Highly Performant & Scalable Ultima Online Server Emulator
https://www.modernuo.com
c-sharpcsharpcsharp-coredotnetdotnet-coreemulatorgplgplv3mmommo-enginemmorpgmmorpg-serveronlinerpgrunuoserverservuoultimaultima-onlineuo
a52ce6ef70
## Summary
Moves spawner entry storage out of the abstract `BaseSpawner` into the concrete owner, so a spawner subclass can store its own entry type while every stock code path keeps working. Motivation: an out-of-tree spawner (ModernSpawner) needs `ModernSpawnerEntry : SpawnerEntry` with extra fields; today `BaseSpawner` owns `List<SpawnerEntry>` and a family of non-virtual members, and the serialization generator constructs list elements from the declared element type, so storage has to live in the class that declares the concrete list.
### What changed
- **`BaseSpawner` v13** no longer owns `_entries`. It reads entries through an abstract view and mutates them through an owner contract (`BaseSpawner.Entries.cs`):
`Entries` (`IReadOnlyList<SpawnerEntry>`, `[IgnoreDupe]`), `EntrySpan` (`ReadOnlySpan<SpawnerEntry>` for hot loops), `CreateEntry`, `AddEntryCore`, `RemoveEntryCore`, `ClearEntriesCore`, `AdoptEntries`, `CloneEntry`, `TransferSpawned`, plus public `RemoveAllEntries()`, `CopyEntriesTo(target)` and protected `RebuildSpawned()`. Every loop inside `BaseSpawner` is an indexed `for` over `EntrySpan`.
- **`Spawner` v2** owns `[SerializedIgnoreDupe] List<SpawnerEntry> _entryList` (generated `EntryList`, protected). `ProximitySpawner`/`RegionSpawner` inherit it unchanged. The `Spawned` rebuild and timer re-arm moved from the base `[AfterDeserialization]` (which runs before derived fields are read) into `Spawner`'s.
- **Save migration**: `MigrateFrom(V12Content)` (and the v10/v11/legacy readers) hand the old list to the owner via `AdoptEntries`; `Spawner.MigrateFrom(V1Content)` restores its own fields and leaves the adopted list alone. Three v12/v1/v0 save blobs captured before the change are committed as fixtures and loaded by tests.
- **Lifecycle hooks** (`BaseSpawner.Hooks.cs`, all no-op by default): `OnStarted`, `OnStopped`, `OnBeforeSpawn(entry)` veto, `OnConfigureSpawned(entry, spawned)` before positioning, entry-aware `GetSpawnPosition(entry, spawned, map)`, `OnSpawned(entry, spawned)`, `OnSpawnedDeath(entry, spawned, killer)`. `BaseCreature.OnDeath` calls `NotifySpawnedDeath` before base death (which deletes the mobile and unlinks the spawner). `Start()` and the `NextSpawn` setter share one start core so `OnStarted` fires on both.
- **`SpawnerEntry` v2**: per-entry `Disabled` (XmlSpawner's entry "lock"), stored inverted so the common case writes nothing in binary or JSON; skipped by weighted selection, live spawns untouched; toggle button per row in `SpawnerGump`. `SetParent` is public and `Parent` is protected so an out-of-tree entry subclass can adopt and dirty-track.
- **DTO**: `SpawnerDto` loses `Entries`; each concrete record declares its own `entries` at the same JSON order, so `Distribution/Data/Spawns/**` is byte-identical. Import adopts the deserialized entry objects instead of recreating them through `AddEntry`, which is what preserves subtype fields (and `disabled`).
### Breaking changes and behaviour changes
- **API:** `BaseSpawner.Entries` is `IReadOnlyList<SpawnerEntry>` instead of `List<SpawnerEntry>`. The generated `AddToEntries`/`RemoveFromEntries`/`InsertIntoEntries`/`RemoveFromEntriesAt`/`ClearEntries` helpers on `BaseSpawner` are gone; use `AddEntry`/`RemoveEntry`/`RemoveAllEntries`/`CopyEntriesTo`. `RemoveAllEntries()` deletes the entries' live spawns as well as the entries (the old generated `ClearEntries()` only cleared the list), which is why it has a new name rather than the old one.
- `SpawnerControllerGump` "copy entries" now goes through `CopyEntriesTo`, which deletes the target's live spawns (previously it cleared the list and left the spawns orphaned) and is a no-op when source == target (previously that wiped the source).
- `RemoveEntry` with an entry the spawner does not own is now a no-op (previously it deleted that entry's spawns).
- `Respawn()` honours `Disabled` because it calls `Spawn()`; `Spawn(int index)`, `RemoveSpawn`, and `RemoveSpawns` ignore it.
- Copying entries between spawners no longer forces a 1-second first spawn; the target re-arms on its normal delay.
