Bartłomiej Dach
1d3e682c5e
- Part of https://github.com/ppy/osu/issues/37818 - Continued from https://github.com/ppy/osu/pull/37355#issuecomment-4449248107 ## Overview This PR introduces an alternative API, `ScoreMultiplierCalculator`, to be used going forward for calculating mod multipliers. The reason for introducing this new API is that it has been requested that: - For any two given mods, it should be possible to have the combined mod multipliers of them in combination be *different* than the product of the individual mods' multipliers in isolation, i.e. $mult( \\{ A, B \\} ) \neq mult( \\{ A \\} ) \cdot mult( \\{ B \\} )$. - For an individual mod, it should be possible to have the mod multipliers depend on a quantity that is *not* the presence of another mod or the direct value of a setting on the mod. This capability is being demonstrated in this PR via the `osu.Game.Tests.Rulesets.Scoring.ScoreMultiplierCalculatorTest` test fixture. ## Parity with `Mod.ScoreMultiplier` This PR contains a `ScoreMultiplierCalculator` implementation for each of the built-in four rulesets. The abstract `osu.Game.Tests.Rulesets.RulesetScoreMultiplierTest` and its four derived ruleset-specific test fixtures were written to ensure that the new implementations do not diverge from the current state of affairs. `Mod.ScoreMultiplier` is not removed in this diff to keep size low. It will be removed as a follow-up. ## Performance This PR contains a benchmark comparing the current implementation via `Mod.ScoreMultiplier` and the new `ScoreMultiplierCalculator` API. Results below. <details> | Method | Times | Mods | Mean | Error | StdDev | Gen0 | Allocated | |---------------------- |------ |--------------------- |--------------:|------------:|------------:|--------:|----------:| | ViaModScoreMultiplier | 1 | mods (...)tings [27] | 121.171 ns | 1.5284 ns | 1.4297 ns | 0.0782 | 656 B | | ViaCalculator | 1 | mods (...)tings [27] | 248.509 ns | 1.9313 ns | 1.6127 ns | 0.1364 | 1144 B | | ViaModScoreMultiplier | 1 | multiple mods | 128.357 ns | 0.4282 ns | 0.4006 ns | 0.0782 | 656 B | | ViaCalculator | 1 | multiple mods | 252.953 ns | 1.2860 ns | 1.2029 ns | 0.1364 | 1144 B | | ViaModScoreMultiplier | 1 | no mods | 3.007 ns | 0.0345 ns | 0.0288 ns | - | - | | ViaCalculator | 1 | no mods | 14.802 ns | 0.0616 ns | 0.0576 ns | 0.0134 | 112 B | | ViaModScoreMultiplier | 1 | single mod | 40.271 ns | 0.1238 ns | 0.1098 ns | 0.0258 | 216 B | | ViaCalculator | 1 | single mod | 113.033 ns | 0.3140 ns | 0.2937 ns | 0.0842 | 704 B | | ViaModScoreMultiplier | 1 | single mod 2 | 3.653 ns | 0.0384 ns | 0.0359 ns | 0.0038 | 32 B | | ViaCalculator | 1 | single mod 2 | 78.172 ns | 0.0680 ns | 0.0603 ns | 0.0621 | 520 B | | ViaModScoreMultiplier | 10 | mods (...)tings [27] | 1,169.609 ns | 4.3058 ns | 4.0276 ns | 0.7839 | 6560 B | | ViaCalculator | 10 | mods (...)tings [27] | 2,575.264 ns | 21.2705 ns | 19.8964 ns | 1.3657 | 11440 B | | ViaModScoreMultiplier | 10 | multiple mods | 1,171.775 ns | 6.2332 ns | 5.2050 ns | 0.7839 | 6560 B | | ViaCalculator | 10 | multiple mods | 2,579.593 ns | 22.1010 ns | 20.6733 ns | 1.3657 | 11440 B | | ViaModScoreMultiplier | 10 | no mods | 35.943 ns | 0.1665 ns | 0.1476 ns | - | - | | ViaCalculator | 10 | no mods | 154.980 ns | 0.2381 ns | 0.1988 ns | 0.1338 | 1120 B | | ViaModScoreMultiplier | 10 | single mod | 404.185 ns | 1.3190 ns | 1.2338 ns | 0.2580 | 2160 B | | ViaCalculator | 10 | single mod | 1,167.279 ns | 6.1641 ns | 5.7659 ns | 0.8411 | 7040 B | | ViaModScoreMultiplier | 10 | single mod 2 | 42.128 ns | 0.2878 ns | 0.2692 ns | 0.0382 | 320 B | | ViaCalculator | 10 | single mod 2 | 775.435 ns | 2.3318 ns | 2.1811 ns | 0.6208 | 5200 B | | ViaModScoreMultiplier | 100 | mods (...)tings [27] | 11,623.346 ns | 51.7174 ns | 43.1863 ns | 7.8430 | 65600 B | | ViaCalculator | 100 | mods (...)tings [27] | 25,252.987 ns | 44.4352 ns | 39.3906 ns | 13.6719 | 114400 B | | ViaModScoreMultiplier | 100 | multiple mods | 11,928.536 ns | 35.2079 ns | 32.9334 ns | 7.8430 | 65600 B | | ViaCalculator | 100 | multiple mods | 25,399.378 ns | 152.4597 ns | 127.3108 ns | 13.6719 | 114400 B | | ViaModScoreMultiplier | 100 | no mods | 