Forge doesn't run client-side commands from sendUnsignedCommand, so we
still require a mixin there.
We do need to change the command name, as Fabric doesn't properly merge
the two command trees.
I didn't make a new years resolution to stop writing build tooling, but
maybe I should have.
This replaces our use of VanillaGradle with a new project,
VanillaExtract. This offers a couple of useful features for multi-loader
dev, including Parchment and Unpick support, both of which we now use in
CC:T.
This was copied over from the old binary handle, and so states we
always return a single number if no count is given. This is only the
case when the file is opened in binary mode.
Rather than mixing-in to CachedOutput, we just wrap our DataProviders to
use a custom CachedOutput which reformats the JSON before writing. This
allows us to drop mixins for common+non-client code.
Disk drives have had a long-standing issue with mutating their contents
on the computer thread, potentially leading to all sorts of odd bugs.
We tried to fix this by moving setDiskLabel and the mounting code to run
on the main thread. Unfortunately, this means there is a slight delay to
mounts being attached, breaking disk startup.
This commit implements an alternative solution - we now do mounting on
the computer thread again. If the disk's stack is modified, we update it
in the peripheral-facing item, but not the actual inventory. The next
time the disk drive is ticked, we then sync the two items.
This does mean that there is a fraction of a tick where the two will be
out-of-sync. This isn't ideal - it would potentially be possible to
cycle through disk ids - but I don't really think that's avoidable
without significantly complicating the IMedia API.
Fixes#1649, fixes#1686.
Originally we exposed a single registerTurtleUpgradeModellermethod which
could be called from both Fabric (during a mod's client init) and Forge
(during FMLClientSetupEvent).
This was fine until we allowed upgrades to specify model dependencies,
which would then automatically loaded, as this means model loading now
depends on upgrade modellers being loaded. Unknown to me, this is not
guaranteed to be the case on Forge - mod setup happens at the same time
as resource reloading!
Unfortunately there's not really a salvageable way of fixing this with
the current API. Forge now uses a registration event-based system,
meaning we can guarantee all modellers are loaded before models are
baked.
- Add support for version overrides/exclusions in our dependency check.
Sometimes mod loaders use different versions to vanilla, and we need
some way to handle that.
- Rescan wired network connections on the tick after invalidation,
rather than when invalidated.
- Convert some constant lambdas to static method references. Lambdas
don't allocate if they don't capture variables, so this has the same
performance and is a little less ugly.
- Small code-style/formatting changes.
Historically we used Forge's SimpleChannel methods (and
PacketDistributor) to send the packets to the client. However, we don't
need to do that - it is sufficient to convert it to a vanilla packet,
and send the packet ourselves.
Given we need to do this on Fabric, it makes sense to do this on Forge
as well. This allows us to unify (and thus simplify) a lot of how packet
sending works.
At the same time, we also remove the handling of speaker audio during
decoding. We originally did this to avoid the additional copy of audio
data. However, this doesn't work on 1.20.4 (as packets aren't
encoded/decoded on singleplayer), so it makes sense to do this
Correctly(TM).
This also allows us to get rid of ClientNetworkContext.get(). We do
still need to service load this class (as Forge's networking isn't split
up in the same way Fabric's is), but we'll be able to drop that in
1.20.4.
Finally, we move the record playing code from ClientNetworkContext to
ClientPlatformHelper. This means the network context no longer needs to
be platform-specific!
After embarrassing, let's do some proper work.
Rather than passing the level and position each time we call
ComponentAccess.get(), we now pass them at construction time (in the
form of the BE). This makes the consuming code a little cleaner, and is
required for the NeoForge changes in 1.20.4.
Everything old is new again!
CC's network message implementation has gone through several iterations:
- Originally network messages were implemented with a single class,
which held an packet id/type and and opaque blobs of data (as
string/int/byte/NBT arrays), and a big switch statement to decode and
process this data.
- In 42d3901ee3, we split the messages
into different classes all inheriting from NetworkMessage - this bit
we've stuck with ever since.
Each packet had a `getId(): int` method, which returned the
discriminator for this packet.
- However, getId() was only used when registering the packet, not when
sending, and so in ce0685c31f we
removed it, just passing in a constant integer at registration
instead.
