Highly Performant & Scalable Ultima Online Server Emulator
https://www.modernuo.com
c-sharpcsharpcsharp-coredotnetdotnet-coreemulatorgplgplv3mmommo-enginemmorpgmmorpg-serveronlinerpgrunuoserverservuoultimaultima-onlineuo
7bd2cb6a2a
## Summary Multi-Z cells (bridges, stairs, paver-over-ground, multi-floor structures) now carry **per-stratum walkability data** in the cache instead of falling through to the slow path. The data is computed at chunk-build time, persisted in the `.swb` file, and selected at query time by matching the request's `sourceZ` against each stratum's `zCenter` (within `StepHeight` tolerance). This is the Tier 4 strata feature, deferred from PR #2447 / PR #2448 / PR #2449. Builds on PR #2449's lazy backing store and public bake helpers. ## Wire format change (v1 → v2) `StepCacheFile.FormatVersion = 2`. `MinSupportedVersion = 2`. v1 `.swb` files are silently rejected at open time (treated as missing) and overwritten on the next `SaveToFile` / `BakeMap`. **No migration** — older files just get re-baked. The `MinSupportedVersion` sentinel is the model going forward: bump the constant when an incompatible change lands; admins re-bake on the next deploy. No matrix of v1↔v2↔v3 migration logic to maintain. ## What changed - **`StepProbe.ComputeStrataAt(map, x, y)`** — enumerates walkable standing-Zs at the cell (one per land surface plus one per walkable static), collapses Zs within `2*StepHeight`, runs `ComputeMaskAt` at each surviving Z. Returns `null` for single-Z cells (caller uses the chunk's main mask). - **`StepChunk`** — replaces the old `MultiZCells` bitmap with a **strata storage pair**: - `ushort[256] StrataOffsetByCell` (sentinel `NoStrata = 0xFFFF` = "no strata for that cell") - `byte[] StrataData` packed: `u8 stratumCount`, then `count × 19-byte stratum` - `sbyte zCenter, byte walkMask, byte wetMask, sbyte walkZ_N..NW (8), sbyte swimZ_N..NW (8)` - `IsCellMultiZ` derives from `StrataOffsetByCell[cell] != NoStrata` — same semantics, single source of truth. - **`StepCache.BuildChunk`** — populates strata for cells flagged multi-Z via `SetStrata`. Chunks with zero multi-Z cells pay zero strata overhead (offset array + data array stay null). - **`StepCache.TryGetMask`** — for multi-Z cells, scans strata with `TryStratumHit`; returns the matching one with `HitKind=Hit`. Falls through to slow path only when no stratum matches the query `sourceZ`. - **`StepCacheFile`** — v2 serialization with strata trailer per chunk + `recordLength` in index entry. Lazy reader sizes scratch per-chunk-record using the recorded length, growing on demand for multi-Z-heavy chunks. Patches `IndexOffset` on `w.Buffer` (BufferWriter's current backing array) since it grows during variable-size chunk writes. ## File layout v2 ``` Header (48 bytes): u32 Magic = 0x42575300 ('SWB\0') u32 Version = 2 u32 MapId u64 Fingerprint XxHash3 over LandTable + ItemTable flags + map files (mapX.mul/.uop, staidxX.mul, staticsX.mul) u64 BakeTimestamp informational u32 ChunkCount u64 IndexOffset position where chunk index begins Per chunk (variable size): u16 ChunkX, ChunkY u32 BuiltMultisVersion u8 HasStrata 0 = no strata trailer; 1 = strata trailer follows byte WalkMask[256], WetMask[256] sbyte SourceZ[256], WalkZN..WalkZNW[256], SwimZN..SwimZNW[256] // Strata trailer (only when HasStrata == 1): u16 StrataOffsetByCell[256] // NoStrata sentinel = 0xFFFF u32 StrataDataLength byte StrataData[StrataDataLength] Per multi-Z cell: u8 count, then count × Stratum (19 bytes) Index trailer (20 × ChunkCount bytes): per chunk: { u64 chunkKey, u64 fileOffset, u32 recordLength } ``` |
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| AGENTS.md | ||
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| 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 | ||
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ModernUO 
Ultima Online Server Emulator for the modern era!
Requirements
Supported Operating Systems
Required Frameworks
All Operating Systems
Windows
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, etc
dnf upgrade --refresh -y
# CentOS does not come with EPEL enabled
dnf install -y epel-release epel-next-release
dnf install -y findutils libicu libdeflate-devel zstd libargon2-devel liburing-devel
Ubuntu, Debian, etc
apt-get update -y
apt-get install -y libicu-dev libdeflate-dev zstd libargon2-dev liburing-dev
OSX Requirements
brew install icu4c libdeflate zstd 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
