add instrument factory

.gitignore

@@ -1,2 +1,4 @@
 
 build/*
+
+*/__pycache__/*

CMakeLists.txt

@@ -46,7 +46,7 @@ find_package(Qt6 REQUIRED COMPONENTS
 qt_standard_project_setup()
 
 add_library(sonobulus_core STATIC
-    src/ConfigService.cpp
+    src/config/ConfigService.cpp
     src/LoggerService.cpp
     src/TimerComponent.cpp
     src/synth/AudioEngine.cpp
@@ -55,10 +55,14 @@ add_library(sonobulus_core STATIC
     src/synth/NoteQueue.cpp
     src/synth/Scope.cpp
     src/synth/Synth.cpp
-    src/synth/Voice.cpp
+    #src/synth/Voice.cpp
     src/synth/Filter.cpp
-    src/synth/Instrument.cpp
+    src/synth/WavetableLoader.cpp
-    src/synth/Instruments/PianoString.cpp
+    src/synth/Envelope.cpp
+    src/synth/InstrumentFactory.cpp
+    src/synth/instruments/Instrument.cpp
+    src/synth/instruments/PianoString.cpp
+    src/synth/instruments/WavetableOscillator.cpp
 )
 
 if (WIN32)

config/sonobulus.cfg

@@ -8,7 +8,7 @@ Logger = (
             "Info",
             "Warning",
             "Error"
-        );
+        ); # TODO: console flags vs file flags
 
         ShowTime = false;
         ShowSourceTrace = false;
@@ -19,6 +19,23 @@ Logger = (
     }
 );
 
+AudioEngine = (
+    {
+        Id = "Main";
+
+        SampleRate = 44100;
+        Channels = 2;
+        StereoMode = 1;
+        BufferSize = 512;
+        PitchStandard = 440.0;
+        MidiHome = 69;
+        NotesPerOctave = 12.0;
+        OctaveConstant = 2.0;
+        MaxVoices = 32;
+    }
+);
+
+# TODO: I don't like this being in the main config, maybe import it in (mainly the notes and keycodes)
 KeyboardController = (
     {
         Id = "Main";

scripts/wavetables/example_wavetable.py

@@ -0,0 +1,52 @@
+
+import math
+from generate_wavetable import generateWavetable
+
+WAVETABLE_FILE_NAME = "config/wavetables/shark_fin.wt"
+
+# process expects a waveform from x=[0, 2pi) centered around f(x)=0
+# normalization is handled by the wavetable generator
+
+def sine(phase):
+    return math.sin(phase)
+
+def square(phase):
+    sample = 1.0
+    if(phase <= math.pi):
+        sample = -1
+    return sample
+
+def saw(phase):
+    return (phase / math.pi) - 1.0
+
+def triangle(phase):
+    sample = 0.0
+    if(phase <= math.pi/2.0):
+        sample = phase * 2.0/math.pi
+    elif(phase <= 3.0*math.pi/2.0):
+        sample = phase * (-2.0/math.pi) + 2.0
+    else:
+        sample = phase * 2.0/math.pi - 4.0
+    return sample
+
+def sharkFin(phase):
+    k = 10.0
+    sample = 0.0
+    if(phase <= math.pi):
+        sample = 2.0 * (phase/math.pi) ** k - 1.0
+    else:
+        sample = -2.0 * (phase/math.pi - 1) ** k + 1.0
+    return sample
+
+def sigmoid(phase):
+    k = 4.0
+    a = -k * (phase - math.pi)
+    sample = 2.0 / (1.0 + math.exp(a)) - 1.0
+    return sample
+
+# pass in the name of your wavetable file and the process function
+def main():
+    generateWavetable(WAVETABLE_FILE_NAME, sharkFin)
+
+if __name__ == "__main__":
+    main()

scripts/wavetables/generate_wavetable.py

@@ -0,0 +1,67 @@
+
+# this is a script for generating a wavetable file
+# a wavetable file consists of a one-dimensional array of samples representing one period of a waveform
+# metadata includes:
+#   - file version (for program compatibilty)
+#   - binary format (float, double, int32, etc.)
+#   - domain (eg phase is represented from [0, 2pi) )
+#   - range (determined by datatype, e.g. float=[-1,1], int32=[-2^15, 2^15-1])
+#   - waveform RMS (for loudness normalization)
+#   - sample count
+# the synth program uses the filename, not any metadata
+
+# this script uses the input function to calculate samples
+# if you want a custom wavetable, copt/edit/modify the example function (i used desmos for brainstorming)
+# import this script and call generateWavetable(processFunction) to generate a custom wavetable
+
+from array import array
+import math
+
+wavetableLength = 2048
+
+def createFile(name):
+    filename = name
+    print("Creating file " + filename)
+    file = open(filename, "wb")
+    return file
+
+def writeMetadata(file):
+    print(">> im writing metadata")
+    
+def writeData(file, processFunction):
+    print(">> im generating the wavetable")
+
+    # init variables
+    data_list = [None] * wavetableLength
+    phaseInc = 2*math.pi / wavetableLength
+    x = 0
+    accumulator = 0
+
+    # generate each discrete sample
+    for i in range(wavetableLength):
+        sample = processFunction(x)
+        accumulator += sample * sample
+        x += phaseInc
+        data_list[i] = sample
+
+    # normalize by rms
+    rms = math.sqrt(accumulator/wavetableLength)
+    print(">> wavetable RMS: ", rms)
+    for i in range(wavetableLength):
+        data_list[i] /= rms
+
+    # write to file
+    binary_data = array("f", data_list)
+    file.write(binary_data)
+
+def closeFile(file):
+    print(">> finishing up")
+    file.close()
+
+def generateWavetable(name, processFunction):
+    print("Hello main")
+    file = createFile(name)
+    writeMetadata(file)
+    writeData(file, processFunction)
+    closeFile(file)
+    print("Done")

