From 30cd1ead46e5ce8061e930d320d5a6ecfc3f5cf3 Mon Sep 17 00:00:00 2001
From: extio-de <github@extio.de>
Date: Sun, 21 Dec 2025 17:27:21 +0100
Subject: [PATCH] Refactor G2DRenderer and G2DRendererControl to replace
 Semaphore with ReentrantReadWriteLock for improved concurrency management

---
 .../game_engine/renderer/g2d/G2DRenderer.java | 20 ++++++++++++-------
 .../renderer/g2d/G2DRendererControl.java      | 17 ++++------------
 2 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/src/main/java/de/extio/game_engine/renderer/g2d/G2DRenderer.java b/src/main/java/de/extio/game_engine/renderer/g2d/G2DRenderer.java
index e3d83e0..a6d1b6a 100644
--- a/src/main/java/de/extio/game_engine/renderer/g2d/G2DRenderer.java
+++ b/src/main/java/de/extio/game_engine/renderer/g2d/G2DRenderer.java
@@ -9,8 +9,9 @@ import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.util.List;
-import java.util.concurrent.Semaphore;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 import javax.imageio.ImageIO;
 
@@ -36,7 +37,7 @@ public class G2DRenderer implements Renderer {
 	
 	private static final Logger LOGGER = LoggerFactory.getLogger(G2DRenderer.class);
 	
-	private static final long SLEEP_PRECISION = TimeUnit.MILLISECONDS.toNanos(3);
+	private static final long SLEEP_PRECISION = TimeUnit.MILLISECONDS.toNanos(2);
 	
 	private final RingBuffer<Integer> fpsHistory = new RingBuffer<>(90);
 	
@@ -54,7 +55,7 @@ public class G2DRenderer implements Renderer {
 	
 	private long frameDur;
 	
-	private final Semaphore semaphore = new Semaphore(1);
+	private final ReentrantReadWriteLock rwLock = new ReentrantReadWriteLock(true);
 	
 	private String title;
 	
@@ -63,6 +64,7 @@ public class G2DRenderer implements Renderer {
 	public G2DRenderer() {
 		LOGGER.info("ctor");
 		
+		System.setProperty("java.awt.headless", "false");
 		System.setProperty("sun.java2d.uiScale", "1");
 		System.setProperty("awt.nativeDoubleBuffering", "true");
 		System.setProperty("awt.useSystemAAFontSettings", "on");
@@ -100,7 +102,7 @@ public class G2DRenderer implements Renderer {
 	@Override
 	public void run(final List<RenderingBo> renderingBOs) throws InterruptedException {
 		try {
-			this.semaphore.acquire();
+			this.rwLock.readLock().lockInterruptibly();
 			try {
 				if (this.mainFrame == null) {
 					return;
@@ -180,7 +182,7 @@ public class G2DRenderer implements Renderer {
 				}
 			}
 			finally {
-				this.semaphore.release();
+				this.rwLock.readLock().unlock();
 			}
 		}
 		catch (final G2DRendererWindowNotInitializedException e) {
@@ -291,8 +293,12 @@ public class G2DRenderer implements Renderer {
 		this.mainFrame = mainFrame;
 	}
 	
-	public Semaphore getSemaphore() {
-		return this.semaphore;
+	public Lock getReadLock() {
+		return this.rwLock.readLock();
+	}
+	
+	public Lock getWriteLock() {
+		return this.rwLock.writeLock();
 	}
 	
 	@Override
diff --git a/src/main/java/de/extio/game_engine/renderer/g2d/G2DRendererControl.java b/src/main/java/de/extio/game_engine/renderer/g2d/G2DRendererControl.java
index d551926..e96dc66 100644
--- a/src/main/java/de/extio/game_engine/renderer/g2d/G2DRendererControl.java
+++ b/src/main/java/de/extio/game_engine/renderer/g2d/G2DRendererControl.java
@@ -49,12 +49,7 @@ public class G2DRendererControl implements RendererControl {
 	@Override
 	public void applyVideoOptions() {
 		final Runnable run = () -> {
-			try {
-				this.renderer.getSemaphore().acquire();
-			}
-			catch (final InterruptedException e) {
-				return;
-			}
+			this.renderer.getWriteLock().lock();
 			try {
 				if (this.renderer.getMainFrame() != null) {
 					this.renderer.getMainFrame().unregisterFullScreenWindow();
@@ -95,7 +90,7 @@ public class G2DRendererControl implements RendererControl {
 				this.updateViewPort(false, false);
 			}
 			finally {
-				this.renderer.getSemaphore().release();
+				this.renderer.getWriteLock().unlock();
 				this.videoOptionsAppliedAt = System.currentTimeMillis();
 			}
 		};
@@ -162,11 +157,7 @@ public class G2DRendererControl implements RendererControl {
 		
 		final Runnable run = () -> {
 			if (lockRenderer) {
-				try {
-					this.renderer.getSemaphore().acquire();
-				}
-				catch (final InterruptedException e) {
-				}
+				this.renderer.getWriteLock().lock();
 			}
 			try {
 				this.updateAbsoluteViewportPortDimension();
@@ -176,7 +167,7 @@ public class G2DRendererControl implements RendererControl {
 			}
 			finally {
 				if (lockRenderer) {
-					this.renderer.getSemaphore().release();
+					this.renderer.getWriteLock().unlock();
 				}
 			}
 		};