- In 53abe5e56e, we made some relatively
minor changes to make the code more multi-loader/split-source
friendly. However, this meant when we finally came to add Fabric
support (8152f19b6e), we had to
re-implement a lot of Forge's network code.
In 1.20.4, Forge moves to a system much closer to Fabric's (and indeed,
Minecraft's own CustomPacketPayload), and so it makes sense to adapt to
that now. As such, we:
- Add a new MessageType interface. This is implemented by the
loader-specific modules, and holds whatever information is needed to
register the packet (e.g. discriminator, reader function).
- Each NetworkMessage now has a type(): MessageType<?> function. This
is used by the Fabric networking code (and for NeoForge's on 1.20.4)
instead of a class lookup.
- NetworkMessages now creates/stores these MessageType<T>s (much like
we'd do for registries), and provides getters for the
clientbound/serverbound messages. Mod initialisers then call these
getters to register packets.
- For Forge, this is relatively unchanged. For Fabric, we now
`FabricPacket`s.
While ComputerFamily is still useful, there's definitely some places
where it adds an extra layer of indirection. This commit attempts to
clean up some places where we no longer need it.
- Remove ComputerFamily from AbstractComputerBlock. The only place this
was needed is in TurtleBlock, and that can be replaced with normal
Minecraft explosion resistence!
- Pass in the fuel limit to the turtle block entity, rather than
deriving it from current family.
- The turtle BERs now derive their model from the turtle's item, rather
than the turtle's family.
- When creating upgrade/overlay recipes, use the item's name, rather
than {pocket,turtle}_family. This means we can drop getFamily() from
IComputerItem (it is still needed on to handle the UI).
- We replace IComputerItem.withFamily with a method to change to a
different item of the same type. ComputerUpgradeRecipe no longer
takes a family, and instead just uses the result's item.
- Computer blocks now use the normal Block.asItem() to find their
corresponding item, rather than looking it up via family.
The above means we can remove all the family-based XyzItem.create(...)
methods, which have always felt a little ugly.
We still need ComputerFamily for a couple of things:
- Permission checks for command computers.
- Checks for mouse/colour support in ServerComputer.
- UI textures.
This is a bit of an odd combination of a few bugs:
- When the terminal component is blurred, we fire a mouse_up event for
the last-held button. However, we had an off-by-1 error here, so this
only triggered for the right/middle buttons.
- This was obsucuring the second bug, which is when we clicked within
the terminal, this caused the terminal to be blurred (thus releasing
the mouse) and then focused again.
We fix this by only setting the focus if there's actually a change.
Fixes#1655
When adding/removing observers, we locked on the observer, then
acquired the global lock. When a metric is observed, then we acquire the
global lock and then the observer lock.
If these happen at the same time, we can easily end up with a deadlock.
We simply avoid holding the observer lock for the entire add/remove
process (instead only locking when actually needed).
Closes#1639
This commit adds abstract classes to describe the interface for our
mod-loader-specific generic peripherals (inventories, fluid storage,
item storage).
This offers several advantages:
- Javadoc to illuaminate conversion no longer needs the Forge project
(just core and common).
- Ensures we have a consistent interface between Forge and Fabric.
Note, this does /not/ implement fluid or energy storage for Fabric. We
probably could do fluid without issue, but not something worth doing
right now.
This adds a new "java_allocation" metric, which tracks the number of
bytes allocated while executing the computer (as measured by Java). This
is not an 100% reliable number, but hopefully gives some insight into
what computers are doing.
Historically CC has supported two modes when working with file handles
(and HTTP requests):
- Text mode, which reads/write using UTF-8.
- Binary mode, which reads/writes the raw bytes.
However, this can be confusing at times. CC/Lua doesn't actually support
unicode, so any characters beyond the 0.255 range were replaced with
'?'. This meant that most of the time you were better off just using
binary mode.
This commit unifies text and binary mode - we now /always/ read the raw
bytes of the file, rather than converting to/from UTF-8. Binary mode now
only specifies whether handle.read() returns a number (and .write(123)
writes a byte rather than coercing to a string).
- Refactor the entire handle hierarchy. We now have an AbstractMount
base class, which has the concrete implementation of all methods. The
public-facing classes then re-export these methods by annotating
them with @LuaFunction.
These implementations are based on the
Binary{Readable,Writable}Handle classes. The Encoded{..}Handle
versions are now entirely removed.
