If you want to look under the hood and find the big production ones like too complex, I can recommend peeking at this one. It's a great example example of just

If you want to look under the hood and find the big production ones like too complex, I can recommend peeking at this one. It's a great example example of just the minimum of a spectral path tracer https://github.com/TomCrypto/Lambda https://github.com/TomCrypto/Lambda