src/ConfigService.hpp

@@ -1,128 +0,0 @@
-
-#pragma once
-
-#include <libconfig.h++>
-
-#include <optional>
-#include <string>
-#include <vector>
-#include <iostream>
-#include <unordered_map>
-
-struct LoggerConfig {
-    std::string id;
-    std::vector<std::string> flagsEnabled;
-    bool showTime = false;
-    bool showSourceTrace = false;
-    bool coutEnabled = false;
-    bool fileEnabled = false;
-    std::string filePath;
-
-    bool parseConfig(const libconfig::Setting& setting) {
-
-        if (!setting.lookupValue("Id", id)) {
-            return false;
-        }
-
-        try {
-            const libconfig::Setting& flags = setting.lookup("FlagsEnabled");
-            for (int index = 0; index < flags.getLength(); ++index) {
-                flagsEnabled.push_back(static_cast<const char*>(flags[index]));
-            }
-        } catch (const libconfig::SettingException&) {
-            flagsEnabled.clear();
-        }
-
-        setting.lookupValue("ShowTime", showTime);
-        setting.lookupValue("ShowSourceTrace", showSourceTrace);
-        setting.lookupValue("CoutEnabled", coutEnabled);
-        setting.lookupValue("FileEnabled", fileEnabled);
-        setting.lookupValue("FilePath", filePath);
-
-        return true;
-    }
-};
-
-struct AudioConfig {
-    uint32_t sampleRate;
-    uint32_t channels;
-    uint32_t stereoMode;
-    uint32_t bufferSize;
-    float pitchStandard;
-    int32_t midiHome;
-    int32_t notesPerOctave;
-};
-
-struct KeymapConfig {
-    std::string id;
-    std::unordered_map<int32_t, uint8_t> keymap;
-
-    bool parseConfig(const libconfig::Setting& setting) {
-
-        if (!setting.lookupValue("Id", id)) {
-            return false;
-        }
-
-        try {
-            const libconfig::Setting& keymapGroup = setting.lookup("Keymap");
-            const libconfig::Setting& notesGroup = setting.lookup("Notes");
-            const libconfig::Setting& keysGroup = setting.lookup("Keys");
-
-            for(size_t i = 0; i < keymapGroup.getLength(); i++) {
-                libconfig::Setting& item = keymapGroup[i];
-                std::string key = item.getName();
-                std::string note = "";
-                if(item.getType() == libconfig::Setting::TypeString) note = std::string(item.c_str());
-
-                int8_t noteId = static_cast<int>(notesGroup[note]) % INT8_MAX;
-                int32_t keyId = static_cast<int>(keysGroup[key]) % INT32_MAX;
-
-                keymap.emplace(keyId, noteId);
-            }
-
-        } catch (const libconfig::SettingException&) {
-            return false;
-        }
-
-        return true;
-    }
-};
-
-class ConfigService {
-
-public:
-
-    ConfigService(const std::string& filePath);
-    ~ConfigService() = default;
-
-    bool loadFromFile(const std::string& filePath);
-
-    template<typename T>
-    bool getConfig(const std::string& type, const std::string& id, T* config) const {
-        try {
-            const libconfig::Setting& configs = config_.lookup(type);
-            for (int index = 0; index < configs.getLength(); ++index) {
-                const libconfig::Setting& configSetting = configs[index];
-
-                std::string configId;
-                if (!configSetting.lookupValue("Id", configId) || configId != id) {
-                    continue;
-                }
-
-                return config->parseConfig(configSetting);
-            }
-        } catch (const libconfig::SettingException& ex) {
-            std::cout << "libconfig setting exception: " << ex.what() << std::endl;
-            return false;
-        }
-
-        return false;
-    }
-
-    const std::string& lastError() const;
-
-private:
-
-    libconfig::Config config_;
-    std::string lastError_;
-};

src/LoggerService.cpp

@@ -13,17 +13,11 @@ namespace fs = std::filesystem;
 
 LoggerService::LoggerService(ConfigService* config, const std::string& loggerId) {
 
-    if(!(config->getConfig<LoggerConfig>("Logger", loggerId, &configuration_))) {
+    if(!(config->getConfig<LoggerParams, LoggerConfig>("Logger", loggerId, &configuration_))) {
-        std::cout << "Failed to get logger configuration fom config service" << std::endl;
+        std::cout << "Failed to get logger configuration from config service" << std::endl;
         return;
     }
     
-    standardOutputEnabled_ = configuration_.coutEnabled;
-    fileOutputEnabled_ = configuration_.fileEnabled;
-    additionaldetailsEnabled_ = configuration_.showSourceTrace;
-    timeEnabled_ = configuration_.showTime;
-    id_ = configuration_.id;
-    
     for(std::string& flag : configuration_.flagsEnabled) {
         bool found = false;
         for(const char* validFlag : LogFlagStrings) {
@@ -55,7 +49,7 @@ LoggerService::LoggerService(ConfigService* config, const std::string& loggerId)
     fs::create_directories(std::string(BINARY_DIR) + "/" + finaltime);
     std::string logPath = std::string(BINARY_DIR) + "/" + finaltime + "/" + configuration_.filePath;
 
-    if(fileOutputEnabled_) outfile_.open(logPath);
+    if(configuration_.fileEnabled) outfile_.open(logPath);
 
     log("Logger", LogFlag::Info, "Logger initialized.");
 }
@@ -78,11 +72,11 @@ void LoggerService::log(std::string component, LogFlag flag, std::string message
 
     std::string finalmessage = "";
 
-    if(timeEnabled_) {
+    if(configuration_.showTime) {
         finalmessage = finalmessage + "[" +  "Not Implemented" + "] "; 
     }
 
-    std::string componentTrace = "[" + id_ + ": " + component + "] ";
+    std::string componentTrace = "[" + configuration_.id + ": " + component + "] ";
     finalmessage += componentTrace; // component is the section of the program (For example Mesh or Engine) that is calling the logger
             
     std::string level = "";
@@ -94,15 +88,15 @@ void LoggerService::log(std::string component, LogFlag flag, std::string message
     finalmessage = finalmessage + "[" + level + "] "; 
     finalmessage = finalmessage + message + " "; 
 
-    if (additionaldetailsEnabled_) {
+    if (configuration_.showSourceTrace) {
         finalmessage = finalmessage  + "[Function: " + Source.function_name() + "]" + " " + "[Line: "  +  std::to_string(Source.line()) + "]" + " " + "[File: "  +  Source.file_name() + "]";
     }
 
-    if(standardOutputEnabled_) {
+    if(configuration_.coutEnabled) {
         std::cout << finalmessage << std::endl;
     }
 
-    if(fileOutputEnabled_) {
+    if(configuration_.fileEnabled) {
         outfile_ << finalmessage << std::endl;
     }
     return;

src/LoggerService.hpp

@@ -5,7 +5,8 @@
 #include <fstream>
 #include <source_location>
 
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
+#include "config/LoggerConfig.hpp"
 
 enum LogFlag {
     Debug,
@@ -33,14 +34,8 @@ public:
 
 private: 
 