- As we no longer need to use BufferedReader/BufferedWriter, we can
remove quite a lot of logic in Filesystem to handle wrapping
closeable objects.
- Add a new WritableMount.openFile method, which generalises
openForWrite/openForAppend to accept OpenOptions. This allows us to
support update mode (r+, w+) in fs.open.
- fs.open now uses the new handle types, and supports update (r+, w+)
mode.
- http.request now uses the new readable handle type. We no longer
encode the request body to UTF-8, nor decode the response from UTF-8.
- Websockets now return text frame's contents directly, rather than
converting it from UTF-8. Sending text frames now attempts to treat
the passed string as UTF-8, rather than treating it as latin1.
Does it count as an emulator when it's official? I hope not, as this'd
make it my fourth or fifth emulator at this point.
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Developing/debugging CraftOS is a massive pain to do inside Minecraft,
as any change to resources requires a compile+hot swap cycle (and
sometimes a `/reload` in-game). As such, it's often more convenient to
spin up an emulator, pointing it to load the ROM from CC:T's sources.
However, this isn't practical when also making changes to the Java
classes. In this case, we either need to go in-game, or build a custom
version of CCEmuX.
This commit offers an alternative option: we now have our own emulator,
which allows us to hot swap both Lua and Java to our heart's content.
Most of the code here is based on our monitor TBO renderer. We probably
could share some more of this, but there's not really a good place for
it - feels a bit weird just to chuck it in :core.
This is *not* a general-purpose emulator. It's limited in a lot of
ways (won't launch on Mac[^1], no support for multiple computers) - just
stick to what's there already.
[^1]: We require OpenGL 4.5 due to our use of DSA.
In practice, we're never going to change this to true by default. The
old Tekkit Legends pack enabled this[^1], and that caused a lot of
problems, though admittedly back in 2016 so things might be better now.
If people do want this functionality, it should be fairly easy to
replicate with a datapack, adding a file to rom/autorun.
[^1]: See https://www.computercraft.info/forums2/index.php?/topic/27663-
Hate that I remember this, why is this still in my brain?
- Move most error message constants to a new MountHelpers class.
- Be a little more consistent in when we throw "No such file" vs "Not a
file/directory" messages.
The two implementations aren't entirely compatible - the implementation
returned by .of will throw an NPE on .contains(null), whereas the
Collections implementations just return false. However, we try to avoid
passing null to collections methods, so this should be safe.
There's no strong reason to do this, but it helps make the code a little
more consistent
As of 1.20, sign messages are immutable - we need to do
text = text.setMesssage(...) instead. Also do a tiny bit of cleanup to
this function while we're here.
Probably not the best use of my lunch break :D:.
Fixes#1611.
Allows registering arbitrary block lookup functions instead of a
platform-specific capability. This is roughly what Fabric did before,
but generalised to also take an invalidation callback.
This callback is a little nasty - it needs to be a NonNullableConsumer
on Forge, but that class isn't available on Fabric. For now, we make the
lookup function (and thus the generic peripheral provider) generic on
some <T extends Runnable> type, then specialise that on the Forge side.
Hopefully we can clean this up when NeoForge reworks capabilities.
Or rather, being published to the wrong place. The java-convention
plugin sets the group, but that was applied after the publishing one - I
was hoping it'd read that property lazy, but clearly not!
Wow, some of this is /old/. All the Maps.newHashMap stuff dates back to
Java 6, so must originally be CCTweaks code?!
We're unlikely to drop our Guava dependency (we use too much other
stuff), but we should make the most of the stdlib where possible.
Previously we had the invariant that if we had a server monitor, we also
had a terminal. When a monitor shrank into a place, we deleted the
monitor, and then recreated it when a peripheral was requested.
As of ab785a0906 this has changed
slightly, and we now just delete the terminal (keeping the ServerMonitor
around). However, we didn't adjust the peripheral code accordingly,
meaning we didn't recreate the /terminal/ when a peripheral was
requested.
The fix for this is very simple - most of the rest of this commit is
some additional code for ensuring monitor invariants hold, so we can
write tests with a little more confidence.
I'm not 100% sold on this approach. It's tricky having a double layer of
nullable state (ServerMonitor, and then the terminal). However, I think
this is reasonable - the ServerMonitor is a reference to the multiblock,
and the Terminal is part of the multiblock's state.
