ScopeBuffer::read(std::vector<float>& out) const {
 
-    while(!spinLock_) { int x = 1 + 1; }
+    // yeah this didn't work, maybe it needs to be atomic or something
+    //while(!spinLock_) { int x = 1 + 1; }
 
     size_t w = writeIndex_.load(std::memory_order_relaxed);
     for (size_t i = 0; i < out.size(); i++) {

src/ui/MainWindow.cpp

@@ -8,7 +8,7 @@
 MainWindow::MainWindow(QWidget *parent) :
     QMainWindow(parent),
     ui_(new Ui::MainWindow),
-    audio_(new AudioEngine()),
+    audio_(new AudioEngine(&config_)),
     keyboard_(audio_->noteQueue()),
     midi_(audio_->noteQueue()) {
 

src/ui/MainWindow.h

@@ -6,6 +6,7 @@
 
 #include "../synth/AudioEngine.h"
 #include "../MidiController.h"
+#include "../ConfigInterface.h"
 
 QT_BEGIN_NAMESPACE
 namespace Ui { class MainWindow; }
@@ -32,5 +33,6 @@ private:
     AudioEngine* audio_ = nullptr;
     KeyboardController keyboard_;
     MidiController midi_;
+    ConfigInterface config_;
 
 };