SDK SceneComposer

Another strange case:
If I change the background color of the ViewPort via an AbstractControl, the color is permanent even if I open another j3o file. Something in memeory that is not reset?

First I create a scene and add my custom AbstractControl to the rootNode.

I close the scene without saving, and then open another j3o file.

 * @author capdevon
public class ViewPortControl extends AbstractControl {

    private ViewPort viewPort;

    // Set the viewport's background color to light blue.
    private ColorRGBA skyColor = new ColorRGBA(0.1f, 0.2f, 0.4f, 1f);

    protected void controlUpdate(float tpf) {

    protected void controlRender(RenderManager rm, ViewPort vp) {
        if (viewPort == null) {
            viewPort = vp;

    public ColorRGBA getSkyColor() {
        return skyColor;

    public void setSkyColor(ColorRGBA skyColor) {

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My guess is that SDK uses a single instance of viewport for rendering scenes, which means that even if you switch the scene, the viewport wouldn’t change.

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Another strange thing:
Maybe I’m getting confused, but is the grid size not symmetrical by any chance? With these dimensions 19x19 it doesn’t seem centered in the origin. I guess it needs to be increased to 21x21 to be symmetrical.
The red box has dimensions x=10, y=1, z=10 and is centered in 0,0,0

Confirmed, the reference grid is not symmetrical with respect to the origin point (0,0,0).
In gray the original grid 19x19 and lineDist=1, in green the test grid 21x21 and lineDist=1

        Geometry geo = new Geometry("WireGrid", new Grid(21, 21, 1f));
        Material mat = new Material(assetManager, "Common/MatDefs/Misc/Unshaded.j3md");
        mat.setColor("Color", ColorRGBA.Green);
        geo.setMaterial(mat); Vector3f(0, 0, 0));

To solve the problem, the grid should be 21x21 with lineDist=1
The dimensions of the red cube are 10x10x10

is it possible to fix the problem in the next SDK release?



More like this?:

Github issue and Pull Request. If you have a few mins to look them over and maybe build/test the change that would be fab.


I can’t do a test, I don’t know how to build the SDK project. However seeing the code and the image, the result looks good to me. Well done :+1:

What is the cause of the ViewPort’s permanent background color problem ?
Could you tell me more about it ?


It is really simple: GitHub - jMonkeyEngine/sdk: The jMonkeyEngine3 SDK based on netbeans. Basically have JDK 17, clone repo and ./gradlew run. That is it (also this is how one would generally do it in any Gradle based app).

But thanks anyway for your feedback. We are processing it :slight_smile:


Hi @tonihele ,
I am glad to know that my feedback was taken into consideration. I really appreciate the work you and the other contributors are doing.
I usually don’t install the SDK, but download the portable version and then unzip it on my computer.
Are you telling me that I can clone the SDK project from git and by running the ./gradlew run statement I can generate the file ?
Is there a guide or template on how to write jme plugins for the SDK ?

Thank you.

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Not exactly. The zip is part of the release process which is a bit harder thing as it requires Ant and all that. If you have Linux, then you are good to go but this setup requires some difficult steps in Windows. But that being said, I have only done this maybe twice in my life to test something. As this is not necessary and I don’t think you need that either.

The gradle run, as with all Gradle apps, runs the application. In this case the SDK. And this is what you want to do whether you are testing it out or developing it. You do not ever need to make a distribution version and run that.

So you can either just simply download the code snapshot or clone the repo (cloning recommended). And with gradle run the SDK will start normally. And one can even use it straight like that to develop your projects.

I’m not sure is there any guides available. But the SDK is just Java + Swing + Netbeans Platform. By looking at the existing modules, it is pretty easy to create a module of your own. We are here to help, Netbeans platform related questions are best to be asked in the Netbeans platform mailing list (rarely needed I’d say…)


Great! I use Windows, so can I clone the SDK project locally, open it with Eclipse, make some changes and then run Netbeans with the SDK via the /gradle run command?
If so I will give it a try as soon as possible.
If I make other changes to the code, then I have to close Netbeans and relaunch it via gradle from Eclipse right?
I don’t have to delete the .jmonkeyplatform folder under the <User> directory each time right ?

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I’m little bit confused about the terminology here. Lets agree that Netbeans and SDK are separate products. This is also more clearer this way since you will actually get a local copy of Netbeans when you do the Gradle build. The Gradle run will run the SDK, not the Netbeans per se. This is just the terminology, for clarity.

You can open the SDK as Gradle project in any IDE. The IDE then just treats it as a normal Gradle project and that most likely works. I however have never done this. The SDK is actually two different things. It is a Gradle project yes, but also Ant based Netbeans Platform project.

If you intend to do some developing on the SDK, this is beyond trying it out, I would suggest you do it like I do:

  • Clone SDK repo
  • Run gradlew run (Windows)
  • Netbeans will be downloaded for you in this process under netbeans folder
  • Delete the Gradle files (build.gradle,, settings.gradle, version.gradle). With this the SDK stops being a Gradle project and is only a Netbeans Platform Ant project
  • Open the Netbeans that was downloaded: /netbeans/bin/netbeans64.exe
  • In Netbeans open the SDK Netbeans Platfrom Project
  • Enjoy coding and use the giant PLAY-button to compile and run the SDK

The SDK development will use local settings folder and it will not mess up your production settings. In Netbeans (if you followed my advice above), clean will clear the development SDK settings as well and you get to start over.

Eventually we are trying to get to Maven. So that it would be a native Netbeans Platform project. Currently the Gradle is used to do some magic glue stuff that Ant can’t (or is too difficult) do. With Maven, hopefully all this hassle will go away as everything is behind one build system. But at least for simply trying out the SDK, this current system is still very easy. As it just looks and functions like every other Gradle project. And the only hassle comes when one starts to develop it, as it is better to open up as a native project in Netbeans and it can’t be done straight (need to delete the Gradle stuff).

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Ok, following your instructions I got here:

As you can see, some forms do not fill out.
By pressing the giant Play button I get this error:

ant -f C:\\Users\\xxxxx\\git\\sdk run
C:\Users\xxxxx\git\sdk\netbeans\harness\suite.xml:106: Cannot open C:\Users\xxxxx\git\sdk\jme3-core-baselibs\nbproject\project.xml
BUILD FAILED (total time: 0 seconds)

How do I solve the problem ?

Does that file exist (C:\Users\xxxxx\git\sdk\jme3-core-baselibs\nbproject\project.xml)?

But did you manage to run the SDK in the first place with the gradlew run?

Mmm no, it’s not there.


Yes, I ran the command and the NetBeans download started. After that I deleted the files as per your instructions; then I opened NetBeans and imported the SDK project.

But did the SDK start? Or did you abort it or get some error before it completed? To me it looks like the repo cloning might not be complete.

gradlew run should run the SDK, if it didn’t, something is clearly wrong.

Hmm, there is no such file in the repo I’m on holiday now and no access to my dev rig. But this process should work… But your problem is not perhaps then the repo cloning.

This project.xml, for this module and few others are actually generated by the Gradle build…

Still curious what the gradlew run output was then.

Edit: I don’t know how familiar you are with version control stuff. But what I do it use a GIT client called GitKraken. With that it is easy to just reverse the changes I made (the gradle files deletion…) to jump back to the Gradle build.

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Sorry, I shouldn’t bother you during the vacations. I will try to re-run all the steps you wrote in a few days. Thank you very much anyway for the support. Let me know when you are available again. See you soon, have fun :wink:

It is fine, I’m now probably more available than normally when I’m at my day job :smiley:

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