Even after all the refactors, monitor code is still nastier than I'd
like :/.
Fixes#1608
We can't use FriendlyByte.readCollection to read to a
pre-allocated/array-backed NonNullList, as that doesn't implement
List.add. Instead, we just need to do a normal loop.
We add a couple of tests to round-trip our recipe specs. Unfortunately
we can't test the recipes themselves as our own registries aren't set
up, so this'll have to do for now.
Oh, this was a really nasty bug to reproduce. I'm not sure why - it's
very simple - I guess I've only just seen screenshots of it, and never
sat down to try myself. Reminder to actually report your bugs folks!
In this case:
1. Place down three down three monitors and then a computer.
2. Display something on the monitor (monitor left paint a) is my go-to.
3. Break the middle monitor.
We'd expect the left most monitor to be cleared, however it actually
preserves the monitor contents, resizing (and skewing it) to fit on its
new size!
This is because we clear the server monitor, but never sync that over to
the client, so the client monitor retains the old contents. To fix that,
instead of nulling out the server monitor, we null out the underlying
Terminal. This causes the change to be synced, fixing the bug.
This moves MemoryMount to the main core module, and converts it to be a
"proper" WritableMount. It's still naively implemented - definitely
would be good to flesh out our tests in the future - but enough for what
we need it for.
We also do the following:
- Remove the FileEntry.path variable, and instead pass the path around
as a variable.
- Clean up BinaryReadableHandle to use ByteBuffers in a more idiomatic
way.
- Add a couple more tests to our FS tests. These are in a bit of an odd
place, where we want both Lua tests (for emulator compliance) and
Java tests (for testing different implementations) - something to
think about in the future.
This attempts to reduce some duplication in recipe serialisation (and
deserialisation) by moving the structure of a recipe (group, category,
ingredients, result) into seprate types.
- Add ShapedRecipeSpec and ShapelessRecipeSpec, which store the core
properties of shaped and shapeless recipes. There's a couple of
additional classes here for handling some of the other shared or
complex logic.
- These classes are now used by two new Custom{Shaped,Shapeless}Recipe
classes, which are (mostly) equivalent to Minecraft's
shaped/shapeless recipes, just with support for nbt in results.
- All the other similar recipes now inherit from these base classes,
which allows us to reuse a lot of this serialisation code. Alas, the
total code size has still gone up - maybe there's too much
abstraction here :).
- Mostly unrelated, but fix the skull recipes using the wrong UUID
format.
This allows us to remove our mixin for nbt in recipes (as we just use
our custom recipe now) and simplify serialisation a bit - hopefully
making the switch to codecs a little easier.
- Add AbstractInMemoryMount, which contains all of ArchiveMount's file
tree logic, but not the caching functionality.
- Convert MemoryMount to inherit from AbstractInMemoryMount.
- Add a helper method to add a file to an AbstractInMemoryMount, and
use that within {Resource,Jar}Mount.
There's definitely more work to be done here - it might be nice to split
FileEntry into separate Directory and File interfaces, or at least make
them slightly more immutable, but that's definitely a future job.
- Placing a command computer requires the player to be in creative and
opped.
- Breaking a command computer now requires the player to be opped, as
well as in creative.
As we've now got a dedicated item class for command comptuers, we move
the command-specific IMedia override to that class.
Fixes#1582.
Rather than having a mess of lambdas, we now move the bulk of the
implemetation to their own methods. The lambdas now just do argument
extraction - it's all stringly typed, so good to keep that with the
argument definition.
This also removes a couple of exception keys (and thus their translation
keys) as we no longer use them.
Wow, this is old. It looks like it's a legacy of when this method was on
TileGeneric (and so returned false by default). As all implementations
now return true (turtle tools no longer block redstone), we don't really
need this any more.
- Split buttons.png into individual textures.
- Split corners_xyz.png into the following:
- borders_xyz.png: A nine-sliced texture of the computer borders.
- pocket_bottom_xyz.png: A horizontally 3-sliced texture of the
bottom part of a pocket computer.
- sidebar_xyz.png: A vertically 3-sliced texture of the computer
sidebar.
While not splitting the sliced textures into smaller ones may seem a
little odd, it's consistent with what vanilla does in 1.20.2, and I
think will make editing them easier than juggling 9 textures.
