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Kamron Batman 1c2e114b21
feat(pathfinding): multi-aware mask synthesizer + warm interior cache for house/boat cells (#2479)
## Problem

Houses and boats (multis) were pathed correctly only by **delegation to the slow path**: `StepCache.TryGetMask` returns `Fallthrough_Multi` for any multi-covered cell, and `GetSuccessors` ran `CheckMovement` **8× per cell** (each re-resolving the tile stack via `GetStaticAndMultiTiles`) — a sustained per-step cost near every house/boat. There was also no automated test pinning multi pathfinding.

This branch is the full multi-pathfinding effort in phases on one branch.

## Phase 1 — characterization tests (the oracle)

Implementation-agnostic invariants: a cache-on≡cache-off whole-path invariant, a per-cell sweep vs `CheckMovement` over footprint+halo (incl. destination Z), hand-verified routing (around walls, demolish-reopens, foundation-redesign-honored), classic-house / foundation / boat fixtures, non-vacuity guards. These gate every later phase byte-for-byte.

## Phase 2 — live single-pass synthesizer

`StepProbe.ComputeMultiMaskAt` synthesizes a covered cell's full 8-direction `StepMask` in one pass (the existing surface/step logic over `GetStaticAndMultiTiles` instead of 8× `CheckMovement`). `GetSuccessors` routes `Fallthrough_Multi` cells through it. No new cache, no `.swb` change. **~1.5×**, zero added allocations.

## Phase 3 / 3.1 — warm per-`multiID` interior cache (airtight)

`MultiMaskCache` caches each fixed multi's local-frame `StepMask` for **interior** cells (cell + all 8 neighbours covered → terrain-neighbour-free → position-invariant), keyed by `multiID & 0x3FFF`, built lazily from the MCL. Interior cells become ~20 ns lookups.

The cache is gated on a **per-instance footprint-clean flag** (`BaseMulti.PathInteriorCacheState`): an instance whose whole footprint terrain is below its floor (`maxTerrain < minFloor`) serves from the cache; a **dirty** instance (terrain intrudes — a contrived/GM placement) **degrades to live-synth, never a wrong mask**. This closes a cross-instance soundness gap (the cached mask depends on neighbour terrain too) found in a holistic review. The gate resets whenever the footprint's world-terrain relationship can change — **location, map, or ItemID** (a boat's heading swaps the MCL).

**Boats are cached too.** Their per-`multiID` deck masks are movement-invariant (built once per heading), so a sailing boat never rebuilds them; only the cheap clean-flag rescan repeats per move (and only when pathed near). Narrow existing boats have little interior; wide galleons (`multi.mul`) would gain Castle-class. `HouseFoundation` (per-instance runtime `DesignState`) is the one type that stays on the live path.

## Verification

- `UOContent.Tests` **454/454**, `Server.Tests` **708/708**, 0 failures.
- The Phase-1 oracle (`MultiPathInvariantTests`, cache-on ≡ cache-off) stays **byte-identical** with the synthesizer + interior cache active.
- Tests pin: footprint-cleanliness (clean vs sunk), dirty/cluttered placement degrades to live-synth while still pathing, clean placement serves, and the gate resets on move/ItemID change.

## Performance (modernuo/ModernUO-Benchmarks#8, full-fixture)

Houses at **Green Acres** (flat staff region → clean footprints, the legit-placement case):

| Route | Slow path | Phase 3.1 (interior cache) | Speedup |
|-------|----------:|---------------------------:|--------:|
| `around_a` (29 steps) | 238.3 µs | **49.1 µs** | **4.85×** |
| `around_b` (29 steps) | 224.3 µs | **49.5 µs** | **4.53×** |

