add instrument factory

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;
+
+};