Thank you!

Please add some automatic tests (1. that ProcessUrls works right, 2. that DeepCopy of prototypes works right). Because this is a difficult thing to test, there are various options. Let's use automated testing to help us (and ensure it will keep working forever :) ).

Short primer how to add tests:

You can test running the test suite in "tests/" , see tests/README.md . Short version: compile the project there, and run it :) At the beginning, just run all tests, to make sure it is OK (it should be -- GitHub Actions also check it).

I usually use the "--console" and "--filter xxx" options when developing a new test. So I would add a method like "TestProcessUrls" to TTestX3DNodes (or maybe several methods) and then continue checking

cd tests/
castle-engine compile --mode=debug
./castle-tester --console --filter=TTestX3DNodes.TestProcessUrls

Of course you can compile and run the testsuite as you like, and use GUI or console runner, whatever is comfortable to you.

The tests don't need to be anything complex, it can be as simple as providing some hardcoded input and looking does it match hardcoded output. Like

procedure TTestX3DNodes.TestProcessUrlsEmbed;
begin
  RootNode := TX3DRootNode.Create;
  ...
  ImageTexture.SetUrl('textures/my.png');
  // add ImageTexture to some ShapeNode within RootNode

  TempLocation := GetTempFileName + '.x3d.';
  ProcessUrls(RootNode, TempLocation, suEmbedResources);

  AssertTrue(ImageTexture.Urls.Count = 1);
  AssertTrue(IsSuffix('data:', ImageTexture.Urls[0]));

  finally ... FreeAndNil everyhing :) end;
end;

Sorry for a delay with this, I have this on a list of TODOs for next week!

I see there are 2 conflicts with this PR, if you want to help me you can solve them. But you can also ignore them, I can do them too next week, look trivial :) Just conflicts around LPK / LPI that we indeed changed in CGE master in the meantime.

No problem, I will merge it into master once the library_update PR is merged (working on it now)

I see you're updating this PR, thank you, and thanks a lot for the patience -- I know I have unreasonable delay now with reviewing.

I had busy February (2026), and March (2026) looks busy too, due to some non-computer stuff happening in my life, and also finalizing one job. I have added to TODO, again, to "review this PR" ASAP. I hope to get to it soon. I should have lots more time for CGE work since April 2026, so please bear with me until then :)

P.S. If GHA fails, note that we have now known issue, introduced by me, which makes GHA fail on "master" too. The PasDoc version in our Docker image is now too old. It should be good again in a few hours. (And in positive news, I hope to make PasDoc 1.0.0 release soon :) ).

Thanks, merging this PR will make my life much easier.

P.S. I'm aware that logical next step is to refresh branch url-processing of our model viewer (merging master into it, so that it's rebased on master) and applying it too. Added to my TODO. I you will make a PR with it, I will be grateful :)

Thanks for merging and sorry for that wrong merge of library header.