-    bool standardOutputEnabled_;
-    bool fileOutputEnabled_;
-    bool additionaldetailsEnabled_;
-    bool timeEnabled_;
     std::ofstream outfile_;
-    std::string id_;
-
     std::vector<LogFlag> activeFlags_;
 
-    LoggerConfig configuration_;
+    LoggerParams configuration_;
 };

src/ParameterStore.cpp

@@ -0,0 +1,18 @@
+
+#include "ParameterStore.hpp"
+
+ParameterStore::ParameterStore() {
+
+}
+
+// set parameter value
+void ParameterStore::set(ParamId id, float value) {
+    Param oldParam = values_[static_cast<size_t>(id)].load(std::memory_order_relaxed);
+    Param updatedParam = { value, oldParam.min, oldParam.max };
+    values_[static_cast<size_t>(id)].store(updatedParam, std::memory_order_relaxed);
+}
+
+// get a single parameter
+float ParameterStore::get(ParamId id) const {
+    return values_[static_cast<size_t>(id)].load(std::memory_order_relaxed).val;
+}

src/ParameterStore.hpp

@@ -0,0 +1,37 @@
+
+#pragma once
+
+#include <vector>
+#include <cstdint>
+
+enum class ParamId : uint8_t {
+    MasterGain,
+    Count
+};
+
+struct Param {
+    float val;
+    float min;
+    float max;
+};
+
+constexpr size_t PARAM_COUNT = static_cast<size_t>(ParamId::Count);
+
+class ParameterStore {
+
+public:
+
+    ParameterStore();
+    ~ParameterStore() = default;
+
+    void set(ParamId id, float value);
+    void set(ParamId id, int32_t value) { set(id, static_cast<float>(value)); }
+    void set(EnvelopeId id, float depth, float a, float d, float s, float r);
+    float get(ParamId id) const;
+    int32_t getInt(ParamId id) const { return static_cast<int32_t>(get(id)); }
+
+private:
+
+    std::array<std::atomic<Param>, PARAM_COUNT> values_;
+
+};

src/config/AudioConfig.hpp

@@ -0,0 +1,45 @@
+
+#pragma once
+
+#include "IConfig.hpp"
+
+struct AudioParams : IParams {
+    std::string id;
+    uint32_t sampleRate;
+    uint32_t channels;
+    uint32_t stereoMode;
+    uint32_t bufferSize;
+    float pitchStandard;
+    int32_t midiHome;
+    float notesPerOctave;
+    float octaveConstant;
+    size_t maxVoices;
+};
+
+
+class AudioConfig : public IConfig<AudioParams> {
+
+public:
+
+    using IConfig<AudioParams>::IConfig;
+
+    bool parseConfig(const libconfig::Setting& setting) override {
+
+        if (!setting.lookupValue("Id", params_->id)) {
+            return false;
+        }
+
+        setting.lookupValue("SampleRate", params_->sampleRate);
+        setting.lookupValue("StereoMode", params_->stereoMode);
+        setting.lookupValue("BufferSize", params_->bufferSize);
+        setting.lookupValue("Channels", params_->channels);
+        setting.lookupValue("PitchStandard", params_->pitchStandard);
+        setting.lookupValue("MidiHome", params_->midiHome);
+        setting.lookupValue("NotesPerOctave", params_->notesPerOctave);
+        setting.lookupValue("OctaveConstant", params_->octaveConstant);
+        setting.lookupValue("MaxVoices", params_->maxVoices);
+
+        return true;
+    }
+
+};

src/config/ConfigService.hpp

@@ -0,0 +1,56 @@
+
+#pragma once
+
+#include <libconfig.h++>
+
+#include <optional>
+#include <string>
+#include <vector>
+#include <iostream>
+#include <unordered_map>
+
+#include "config/IConfig.hpp"
+
+// TODO: would be cool for the config file to include other config files so theyre a bit more compartmentalized
+// then the main file will be like a hub and would be more like each component having its own config file
+class ConfigService {
+
+public:
+
+    ConfigService(const std::string& filePath);
+    ~ConfigService() = default;
+
+    bool loadFromFile(const std::string& filePath);
+
+    template<typename T1, typename T2>
+    bool getConfig(const std::string& type, const std::string& id, T1* params) const {
+
+        T2 config { params };
+
+        try {
+            const libconfig::Setting& configs = config_.lookup(type);
+            for (int index = 0; index < configs.getLength(); ++index) {
+                const libconfig::Setting& configSetting = configs[index];
+
+                std::string configId;
+                if (!configSetting.lookupValue("Id", configId) || configId != id) {
+                    continue;
+                }
+
+                return config.parseConfig(configSetting);
+            }
+        } catch (const libconfig::SettingException& ex) {
+            std::cout << "libconfig setting exception: " << ex.what() << std::endl;
+            return false;
+        }
+
+        return false;
+    }
+
+    const std::string& lastError() const;
+
+private:
+
+    libconfig::Config config_;
+    std::string lastError_;
+};

src/config/IConfig.hpp

@@ -0,0 +1,24 @@
+
+#pragma once
+
+#include <libconfig.h++>
+
+struct IParams {
+
+};
+
+template <typename T>
+class IConfig {
+
+public:
+
+    IConfig(T* params) : params_(params) { }
+    ~IConfig() = default;
+
+    virtual bool parseConfig(const libconfig::Setting& setting) = 0;
+    IParams* params() { return params_; }
+
+protected:
+    T* params_;
+
+};

src/config/KeymapConfig.hpp

@@ -0,0 +1,47 @@
+
+#pragma once
+
+#include "IConfig.hpp"
+
+struct KeymapParams : IParams {
+    std::string id;
+    std::unordered_map<int32_t, uint8_t> keymap;
+};
+
+class KeymapConfig : public IConfig<KeymapParams> {
+
+public:
+
+    using IConfig<KeymapParams>::IConfig;
+
+    bool parseConfig(const libconfig::Setting& setting) override {
+
+        if (!setting.lookupValue("Id", params_->id)) {
+            return false;
+        }
+
+        try {
+            const libconfig::Setting& keymapGroup = setting.lookup("Keymap");
+            const libconfig::Setting& notesGroup = setting.lookup("Notes");
+            const libconfig::Setting& keysGroup = setting.lookup("Keys");
+
+            for(size_t i = 0; i < keymapGroup.getLength(); i++) {
+                libconfig::Setting& item = keymapGroup[i];
+                std::string key = item.getName();
+                std::string note = "";
+                if(item.getType() == libconfig::Setting::TypeString) note = std::string(item.c_str());
+
+                int8_t noteId = static_cast<int>(notesGroup[note]) % INT8_MAX;
+                int32_t keyId = static_cast<int>(keysGroup[key]) % INT32_MAX;
+
+                params_->keymap.emplace(keyId, noteId);
+            }
+
+        } catch (const libconfig::SettingException&) {
+            return false;
+        }
+
+        return true;
+    }
+
+};

