From 27f6a546aa7ad5b1c4aff3f7ad80d5929585efc9 Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Sat, 16 Feb 2019 17:02:54 -0500
Subject: [PATCH] Add dsp::Counter. Rename dsp::VUMeter to VuMeter. Add
 Light::setSmoothBrightness(), deprecate setBrightnessSmooth().

---
 include/dsp/digital.hpp  | 24 ++++++++++++++++++++++++
 include/dsp/vumeter.hpp  |  9 ++++++---
 include/engine/Light.hpp | 23 ++++++++++++-----------
 include/engine/Port.hpp  |  2 +-
 src/engine/Engine.cpp    |  7 ++++---
 src/engine/Port.cpp      |  8 ++++----
 6 files changed, 51 insertions(+), 22 deletions(-)

diff --git a/include/dsp/digital.hpp b/include/dsp/digital.hpp
index 9152d310..9961974d 100644
--- a/include/dsp/digital.hpp
+++ b/include/dsp/digital.hpp
@@ -130,5 +130,29 @@ struct Timer {
 };
 
 
+struct Counter {
+	int count;
+	int period;
+
+	Counter() {
+		reset();
+	}
+
+	void reset() {
+		count = 0;
+		period = 1;
+	}
+
+	/** Returns true if the counter reaches `period` and resets. */
+	bool process() {
+		if (++count >= period) {
+			count = 0;
+			return true;
+		}
+		return false;
+	}
+};
+
+
 } // namespace dsp
 } // namespace rack
diff --git a/include/dsp/vumeter.hpp b/include/dsp/vumeter.hpp
index 098a4592..c22038c9 100644
--- a/include/dsp/vumeter.hpp
+++ b/include/dsp/vumeter.hpp
@@ -6,8 +6,8 @@ namespace rack {
 namespace dsp {
 
 
-/** Deprecated. Use VUMeter2. */
-struct VUMeter {
+/** Deprecated. Use VuMeter2. */
+struct VuMeter {
 	/** Decibel level difference between adjacent meter lights */
 	float dBInterval = 3.0;
 	float dBScaled;
@@ -30,7 +30,10 @@ struct VUMeter {
 };
 
 
-struct VUMeter2 {
+DEPRECATED typedef VuMeter VUMeter;
+
+
+struct VuMeter2 {
 	enum Mode {
 		PEAK,
 		RMS
diff --git a/include/engine/Light.hpp b/include/engine/Light.hpp
index c160dc7b..46029b2c 100644
--- a/include/engine/Light.hpp
+++ b/include/engine/Light.hpp
@@ -7,12 +7,12 @@ namespace engine {
 
 
 struct Light {
-	/** The mean-square of the brightness.
+	/** The square of the brightness.
 	Unstable API. Use set/getBrightness().
 	*/
 	float value = 0.f;
 
-	/** Sets the brightness directly with no LED modeling. */
+	/** Sets the brightness immediately with no light decay. */
 	void setBrightness(float brightness) {
 		value = (brightness > 0.f) ? std::pow(brightness, 2) : 0.f;
 	}
@@ -21,23 +21,24 @@ struct Light {
 		return std::sqrt(value);
 	}
 
-	/** Emulates slow fall (but immediate rise) of LED brightness.
-	`frames` rescales the timestep.
-	For example, if your module calls this method every 16 frames, use 16.f.
-	*/
-	void setBrightnessSmooth(float brightness, float frames = 1.f) {
+	/** Emulates light decay with slow fall but immediate rise. */
+	void setSmoothBrightness(float brightness, float deltaTime) {
 		float v = (brightness > 0.f) ? std::pow(brightness, 2) : 0.f;
 		if (v < value) {
-			// Fade out light with lambda = framerate
-			// Use 44.1k here to avoid the call to Engine::getSampleRate().
-			// This is close enough to look okay up to 96k
-			value += (v - value) * frames * 30.f / 44100.f;
+			// Fade out light
+			const float lambda = 30.f;
+			value += (v - value) * lambda * deltaTime;
 		}
 		else {
 			// Immediately illuminate light
 			value = v;
 		}
 	}
+
+	/** Use `setSmoothBrightness(brightness, APP->engine->getSampleTime())` instead. */
+	DEPRECATED void setBrightnessSmooth(float brightness, float frames = 1.f) {
+		setSmoothBrightness(brightness, frames / 44100.f);
+	}
 };
 
 
diff --git a/include/engine/Port.hpp b/include/engine/Port.hpp
index ece1002d..df1fde89 100644
--- a/include/engine/Port.hpp
+++ b/include/engine/Port.hpp
@@ -75,7 +75,7 @@ struct Port {
 		return active;
 	}
 
-	void step();
+	void process(float deltaTime);
 
 	/** Use getNormalVoltage() instead. */
 	DEPRECATED float normalize(float normalVoltage) {
diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 77733962..aefb84cc 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -190,6 +190,7 @@ static void Engine_stepModules(Engine *engine, int threadId) {
 
 	// int threadCount = internal->threadCount;
 	int modulesLen = internal->modules.size();
+	float deltaTime = internal->sampleTime;
 
 	// Step each module
 	// for (int i = threadId; i < modulesLen; i += threadCount) {
@@ -211,7 +212,7 @@ static void Engine_stepModules(Engine *engine, int threadId) {
 				float cpuTime = std::chrono::duration<float>(stopTime - startTime).count();
 				// Smooth CPU time
 				const float cpuTau = 2.f /* seconds */;
-				module->cpuTime += (cpuTime - module->cpuTime) * internal->sampleTime / cpuTau;
+				module->cpuTime += (cpuTime - module->cpuTime) * deltaTime / cpuTau;
 			}
 			else {
 				module->step();
@@ -220,10 +221,10 @@ static void Engine_stepModules(Engine *engine, int threadId) {
 
 		// Iterate ports to step plug lights
 		for (Input &input : module->inputs) {
-			input.step();
+			input.process(deltaTime);
 		}
 		for (Output &output : module->outputs) {
-			output.step();
+			output.process(deltaTime);
 		}
 	}
 }
diff --git a/src/engine/Port.cpp b/src/engine/Port.cpp
index 091eb2a8..4b84f105 100644
--- a/src/engine/Port.cpp
+++ b/src/engine/Port.cpp
@@ -5,7 +5,7 @@ namespace rack {
 namespace engine {
 
 
-void Port::step() {
+void Port::process(float deltaTime) {
 	// Set plug lights
 	if (!isConnected() || getChannels() == 0) {
 		plugLights[0].setBrightness(0.f);
@@ -14,8 +14,8 @@ void Port::step() {
 	}
 	else if (getChannels() == 1) {
 		float v = getVoltage() / 10.f;
-		plugLights[0].setBrightnessSmooth(v);
-		plugLights[1].setBrightnessSmooth(-v);
+		plugLights[0].setSmoothBrightness(v, deltaTime);
+		plugLights[1].setSmoothBrightness(-v, deltaTime);
 		plugLights[2].setBrightness(0.f);
 	}
 	else {
@@ -26,7 +26,7 @@ void Port::step() {
 		float v = std::sqrt(v2) / 10.f;
 		plugLights[0].setBrightness(0.f);
 		plugLights[1].setBrightness(0.f);
-		plugLights[2].setBrightnessSmooth(v);
+		plugLights[2].setSmoothBrightness(v, deltaTime);
 	}
 }