7 files changed, 95 insertions, 14 deletions

diff --git a/src/drumgizmo.cc b/src/drumgizmo.cc
index 9874bbe..d30952e 100644
--- a/src/drumgizmo.cc
+++ b/src/drumgizmo.cc
@@ -47,7 +47,7 @@ DrumGizmo::DrumGizmo(Settings& settings,
 	, oe(o)
 	, ie(i)
 	, audio_cache(settings)
-	, input_processor(settings, kit, activeevents)
+	, input_processor(settings, kit, activeevents, rand)
 	, settings(settings)
 	, settings_getter(settings)
 {
diff --git a/src/events.h b/src/events.h
index 30a9e8b..f953031 100644
--- a/src/events.h
+++ b/src/events.h
@@ -54,7 +54,7 @@ public:
 	virtual type_t getType() const = 0;
 
 	channel_t channel;
-	timepos_t offset;
+	timepos_t offset; //< Global position (ie. not relative to buffer)
 };
 
 #define NO_RAMPDOWN -1
diff --git a/src/inputprocessor.cc b/src/inputprocessor.cc
index 5d96e2d..1dbd79e 100644
--- a/src/inputprocessor.cc
+++ b/src/inputprocessor.cc
@@ -39,14 +39,15 @@
 
 InputProcessor::InputProcessor(Settings& settings,
                                DrumKit& kit,
-                               std::list<Event*>* activeevents)
+                               std::list<Event*>* activeevents,
+                               Random& random)
 	: kit(kit)
 	, activeevents(activeevents)
 	, is_stopping(false)
 {
 	// Build filter list
 	filters.emplace_back(std::make_unique<StaminaFilter>(settings));
-	filters.emplace_back(std::make_unique<LatencyFilter>(settings));
+	filters.emplace_back(std::make_unique<LatencyFilter>(settings, random));
 }
 
 bool InputProcessor::process(std::vector<event_t>& events,
diff --git a/src/inputprocessor.h b/src/inputprocessor.h
index fe72292..cf62ea2 100644
--- a/src/inputprocessor.h
+++ b/src/inputprocessor.h
@@ -37,13 +37,15 @@
 #include "inputfilter.h"
 
 struct Settings;
+class Random;
 
 class InputProcessor
 {
 public:
 	InputProcessor(Settings& settings,
 	               DrumKit& kit,
-	               std::list<Event*>* activeevents);
+	               std::list<Event*>* activeevents,
+	               Random& random);
 
 	bool process(std::vector<event_t>& events,
 	             std::size_t pos,
diff --git a/src/latencyfilter.cc b/src/latencyfilter.cc
index d83eab6..2f4bfe5 100644
--- a/src/latencyfilter.cc
+++ b/src/latencyfilter.cc
@@ -26,19 +26,70 @@
  */
 #include "latencyfilter.h"
 
-LatencyFilter::LatencyFilter(Settings& settings)
-	//: settings(settings)
+#include <cmath>
+#include <hugin.hpp>
+
+#include "settings.h"
+#include "random.h"
+
+LatencyFilter::LatencyFilter(Settings& settings, Random& random)
+	: settings(settings)
+	, random(random)
 {
 }
 
-bool LatencyFilter::filter(event_t& events, size_t pos)
+bool LatencyFilter::filter(event_t& event, std::size_t pos)
 {
+	auto enabled = settings.enable_latency_modifier.load();
+	auto latency = settings.latency_max.load();
+	auto samplerate = settings.samplerate.load();
+	auto latency_laid_back = settings.latency_laid_back.load();
+	auto latency_stddev = settings.latency_stddev.load();
+	auto latency_regain = settings.latency_regain.load();
+
+	if(!enabled)
+	{
+		return true;
+	}
+
+	// Assert latency_regain is within range [0; 1].
+	assert(latency_regain >= 0.0f && latency_regain <= 1.0f);
+
+	float duration = (pos - latency_last_pos) / samplerate;
+	latency_offset *= pow(latency_regain, duration);
+
+	latency_last_pos = pos;
+
+	float offset_min = latency * -1.0f;
+	float offset_max = latency * 1.0f;
+
+	float mean = latency_laid_back;
+	float stddev = latency_stddev;
+
+	float offset = random.normalDistribution(mean, stddev);
+
+	latency_offset += offset;
+
+	if(latency_offset > offset_max) latency_offset = offset_max;
+	if(latency_offset < offset_min) latency_offset = offset_min;
+
+	DEBUG(offset, "latency: %d, offset: %f, drift: %f",
+	      (int)latency, offset, latency_offset);
+
+	event.offset += latency;
+	event.offset += latency_offset;//(int)std::round(offset);
+
 	return true;
 }
 
 std::size_t LatencyFilter::getLatency() const
 {
-	// TODO: If enabled in settings, return the maximum number of samples
-	// with which the latency filter can move notes forward.
-	return 0;
+	bool enabled = settings.enable_latency_modifier.load();
+	std::size_t max_latency = settings.latency_max.load();
+	if(enabled)
+	{
+		return max_latency;
+	}
+
+	return 0u;
 }
diff --git a/src/latencyfilter.h b/src/latencyfilter.h
index e34b050..a49dd47 100644
--- a/src/latencyfilter.h
+++ b/src/latencyfilter.h
@@ -29,17 +29,21 @@
 #include "inputfilter.h"
 
 struct Settings;
+class Random;
 
 class LatencyFilter
 	: public InputFilter
 {
 public:
-	LatencyFilter(Settings& settings);
+	LatencyFilter(Settings& settings, Random& random);
 
-	bool filter(event_t& events, size_t pos) override;
+	bool filter(event_t& events, std::size_t pos) override;
 
 	std::size_t getLatency() const override;
 
 private:
-	//Settings& settings;
+	Settings& settings;
+	Random& random;
+	double latency_offset{0.0};
+	std::size_t latency_last_pos{0};
 };
diff --git a/src/settings.h b/src/settings.h
index 6bba237..cdce066 100644
--- a/src/settings.h
+++ b/src/settings.h
@@ -90,6 +90,29 @@ struct Settings
 
 	Atomic<bool> enable_bleed_control{false};
 	Atomic<float> master_bleed{1.0f};
+
+	Atomic<bool> enable_latency_modifier{true};
+
+	//! Maximum "early hits" introduces latency. In no. samples.
+	Atomic<std::size_t> latency_max{5000u};
+
+	//! 0 := on-beat
+	//! positive := laid back
+	//! negative := up-beat
+	Atomic<int> latency_laid_back{0};
+
+	//!   0 := Robot
+	//! 100 := Good drummer
+	//! 200 := Decent drummer
+	//! 300 := Decent drummer on a bad day
+	//! 400 := Bad drummer
+	//! 500 := Bad and drunk drummer
+	Atomic<float> latency_stddev{100.0f};
+
+	//! Regain on-beat position.
+	//! 0: instantaniously
+	//! 1: never
+	Atomic<float> latency_regain{0.9f};
 };
 
 //! Settings getter class.