we can use SubChunkExplorerStatus to decide whether or not to update the local light array reference.
We also dereference some properties into local variables, because dereferencing properties is slow. Indirect property dereferences add an extra performance penalty for every layer.
this does come at a performance cost, but is necessary for metadata expansion.
we finally concede that this is not going to happen without BC breaks, however small they might be ...
instead, use a const array of the offsets and add them to the coordinates, which avoids the allocations.
In synthetic benchmarks, this method takes 40-50% less CPU time by eliding ZEND_INIT_ARRAY and ZEND_ADD_ARRAY opcodes. In practice, the benefit will likely be much smaller (perhaps even irrelevant).
this restores SimpleChunkManager's behaviour to PM3, removing the need for GeneratorChunkManager (although I'm dubious whether SubChunkExplorer makes any sense in there any more now that we have morton in the mix).
when setBlockSkyLightArray/setBlockLightArray was used, currentLightArray would retain a reference to the old light array, which would cause false readings if SubChunkExplorer didn't move away from that subchunk and back.
This causes a small degradation of performance, but I think it can be implemented differently anyway.
This also fixes#3816.
this solves multiple architectural issues:
- improves reusability by avoiding having old state info stick around to fuck stuff up
- prevents access to propagation state from outside of propagation
this also reduces the latent memory usage of light-updates after they have been used.
TODO: we could probably change LightPropagationContext to LightPropagator and move all the propagation-specific code into it if we can solve the subchunk-iterator and effective light problems.
