Can I use three_js on an OpenGL surface

[RobertRoeb]

Hi again,
I am writing Dart binding for a C++ GUI library on Windows, macOS and Linux(GTK+) and I would like use three js in it. The library has built-in support for OpenGL, not OpenGL ES. The Dart bindings for this library do not use Flutter. Here is a link to the doc of the OpenGL window the library provides:
https://docs.wxwidgets.org/3.2/classwx_g_l_canvas.html

From what I understand, flutter_angle draws into a OpenGL ES surface which on macOS is created from a Metal surface using ANGLE. Again, the library I am using provides an OpenGL surface, not an OpenGL ES surface, so I am stuck. I see that the three_dart project (which, I think shares code with this one) is actually based on flutter_gl so the ThreeJS code has been made to work on OpenGL - in principle.
three_dart does not seem to be maintained anymore - I don't know how much difference there is in the core classes between three_js and three_dart - maybe none. Now I am wondering what to do.
There seem to be three scenarios for me (specifically on macOS):
a) Make my C++ library create a Metal surface and use that with flutter_angle. I am not the sole author of that C++ library and this might not be straight forward, but it should be possible.
b) I switch to using the unmaintained three_dart project and I would probably need to fork it. Also, I would need to remove the Flutter code, I need Dart code directly using OpenGL. I really do not want to create yet another fork of Dart ThreeJS, but it should be possible as well.
c) You integrate the flutter_gl variant into your codebase as another renderer. I am no OpenGL vs. OpenGL ES expert - they look similar to me... it probably is possible as well.

What do you suggest is the best way? Possibly yet another one.

[Knightro63]

Hi @RobertRoeb,

I am not sure you will be able to use flutter_gl for this. I am pretty sure it also uses opengl es calls. I can make one that uses this maybe. The other thing you could do is since wx uses opengl you should just be able to get those bins and make a renderer that uses them. Just clone the three_js_angle_renderer and replace flutter_angle in on or 2 files with the opengl one you have and just make sure it has a texture or fbo to draw on.

[RobertRoeb]

Hi again,
thank you for the suggestion which I will try to do. As a first step, I have actually integrated flutter_angle into the Flutter version of wxDart, you can see it documented here: https://pub.dev/documentation/wx_dart/latest/wx_dart/WxGLContext-class.html
and I then created identical classes in the native version of wxDart using wxWidgets' OpenGL calls. This took me a little while, but I can now run your samples/lessons in both versions of wxDart. The next step would then be to replace the flutter_angle calls with wxGLContext calls. Let's see how that will go. Thanks for your great work again.

[Knightro63]

Hi @RobertRoeb,

I am glad to hear you got it working and I think that is the best approach for your project.