A desktop platform with the .NET 6.0 SDK 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 the latest version of Visual Studio, 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/sim1222/osukey
cd osukey

To update the source code to the latest commit, run the following command inside the osukey 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.

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. Alternatively, you can install ReSharper or use Rider to get inline support in your IDE of choice.

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.