[SOLVED] Application.restart() with LWJGL v3

sgold · January 2, 2025, 9:57pm

Is anyone besides me using JME’s Application.restart() method with LWJGL v3 (jme3-lwjgl3)?

Today I discovered an issue in my Acorus project, where pressing the Enter key invokes restart() and blanks the application window. The app continues running with a blank gray window; there’s no stack trace. However, the window isn’t supposed to go blank!

Here’s the relevant code in my project:

github.com

stephengold/Acorus/blob/0ac14cf8d61c475ee187c5718466fd98bc69e084/AcorusLibrary/src/main/java/jme3utilities/ui/DisplaySettings.java#L148-L162


      
          /**
           * Apply the proposed settings to the graphics context and restart the
           * context to put them into effect.
           */
          public void applyToContext() {
              assert canApply();
              assert !areApplied;
          
              AppSettings clone = new AppSettings(false);
              clone.copyFrom(proposedSettings);
          
              application.setSettings(clone);
              application.restart();
              this.areApplied = true;
          }

If I comment out line 160, the window displays normally after I press Enter, but of course the new settings don’t get applied either.

I’m puzzled why I didn’t notice this issue sooner. I’m pretty sure the applyToContext() feature worked last year.

At first I suspected it was a regression related to JME v3.8.0-alpha1, but then I found the issue occurs also with JME v3.6.1-stable.

LWJGL v2 (jme3-lwjgl) doesn’t seem to have this issue.

pspeed · January 2, 2025, 10:15pm

For forestall what a lot of folks will presumably immediately think at first…

Presumably, proposedSettings are settings that would otherwise work ok.

sgold · January 3, 2025, 12:27am

Good point. I added code to dump clone before the restart(), and here are its entries:

{DepthBits=24, 
WindowWidth=-2147483648, 
MinHeight=0, 
DisableJoysticks=true, 
SwapBuffers=true, 
Resizable=true, 
CenterWindow=true, 
Height=500, 
BitsPerPixel=24, 
Width=746, 
UseRetinaFrameBuffer=false, 
UseInput=true, 
FrameRate=-1, 
Title=TestDsEdit , 
GammaCorrection=true, 
AudioRenderer=null, 
WindowXPosition=0, 
WindowHeight=-2147483648, 
WindowYPosition=0, 
MinWidth=0, 
VSync=false, 
Samples=1, 
StencilBits=0, 
SettingsDialogImage=/com/jme3/app/Monkey.png, 
Renderer=LWJGL-OpenGL3,
OpenCLPlatformChooser=com.jme3.opencl.DefaultPlatformChooser, 
Frequency=60, 
Fullscreen=false, 
OpenCL=false}

WindowWidth and WindowHeight look problematic. I am investigating.

EDIT: negative values for “WindowWidth” and “WindowHeight” are valid. They indicate to create the window using the width and height of the primary monitor’s current mode.

github.com

jMonkeyEngine/jmonkeyengine/blob/9da10799ba9517de8b571981d8d9773824cb9eb7/jme3-lwjgl3/src/main/java/com/jme3/system/lwjgl/LwjglWindow.java#L294-L301


      
          final GLFWVidMode videoMode = glfwGetVideoMode(glfwGetPrimaryMonitor());
          int requestWidth = settings.getWindowWidth();
          int requestHeight = settings.getWindowHeight();
          if (requestWidth <= 0 || requestHeight <= 0) {
              requestWidth = videoMode.width();
              requestHeight = videoMode.height();
          }
          window = glfwCreateWindow(requestWidth, requestHeight, settings.getTitle(), monitor, NULL);

zzuegg · January 3, 2025, 1:02am

The glfwCreateWindow call has to be made on the primary thread. Unfortunately it does not always generate an error if that is not the case.

sgold · January 3, 2025, 1:10am

Do you know an easy way to test whether the current thread is the primary one?

zzuegg · January 3, 2025, 1:17am

mhm. as far i can see jme should handle that since the restart is executed in the update loop.

zzuegg · January 3, 2025, 1:27am

package example;

import com.jme3.app.SimpleApplication;
import com.jme3.system.AppSettings;

public class MonkeyTest extends SimpleApplication {
    @Override
    public void simpleInitApp() {

    }

    float time=0;

