From c9c7e69714707262e8bdea25853bf33447a57951 Mon Sep 17 00:00:00 2001 From: Elizabeth Alexander Hunt Date: Sun, 22 Feb 2026 14:48:06 -0800 Subject: Initialization --- .../java/coffee/liz/dyl/lwjgl3/Lwjgl3Launcher.java | 48 +++++ .../java/coffee/liz/dyl/lwjgl3/StartupHelper.java | 227 +++++++++++++++++++++ 2 files changed, 275 insertions(+) create mode 100644 lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/Lwjgl3Launcher.java create mode 100644 lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/StartupHelper.java (limited to 'lwjgl3/src/main/java/coffee') diff --git a/lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/Lwjgl3Launcher.java b/lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/Lwjgl3Launcher.java new file mode 100644 index 0000000..a8c9c4f --- /dev/null +++ b/lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/Lwjgl3Launcher.java @@ -0,0 +1,48 @@ +package coffee.liz.dyl.lwjgl3; + +import com.badlogic.gdx.backends.lwjgl3.Lwjgl3Application; +import com.badlogic.gdx.backends.lwjgl3.Lwjgl3ApplicationConfiguration; +import coffee.liz.dyl.Main; + +/** Launches the desktop (LWJGL3) application. */ +public class Lwjgl3Launcher { + public static void main(String[] args) { + if (StartupHelper.startNewJvmIfRequired()) return; // This handles macOS support and helps on Windows. + createApplication(); + } + + private static Lwjgl3Application createApplication() { + return new Lwjgl3Application(new Main(), getDefaultConfiguration()); + } + + private static Lwjgl3ApplicationConfiguration getDefaultConfiguration() { + Lwjgl3ApplicationConfiguration configuration = new Lwjgl3ApplicationConfiguration(); + configuration.setTitle("dyl"); + //// Vsync limits the frames per second to what your hardware can display, and helps eliminate + //// screen tearing. This setting doesn't always work on Linux, so the line after is a safeguard. + configuration.useVsync(true); + //// Limits FPS to the refresh rate of the currently active monitor, plus 1 to try to match fractional + //// refresh rates. The Vsync setting above should limit the actual FPS to match the monitor. + configuration.setForegroundFPS(Lwjgl3ApplicationConfiguration.getDisplayMode().refreshRate + 1); + //// If you remove the above line and set Vsync to false, you can get unlimited FPS, which can be + //// useful for testing performance, but can also be very stressful to some hardware. + //// You may also need to configure GPU drivers to fully disable Vsync; this can cause screen tearing. + + configuration.setWindowedMode(640, 480); + //// You can change these files; they are in lwjgl3/src/main/resources/ . + //// They can also be loaded from the root of assets/ . + configuration.setWindowIcon("libgdx128.png", "libgdx64.png", "libgdx32.png", "libgdx16.png"); + + //// This could improve compatibility with Windows machines with buggy OpenGL drivers, Macs + //// with Apple Silicon that have to emulate compatibility with OpenGL anyway, and more. + //// This uses the dependency `com.badlogicgames.gdx:gdx-lwjgl3-angle` to function. + //// You would need to add this line to lwjgl3/build.gradle , below the dependency on `gdx-backend-lwjgl3`: + //// implementation "com.badlogicgames.gdx:gdx-lwjgl3-angle:$gdxVersion" + //// You can choose to add the following line and the mentioned dependency if you want; they + //// are not intended for games that use GL30 (which is compatibility with OpenGL ES 3.0). + //// Know that it might not work well in some cases. +// configuration.setOpenGLEmulation(Lwjgl3ApplicationConfiguration.GLEmulation.ANGLE_GLES20, 0, 0); + + return configuration; + } +} \ No newline at end of file diff --git a/lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/StartupHelper.java b/lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/StartupHelper.java new file mode 100644 index 0000000..e47ba51 --- /dev/null +++ b/lwjgl3/src/main/java/coffee/liz/dyl/lwjgl3/StartupHelper.java @@ -0,0 +1,227 @@ +/* + * Copyright 2020 damios + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * https://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +// Note, the above license and copyright applies to this file only. +package coffee.liz.dyl.lwjgl3; + +import com.badlogic.gdx.Version; +import com.badlogic.gdx.backends.lwjgl3.Lwjgl3NativesLoader; + +import org.lwjgl.system.JNI; +import org.lwjgl.system.linux.UNISTD; +import org.lwjgl.system.macosx.LibC; +import org.lwjgl.system.macosx.ObjCRuntime; + +import java.io.File; +import java.lang.management.ManagementFactory; +import java.util.ArrayList; +import java.util.List; +import java.util.Locale; + +/** + * A helper object for game startup, featuring three utilities related to LWJGL3 on various operating systems. + *