src/config/LoggerConfig.hpp

@@ -0,0 +1,47 @@
+
+#pragma once
+
+#include "IConfig.hpp"
+
+struct LoggerParams : IParams {
+    std::string id;
+    std::vector<std::string> flagsEnabled;
+    bool showTime = false;
+    bool showSourceTrace = false;
+    bool coutEnabled = false;
+    bool fileEnabled = false;
+    std::string filePath;
+};
+
+class LoggerConfig : public IConfig<LoggerParams> {
+
+public:
+
+    using IConfig<LoggerParams>::IConfig;
+
+    bool parseConfig(const libconfig::Setting& setting) override {
+
+        if (!setting.lookupValue("Id", params_->id)) {
+            return false;
+        }
+
+        try {
+            const libconfig::Setting& flags = setting.lookup("FlagsEnabled");
+            for (int index = 0; index < flags.getLength(); ++index) {
+                params_->flagsEnabled.push_back(static_cast<const char*>(flags[index]));
+            }
+        } catch (const libconfig::SettingException&) {
+            params_->flagsEnabled.clear();
+            return false;
+        }
+
+        setting.lookupValue("ShowTime", params_->showTime);
+        setting.lookupValue("ShowSourceTrace", params_->showSourceTrace);
+        setting.lookupValue("CoutEnabled", params_->coutEnabled);
+        setting.lookupValue("FileEnabled", params_->fileEnabled);
+        setting.lookupValue("FilePath", params_->filePath);
+
+        return true;
+    }
+
+};

src/main.cpp

@@ -7,7 +7,7 @@
 
 #include "TimerComponent.hpp"
 #include "LoggerService.hpp"
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
 #include "synth/AudioEngine.hpp"
 #include "synth/KeyboardController.hpp"
 #include "synth/Scope.hpp"

src/synth/AudioEngine.cpp

@@ -8,6 +8,12 @@
 
 AudioEngine::AudioEngine(ConfigService* config, LoggerService* logger, Synth* synth) : config_(config), logger_(logger), synth_(synth) {
 
+    // load audio settings from config service
+    if(!(config->getConfig<AudioParams, AudioConfig>("AudioEngine", "Main", &configuration_))) {
+        logger_->log("Audio", LogFlag::Error, "Failed to get logger configuration from config service");
+        return;
+    }
+
     if(audioDevice_.getDeviceCount() < 1) {
         logger_->log("Audio", LogFlag::Error, "No audio devices found.");
     }
@@ -22,13 +28,22 @@ bool AudioEngine::start() {
     // initialize the audio engine
     RtAudio::StreamParameters params;
     params.deviceId = audioDevice_.getDefaultOutputDevice();
-    params.nChannels = channels_; // we're doing two duplicate channels for pseudo-mono
+    params.nChannels = configuration_.channels; // we're doing two duplicate channels for pseudo-mono
     params.firstChannel = 0;
 
     RtAudio::StreamOptions options;
     options.flags = RTAUDIO_MINIMIZE_LATENCY;
 
-    RtAudioErrorType status = audioDevice_.openStream(&params, nullptr, RTAUDIO_FLOAT32, sampleRate_, &bufferFrames_, &AudioEngine::audioCallback, this, &options);
+    RtAudioErrorType status = audioDevice_.openStream(
+        &params, 
+        nullptr, 
+        RTAUDIO_FLOAT32, 
+        configuration_.sampleRate, 
+        &configuration_.bufferSize, 
+        &AudioEngine::audioCallback, 
+        this, 
+        &options
+    );
     if(status != RTAUDIO_NO_ERROR) {
         logger_->log("Audio", LogFlag::Error, "Error opening RtAudio stream.");
         return false;
@@ -41,7 +56,7 @@ bool AudioEngine::start() {
     } 
 
     // sanity check
-    std::string msg = "sample rate: " + std::to_string(sampleRate_) + ", buffer frames: " + std::to_string(bufferFrames_);
+    std::string msg = "sample rate: " + std::to_string(configuration_.sampleRate) + ", buffer frames: " + std::to_string(configuration_.bufferSize);
     logger_->log("AudioEngine", LogFlag::Info, msg);
     return true;
 

src/synth/AudioEngine.hpp

@@ -6,7 +6,8 @@
 #include <RtAudio.h>
 
 #include "LoggerService.hpp"
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
+#include "config/AudioConfig.hpp"
 #include "Synth.hpp"
 #include "NoteQueue.hpp"
 
@@ -35,13 +36,10 @@ private:
 
     RtAudio audioDevice_ { AUDIO_API };
 
-    // TODO: make these configurable
-    uint32_t sampleRate_ = 44100;
-    uint32_t bufferFrames_ = 512;
-    uint32_t channels_ = 2;
-
     LoggerService* logger_;
     ConfigService* config_;
+    AudioParams configuration_;
+
     Synth* synth_;
 
 };

src/synth/Envelope.cpp

@@ -0,0 +1,24 @@
+
+#include "Envelope.hpp"
+
+Envelope::Envelope() {
+
+}
+
+Envelope::Envelope(float sampleRate) {
+
+}
+
+void Envelope::noteOn() {
+
+}
+
+void Envelope::noteOff() {
+
+}
+
+float Envelope::process() {
+
+    return 0.0f;
+
+}