- Subclasses that own a different entry list than `Spawner`'s must call `RebuildSpawned()` from their own `[AfterDeserialization]` (`Spawner`'s call runs before their list is read) and, when converting adopted entries into their own type, carry live spawns across with `TransferSpawned`. The in-repo test subclass demonstrates both.
### Performance
Manual harness (`Benchmark_SpawnPath_Manual`, skipped by default): 100k calls, entries all full so `Spawn()` does selection only.
| Path | Before (
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| .config | ||
| .github | ||
| branding | ||
| dev-docs | ||
| Distribution/Data | ||
| Projects | ||
| tools | ||
| .cursorrules | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| AGENTS.md | ||
| azure-pipelines.yml | ||
| CLAUDE.md | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| Directory.Build.props | ||
| FAQ.md | ||
| GEMINI.md | ||
| global.json | ||
| LICENSE | ||
| ModernUO.slnx | ||
| publish.cmd | ||
| publish.ps1 | ||
| publish.sh | ||
| README.md | ||
| rider-settings.zip | ||
| Rules.ruleset | ||
| SPONSORS.md | ||
| stylecop.json | ||
| THIRD-PARTY-NOTICES | ||
| version.json | ||
ModernUO 
Ultima Online Server Emulator for the modern era!
Requirements
Supported Operating Systems
Required Frameworks
All Operating Systems
Windows
Hardware
| Use | vCPU | RAM | Storage |
|---|---|---|---|
| Development / test | 2 dedicated | 2 GB | SSD |
| Small live shard (< 50 concurrent) | 4 dedicated | 4 GB | NVMe |
| Medium (50–200) | 4–8 | 8 GB | NVMe |
| Large (200+) | 8+, high clock | 16 GB+ | NVMe |
See dev-docs/server-requirements.md for more information.
Development
Supported IDEs
Getting Started
- Install prerequisite requirements
- Clone this repository (or download the latest):
git clone https://github.com/modernuo/ModernUO.git
- Open
ModernUO.slnto start developing
Building/Publishing
Interactive Mode (Recommended for new users)
Run ./publish.cmd (Windows) or ./publish.sh (Linux/macOS) with no arguments to launch the guided build tool. It will:
- Check prerequisites (.NET SDK, native libraries)
- Walk you through configuration and platform selection
- Build and publish the server to the
Distributiondirectory - Show deployment instructions for cross-compiled builds
Command Line
./publish.cmd [release|debug] [os] [arch]
os- Supported operating systemsarchx64- Intel/AMD 64-bitarm64- ARM 64-bit
Linux Prerequisites
Fedora, CentOS, RHEL, AlmaLinux, Rocky, etc
dnf upgrade --refresh -y
# RHEL-family distributions (CentOS Stream, AlmaLinux, Rocky, RHEL) need CRB and EPEL enabled.
# Fedora skips this block.
dnf install -y dnf-plugins-core
dnf config-manager --set-enabled crb
dnf install -y epel-release
# Prerequisites
dnf install -y findutils libicu libdeflate libargon2 tzdata
Ubuntu, Debian, etc
apt-get update -y
# The ICU runtime package carries the ABI version in its name (libicu74, libicu76, …) and has no
# stable alias, so match it by pattern rather than pinning a release-specific name.
apt-get install -y '^libicu[0-9]+$' libdeflate0 libargon2-1 tzdata
Only the runtime libraries are needed — the -dev/-devel packages are not. Run
./build-tool --check-prereqs to check the current machine and print the exact packages your
release needs.
zstd is not listed because ZstdNet bundles libzstd for every platform, and liburing is not
listed because IORingGroup issues io_uring syscalls directly.
If the shard's configured time zone is a legacy alias such as US/Eastern, Debian 12 and Ubuntu
24.04 also need tzdata-legacy. See Platform Prerequisites
for what each dependency is for and what breaks without it.
OSX Requirements
brew install icu4c libdeflate argon2
Running the Server
- Follow the publish instructions
- The
Distributiondirectory is portable — copy it to your production server for deployment - Run
ModernUO.exeordotnet ModernUO.dllfrom theDistributiondirectory - On first run, the server will prompt you to configure game data file locations
Troubleshooting / FAQ
- See FAQ
Want to sponsor?
Thank you for supporting us! You can find out how by visiting the sponsors page.
Collaborators
Thanks
- RunUO Team & Community
- Voxpire, the ServUO Team & Community
- Karasho, Jaedan and the ClassicUO Community
Development Tools & Plugins provided with ♥ by
Code Signing Policy
Free code signing provided by SignPath.io, certificate by SignPath Foundation.
This program will not transfer any information to other networked systems unless specifically requested by the user or the person installing or operating it
Teams & Roles
Approvers & Committers: Development Team