    @Override
    public void simpleUpdate(float tpf) {
        super.simpleUpdate(tpf);
        time+=tpf;
        if(time>10){
            time=0;
            AppSettings appSettings = new AppSettings(true);
            setSettings(appSettings);
            restart();
        }
    }

    public static void main(String[] args) {
        AppSettings settings = new AppSettings(true);
        settings.setVSync(false);
        MonkeyTest monkeyTest = new MonkeyTest();
        monkeyTest.setSettings(settings);
        monkeyTest.start();
    }
}

this code works on my machine

sgold · January 3, 2025, 1:57am

Mine too.

sgold · January 3, 2025, 5:13am

Correction: your test application doesn’t crash, but the render statistics vanish after 10 seconds, which I think is the same bug I’m seeing in Acorus.

Using printlns, I convinced myself that the thread executing restart() (“jME3 Main”) isn’t the same thread that executed start() (“main”):

Jan 02, 2025 9:09:04 PM com.jme3.system.JmeSystemDelegate lambda$new$1
WARNING: JmeDialogsFactory implementation not found.
Jan 02, 2025 9:09:04 PM com.jme3.system.JmeDesktopSystem initialize
INFO: Running on jMonkeyEngine 3.7.0-stable
 * Branch: HEAD
 * Git Hash: bc6cdf5
 * Build Date: 2024-10-21
start thread: main
Jan 02, 2025 9:09:05 PM com.jme3.system.lwjgl.LwjglContext printContextInitInfo
INFO: LWJGL 3.3.3+5 context running on thread jME3 Main
 * Graphics Adapter: GLFW 3.4.0 Wayland X11 GLX Null EGL OSMesa monotonic shared
Jan 02, 2025 9:09:05 PM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: NVIDIA Corporation
 * Renderer: NVIDIA GeForce RTX 2070/PCIe/SSE2
 * OpenGL Version: 3.2.0 NVIDIA 550.120
 * GLSL Version: 1.50 NVIDIA via Cg compiler
 * Profile: Core
Jan 02, 2025 9:09:05 PM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio Renderer Information
 * Device: OpenAL Soft
 * Vendor: OpenAL Community
 * Renderer: OpenAL Soft
 * Version: 1.1 ALSOFT 1.23.1
 * Supported channels: 64
 * ALC extensions: ALC_ENUMERATE_ALL_EXT ALC_ENUMERATION_EXT ALC_EXT_CAPTURE ALC_EXT_DEDICATED ALC_EXT_disconnect ALC_EXT_EFX ALC_EXT_thread_local_context ALC_SOFT_device_clock ALC_SOFT_HRTF ALC_SOFT_loopback ALC_SOFT_loopback_bformat ALC_SOFT_output_limiter ALC_SOFT_output_mode ALC_SOFT_pause_device ALC_SOFT_reopen_device
 * AL extensions: AL_EXT_ALAW AL_EXT_BFORMAT AL_EXT_DOUBLE AL_EXT_EXPONENT_DISTANCE AL_EXT_FLOAT32 AL_EXT_IMA4 AL_EXT_LINEAR_DISTANCE AL_EXT_MCFORMATS AL_EXT_MULAW AL_EXT_MULAW_BFORMAT AL_EXT_MULAW_MCFORMATS AL_EXT_OFFSET AL_EXT_source_distance_model AL_EXT_SOURCE_RADIUS AL_EXT_STATIC_BUFFER AL_EXT_STEREO_ANGLES AL_LOKI_quadriphonic AL_SOFT_bformat_ex AL_SOFTX_bformat_hoa AL_SOFT_block_alignment AL_SOFT_buffer_length_query AL_SOFT_callback_buffer AL_SOFTX_convolution_reverb AL_SOFT_deferred_updates AL_SOFT_direct_channels AL_SOFT_direct_channels_remix AL_SOFT_effect_target AL_SOFT_events AL_SOFT_gain_clamp_ex AL_SOFTX_hold_on_disconnect AL_SOFT_loop_points AL_SOFTX_map_buffer AL_SOFT_MSADPCM AL_SOFT_source_latency AL_SOFT_source_length AL_SOFT_source_resampler AL_SOFT_source_spatialize AL_SOFT_source_start_delay AL_SOFT_UHJ AL_SOFT_UHJ_ex
Jan 02, 2025 9:09:05 PM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio effect extension version: 1.0
Jan 02, 2025 9:09:05 PM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio max auxiliary sends: 2
restart thread: jME3 Main
Jan 02, 2025 9:09:15 PM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: NVIDIA Corporation
 * Renderer: NVIDIA GeForce RTX 2070/PCIe/SSE2
 * OpenGL Version: 3.2.0 NVIDIA 550.120
 * GLSL Version: 1.50 NVIDIA via Cg compiler
 * Profile: Core