+ * The utilities are as follows: + *

+ * Based on this java-gaming.org post by kappa + * @author damios + */ +public class StartupHelper { + + private StartupHelper() {} + + private static final String JVM_RESTARTED_ARG = "jvmIsRestarted"; + + /** + * Must only be called on Linux. Check OS first (or use short-circuit evaluation)! + * @return whether NVIDIA drivers are present on Linux. + */ + public static boolean isLinuxNvidia() { + String[] drivers = new File("/proc/driver").list( + (dir, path) -> path.toUpperCase(Locale.ROOT).contains("NVIDIA") + ); + if (drivers == null) return false; + return drivers.length > 0; + } + + /** + * Applies the utilities as described by {@link StartupHelper}'s Javadoc. + *

+ * All {@link System#getenv() Environment Variables} are copied to the child JVM process (if it is spawned), as + * specified by {@link ProcessBuilder#environment()}; the same applies for + * {@link System#getProperties() System Properties}. + *

+ * Usage: + * 


+	 * public static void main(String[] args) {
+	 * 	 if (StartupHelper.startNewJvmIfRequired()) return;
+	 * 	 // ... The rest of main() goes here, as normal.
+	 * }
+	 *
+ * @return whether a child JVM process was spawned or not. + */ + public static boolean startNewJvmIfRequired() { + return startNewJvmIfRequired(true); + } + + /** + * Applies the utilities as described by {@link StartupHelper}'s Javadoc. + *

+ * All {@link System#getenv() Environment Variables} are copied to the child JVM process (if it is spawned), as + * specified by {@link ProcessBuilder#environment()}; the same applies for + * {@link System#getProperties() System Properties}. + *

+ * Usage: + * 


+	 * public static void main(String[] args) {
+	 *   // The parameter on the next line could instead be false if you don't want to inherit IO.
+	 * 	 if (StartupHelper.startNewJvmIfRequired(true)) return;
+	 * 	 // ... The rest of main() goes here, as normal.
+	 * }
+	 *
+ * @param inheritIO whether I/O should be inherited in the child JVM process. Please note that enabling this will + * block the thread until the child JVM process stops executing. + * @return whether a child JVM process was spawned or not. + */ + public static boolean startNewJvmIfRequired(boolean inheritIO) { + String osName = System.getProperty("os.name").toLowerCase(Locale.ROOT); + if (osName.contains("mac")) return startNewJvm0(/*isMac =*/ true, inheritIO); + if (osName.contains("windows")) { + // Here, we are trying to work around an issue with how LWJGL3 loads its extracted .dll files. + // By default, LWJGL3 extracts to the directory specified by "java.io.tmpdir": usually, the user's home. + // If the user's name has non-ASCII (or some non-alphanumeric) characters in it, that would fail. + // By extracting to the relevant "ProgramData" folder, which is usually "C:\ProgramData", we avoid this. + // We also temporarily change the "user.name" property to one without any chars that would be invalid. + // We revert our changes immediately after loading LWJGL3 natives. + String programData = System.getenv("ProgramData"); + if (programData == null) programData = "C:\\Temp"; // if ProgramData isn't set, try some fallback. + String prevTmpDir = System.getProperty("java.io.tmpdir", programData); + String prevUser = System.getProperty("user.name", "libGDX_User"); + System.setProperty("java.io.tmpdir", programData + "\\libGDX-temp"); + System.setProperty( + "user.name", + ("User_" + prevUser.hashCode() + "_GDX" + Version.VERSION).replace('.', '_') + ); + Lwjgl3NativesLoader.load(); + System.setProperty("java.io.tmpdir", prevTmpDir); + System.setProperty("user.name", prevUser); + return false; + } + return startNewJvm0(/*isMac =*/ false, inheritIO); + } + + private static final String MAC_JRE_ERR_MSG = "A Java installation could not be found. If you are distributing this app with a bundled JRE, be sure to set the '-XstartOnFirstThread' argument manually!"; + private static final String LINUX_JRE_ERR_MSG = "A Java installation could not be found. If you are distributing this app with a bundled JRE, be sure to set the environment variable '__GL_THREADED_OPTIMIZATIONS' to '0'!"; + private static final String CHILD_LOOP_ERR_MSG = "The current JVM process is a spawned child JVM process, but StartupHelper has attempted to spawn another child JVM process! This is a broken state, and should not normally happen! Your game may crash or not function properly!"; + + /** + * Spawns a child JVM process if on macOS, or on Linux with NVIDIA drivers. + *