src/synth/Envelope.hpp

@@ -0,0 +1,55 @@
+
+#pragma once
+
+#define ENVELOPE_MIN_TIME 0.001f // 1 ms
+
+#include <cstdint>
+#include <algorithm>
+
+class Envelope {
+
+    enum class State {
+        Idle,
+        Attack,
+        Decay,
+        Sustain,
+        Release
+    };
+
+    public:
+
+    Envelope(); // we shouldn't need services for this
+    Envelope(float sampleRate);
+    ~Envelope() = default;
+
+    void setSampleRate(float sampleRate) { sampleRate_ = sampleRate; }
+    void setAttack(float seconds) { attack_ = std::max(seconds, ENVELOPE_MIN_TIME); }
+    void setDecay(float seconds) { decay_ = std::max(seconds, ENVELOPE_MIN_TIME); }
+    void setSustain(float level) { sustain_ = level; }
+    void setRelease(float seconds) { release_ = std::max(seconds, ENVELOPE_MIN_TIME); }
+    // values close to zero cause some popping sounds on noteOns/noteOffs
+
+    State state() { return state_; }
+
+    // note events
+    void noteOn(); // transitions from idle state to attack
+    void noteOff(); // transitions from sustain to release
+
+    float process();
+
+    bool isActive() { return state_ != State::Idle; }
+
+    private:
+
+    State state_ = State::Idle;
+
+    float sampleRate_ = 44100.0f;
+
+    float attack_ = 0.0f;
+    float decay_ = 0.0f;
+    float sustain_ = 0.0f;
+    float release_ = 0.0f;
+
+    float value_ = 0.0f;
+
+};

src/synth/InstrumentFactory.cpp

@@ -0,0 +1,38 @@
+
+#include "InstrumentFactory.hpp"
+
+#include "Instruments/PianoString.hpp"
+#include "Instruments/WavetableOscillator.hpp"
+
+InstrumentFactory::InstrumentFactory(ConfigService* config, LoggerService* logger) : 
+    config_(config), logger_(logger) {
+
+}
+
+Instrument* InstrumentFactory::createInstrument(InstrumentType type, float sampleRate, AudioParams* params) {
+
+    switch(type) {
+        case InstrumentType::Default:
+            return new Instrument(config_, logger_, sampleRate, params);
+        case InstrumentType::PianoString:
+            return new PianoString(config_, logger_, sampleRate, params);
+        case InstrumentType::WavetableOscillator:
+            return new WavetableOscillator(config_, logger_, wavetableLoader_, sampleRate, params);
+        default:
+            return nullptr;
+    }
+}
+
+int32_t InstrumentFactory::createInstruments(std::vector<Instrument*>* instruments, size_t voiceCount, float sampleRate, AudioParams* params) {
+
+    // parse the config file
+    // if there's wavetables then we need a wavetable loader
+    // initialize wavetableLoader_ here
+
+    for(size_t i = 0; i < params->maxVoices; i++) {
+        instruments->push_back(createInstrument(InstrumentType::PianoString, static_cast<float>(params->sampleRate), params));
+    }
+
+    return params->maxVoices;
+
+}

src/synth/InstrumentFactory.hpp

@@ -0,0 +1,35 @@
+
+#pragma once
+
+#include "config/ConfigService.hpp"
+#include "config/AudioConfig.hpp"
+#include "LoggerService.hpp"
+#include "Instruments/Instrument.hpp"
+#include "WavetableLoader.hpp"
+
+class InstrumentFactory {
+
+public:
+
+    InstrumentFactory(ConfigService* config, LoggerService* logger);
+    ~InstrumentFactory() = default;
+
+    int32_t createInstruments(std::vector<Instrument*>* instruments, size_t voiceCount, float sampleRate, AudioParams* params);
+
+    enum class InstrumentType {
+        Default,
+        PianoString,
+        WavetableOscillator
+    };
+
+private:
+
+    Instrument* createInstrument(InstrumentType type, float sampleRate, AudioParams* params);
+
+    ConfigService* config_;
+    LoggerService* logger_;
+
+    // optional creators
+    WavetableLoader* wavetableLoader_ = nullptr;
+
+};

src/synth/Instruments/Instrument.cpp

@@ -3,8 +3,16 @@
 
 #include "string"
 
-Instrument::Instrument(ConfigService* config, LoggerService* logger) :
+Instrument::Instrument(ConfigService* config, LoggerService* logger, float sampleRate, AudioParams* params) :
-    config_(config), logger_(logger) {
+    config_(config), logger_(logger), sampleRate_(sampleRate), params_(params) {
+
+}
+
+void Instrument::startNote(uint8_t midiNote, float velocity) {
+
+    note_ = midiNote;
+
+    noteOn(noteToFrequency(midiNote), velocity);
 
 }
 

src/synth/Instruments/Instrument.hpp

@@ -1,19 +1,21 @@
 
 #pragma once
 
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
 #include "LoggerService.hpp"
+#include "config/AudioConfig.hpp"
 
 // an instrument is our state space model. it calculates discrete samples as a function of time, the current states, and the inputs
-// an instrumeent is owned by a voice
+// an instrument is owned by a voice
 class Instrument {
 
 public:
 
     Instrument() = default;
-    Instrument(ConfigService* config, LoggerService* logger);
+    Instrument(ConfigService* config, LoggerService* logger, float sampleRate, AudioParams* params);
     ~Instrument() = default;
 
+    void startNote(uint8_t midiNote, float velocity);
     virtual void noteOn(float frequency, float velocity);
     virtual void noteOff();
 
@@ -21,13 +23,23 @@ public:
 
     virtual float process(bool& scopeTrigger);
 
+    uint8_t note() { return note_; }
+    float frequency() { return noteToFrequency(note_); }
+
 protected:
 
-    float sampleRate_ = 44100.0f;
+    inline float noteToFrequency(uint8_t note) {
+        return params_->pitchStandard * pow(params_->octaveConstant, static_cast<float>(note - params_->midiHome) / params_->notesPerOctave); 
+    }
+
+    float sampleRate_ = 1.0f;
     bool active_ = false;
 
     ConfigService* config_;
     LoggerService* logger_;
+    AudioParams* params_;
+
+    uint8_t note_;
 
     static constexpr float pi = 3.14159265358979323846f;
     float phase_ = 0.0f;

src/synth/Instruments/PianoString.cpp

@@ -1,7 +1,7 @@
 
 #include "PianoString.hpp"
 
