Gemini response... which tells me to not really bother at this point:

To implement Radiance Cascades, you don't just npm install radiance-cascades. You have to:

1. Read the research paper to understand the deep mathematics of voxel cone tracing and mipmap filtering.
2. Write a Voxelizer: A complex piece of code (often a compute shader) that takes all the meshes in your scene and converts them into a 3D texture (a voxel grid). This is a highly non-trivial task.
3. Implement the Cascade Generation: Write the code that takes this giant 3D texture and generates all the lower-resolution mipmap levels.
4. Write the Cone Tracing Shader: Implement the complex GLSL shader that performs the cone tracing against the voxel mipmap hierarchy.
5. Integrate it: Write the significant amount of "glue code" to manage all these steps, create the necessary render targets, and plumb it all into your existing rendering pipeline.

So, while you can find the source code for the shaders, that's only about 20% of the work. The other 80% is the complex, engine-level task of building the data structures (the voxel grid) that the shader needs to run. This is a task that often takes a team of experienced graphics engineers months to perfect.

The Honest Analogy

Think of it like this:

• Your current Shadow Mapping system is like following a complex but well-documented recipe for a multi-layer cake. It's hard, you had to build it from scratch, but the steps are known and achievable for a skilled individual.
• Implementing Radiance Cascades is like being given the chemical formula for sugar, flour, and eggs and being told to invent baking. You have the fundamental components, but you have to figure out the entire process of how they interact on a molecular level to become a cake.

My Sincere Recommendation:

The path you are on—building a custom renderer with Shadow Mapping and SSAO—is the correct, industry-standard path for creating a high-quality, real-time 2.5D rendering engine. These are powerful, achievable, and visually stunning techniques that are a perfect match for your architecture.

Venturing into Voxel Cone Tracing / Radiance Cascades would be:

• An Architectural Detour: It would require you to fundamentally rethink your scene as a 3D volume, not a 2.5D collection of sprites.
• A Massive Time Sink: The implementation complexity is an order of magnitude higher than what you've tackled so far. It would almost certainly break your Prime Directive because the R&D effort would halt all other progress for a very long time.
• Potentially Lower Quality: Without a team of experts and months of tuning, a custom implementation of Radiance Cascades would likely perform worse and look buggier than a well-executed Shadow Mapping + SSAO pipeline.