+ * All {@link System#getenv() Environment Variables} are copied to the child JVM process (if it is spawned), as + * specified by {@link ProcessBuilder#environment()}; the same applies for + * {@link System#getProperties() System Properties}. + * @param isMac whether the current OS is macOS. If this is `false` then the current OS is assumed to be Linux (and + * an immediate check for NVIDIA drivers is performed). + * @param inheritIO whether I/O should be inherited in the child JVM process. Please note that enabling this will + * block the thread until the child JVM process stops executing. + * @return whether a child JVM process was spawned or not. + */ + public static boolean startNewJvm0(boolean isMac, boolean inheritIO) { + long processID = getProcessID(isMac); + if (!isMac) { + // No need to restart non-NVIDIA Linux + if (!isLinuxNvidia()) return false; + // check whether __GL_THREADED_OPTIMIZATIONS is already disabled + if ("0".equals(System.getenv("__GL_THREADED_OPTIMIZATIONS"))) return false; + } else { + // There is no need for -XstartOnFirstThread on Graal native image + if (!System.getProperty("org.graalvm.nativeimage.imagecode", "").isEmpty()) return false; + + // Checks if we are already on the main thread, such as from running via Construo. + long objcMsgSend = ObjCRuntime.getLibrary().getFunctionAddress("objc_msgSend"); + long nsThread = ObjCRuntime.objc_getClass("NSThread"); + long currentThread = JNI.invokePPP(nsThread, ObjCRuntime.sel_getUid("currentThread"), objcMsgSend); + boolean isMainThread = JNI.invokePPZ(currentThread, ObjCRuntime.sel_getUid("isMainThread"), objcMsgSend); + if (isMainThread) return false; + + if ("1".equals(System.getenv("JAVA_STARTED_ON_FIRST_THREAD_" + processID))) return false; + } + + // Check whether this JVM process is a child JVM process already. + // This state shouldn't usually be reachable, but this stops us from endlessly spawning new child JVM processes. + if ("true".equals(System.getProperty(JVM_RESTARTED_ARG))) { + System.err.println(CHILD_LOOP_ERR_MSG); + return false; + } + + // Spawn the child JVM process with updated environment variables or JVM args + List jvmArgs = new ArrayList<>(); + // The following line is used assuming you target Java 8, the minimum for LWJGL3. + String javaExecPath = System.getProperty("java.home") + "/bin/java"; + // If targeting Java 9 or higher, you could use the following instead of the above line: + //String javaExecPath = ProcessHandle.current().info().command().orElseThrow() + if (!(new File(javaExecPath).exists())) { + System.err.println(getJreErrMsg(isMac)); + return false; + } + + jvmArgs.add(javaExecPath); + if (isMac) jvmArgs.add("-XstartOnFirstThread"); + jvmArgs.add("-D" + JVM_RESTARTED_ARG + "=true"); + jvmArgs.addAll(ManagementFactory.getRuntimeMXBean().getInputArguments()); + jvmArgs.add("-cp"); + jvmArgs.add(System.getProperty("java.class.path")); + String mainClass = System.getenv("JAVA_MAIN_CLASS_" + processID); + if (mainClass == null) { + StackTraceElement[] trace = Thread.currentThread().getStackTrace(); + if (trace.length > 0) mainClass = trace[trace.length - 1].getClassName(); + else { + System.err.println("The main class could not be determined."); + return false; + } + } + jvmArgs.add(mainClass); + + try { + ProcessBuilder processBuilder = new ProcessBuilder(jvmArgs); + if (!isMac) processBuilder.environment().put("__GL_THREADED_OPTIMIZATIONS", "0"); + + if (!inheritIO) processBuilder.start(); + else processBuilder.inheritIO().start().waitFor(); + } catch (Exception e) { + System.err.println("There was a problem restarting the JVM."); + // noinspection CallToPrintStackTrace + e.printStackTrace(); + } + + return true; + } + + private static String getJreErrMsg(boolean isMac) { + if (isMac) return MAC_JRE_ERR_MSG; + else return LINUX_JRE_ERR_MSG; + } + + private static long getProcessID(boolean isMac) { + if (isMac) return LibC.getpid(); + else return UNISTD.getpid(); + } +} \ No newline at end of file -- cgit v1.2.3-70-g09d2