osu!

Rhythm is just a click away. The future of osu! and the beginning of an open era! Commonly known by the codename osu!lazer. Pew pew.

Status

This project is under heavy development, but is 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 passses come at the end of development, preceeded 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 the stable releases of osu! (found on the website). 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.
• Read peppy's latest blog post exploring where lazer is currently and the roadmap going forward.

Running osu!

If you are looking to install or test osu! without setting up a development environment, you can consume our binary releases. Handy links below will download the latest version for your operating system of choice:

Latest build:

Windows (x64)	macOS 10.12+	Linux (x64)	iOS(iOS 10+)	Android (5+)

• When running on Windows 7 or 8.1, additional prerequisites may be required to correctly run .NET Core applications if your operating system is not up-to-date with the latest service packs.

If your platform is not listed above, there is still a chance you can manually build it by following the instructions below.

Developing or debugging

Please make sure you have the following prerequisites:

• A desktop platform with the .NET Core 3.1 SDK or higher installed.
• When developing with mobile, Xamarin is required, which is shipped together with Visual Studio or Visual Studio for Mac.
• When working with the codebase, we recommend using an IDE with intelligent code completion and syntax highlighting, such as Visual Studio 2019+, JetBrains Rider or Visual Studio Code.
• When running on Linux, please have a system-wide FFmpeg installation available to support video decoding.

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 .slnf files, rather than the main .sln. This will allow access to template run configurations.
• Visual Studio Code users must run the Restore task before any build attempt.

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 achieved by running some commands as documented on the osu-resources and osu-framework wiki pages.

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, which is only supported on Windows. Alternatively, you can install ReSharper or use Rider to get inline support in your IDE of choice.

Contributing

We welcome all contributions, but keep in mind that we already have a lot of the UI designed. If you wish to work on something with the intention of having it included in the official distribution, please open an issue for discussion and we will give you what you need from a design perspective to proceed. If you want to make changes to the design, we recommend you open an issue with your intentions before spending too much time to ensure no effort is wasted.

If you're unsure of what you can help with, check out the list of open issues (especially those with the "good first issue" label).

Before starting, please make sure you are familiar with the development and testing procedure we have set up. New component development, and where possible, bug fixing and debugging existing components should always be done under VisualTests.

Note that while we already have certain standards in place, nothing is set in stone. If you have an issue with the way code is structured, with any libraries we are using, or with any processes involved with contributing, please bring it up. We welcome all feedback so we can make contributing to this project as painless as possible.

For those interested, we love to reward quality contributions via bounties, paid out via PayPal or osu!supporter tags. Don't hesitate to request a bounty for your work on this project.

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.