Farmland can end up scanning up to 162 blocks looking for water in the worst case. This is obviously not great for huge farms where there are thousands of blocks of the stuff.
In most farms, the water won't be moved, and nor will the farmland. This means that we can avoid this costly search on random updates.
This PR implements a cache using blockstate data (only possible in PM5) which stores an index mapping to a coordinate offset where water was previously found by this farmland block. This allows the farmland to avoid water searching entirely in most cases.
This is a colossal improvement as compared to scanning the whole 9x2x9 area every time, which, on average, scans about 40 blocks to find water if the water is at the same Y coordinate. In real terms this translates into about a 8x performance improvement for farmland (see timings below).
the following things are currently not implemented:
- particle/sound effects when an entity extinguishes itself
- particle/sound effects when mixing different stuff in a cauldron
- powder snow cauldron
both of these things are contingent on #5169, but for the time being, the PR is functionally complete and I want to move on to something else without being stalled by the particle+sound problem (which I haven't yet decided how to solve).
this reduces the footprint of RuntimeBlockMapping by a further 1 MB, as well as simplifying various parts of the code, and solidifying the immutability guarantee of BlockStateData.
the terminology of this needs improvement, but...
the basic concept here is that 'type' data will persist on an itemstack, while 'state' data will not.
Type data consists of things like:
- Colour
- Coral type
- Wet/dry (sponges)
- Live/dead (coral)
- Wood type
State data consists of things like:
- Facing
- Axis
- Powered/unpowered
- Open/closed
In the past, with the old system, this information was separated by way of getStateBitmask(). This solution was fraught with problems, but achieved the basic goal: removing unwanted block properties from items.
This commit completely revamps the way that blocks are represented in memory at runtime.
Instead of being represented by legacy Mojang block IDs and metadata, which are dated, limited and unchangeable, we now use custom PM block IDs, which are generated from VanillaBlocks.
This means we have full control of how they are assigned, which opens the doors to finally addressing inconsistencies like glazed terracotta, stripped logs handling, etc.
To represent state, BlockDataReader and BlockDataWriter have been introduced, and are used by blocks with state information to pack said information into a binary form that can be stored on a chunk at runtime.
Conceptually it's pretty similar to legacy metadata, but the actual format shares no resemblance whatsoever to legacy metadata, and is fully controlled by PM.
This means that the 'state data' may change in serialization format at any time, so it should **NOT** be stored on disk or in a config.
In the future, this will be improved using more auto-generated code and attributes, instead of hand-baked decodeState() and encodeState(). For now, this opens the gateway to a significant expansion of features.
It's not ideal, but it's a big step forwards.