-PianoString::PianoString(ConfigService* config, LoggerService* logger) : Instrument(config, logger) {
+PianoString::PianoString(ConfigService* config, LoggerService* logger, float sampleRate, AudioParams* params) : Instrument(config, logger, sampleRate, params) {
 
     stringY_current_.resize(segmentCount_ + 1);
     stringY_previous_.resize(segmentCount_ + 1);
@@ -13,7 +13,7 @@ PianoString::PianoString(ConfigService* config, LoggerService* logger) : Instrum
 void PianoString::noteOn(float frequency, float velocity) {
 
     active_ = true;
-    frequency_ = frequency;
+    frequency_ = frequency / 1.03746174945f; // empirical adjustment (original was 83 cents sharp)
 
     damping_ = 0.5f;
     rms_ = 5.0f;
@@ -84,9 +84,9 @@ float PianoString::process(bool& scopeTrigger) {
     }
 
     phaseTracker_ += frequency_ / sampleRate_;
-    if(phaseTracker_ > 1.0f) {
+    if(phaseTracker_ > 2.0f) {
-        phaseTracker_ -= 1.0f;
+        phaseTracker_ -= 2.0f;
-        scopeTrigger = true;
+        if(!scopeTrigger) scopeTrigger = true;
     }
 
     float sampleOut = stringY_next_[static_cast<size_t>(samplePosition_*segmentCount_)];
@@ -103,6 +103,7 @@ void PianoString::recalculateConstants() {
 
     waveVelocity_ = 2.0f * frequency_ * L_;
 
+    // calculate number of super-sampling steps needed to maintain string stability
     samplingSteps_ = 0;
     do {
         samplingSteps_++;
@@ -117,8 +118,8 @@ void PianoString::recalculateConstants() {
             segmentCount_ = static_cast<size_t>(std::sqrt((-a+std::sqrt(a*a+4.0*b))/(2.0*b))) - 1;
         }
 
-    } while (segmentCount_ < 60);
+    } while (segmentCount_ < 80);
-
+    // cap segment count at 80 if above
     segmentCount_ = std::min(segmentCount_, static_cast<size_t>(80));
 
     dx_ = L_ / static_cast<float>(segmentCount_);

src/synth/Instruments/PianoString.hpp

@@ -3,14 +3,14 @@
 
 #include <cmath>
 
-#include "synth/Instrument.hpp"
+#include "synth/instruments/Instrument.hpp"
 
 class PianoString : public Instrument {
 
 public:
 
     PianoString() = default;
-    PianoString(ConfigService* config, LoggerService* logger);
+    PianoString(ConfigService* config, LoggerService* logger, float sampleRate, AudioParams* params);
     ~PianoString() = default;
     
     void noteOn(float frequency, float velocity) override;

src/synth/Instruments/WavetableOscillator.cpp

@@ -0,0 +1,41 @@
+
+#include "WavetableOscillator.hpp"
+
+
+WavetableOscillator::WavetableOscillator(ConfigService* config, LoggerService* logger, WavetableLoader* wavetabler, float sampleRate, AudioParams* params) 
+    : Instrument(config, logger, sampleRate, params), wavetableLoader_(wavetabler) {
+
+}
+
+void WavetableOscillator::noteOn(float frequency, float velocity) {
+    envelope_.noteOn(); // hmm we can scale this by velocity
+
+    frequency_ = frequency;
+    phaseIncrement_ = 2.0f * kPi_ * frequency_ / sampleRate_;
+    
+}
+
+void WavetableOscillator::noteOff() {
+    envelope_.noteOff();
+}
+
+bool WavetableOscillator::isActive() {
+    return envelope_.isActive();
+}
+
+float WavetableOscillator::process(bool& scopeTrigger) {
+
+    if(wavetableLoader_ == nullptr) {
+        return 0.0f;
+    }
+
+    float sampleOut = wavetableLoader_->sample(wavetableId_, phase_);
+
+    phase_ += phaseIncrement_;
+    if(phase_ > 2.0f * kPi_) {
+        phase_ -= 2.0f * kPi_;
+        scopeTrigger = true;
+    }
+
+    return sampleOut;
+}

src/synth/Instruments/WavetableOscillator.hpp

@@ -0,0 +1,40 @@
+
+#pragma once
+
+#include <cmath>
+
+#include "synth/instruments/Instrument.hpp"
+#include "synth/Envelope.hpp"
+#include "synth/WavetableLoader.hpp"
+
+class WavetableOscillator : public Instrument {
+
+public:
+
+    WavetableOscillator() = default;
+    WavetableOscillator(ConfigService* config, LoggerService* logger, WavetableLoader* wavetabler, float sampleRate, AudioParams* params);
+    ~WavetableOscillator() = default;
+    
+    void noteOn(float frequency, float velocity) override;
+    void noteOff() override;
+
+    bool isActive() override;
+
+    float process(bool& scopeTrigger) override;
+
+    bool setWavetableId(size_t id) { wavetableId_ = id; }
+
+private:
+
+    WavetableLoader* wavetableLoader_;
+    size_t wavetableId_ = 0;
+
+    Envelope envelope_;
+
+    // float phase_ = 0.0f; inherited from parent class
+    float frequency_ = 0.0f;
+    float phaseIncrement = 0.0f;
+
+    static constexpr float kPi_ = 3.14159265358979323846;
+
+};

src/synth/KeyboardController.cpp

@@ -12,8 +12,8 @@ KeyboardController::KeyboardController(QObject* parent) : QObject(parent) {
 KeyboardController::KeyboardController(ConfigService* config, LoggerService* logger, NoteQueue* queue) : config_(config), logger_(logger), queue_(queue) {
 
     // load keymap from config service
-    if(!(config->getConfig<KeymapConfig>("KeyboardController", "Main", &configuration_))) {
+    if(!(config->getConfig<KeymapParams, KeymapConfig>("KeyboardController", "Main", &configuration_))) {
-        logger_->log("Keyboard", LogFlag::Error, "Failed to get logger configuration fom config service");
+        logger_->log("Keyboard", LogFlag::Error, "Failed to get logger configuration from config service");
         return;
     }
 

src/synth/KeyboardController.hpp

@@ -7,7 +7,8 @@
 #include <unordered_map>
 
 #include "NoteQueue.hpp"
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
+#include "config/KeymapConfig.hpp"
 #include "LoggerService.hpp"
 
 // The keyboardcontroller handles user inputs from a keyboard and maps them to note events
@@ -32,7 +33,7 @@ private:
     LoggerService* logger_;
 
     // keymap is key -> midi note id
-    KeymapConfig configuration_;
+    KeymapParams configuration_;
 
     static constexpr float defaultVelocity_ = 0.8f;
 

src/synth/MidiController.hpp

@@ -7,7 +7,7 @@
 #include <unordered_set>
 
 #include "NoteQueue.hpp"
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
 #include "LoggerService.hpp"
 
 class MidiController {

src/synth/NoteQueue.hpp

@@ -7,7 +7,7 @@
 #include <cstdint>
 #include <chrono>
 
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
 #include "LoggerService.hpp"
 
 enum NoteEventType {

src/synth/Scope.cpp

@@ -4,7 +4,7 @@
 #include <iostream>
 
 ScopeBuffer::ScopeBuffer(QObject *parent) : QObject(parent) {
-
+    // timer is set in qml
 }
 
