Automatic chunk loading

How hard do you think it would it be to have Chunky automatically load chunks during tracing? I'm thinking this could be done with a first pass that figures out which chunks rays would enter, then loads only those chunks, after which Chunky would proceed to do the full render. You'd probably want limits set, like no loading chunks that would appear <10 pixels wide, or not loading chunks hit after a ray has already bounced twice, in order to avoid loading up the whole world when someone points the camera too high. There could also be a hard limit of N chunks, which would be prioritized by closeness to the camera. (I have ideas for how this could be done pretty simply and efficiently, but I don't know how easy it would be to work in to Chunky's current architecture.)

The issue does not name files, tests, or entry points. Start by tracing how Chunky currently loads world chunks and begins rendering, then assess whether a ray-tracing prepass can fit that architecture. Done would require an agreed loading policy, limits, prioritization behavior, and validation that rendering loads only the needed chunks.

Written by the indexing model from the issue text.