From cc711b6d2df1b97323e46025846af39ac6411a6b Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Thu, 14 Nov 2019 07:53:28 -0500
Subject: [PATCH] Replace module disabling with bypassing using BypassRoute and
 Module::configBypass().

---
 include/engine/Module.hpp | 25 +++++++++++++++++++++++++
 src/app/ModuleWidget.cpp  |  2 +-
 src/engine/Engine.cpp     | 37 ++++++++++++++++++++++---------------
 src/engine/Module.cpp     | 14 ++++++++++++++
 4 files changed, 62 insertions(+), 16 deletions(-)

diff --git a/include/engine/Module.hpp b/include/engine/Module.hpp
index f17111ac..2275754d 100644
--- a/include/engine/Module.hpp
+++ b/include/engine/Module.hpp
@@ -75,6 +75,12 @@ struct Module {
 	Expander leftExpander;
 	Expander rightExpander;
 
+	struct BypassRoute {
+		int inputId = -1;
+		int outputId = -1;
+	};
+	std::vector<BypassRoute> bypassRoutes;
+
 	/** Seconds spent in the process() method, with exponential smoothing.
 	Only written when CPU timing is enabled, since time measurement is expensive.
 	*/
@@ -146,6 +152,21 @@ struct Module {
 		outputInfos[portId] = p;
 	}
 
+	/** Adds a direct route from an input to an output when the module is bypassed. */
+	void configBypass(int inputId, int outputId) {
+		assert(inputId < (int) inputs.size());
+		assert(outputId < (int) outputs.size());
+		// Check that output is not yet routed
+		for (BypassRoute& br : bypassRoutes) {
+			assert(br.outputId != outputId);
+		}
+
+		BypassRoute br;
+		br.inputId = inputId;
+		br.outputId = outputId;
+		bypassRoutes.push_back(br);
+	}
+
 	struct ProcessArgs {
 		float sampleRate;
 		float sampleTime;
@@ -158,6 +179,10 @@ struct Module {
 	}
 	/** DEPRECATED. Override `process(const ProcessArgs& args)` instead. */
 	virtual void step() {}
+	/** Called instead of process() when Module is bypassed.
+	Typically you do not need to override this. Use configBypass() instead.
+	*/
+	virtual void processBypass(const ProcessArgs& args);
 
 	json_t* toJson();
 	/** This is virtual only for the purpose of unserializing legacy data when you could set properties of the `.modules[]` object itself.
diff --git a/src/app/ModuleWidget.cpp b/src/app/ModuleWidget.cpp
index 11b4c1d0..c64a1d25 100644
--- a/src/app/ModuleWidget.cpp
+++ b/src/app/ModuleWidget.cpp
@@ -306,7 +306,7 @@ void ModuleWidget::draw(const DrawArgs& args) {
 	Widget::draw(args);
 
 	// Power meter
-	if (module && settings::cpuMeter && !module->disabled) {
+	if (module && settings::cpuMeter) {
 		nvgBeginPath(args.vg);
 		nvgRect(args.vg,
 		        0, box.size.y - 35,
diff --git a/src/engine/Engine.cpp b/src/engine/Engine.cpp
index 5ef6a313..05dd14c0 100644
--- a/src/engine/Engine.cpp
+++ b/src/engine/Engine.cpp
@@ -220,21 +220,28 @@ static void Engine_stepModulesWorker(Engine* that, int threadId) {
 			break;
 
 		Module* module = internal->modules[i];
-		if (!module->disabled) {
-			// Step module
-			if (cpuMeter) {
-				auto beginTime = std::chrono::high_resolution_clock::now();
-				module->process(processArgs);
-				auto endTime = std::chrono::high_resolution_clock::now();
-				float duration = std::chrono::duration<float>(endTime - beginTime).count();
-
-				// Smooth CPU time
-				const float cpuTau = 2.f /* seconds */;
-				module->cpuTime += (duration - module->cpuTime) * processArgs.sampleTime / cpuTau;
-			}
-			else {
-				module->process(processArgs);
-			}
+
+		// Start CPU timer
+		using time_point = std::chrono::time_point<std::chrono::high_resolution_clock>;
+		time_point beginTime;
+		if (cpuMeter) {
+			beginTime = std::chrono::high_resolution_clock::now();
+		}
+
+		// Step module
+		if (!module->disabled)
+			module->process(processArgs);
+		else
+			module->processBypass(processArgs);
+
+		// Stop CPU timer
+		if (cpuMeter) {
+			time_point endTime = std::chrono::high_resolution_clock::now();
+			float duration = std::chrono::duration<float>(endTime - beginTime).count();
+
+			// Smooth CPU time
+			const float cpuTau = 2.f /* seconds */;
+			module->cpuTime += (duration - module->cpuTime) * processArgs.sampleTime / cpuTau;
 		}
 
 		// Iterate ports to step plug lights
diff --git a/src/engine/Module.cpp b/src/engine/Module.cpp
index 63b2be91..d6cffe90 100644
--- a/src/engine/Module.cpp
+++ b/src/engine/Module.cpp
@@ -47,6 +47,20 @@ void Module::config(int numParams, int numInputs, int numOutputs, int numLights)
 	}
 }
 
+void Module::processBypass(const ProcessArgs& args) {
+	for (BypassRoute& bypassRoute : bypassRoutes) {
+		// Route input voltages to output
+		Input& input = inputs[bypassRoute.inputId];
+		Output& output = outputs[bypassRoute.outputId];
+		int channels = input.getChannels();
+		for (int c = 0; c < channels; c++) {
+			float v = input.getVoltage(c);
+			output.setVoltage(v, c);
+		}
+		output.setChannels(channels);
+	}
+}
+
 json_t* Module::toJson() {
 	json_t* rootJ = json_object();