When I apply the WorldEnvironment, it makes the ship glow too. However, in the GIF above only the lightning beam glows. How do we exclude the ship from the WorldEnvironment's effect?
Asked a colleague of mine who knows way more than I do and he told me that
"If you're asking about the built-in Environment post-processing effects, they apply to the entire scene, there's no way to make it apply only to specific objects.
if you're talking in general about custom post-processing effects, that can be done in multiple ways, affecting only specific objects. For example one way is with a SubViewportContainer/SubViewport/Object setup. This method can be used to reimplement some of the built-in post-processing effects like glow and what not for individual scenes/objects."
It's a bit of an advanced topic but if you are interested I would start here:
https://docs.godotengine.org/en/3.5/tutorials/shaders/custom_postprocessing.html?highlight=Custom%20Post%20Processing
And then once you feel like you understand that you can try
https://docs.godotengine.org/en/3.5/tutorials/shaders/advanced_postprocessing.html?highlight=advanced%20post%20processing
A thorough understanding of Godot's Viewports and how they work is also required:
https://docs.godotengine.org/en/3.5/classes/class_viewport.html?highlight=Viewport
My guess is that the GIF you are seeing has had the Glow parameters dialed in to where it is only applying to the pixels that have crossed the luminance threshold and that might be achievable with your artwork it might not.