81 lines
3.8 KiB
Typst
81 lines
3.8 KiB
Typst
#import "/lib.typ": note, tip, todo
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= Interference
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We need precise control over the entity age and ID for this to work, so sources of interference are
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generally unexpected entity spawns that mess up the ID.
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== Other Entities
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Recall that *any* entity spawning will increment the ID counter, and the full list of entities is
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surprising. An exhaustive list is available at
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#link("https://minecraft.wiki/w/Entity#Types_of_entities")[The Minecraft Wiki].
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In general, the solution is to spawn our item entities at nearly the same time, so there is no
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chance for other entities to spawn in-between. For example, by spawning all items with droppers in
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the same game tick, all the items are created in the same tick phase, so player inputs and world
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events cannot affect it. See @timing for details.
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== Singleplayer (before 26.2) <singleplayer>
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In singleplayer worlds, there are separate execution threads for the renderer and game world. The
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game world ("server thread") contains the item entities we care about for the purposes of EID
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Wireless, as these are the entities we can detect with redstone. However, the renderer ("client
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thread") *also* tracks some entities.
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In versions before 26.2, there was a bug that caused the client thread and server thread to use the
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*same* global ID counter. Therefore every entity might increment the counter twice: once when it
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spawns in the server, and once when the client begins to track it. Because this depends on the
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position and orientation of the player, and also on the unpredictable scheduling of the two
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execution threads, it is impossible to truly compensate for these effects.
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The solution is to either use a dedicated minecraft server, so that the client and servers run in
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separate processes, or install a mod which patches the game to use a separate counter for the
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client.
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#todo[Grab links for these mods and figure out exactly which versions they're good for.]
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== Paper Servers <paper>
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#todo[Figure out which versions of Paper broke the thing.]
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Most recent versions of Paper server are compatible with EID Wireless. However, there are old
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versions of Spigot which include a *different* stationary item optimization which corrupts this. A
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few versions of Paper erroneously included this old optimization (on top of the mod 4 optimization)
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which breaks EID Wireless.
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#todo[Show the patch with the busted optimization.]
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== Unloaded Chunks
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When a chunk unloads and reloads, all entities contained within it are destroyed and recreated with
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new entity IDs. Therefore any information encoded in the ID group offsets is destroyed.
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#tip[ When a chunk containing an EID Wireless receiver is reloaded, every in-progress transmission
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*MUST* be discarded. ]
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The best thing to do is to use a reload detector and lock the receiver output for one full cycle
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after a reload.
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#todo[Get links to frost walker and sculk sensor reload detector designs.]
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== Lazy Chunks
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Entities in lazy chunks do not age or move, and their IDs are preserved. However, the redstone
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circuitry will continue to function. If a chunk becomes lazy while a transmission is being
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processed, the detection circuits will not observe the right drop delays and so the transmission is
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corrupted.
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#tip[ When a chunk containing an EID Wireless receiver becomes lazy, every in-progress transmission
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*MUST* be discarded. ]
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Further, depending on the receiver design, there is a small chance the items become clipped into
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blocks. When the chunk becomes entity-processing again, the clipped items will fly out of the
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machine instead of being recycled.
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The best thing to do is to use a chunkloader to prevent the receiver ever being lazy-loaded. If
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chunkloaders cannot be used, a lazy-chunk detector can be used to lock the outputs while the chunk
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is lazy-loaded and for one full cycle after it becomes entity-processing.
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#todo[Get links to lazy-chunk detectors.]
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