I do want to make this more data-driven in the future, but that will
have to wait until the changes in 1.20.2.
This also adds a tools/update-resources.py program, which performs this
transformation on a given resource pack.
- Add a generic PermissionRegistry interface. This behaves similarly to
our ShaderMod interface, searching all providers until it finds a
compatible one.
We could just make this part of the platform code instead, but this
allows us to support multiple systems on Fabric, where things are
less standardised.
This interface behaves like a registry, rather than a straight
`getPermission(node, player)` method, as Forge requires us to list
our nodes up-front.
- Add Forge (using the built-in system) and Fabric (using
fabric-permissions-api) implementations of the above interface.
- Register permission nodes for our commands, and use those
instead. This does mean that the permissions check for the root
/computercraft command now requires enumerating all child
commands (and so potential does 7 permission lookups), but hopefully
this isn't too bad in practice.
- Remove UserLevel.OWNER - we never used this anywhere, and I can't
imagine we'll want to in the future.
Should be max_websocket_message, not just websocket_message.
Also add some additional validation to address rules, to check no
unrecognised keys are present.
Closes#1566.
We're very inconsistent with whether we use locks or concurrent maps
here. Something to sort out in the future, but for now add some missing
@GuardedBy annotations.
- Prefer {read,write}Nullable when possible.
- Use SoundEvent.{writeTo,readFrom}Network, instead of sending the
registry entries. This allows playing discs which don't register
their SoundEvent on the server.
- Add a couple of tests for round-tripping these packets.
This requires supporting registries in our platform test
code. Thankfully this is mostly the same as what we can do in Fabric -
the duplication is unfortunate - but it's easy enough.
This made more sense on 1.19.2 and before, but now that we have to do
this for tooltips, we might as well do it for messages as well.
Closes#1538, though hopefully will be resolved on the VO side too.
- Remove some unused translation keys.
- Run tools/language.py to sort the current translations and remove the
aforementioned unused keys.
- Update turtle tool impostor recipes - these now include the tool NBT!
Translations for Polish
Translations for French
Translations for Spanish
Translations for German
Co-authored-by: Patriik <apatriik0@gmail.com>
Co-authored-by: Sammy <SammyKoch@pm.me>
Co-authored-by: SquidDev <git@squiddev.cc>
- Move the tool action before the "is block present" check, fixes
#1527. This is where it was before, but we flipped it around in the
tool rewrite.
- Don't reuse as much turtle.place logic for tool actions. This fixes
some instances where tools could till/level dirt through solid
blocks.
- Overhaul model loading to work with the new API. This allows for
using the emissive texture system in a more generic way, which is
nice!
- Convert some of our custom models to use Fabric's model hooks (i.e.
emitItemQuads). We don't make use of this right now, but might be
useful for rendering tools with enchantment glints.
Note this does /not/ change any of the turtle block entity rendering
code to use Fabric/Forge's model code. This will be a change we want
to make in the future.
- Some cleanup of our config API. This fixes us printing lots of
warnings when creating a new config file on Fabric (same bug also
occurs on Forge, but that's a loader problem).
- Fix a few warnings
We've supported resource conditions in the upgrade JSON for an age, but
don't expose it in our data generators at all.
Indeed, using these hooks is a bit of a pain to do in multi-loader
setups, as the JSON is different between the two loaders. We could
generate the JSON for all loaders at once, but it feels nicer to use
the per-loader APIs to add the conditions.
For now, we just support generating a single condition - whether a mod
is loaded not, via the requireMod(...) method.
We switched to Forge's loot modifier system in the 1.20 update, as
LootTable.addPool had been removed. Turns out this was by accident, and
so we switch back to the previous implementation, as it's much simpler
and efficient.
- Attach permission checks to the first argument (so the literal
command name) rather than the last argument. This fixes commands
showing up when they shouldn't.
- HelpingArgumentBuilder now inherits permissions of its leaf nodes.
This only really impacts the "track" subcommand.
- Don't autocomplete the computer selector for the "queue" subcommand.
As everyone has permission for this command, it's possible to find
all computer ids and labels in the world.
I'm in mixed minds about this, but don't think this is an exploit -
computer ids/labels are sent to in-range players so shouldn't be
considered secret - but worth patching none-the-less.
- Normalise upgrade keys, to be "allowEnchantments" and
"consumeDurability". We were previously inconsistent with
allow/allows and consumes.