@zzuegg Do the render statistics vanish on your machine?

zzuegg · January 3, 2025, 6:15am

Yeah, everything renders correct on my side:

Jan 03, 2025 7:13:20 AM com.jme3.system.JmeSystemDelegate lambda$new$1
WARNING: JmeDialogsFactory implementation not found.
Jan 03, 2025 7:13:20 AM com.jme3.system.JmeDesktopSystem initialize
INFO: Running on jMonkeyEngine 3.6.0-stable
 * Branch: HEAD
 * Git Hash: 53f2a49
 * Build Date: 2023-03-20
[LWJGL] [ThreadLocalUtil] Unsupported JNI version detected, this may result in a crash. Please inform LWJGL developers.
Jan 03, 2025 7:13:20 AM com.jme3.system.lwjgl.LwjglContext printContextInitInfo
INFO: LWJGL 3.3.1 build 7 context running on thread jME3 Main
 * Graphics Adapter: GLFW 3.4.0 Win32 WGL Null EGL OSMesa VisualC DLL
Jan 03, 2025 7:13:21 AM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: NVIDIA Corporation
 * Renderer: NVIDIA GeForce GTX 1080 Ti/PCIe/SSE2
 * OpenGL Version: 3.2.0 NVIDIA 566.36
 * GLSL Version: 1.50 NVIDIA via Cg compiler
 * Profile: Core
Jan 03, 2025 7:13:21 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio Renderer Information
 * Device: OpenAL Soft
 * Vendor: OpenAL Community
 * Renderer: OpenAL Soft
 * Version: 1.1 ALSOFT 1.21.1
 * Supported channels: 64
 * ALC extensions: ALC_ENUMERATE_ALL_EXT ALC_ENUMERATION_EXT ALC_EXT_CAPTURE ALC_EXT_DEDICATED ALC_EXT_disconnect ALC_EXT_EFX ALC_EXT_thread_local_context ALC_SOFT_device_clock ALC_SOFT_HRTF ALC_SOFT_loopback ALC_SOFT_loopback_bformat ALC_SOFT_output_limiter ALC_SOFT_pause_device
 * AL extensions: AL_EXT_ALAW AL_EXT_BFORMAT AL_EXT_DOUBLE AL_EXT_EXPONENT_DISTANCE AL_EXT_FLOAT32 AL_EXT_IMA4 AL_EXT_LINEAR_DISTANCE AL_EXT_MCFORMATS AL_EXT_MULAW AL_EXT_MULAW_BFORMAT AL_EXT_MULAW_MCFORMATS AL_EXT_OFFSET AL_EXT_source_distance_model AL_EXT_SOURCE_RADIUS AL_EXT_STEREO_ANGLES AL_LOKI_quadriphonic AL_SOFT_bformat_ex AL_SOFTX_bformat_hoa AL_SOFT_block_alignment AL_SOFTX_callback_buffer AL_SOFTX_convolution_reverb AL_SOFT_deferred_updates AL_SOFT_direct_channels AL_SOFT_direct_channels_remix AL_SOFT_effect_target AL_SOFT_events AL_SOFTX_filter_gain_ex AL_SOFT_gain_clamp_ex AL_SOFT_loop_points AL_SOFTX_map_buffer AL_SOFT_MSADPCM AL_SOFT_source_latency AL_SOFT_source_length AL_SOFT_source_resampler AL_SOFT_source_spatialize
Jan 03, 2025 7:13:21 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio effect extension version: 1.0
Jan 03, 2025 7:13:21 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio max auxiliary sends: 2
Jan 03, 2025 7:13:24 AM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: NVIDIA Corporation
 * Renderer: NVIDIA GeForce GTX 1080 Ti/PCIe/SSE2
 * OpenGL Version: 3.2.0 NVIDIA 566.36
 * GLSL Version: 1.50 NVIDIA via Cg compiler
 * Profile: Core
Jan 03, 2025 7:13:27 AM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: NVIDIA Corporation
 * Renderer: NVIDIA GeForce GTX 1080 Ti/PCIe/SSE2
 * OpenGL Version: 3.2.0 NVIDIA 566.36
 * GLSL Version: 1.50 NVIDIA via Cg compiler
 * Profile: Core

Jme does rename the thread in the context creation code.