~130 of ~167 multi cells/route serve from the cache (~20 ns) vs 37 live-synth. Per-cell, the slow path's 8× `CheckMovement` grows with multi complexity (GuildHouse ~857 ns → Castle ~1,194 ns), the synthesizer is a flat ~780 ns, and the cache serve is ~20 ns — so big/tall multis (and wide galleons) gain most. Identical allocations throughout.
2026-06-09 08:02:05 -07:00
.config feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
.github chore: Change signing policy slug to 'release-signing' (#2466) 2026-06-06 15:00:06 -07:00
dev-docs fix: Fixes pathfinding prebake and pathfinding multi-fallthrough. (#2478) 2026-06-08 11:59:24 -07:00
Distribution/Data feat: Adds rope teleporter for New Haven Mines (#2439) 2026-05-03 17:23:31 -07:00
Projects feat(pathfinding): multi-aware mask synthesizer + warm interior cache for house/boat cells (#2479) 2026-06-09 08:02:05 -07:00
.cursorrules chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
.editorconfig chore(docs): Adds UnmanagedDataReader & BinaryFileReader documentation (#1968) 2024-10-01 17:07:51 -07:00
.gitattributes fix: Adds migration checks to CICD, updates dependencies, adds Fedora 37, alpine 3.17 support (#1309) 2022-12-22 12:12:47 -08:00
.gitignore feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
AGENTS.md chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
azure-pipelines.yml chore: Cleans workflows for NodeJS 24 (#2394) 2026-03-28 21:55:29 -07:00
CLAUDE.md feat(pathfinding): first-boot prompt to pre-bake the .swb map cache (#2475) 2026-06-07 16:30:33 -07:00
CODE_OF_CONDUCT.md Create CODE_OF_CONDUCT.md 2020-05-05 08:51:39 -07:00
CONTRIBUTING.md chore(license): Removes CLA requirement. All contributors moving forward will retain copyright. (#2038) 2024-12-31 02:52:58 -08:00
Directory.Build.props fix: Fixes publishing with build tool (#2398) 2026-04-04 00:35:39 -07:00
FAQ.md docs: Updates FAQ for time zone issues. (#1368) 2023-03-10 00:18:36 -08:00
GEMINI.md chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
global.json feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
LICENSE Fixes more line ending issues (#267) 2020-09-27 13:54:56 -07:00
ModernUO.slnx feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
publish.cmd feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
publish.ps1 fix: Adds stamp check for build tool versioning (#2400) 2026-04-06 16:18:02 -06:00
publish.sh fix: Adds stamp check for build tool versioning (#2400) 2026-04-06 16:18:02 -06:00
README.md chore: Update README with Code Signing Policy (#2467) 2026-06-06 15:32:01 -07:00
rider-settings.zip Cleanup/Housekeeping (#242) 2020-09-12 15:31:21 -07:00
Rules.ruleset chore(docs): Adds UnmanagedDataReader & BinaryFileReader documentation (#1968) 2024-10-01 17:07:51 -07:00
SPONSORS.md chore: Updates readme files (#2247) 2025-07-27 11:04:32 -07:00
stylecop.json Updates formatting rules (#199) 2020-08-25 18:00:51 -07:00
THIRD-PARTY-NOTICES docs: Adds RunUO-Encryption notice attribution to DarkStorm (#2369) 2026-03-12 23:35:47 -07:00
version.json feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00

ModernUO - Ultima Online Server Emulator for the modern era!

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Ultima Online Server Emulator for the modern era!

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Requirements

Supported Operating Systems

Windows 10/11/2012/2016/2019/2022/2025 MacOS 14+ Debian 12+ Ubuntu 22+ LTS
Alpine 3.22+ Fedora 42+ RedHat 9+ CentOS Stream 9+ openSUSE 15.6+ SUSE Enterprise 15 SP6 Linux Mint 21+ Arch

Required Frameworks

All Operating Systems

.NET

Windows

VC++ Redistributable v14

Development

git .NET

Supported IDEs

Jetbrains Rider 2025.3+ space VSCode space Visual Studio 2026

Getting Started

  • Install prerequisite requirements
  • Clone this repository (or download the latest):
    • git clone https://github.com/modernuo/ModernUO.git
  • Open ModernUO.sln to start developing

Building/Publishing

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 Distribution directory
  • Show deployment instructions for cross-compiled builds

Command Line

./publish.cmd [release|debug] [os] [arch]

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 Distribution directory is portable — copy it to your production server for deployment
  • Run ModernUO.exe or dotnet ModernUO.dll from the Distribution directory
  • On first run, the server will prompt you to configure game data file locations

Troubleshooting / FAQ

Want to sponsor?

Thank you for supporting us! You can find out how by visiting the sponsors page.

Collaborators

Kamron Batman Mark1145

Thanks

  • RunUO Team & Community
  • Voxpire, the ServUO Team & Community
  • Karasho, Jaedan and the ClassicUO Community



Development Tools & Plugins provided with ♥ by

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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