the dda idea your using

[octanejohn]

alternative or more complex ideas new rendering method from godot called hddagi https://github.com/godotengine/godot/pull/86267 nanovdb library from openvdb called hdda roma ray tracing radiance cascades amd brixelizer

[DouglasDwyer]

Thanks for the suggestions! I definitely want to learn about GI, so the Godot engine link looks particularly interesting.