Osx gets is special threatment, maybe linux/wayland requires a bit extra love too. Could it be that you changed os/windowmanager since the last time you remember it working?

tonihele · January 3, 2025, 6:34am

Story old as time Nifty GUI doesn't display correctly after context restart · Issue #1013 · jMonkeyEngine/jmonkeyengine · GitHub. Although marked as Nifty bug, other parts of jME also suffer.

zzuegg · January 3, 2025, 8:02am

With the additional hint that if windowWidth or windowHeight == Integer.MinValue then width or height is used. very confusing

sgold · January 3, 2025, 7:29pm

Jme does rename the thread in the context creation code.

I don’t think the thread gets renamed on my machine; I think Application.start() creates a new thread. To verify this, I printed the thread IDs in main() and simpleUpdate(), and they’re different.

Examining the code, I think thread renaming occurs only on MacOS:

github.com

jMonkeyEngine/jmonkeyengine/blob/9da10799ba9517de8b571981d8d9773824cb9eb7/jme3-lwjgl3/src/main/java/com/jme3/system/lwjgl/LwjglWindow.java#L546-L560


      
          if (Platform.get() == Platform.MACOSX) {
              // NOTE: this is required for Mac OS X!
              mainThread = Thread.currentThread();
              mainThread.setName("jME3 Main");
              if (waitFor) {
                  LOGGER.warning("create(true) is not supported for macOS!");
              }
              run();
          } else {
              mainThread = new Thread(this, "jME3 Main");
              mainThread.start();
              if (waitFor) {
                  waitFor(true);
              }
          }

Different hardware and different Linux releases, perhaps, but surely still using Cinnamon/X11/Linux.

sgold · January 3, 2025, 7:44pm

I hacked LjwglWindow.java to reuse the primary thread in create(), even on Linux. Even with restart() invoked on the primary thread, the render stats still disappear after 10 seconds. So I don’t think it’s a threading issue.

sgold · January 3, 2025, 8:41pm

I re-tested Acorus on the same hardware running JME 3.8.0-alpha1/Windows 11, and restart() didn’t blank the window there. (It did, however cause the window to jump back to the primary monitor.) JME 3.6.1-stable gave similar results.

This suggests my issue might be Linux-specific. @zzuegg have you been testing on Windows?

zzuegg · January 3, 2025, 8:54pm

Yeah i am running windows. I have currently no access to another OS so i cannot test anything.

Can you move the blanked out window? if yes the new window gets created successfully and glfwPollEvents() does it’s job.

sgold · January 3, 2025, 9:39pm

Yes, I can move the blank window using the mouse.

zzuegg · January 3, 2025, 9:44pm

can you try to resize the window and maybe log if the changes are passed to jme?

sgold · January 3, 2025, 10:06pm

After the window was blanked, resizing it caused SceneProcessor.reshape() to be invoked.

xuan · January 4, 2025, 1:21am

Hi, I remember discussing this here: SceneProcessor reshape() not called in 3.7.0-beta1.2 - #9 by xuan

I cannot reproduce it with my laptop (intel graphics and linux+x11).
I tried zzuegg’s example and the text doesn’t disappear after restarting, all looks fine.
Could it be only a problem with Nvidia drivers? what about AMD?

