7e5533e205
Closes #23862. Score V2 is a scoring algorithm, which aside from the raw numerical values of each judgement, incorporates a combo component, wherein each judgement's "combo score" is derived from both the raw numerical value of the object and the current combo after the given judgement. In particular, this means that Score V2 is sensitive to the _order_ of judging objects, as if two objects with the same start time are judged using different ordering, they can end up having a different "combo score". The issue that this change is fixing is an instance of one such reordering. Upon inspection, it turned out that the simulated autoplay run, which is used to determine max possible score so that it can be standardised to 1 million again, was processing a slider repeat before a slider tail circle, while actual gameplay was processing the same slider repeat _after_ the slider tail circle. The cause of that behaviour is unfortunately due to `LegacyLastTick`. The sliders which cause the issue are extremely short. Stable had a behaviour, in which to provide leniency, slider tails were artificially offset back by 36ms. However, if the slider is not long enough to make this possible, the last tick is placed in the middle of the slider. If that slider also happens to have exactly 1 repeat, then this means that the last tick and the repeat have the same time instant. Because of the time equality, what begins to matter now is the _order_ of processing the elements of the drawable slider in the hierarchy. For the purposes of legacy skins, tail circles were moved below ticks in fce3eacd7de3254ce75619efaa2d15d59d564623 - but in this particular case, it means that the order of processing the slider elements is now inadvertently inverted, causing the entire debacle. While the fact that scoring depends on order of processing of visuals is suboptimal, there isn't a great way to address this without significant restructuring. Due to the structure of processing judgements currently in place, in which each judgement is processed independently from others by its corresponding drawable hit object, this is probably the best that can be done for the time being at least.
osu!
A free-to-win rhythm game. Rhythm is just a click away!
The future of osu! and the beginning of an open era! Currently known by and released under the release codename "lazer". As in sharper than cutting-edge.
Status
This project is under constant development, but we aim to keep things in a stable state. Users are encouraged to try it out and keep it installed alongside the stable osu! client. It will continue to evolve to the point of eventually replacing the existing stable client as an update.
IMPORTANT: Gameplay mechanics (and other features which you may have come to know and love) are in a constant state of flux. Game balance and final quality-of-life passes come at the end of development, preceded by experimentation and changes which may potentially reduce playability or usability. This is done in order to allow us to move forward as developers and designers more efficiently. If this offends you, please consider sticking to a stable release of osu!. We are not yet open to heated discussion over game mechanics and will not be using github as a forum for such discussions just yet.
We are accepting bug reports (please report with as much detail as possible and follow the existing issue templates). Feature requests are also welcome, but understand that our focus is on completing the game to feature parity before adding new features. A few resources are available as starting points to getting involved and understanding the project:
- Detailed release changelogs are available on the official osu! site.
- You can learn more about our approach to project management.
Running osu!
If you are looking to install or test osu! without setting up a development environment, you can consume our releases. You can also generally download a version for your current device from the osu! site. Failing that, you may use the links below to download the latest version for your operating system of choice:
Latest release:
| Windows 8.1+ (x64) | macOS 10.15+ (Intel, Apple Silicon) | Linux (x64) | iOS 13.4+ | Android 5+ |
|---|
- The iOS testflight link may fill up (Apple has a hard limit of 10,000 users). We reset it occasionally when this happens. Please do not ask about this. Check back regularly for link resets or follow peppy on twitter for announcements of link resets.
If your platform is not listed above, there is still a chance you can manually build it by following the instructions below.
Developing a custom ruleset
osu! is designed to have extensible modular gameplay modes, called "rulesets". Building one of these allows a developer to harness the power of osu! for their own game style. To get started working on a ruleset, we have some templates available here.
You can see some examples of custom rulesets by visiting the custom ruleset directory.
Developing osu!
Please make sure you have the following prerequisites:
- A desktop platform with the .NET 6.0 SDK installed.
When working with the codebase, we recommend using an IDE with intelligent code completion and syntax highlighting, such as the latest version of Visual Studio, JetBrains Rider or Visual Studio Code.
Downloading the source code
Clone the repository:
git clone https://github.com/ppy/osu
cd osu
To update the source code to the latest commit, run the following command inside the osu directory:
git pull
Building
Build configurations for the recommended IDEs (listed above) are included. You should use the provided Build/Run functionality of your IDE to get things going. When testing or building new components, it's highly encouraged you use the VisualTests project/configuration. More information on this is provided below.
- Visual Studio / Rider users should load the project via one of the platform-specific
.slnffiles, rather than the main.sln. This will allow access to template run configurations.
You can also build and run osu! from the command-line with a single command:
dotnet run --project osu.Desktop
If you are not interested in debugging osu!, you can add -c Release to gain performance. In this case, you must replace Debug with Release in any commands mentioned in this document.
If the build fails, try to restore NuGet packages with dotnet restore.
Due to a historical feature gap between .NET Core and Xamarin, running dotnet CLI from the root directory will not work for most commands. This can be resolved by specifying a target .csproj or the helper project at build/Desktop.proj. Configurations have been provided to work around this issue for all supported IDEs mentioned above.
Testing with resource/framework modifications
Sometimes it may be necessary to cross-test changes in osu-resources or osu-framework. This can be quickly achieved using included commands:
Windows:
UseLocalFramework.ps1
UseLocalResources.ps1
macOS / Linux:
UseLocalFramework.sh
UseLocalResources.sh
Note that these commands assume you have the relevant project(s) checked out in adjacent directories:
|- osu // this repository
|- osu-framework
|- osu-resources
Code analysis
Before committing your code, please run a code formatter. This can be achieved by running dotnet format in the command line, or using the Format code command in your IDE.
We have adopted some cross-platform, compiler integrated analyzers. They can provide warnings when you are editing, building inside IDE or from command line, as-if they are provided by the compiler itself.
JetBrains ReSharper InspectCode is also used for wider rule sets. You can run it from PowerShell with .\InspectCode.ps1. Alternatively, you can install ReSharper or use Rider to get inline support in your IDE of choice.
Contributing
When it comes to contributing to the project, the two main things you can do to help out are reporting issues and submitting pull requests. Please refer to the contributing guidelines to understand how to help in the most effective way possible.
If you wish to help with localisation efforts, head over to crowdin.
We love to reward quality contributions. If you have made a large contribution, or are a regular contributor, you are welcome to submit an expense via opencollective. If you have any questions, feel free to reach out to peppy before doing so.
Licence
osu!'s code and framework are licensed under the MIT licence. Please see the licence file for more information. tl;dr you can do whatever you want as long as you include the original copyright and license notice in any copy of the software/source.
Please note that this does not cover the usage of the "osu!" or "ppy" branding in any software, resources, advertising or promotion, as this is protected by trademark law.
Please also note that game resources are covered by a separate licence. Please see the ppy/osu-resources repository for clarifications.