 ScopeBuffer::ScopeBuffer(ConfigService* config, LoggerService* logger, size_t size) :
@@ -45,7 +45,7 @@ void Scope::paint(QPainter *painter) {
 
     if(scopeBuffer_ != nullptr) scopeBuffer_->read(buffer_);
 
-    // TODO: scale to max amplitude ?
+    // TODO: scale to max amplitude ? probably make it configurable if you want to make scope options
     float maxAmp = 1.0f;
     /*
     for(float s : buffer_) {

src/synth/Scope.hpp

@@ -8,7 +8,7 @@
 #include <vector>
 #include <atomic>
 
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
 #include "LoggerService.hpp"
 
 class ScopeBuffer : public QObject  {

src/synth/Synth.cpp

@@ -2,31 +2,43 @@
 #include "Synth.hpp"
 
 Synth::Synth(ConfigService* config, LoggerService* logger, ScopeBuffer* scope, NoteQueue* queue) :
-    config_(config), logger_(logger), scope_(scope), noteQueue_(queue) {
+    config_(config), logger_(logger), scope_(scope), noteQueue_(queue), instrumentFactory_(config_, logger_) {
 
-    voices_.fill(Voice(config_, logger_));
+    // load audio settings from config service
+    if(!(config->getConfig<AudioParams, AudioConfig>("AudioEngine", "Main", &engineConfiguration_))) {
+        logger_->log("Audio", LogFlag::Error, "Failed to get logger configuration from config service");
+        return;
+    }
+    // note: this is the audio engine's configuration so we can grab sample rate
+    // it includes some synth params as well, so when synth gets its own config node they all need to be moved
     
-    filter_.setSampleRate(44100.0f);
+    int32_t instrumentsCreated = instrumentFactory_.createInstruments(&instruments_, engineConfiguration_.maxVoices, static_cast<float>(engineConfiguration_.sampleRate), &engineConfiguration_);
+    if(instrumentsCreated == 0) {
+        logger_->log("Audio", LogFlag::Error, "Failed to create any voices from factory.");
+    } else if(instrumentsCreated > engineConfiguration_.maxVoices) {
+        logger_->log("Audio", LogFlag::Warning, "Created too many voices, possible truncation or overflow.");
+    } else {
+        logger_->log("Audio", LogFlag::Info, "Created voices from factory.");
+    }
+
+    filter_.setSampleRate(engineConfiguration_.sampleRate);
     filter_.setParams(Filter::Type::BiquadLowpass, 4000.0f, 0.707f);
 
 }
 
 void Synth::handleNoteEvent(const NoteEvent& event) {
 
-    // Voice* v = findVoiceByNote(event.note);
-    // if(v != nullptr) v->noteOff();
-
     // stop all voices that are currently playing this note
-    for(Voice& v : voices_) {
+    for(Instrument* i : instruments_) {
-        if(v.isActive() && v.note() == event.note) {
+        if(i->isActive() && i->note() == event.note) {
-            v.noteOff();
+            i->noteOff();
         }
     }
 
+    // call note-on for an idle voice for the note-event
     if(event.type == NoteEventType::NoteOn) {
-
+        Instrument* i = findFreeVoice();
-        Voice* v = findFreeVoice();
+        if(i != nullptr) i->startNote(event.note, event.velocity);
-        if(v != nullptr) v->noteOn(event.note, event.velocity);
     }
     
 }
@@ -38,11 +50,12 @@ void Synth::process(float* out, size_t nFrames) {
         handleNoteEvent(noteEvent);
     }
 
+    // find lowest frequency voice for scope triggering
     size_t lowestVoice = 0;
-    float lowestFreq = 100000.0f;
+    float lowestFreq = FLT_MAX;
-    for(size_t i = 0; i < voices_.size(); i++) {
+    for(size_t i = 0; i < instruments_.size(); i++) {
-        if(!voices_[i].isActive()) continue;
+        if(!instruments_[i]->isActive()) continue;
-        float currentFreq = voices_[i].frequency();
+        float currentFreq = instruments_[i]->frequency();
         if(currentFreq < lowestFreq) {
             lowestVoice = i;
             lowestFreq = currentFreq;
@@ -54,13 +67,16 @@ void Synth::process(float* out, size_t nFrames) {
     float sampleOut = 0.0f;
     bool triggered = false;
     bool once = false;
+
+    // generate n samples for the output buffer
     for(size_t i = 0; i < nFrames; i++) {
 
+        // process all active voices and mix their produced samples
         float mix = 0.0f;
-        for(size_t j = 0; j < voices_.size(); j++) {
+        for(size_t j = 0; j < instruments_.size(); j++) {
             bool temp = false;
-            if(!voices_[j].isActive()) continue;
+            if(!instruments_[j]->isActive()) continue;
-            mix += voices_[j].process(temp);
+            mix += instruments_[j]->process(temp);
             if(j == lowestVoice) triggered = temp;
         }
         mix = tanh(mix); // prevent clipping
@@ -78,24 +94,23 @@ void Synth::process(float* out, size_t nFrames) {
 
     scope_->spinlock(false);
 
-
 }
 
-Voice* Synth::findFreeVoice() {
+Instrument* Synth::findFreeVoice() {
 
-    for(Voice& v : voices_) {
+    for(Instrument* i : instruments_) {
-        if(!v.isActive()) {
+        if(!i->isActive()) {
-            return &v;
+            return i;
         }
     }
     return nullptr;
 }
 
-Voice* Synth::findVoiceByNote(uint8_t note) {
+Instrument* Synth::findVoiceByNote(uint8_t note) {
 
-    for(Voice& v : voices_) {
+    for(Instrument* i : instruments_) {
-        if(v.isActive() && v.note() == note) {
+        if(i->isActive() && i->note() == note) {
-            return &v;
+            return i;
         }
     }
     return nullptr;

src/synth/Synth.hpp

@@ -1,12 +1,14 @@
 
 #pragma once
 
-#include "ConfigService.hpp"
+#include "config/ConfigService.hpp"
+#include "config/AudioConfig.hpp"
 #include "LoggerService.hpp"
 #include "NoteQueue.hpp"
-#include "Voice.hpp"
 #include "Scope.hpp"
 #include "Filter.hpp"
+#include "Instruments/Instrument.hpp"
+#include "InstrumentFactory.hpp"
 