- Add tests for durability and enchantments of pickaxes.
- Fix a couple of issues with the original upgrade NBT being modified.
- Now store the item's tag under a separate key rather than on the
root. This makes syncing the NBT between the two much nicer.
Turtle tools now accept two additional JSON fields
- allowEnchantments: Whether items with enchantments (or any
non-standard NBT) can be equipped.
- consumesDurability: Whether durability will be consumed. This can be
"never" (the current and default behaviour), "always", and
"when_enchanted".
Closes#1501.
This is a pre-requisite for #1501, and some other refactorings I want to do.
Also fix items in the turtle upgrade slots vanishing. We now explicitly
invalidate the cache when setting the item.
I think this left over from CCTweaks or Peripheral++. It doesn't really
make sense as an API - if/when we add multiple upgrades, we'll want a
different API for this.
This removes a tiny bit of duplication (at the cost of mode code), but
makes the interface more intuitive, as there's no bouncing between
getCombination -> cache -> buildModel.
It turns out we don't document the "port" option anywhere, so probably
worth doing a bit of an overhaul here.
- Expand the top-level HTTP rules comment, clarifying how things are
matched and describing each field.
- Improve the comments on the default HTTP rule. We now also describe
the $private rule and its motivation.
- Don't drop/ignore invalid rules. This gets written back to the
original config file, so is very annoying! Instead we now log an
error and convert the rule into a "deny all" rule, which should make
it obvious something is wrong.
- Update to Loom 1.2 and FG 6.0. ForgeGradle has changed how it
generates the runXyz tasks, which makes running our tests much
harder. I've raised an issue upstream, but for now we do some nasty
poking of internals.
- Fix Sodium/Iris tests. Loom 1.1 changed how remapped configurations
are generated - we create a dummy source set and associate the
remapped configuration with that. All nasty stuff.
- Publish the common library. I'm not a fan of this, but given how much
internals I'm poking elsewhere, should probably get off my high
horse.
- Add renderdoc support to the client gametests, enabled with
-Prenderdoc.
- Move the class cache out of Generator into MethodSupplierImpl. This
means we cache class generation globally (that's really expensive!),
but the class -> method list lookup is local.
- Move the global GenericSource/GenericMethod registry out of core,
passing in the list of generic methods to the ComputerContext.
I'm not entirely thrilled by the slight overlap of MethodSupplierImpl and
Generator here, something to clean up in the future.
- Move several interfaces out of `d00.computercraft.core.asm` into a
new `aethods` package. It may make sense to expose this to the
public API in a future commit (possibly part of #1462).
- Add a new MethodSupplier<T> interface, which provides methods to
iterate over all methods exported by an object (either directly, or
including those from ObjectSources).
This interface's concrete implementation (asm.MethodSupplierImpl),
uses Generators and IntCaches as before - we can now make that all
package-private though, which is nice!
- Make the LuaMethod and PeripheralMethod MethodSupplier local to the
ComputerContext. This currently has no effect (the underlying
Generator is still global), but eventually we'll make GenericMethods
non-global, which unlocks the door for #1382.
- Update everything to use this new interface. This is mostly pretty
sensible, but is a little uglier on the MC side (especially in
generic peripherals), as we need to access the global ServerContext.
- Remove SidedGenericPeripheral (we never used this!), adding the
functionality to GenericPeripheral directly. This is just used on the
Fabric side for now, but might make sense with Forge too.
- Move GenericPeripheralBuilder into the common project - this is
identical between the two projects!
- GenericPeripheralBuilder now generates a list of methods internally,
rather than being passed the methods.
- Add a tiny bit of documentation.
When a turtle attempts to place a block, it does so by searching for
nearby blocks and attempting to place the item against that block.
This has slightly strange behaviour when working with "placable"
non-block items though (such as buckets or boats). In this case, we call
Item.use, which doesn't take in the position of the block we're placing
against. Instead these items do their own ray trace, using the default
reach distance.
If the block we're trying to place against is non-solid, the ray trace
will go straight through it and continue (up to the maximum of 5
blocks), allowing placing the item much further away.
Our fix here is to override the default reach distance of our fake
players, limiting it to 2. This is easy on Forge (it has built-in
support), and requires a mixin on Fabric.
Closes#1497.
