From 383561c3f50ade64669cd6d958ee1556c341755a Mon Sep 17 00:00:00 2001
From: Benjamin Kraft <benjamin.kraft@online.de>
Date: Tue, 19 Sep 2023 23:46:49 +0200
Subject: [PATCH] using semaphores instead of mutex

---
 src/GLWidget.cpp   | 5 +++--
 src/Simulation.cpp | 6 +++---
 src/Simulation.h   | 4 ++--
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/GLWidget.cpp b/src/GLWidget.cpp
index b7a0e54..382cd45 100644
--- a/src/GLWidget.cpp
+++ b/src/GLWidget.cpp
@@ -41,6 +41,7 @@ void GLWidget::initializeGL() {
 	glClearDepth(1);
 	glClearColor(.15, .15, .15, 1);
 
+	simulation->semaphore.acquire();
 	uploadStaticDataToGPU();
 
 	overlay->init();
@@ -180,7 +181,7 @@ void GLWidget::uploadStaticDataToGPU() {
 
 	glBindVertexArray(0);
 
-	simulation->pendulaMutex.unlock();
+	simulation->semaphore.release();
 }
 
 void GLWidget::changePosition() {
@@ -196,7 +197,7 @@ void GLWidget::changePosition() {
 		}
 	}
 	glUnmapBuffer(GL_ARRAY_BUFFER);
-	simulation->pendulaMutex.unlock();
+	simulation->semaphore.release();
 }
 
 void GLWidget::resizeGL(int w, int h) {
diff --git a/src/Simulation.cpp b/src/Simulation.cpp
index 89c1619..dae7836 100644
--- a/src/Simulation.cpp
+++ b/src/Simulation.cpp
@@ -24,7 +24,7 @@ void Simulation::update() {
 
 	double h = (timescale * updateInterval) / 1000 / substeps;
 
-	pendulaMutex.lock();
+	semaphore.acquire();
 
 	double newPotentialEnergy = 0;
 	double newKineticEnergy = 0;
@@ -48,7 +48,7 @@ void Simulation::update() {
 }
 
 void Simulation::clearPendula() {
-	pendulaMutex.lock();
+	semaphore.acquire();
 
 	for (Pendulum* &p : pendula){
 		delete p;
@@ -64,7 +64,7 @@ void Simulation::clearPendula() {
 }
 
 void Simulation::addPendula(const std::vector<Pendulum *> &add) {
-	pendulaMutex.lock();
+	semaphore.acquire();
 
 	for (auto p : add)
 		pendula.push_back(p);
diff --git a/src/Simulation.h b/src/Simulation.h
index c3a204f..b2f6ef2 100644
--- a/src/Simulation.h
+++ b/src/Simulation.h
@@ -2,8 +2,8 @@
 #include <cstdint>
 #include <QObject>
 #include <chrono>
-#include <mutex>
 #include "Pendulum.h"
+#include <semaphore>
 
 using namespace std::chrono;
 
@@ -27,7 +27,7 @@ public:
 
 	std::vector<Pendulum *> pendula;
 
-	std::mutex pendulaMutex;
+	std::binary_semaphore semaphore = std::binary_semaphore(1);
 	FPS * ups;
 
 	void updateEnergy();