 #include <vector>
 
@@ -22,19 +24,21 @@ public:
 
 private:
 
-    Voice* findFreeVoice();
+    Instrument* findFreeVoice();
-    Voice* findVoiceByNote(uint8_t note);
+    Instrument* findVoiceByNote(uint8_t note);
 
     std::vector<uint8_t> sustainedNotes_;
     Filter filter_;
 
     // voices
-    static constexpr size_t MAX_VOICES = 32;
+    size_t maxVoices;
-    std::array<Voice, MAX_VOICES> voices_;
+    std::vector<Instrument*> instruments_;
 
     ConfigService* config_;
+    AudioParams engineConfiguration_;
     LoggerService* logger_;
-    ScopeBuffer* scope_;;
+    ScopeBuffer* scope_;
     NoteQueue* noteQueue_;
+    InstrumentFactory instrumentFactory_;
 
 };

src/synth/Voice.cpp

@@ -1,35 +0,0 @@
-
-#include "Voice.hpp"
-
-Voice::Voice(ConfigService* config, LoggerService* logger) :
-    config_(config), logger_(logger) {
-
-    // TODO: instrument factory
-    instrument_ = PianoString(config_, logger_);
-
-}
-
-void Voice::noteOn(uint8_t midiNote, float velocity) {
-
-    note_ = midiNote;
-    instrument_.noteOn(noteToFrequency(midiNote), velocity);
-
-}
-
-void Voice::noteOff() {
-
-    instrument_.noteOff();
-
-}
-
-bool Voice::isActive() {
-
-    return instrument_.isActive();
-
-}
-
-float Voice::process(bool& scopeTrigger) {
-
-    return instrument_.process(scopeTrigger);
-
-}

src/synth/Voice.hpp

@@ -1,43 +0,0 @@
-
-#pragma once
-
-#include <stdint.h>
-
-#include "Instrument.hpp"
-#include "Instruments/PianoString.hpp"
-
-// a voice is a tone generator that the synth uses for polyphony
-// the synth mixes multiple voices together into a polyphonic audio. calculations for samples are handled in the instrument
-class Voice {
-
-public:
-
-    Voice() = default;
-    Voice(ConfigService* config, LoggerService* logger);
-    ~Voice() = default;
-
-    void noteOn(uint8_t midiNote, float velocity);
-    void noteOff();
-    bool isActive();
-
-    float process(bool& scopeTrigger);
-    uint8_t note() { return note_; }
-    float frequency() { return noteToFrequency(note_); }
-
-private:
-
-    float sampleRate_ = 44100.0f;
-
-    inline float noteToFrequency(uint8_t note) {
-        return 440.0f * pow(2.0f, static_cast<float>(note - 69) / static_cast<float>(12)); 
-    }
-    
-    uint8_t note_ = 0;
-    float velocity_ = 1.0f;
-    bool active_ = false;
-
-    ConfigService* config_;
-    LoggerService* logger_;
-    PianoString instrument_;
-
-};

src/synth/WavetableLoader.cpp

@@ -0,0 +1,58 @@
+
+#include "WavetableLoader.hpp"
+
+WavetableLoader::WavetableLoader(ConfigService* config, LoggerService* logger) : config_(config), logger_(logger) { 
+
+}
+
+int32_t WavetableLoader::loadWavetables() {
+
+    // find wavetable files
+    std::vector<std::filesystem::path> wavetableFiles;
+    for(std::filesystem::directory_entry entry : std::filesystem::directory_iterator(wavetableFilepath_)) {
+        if(std::filesystem::is_regular_file(entry.status())) {
+            wavetableFiles.push_back(entry.path()); // TODO: check this file to see if it is valid
+        }
+    }
+    wavetableCount_ = wavetableFiles.size();
+    wavetables_.resize(wavetableCount_);
+
+    // load from file to vector
+    for(size_t i = 0; i < wavetableCount_; i++) {
+        // logger->log(loading wavetable file...)
+        std::ifstream inputFile(wavetableFiles[i], std::ios::in | std::ios::binary);
+        if(!inputFile) // logger->log("error oppening file...")
+        inputFile.read(reinterpret_cast<char*>(wavetables_[i].data()), 2048 * sizeof(float));
+    }
+
+    // TODO: wavetable header should contain info like number of samples
+
+    return wavetableCount_;
+
+}
+
+float WavetableLoader::sample(size_t wavetableIndex, float phase) {
+    
+    float sampleValue = 0.0f;
+
+    if(phase >= 0.0f) {
+        while(phase >= 2.0f*kPi_) {
+            phase -= 2.0f*kPi_;
+        }
+    } else {
+        while(phase <= 0.0f) {
+            phase += 2.0f*kPi_;
+        }
+    }
+
+    float scaledPhase = phase * static_cast<float>(2048) / (2.0f*kPi_);
+    // TODO: I'd like the default domain of wavetables to be [0, 1) but it should also be loaded in from the wavetable file metadata
+    size_t index = static_cast<size_t>(round(scaledPhase));
+    if(index >= 2048) index = 2048 - 1;
+
+    if(wavetableIndex >= wavetableCount_) {
+        wavetableIndex = wavetableCount_ - 1;
+    }
+
+    return wavetables_[wavetableIndex][index];
+}

src/synth/WavetableLoader.hpp

@@ -0,0 +1,42 @@
+
+#pragma once
+
+#pragma once
+
+// placeholder to handle loading wavetables from files
+// so that wavetables can be shared to each voice/instrument
+// only need to need to load once for x number of voices
+
+#include <vector>
+#include <cstdint>
+#include <filesystem>
+
+#include "config/ConfigService.hpp"
+#include "LoggerService.hpp"
+
+class WavetableLoader {
+
+    public:
+
+    WavetableLoader(ConfigService* config, LoggerService* logger);
+    ~WavetableLoader() = default;
+
+    float sample(size_t wavetableIndex, float phase);
+
+    private:
+
+    int32_t loadWavetables();
+
+    size_t wavetableCount_ = 0;
+    std::vector<std::vector<float>> wavetables_;
+
+    // TODO: this will be configurable
+
+    const std::filesystem::path wavetableFilepath_ = "./config/wavetables";
+
+    LoggerService* logger_;
+    ConfigService* config_;
+
+    static constexpr float kPi_ = 3.14159265358979323846;
+
+};