block based processing

synth/ivoice.h

@@ -1,9 +1,11 @@
 #pragma once
 
 namespace trnr {
+template <typename t_sample>
 struct ivoice {
 	virtual ~ivoice() = default;
-	virtual float process_sample() = 0;
+	//virtual float process_sample() = 0;
+	virtual void process_samples(t_sample** _outputs, int _start_index, int _block_size) = 0;
 	virtual bool is_busy() = 0;
 	virtual void set_samplerate(double samplerate) = 0;
 	virtual void note_on(int _note, float _velocity) = 0;
@@ -12,7 +14,7 @@ struct ivoice {
 };
 
 // check if a template derives from ivoice
-template <class derived>
+template <class derived, typename sample>
 struct is_convertible {
 	template <class T>
 	static char test(T*);
@@ -20,6 +22,6 @@ struct is_convertible {
 	template <class T>
 	static double test(...);
 
-	static const bool value = sizeof(test<ivoice>(static_cast<derived*>(0))) == 1;
+	static const bool value = sizeof(test<ivoice<sample>>(static_cast<derived*>(0))) == 1;
 };
 } // namespace trnr

synth/midi_synth.h

@@ -16,7 +16,7 @@ public:
 		: m_voices_active {false}
 	{
 		// checks whether template derives from ivoice
-		typedef t_voice assert_at_compile_time[is_convertible<t_voice>::value ? 1 : -1];
+		typedef t_voice assert_at_compile_time[is_convertible<t_voice, t_sample>::value ? 1 : -1];
 	}
 
 	void set_samplerate_blocksize(double _samplerate, int _block_size)
@@ -27,6 +27,9 @@ public:
 
 	void process_block(t_sample** _outputs, int _n_frames)
 	{
+		// clear outputs
+		for (auto i = 0; i < 2; i++) { memset(_outputs[i], 0, _n_frames * sizeof(t_sample)); }
+
 		// sample accurate event handling based on the iPlug2 synth by Oli Larkin
 		if (m_voices_active || !m_event_queue.empty()) {
 			int block_size = m_block_size;

synth/tx_voice.h

@@ -7,7 +7,8 @@
 
 namespace trnr {
 
-class tx_voice : public ivoice {
+template <typename t_sample>
+class tx_voice : public ivoice<t_sample> {
 public:
 	tx_voice()
 		: algorithm {0}
@@ -46,11 +47,13 @@ public:
 	// modulates the pitch in semitones
 	void modulate_pitch(float _pitch) override { this->pitch_mod = _pitch; }
 
-	float process_sample() override
+	void process_samples(t_sample** _outputs, int _start_index, int _block_size) override
 	{
 		float pitch_env_signal = pitch_env.process_sample(gate, trigger) * pitch_env_amt;
 		float pitched_freq = midi_to_frequency(midi_note + pitch_mod + additional_pitch_mod) + pitch_env_signal;
 
+		for (int s = _start_index; s < _start_index + _block_size; s++) {
+
 			float output = 0.f;
 
 			// mix operator signals according to selected algorithm
@@ -75,7 +78,11 @@ public:
 			// reset trigger
 			trigger = false;
 
-		return redux(output, bit_resolution);
+			redux(output, bit_resolution);
+
+                        _outputs[0][s] += output / 3.;
+			_outputs[1][s] = _outputs[0][s];
+		}
 	}
 
 	bool is_busy() override

synth/voice_allocator.h

@@ -14,7 +14,7 @@ public:
 		: voices(4, t_voice())
 	{
 		// checks whether template derives from ivoice
-		typedef t_voice assert_at_compile_time[is_convertible<t_voice>::value ? 1 : -1];
+		 typedef t_voice assert_at_compile_time[is_convertible<t_voice, t_sample>::value ? 1 : -1];
 	}
 
 	void set_voice_count(const int& voice_count) { voices.resize(voice_count, voices.at(0)); }
@@ -39,17 +39,16 @@ public:
 
 	void process_samples(t_sample** _outputs, int _start_index, int _block_size)
 	{
-		for (int s = _start_index; s < _start_index + _block_size; s++) {
+		for (int b = _start_index; b < _start_index + _block_size; b += internal_block_size) {
 
-			process_events(s);
+			const int block_size = internal_block_size;
 
-			float voices_signal = 0.;
+			// process all events in the block (introduces potential inaccuracy of up to 16 samples)
+			process_events(b, block_size);
 
-			std::for_each(voices.begin(), voices.end(),
+			std::for_each(voices.begin(), voices.end(), [&_outputs, &b, &block_size](t_voice& voice) {
-						  [&voices_signal](t_voice& voice) { voices_signal += (voice.process_sample() / 3.); });
+				voice.process_samples(_outputs, b, block_size);
-
+			});
-			_outputs[0][s] = voices_signal;
-			_outputs[1][s] = voices_signal;
 		}
 	}
 
@@ -75,6 +74,7 @@ public:
 private:
 	std::vector<midi_event> input_queue;
 	int index_to_steal = 0;
+	const int internal_block_size = 16;
 
 	t_voice* get_free_voice(float frequency)
 	{
@@ -111,8 +111,9 @@ private:
 		return free_voice;
 	}
 
-	void process_events(int _start_index)
+	void process_events(int _start_index, int _block_size)
 	{
+		for (int s = _start_index; s < _start_index + _block_size; s++) {
 			auto iterator = input_queue.begin();
 			while (iterator != input_queue.end()) {
 
@@ -139,5 +140,6 @@ private:
 				}
 			}
 		}
+	}
 };
 } // namespace trnr