Jan 04, 2025 2:07:53 AM com.jme3.system.JmeSystemDelegate lambda$new$1
WARNING: JmeDialogsFactory implementation not found.
Jan 04, 2025 2:07:53 AM com.jme3.system.JmeDesktopSystem initialize
INFO: Running on jMonkeyEngine 3.7.0-stable
 * Branch: HEAD
 * Git Hash: bc6cdf5
 * Build Date: 2024-10-21
Jan 04, 2025 2:07:53 AM com.jme3.system.lwjgl.LwjglContext printContextInitInfo
INFO: LWJGL 3.3.3+5 context running on thread jME3 Main
 * Graphics Adapter: GLFW 3.4.0 Wayland X11 GLX Null EGL OSMesa monotonic shared
Jan 04, 2025 2:07:53 AM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: Intel
 * Renderer: Mesa Intel(R) UHD Graphics 620 (WHL GT2)
 * OpenGL Version: 4.6 (Core Profile) Mesa 20.3.5
 * GLSL Version: 4.60
 * Profile: Core
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.ogre.MeshLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.ogre.SkeletonLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.ogre.MaterialLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.ogre.SceneLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.fbx.FbxLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.gltf.GltfLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.gltf.BinLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.scene.plugins.gltf.GlbLoader
Jan 04, 2025 2:07:53 AM com.jme3.asset.AssetConfig loadText
WARNING: Cannot find loader com.jme3.audio.plugins.OGGLoader
Jan 04, 2025 2:07:53 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio Renderer Information
 * Device: OpenAL Soft
 * Vendor: OpenAL Community
 * Renderer: OpenAL Soft
 * Version: 1.1 ALSOFT 1.23.1
 * Supported channels: 64
 * ALC extensions: ALC_ENUMERATE_ALL_EXT ALC_ENUMERATION_EXT ALC_EXT_CAPTURE ALC_EXT_DEDICATED ALC_EXT_disconnect ALC_EXT_EFX ALC_EXT_thread_local_context ALC_SOFT_device_clock ALC_SOFT_HRTF ALC_SOFT_loopback ALC_SOFT_loopback_bformat ALC_SOFT_output_limiter ALC_SOFT_output_mode ALC_SOFT_pause_device ALC_SOFT_reopen_device
 * AL extensions: AL_EXT_ALAW AL_EXT_BFORMAT AL_EXT_DOUBLE AL_EXT_EXPONENT_DISTANCE AL_EXT_FLOAT32 AL_EXT_IMA4 AL_EXT_LINEAR_DISTANCE AL_EXT_MCFORMATS AL_EXT_MULAW AL_EXT_MULAW_BFORMAT AL_EXT_MULAW_MCFORMATS AL_EXT_OFFSET AL_EXT_source_distance_model AL_EXT_SOURCE_RADIUS AL_EXT_STATIC_BUFFER AL_EXT_STEREO_ANGLES AL_LOKI_quadriphonic AL_SOFT_bformat_ex AL_SOFTX_bformat_hoa AL_SOFT_block_alignment AL_SOFT_buffer_length_query AL_SOFT_callback_buffer AL_SOFTX_convolution_reverb AL_SOFT_deferred_updates AL_SOFT_direct_channels AL_SOFT_direct_channels_remix AL_SOFT_effect_target AL_SOFT_events AL_SOFT_gain_clamp_ex AL_SOFTX_hold_on_disconnect AL_SOFT_loop_points AL_SOFTX_map_buffer AL_SOFT_MSADPCM AL_SOFT_source_latency AL_SOFT_source_length AL_SOFT_source_resampler AL_SOFT_source_spatialize AL_SOFT_source_start_delay AL_SOFT_UHJ AL_SOFT_UHJ_ex
Jan 04, 2025 2:07:53 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio effect extension version: 1.0
Jan 04, 2025 2:07:53 AM com.jme3.audio.openal.ALAudioRenderer initOpenAL
INFO: Audio max auxiliary sends: 2
Jan 04, 2025 2:08:04 AM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: Intel
 * Renderer: Mesa Intel(R) UHD Graphics 620 (WHL GT2)
 * OpenGL Version: 4.6 (Core Profile) Mesa 20.3.5
 * GLSL Version: 4.60
 * Profile: Core
Jan 04, 2025 2:08:14 AM com.jme3.renderer.opengl.GLRenderer loadCapabilitiesCommon
INFO: OpenGL Renderer Information
 * Vendor: Intel
 * Renderer: Mesa Intel(R) UHD Graphics 620 (WHL GT2)
 * OpenGL Version: 4.6 (Core Profile) Mesa 20.3.5
 * GLSL Version: 4.60
 * Profile: Core