Highly Performant & Scalable Ultima Online Server Emulator
https://www.modernuo.com
c-sharpcsharpcsharp-coredotnetdotnet-coreemulatorgplgplv3mmommo-enginemmorpgmmorpg-serveronlinerpgrunuoserverservuoultimaultima-onlineuo
## Issue Fixes #2452. A player with 30 Ninjitsu reported that the Animal Form menu showed **every** form; selecting one above their skill (e.g. Dog, req 40) **consumed mana** and returned "you need at least 40 skill", and afterwards the **gump never reopened** — every recast silently re-attempted the unusable form and drained more mana. ## Root cause Three linked bugs, all reproduced from the code: 1. **Gump not gated by skill.** `AnimalFormGump.BuildLayout` compared `Skill.Fixed` (which is `Value * 10`, so 30 skill → `300`) against the raw 0–100 `ReqSkill` (Dog = `40`). `300 >= 40` is always true, so all forms were shown. `Morph` itself correctly uses `.Value`. 2. **Mana charged on a no-skill cast.** `Morph` returns `MorphResult.NoSkill` for an under-skilled form, but both call sites (`OnCast`, `OnResponse`) only special-cased `MorphResult.Fail`; `NoSkill` fell through to the branch that deducts mana. 3. **Menu never reopened.** Per OSI ([uo.com](https://uo.com/wiki/ultima-online-wiki/skills/ninjitsu/), [uoguide](https://www.uoguide.com/Animal_Form)), casting while **standing still always opens the selection menu**, and casting while **moving** quick-transforms into the last selected form. ModernUO only opened the menu when `lastAnimalForm == -1`, so once any form was selected a stationary recast skipped the menu. ## Fix - Add `AnimalForm.CanSelectEntry` (compares `Skill.Value` to `ReqSkill`, plus the talisman check) and use it for the gump's per-entry enable check. - `OnCast`: standing still always opens the menu; moving quick-transforms into the last form. `NoSkill` no longer costs mana. - `OnResponse`: handle `Success` / `Fail` / `NoSkill` explicitly so `NoSkill` costs no mana. ## Tests Adds `AnimalFormTests`: - `CanSelectEntry` rejects forms above skill, accepts forms at/below skill, and requires a talisman for talisman-gated forms. - `Morph` returns `NoSkill` (without transforming) when under-skilled, and `Success` when sufficiently skilled. Verified the gating test catches the regression (reintroducing `.Fixed` fails it). Full solution build is clean; the 5 new tests plus 284 other UOContent tests pass (the pathfinding/AI sequential tests were excluded only because they deadlock under concurrent local runs — they are unrelated to this change). |
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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
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