328.158 ns | 0.5827 ns | 0.5165 ns | - | - | | ViaCalculator | 100 | no mods | 1,517.485 ns | 10.2304 ns | 9.5695 ns | 1.3390 | 11200 B | | ViaModScoreMultiplier | 100 | single mod | 3,986.251 ns | 24.2523 ns | 21.4991 ns | 2.5787 | 21600 B | | ViaCalculator | 100 | single mod | 11,479.514 ns | 23.3738 ns | 20.7203 ns | 8.4076 | 70400 B | | ViaModScoreMultiplier | 100 | single mod 2 | 385.679 ns | 3.5190 ns | 3.2917 ns | 0.3824 | 3200 B | | ViaCalculator | 100 | single mod 2 | 7,658.646 ns | 21.8274 ns | 19.3494 ns | 6.2103 | 52000 B | </details> While the calculator is obviously slower, in my view it is not egregiously so. The main overheads both time- and memory-wise are collection allocations for the dictionary and the set which I consider to be directly caused by the requested additional complexity and as such I don't really consider them eliminable. I have tried and applied some micro-optimisations (e2469ce338,cb33abec17), albeit with negligible effect. I have also tried to key the mods by `Acronym` instead of by `Type` and the difference was basically nil. <details> <summary>patch for keying by acronym</summary> ```diff diff --git a/osu.Game/Rulesets/Scoring/ScoreMultiplierCalculator.cs b/osu.Game/Rulesets/Scoring/ScoreMultiplierCalculator.cs index 772f9d178b..7f5907cbda 100644 --- a/osu.Game/Rulesets/Scoring/ScoreMultiplierCalculator.cs +++ b/osu.Game/Rulesets/Scoring/ScoreMultiplierCalculator.cs @@ -13,26 +13,26 @@ namespace osu.Game.Rulesets.Scoring /// </summary> public class ScoreMultiplierCalculator { - private static readonly List<(Type[] mods, Func<Mod[], double> multiplier)> combination_multipliers = []; - private static readonly Dictionary<Type, Func<Mod, ScoreMultiplierCalculator, double>> single_multipliers_with_context = []; - private static readonly Dictionary<Type, Func<Mod, double>> single_multipliers = []; + private static readonly List<(string[] modAcronyms, Func<Mod[], double> multiplier)> combination_multipliers = []; + private static readonly Dictionary<string, Func<Mod, ScoreMultiplierCalculator, double>> single_multipliers_with_context = []; + private static readonly Dictionary<string, Func<Mod, double>> single_multipliers = []; /// <summary> /// Defines a flat, setting-independent score multiplier for the given <typeparamref name="TMod"/>. /// </summary> public static void Single<TMod>(double hasMultiplier) - where TMod : Mod + where TMod : Mod, new() { - single_multipliers[typeof(TMod)] = _ => hasMultiplier; + single_multipliers[new TMod().Acronym] = _ => hasMultiplier; } /// <summary> /// Defines a setting-dependent score multiplier for the given <typeparamref name="TMod"/>. /// </summary> public static void Single<TMod>(Func<TMod, double> hasMultiplier) - where TMod : Mod + where TMod : Mod, new() { - single_multipliers[typeof(TMod)] = mod => hasMultiplier.Invoke((TMod)mod); + single_multipliers[new TMod().Acronym] = mod => hasMultiplier.Invoke((TMod)mod); } /// <summary> @@ -40,20 +40,20 @@ public static void Single<TMod>(Func<TMod, double> hasMultiplier) /// The multiplier calculation is given additional context to calculate the multiplier via the <typeparamref name="TContext"/> type instance. /// </summary> public static void Single<TMod, TContext>(Func<TMod, TContext, double> hasMultiplier) - where TMod : Mod + where TMod : Mod, new() where TContext : ScoreMultiplierCalculator { - single_multipliers_with_context[typeof(TMod)] = (mod, context) => hasMultiplier.Invoke((TMod)mod, (TContext)context); + single_multipliers_with_context[new TMod().Acronym] = (mod, context) => hasMultiplier.Invoke((TMod)mod, (TContext)context); } /// <summary> /// Defines a score multiplier specific to when both <typeparamref name="T1"/> and <typeparamref name="T2"/> mods are present. /// </summary> public static void Combination<T1, T2>(Func<T1, T2, double> hasMultiplier) - where T1 : Mod - where T2 : Mod + where T1 : Mod, new() + where T2 : Mod, new() { - combination_multipliers.Add(([typeof(T1), typeof(T2)], mods => hasMultiplier((T1)mods[0], (T2)mods[1]))); + combination_multipliers.Add(([new T1().Acronym, new T2().Acronym], mods => hasMultiplier((T1)mods[0], (T2)mods[1]))); } /// <summary> @@ -61,7 +61,7 @@ public static void Combination<T1, T2>(Func<T1, T2, double> hasMultiplier) /// </summary> public double CalculateFor(IEnumerable<Mod> mods) { - var allModsByType = mods.ToDictionary(m => m.GetType()); + var allModsByType = mods.ToDictionary(m => m.Acronym); if (allModsByType.Count == 0) return 1; @@ -83,7 +83,7 @@ public double CalculateFor(IEnumerable<Mod> mods) } } - foreach (var modType in remainingModTypes) + foreach (string modType in remainingModTypes) { if (single_multipliers.TryGetValue(modType, out var multiplier)) result *= multiplier(allModsByType[modType]); ``` </details> One particular parallel thread that may warrant follow-up is that `Mod.UsesDefaultConfiguration` is disproportionately expensive due to calling into regexes via Humanizer internals. <img width="1517" height="517" alt="Screenshot_2026-05-19_at_10 58 30" src="https://github.com/user-attachments/assets/68309a8c-74e7-4f96-8ef9-62868eeca337" />
osu!
A free-to-win rhythm game. Rhythm is just a click away!
This is the future – and final – iteration of the osu! game client which marks 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 do our best to keep things in a stable state. Players are encouraged to install from a release alongside their stable osu! client. This project will continue to evolve until we eventually reach the point where most users prefer it over the previous "osu!stable" release.
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.
- Track our current efforts towards improving the game.
Running osu!
If you are just looking to give the game a whirl, you can grab the latest release for your platform:
Latest release:
| Windows 10+ (x64) | macOS 12+ (Intel, Apple Silicon) | Linux (x64) | iOS 13.4+ | Android 5+ |
|---|
You can also generally download a version for your current device from the osu! site.
If your platform is unsupported or not listed above, there is still a chance you can run the release or manually build it by following the instructions below.
For iOS/iPadOS users: The iOS testflight link fills up very fast (Apple has a hard limit of 10,000 users). We reset it occasionally. Please do not ask about this. Check back regularly for link resets or follow peppy on twitter for announcements. Our goal is to get the game on mobile app stores very soon so we don't have to live with this limitation.
Developing a custom ruleset
osu! is designed to allow user-created gameplay variations, called "rulesets". Building one of these allows a developer to harness the power of the osu! beatmap library, game engine, and general UX for a new style of gameplay. 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!
Prerequisites
Please make sure you have the following prerequisites:
- A desktop platform with the .NET 8.0 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 with the EditorConfig and C# Dev Kit plugin installed.
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
From an IDE
You should load the solution via one of the platform-specific .slnf files, rather than the main .sln. This will reduce dependencies and hide platforms that you don't care about. Valid .slnf files are:
osu.Desktop.slnf(most common)osu.Android.slnfosu.iOS.slnf
Run 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 osu! (Tests) project/configuration. More information on this is provided below.
To build for mobile platforms, you will likely need to run sudo dotnet workload restore if you haven't done so previously. This will install Android/iOS tooling required to complete the build.
From CLI
You can also build and run osu! from the command-line with a single command:
dotnet run --project osu.Desktop
When running locally to do any kind of performance testing, make sure to add -c Release to the build command, as the overhead of running with the default Debug configuration can be large (especially when testing with local framework modifications as below).
If the build fails, try to restore NuGet packages with dotnet restore.
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.
Our team believes in human contributions. Any contribution – be it an issue report or a pull request – which is created by, documented by, or aided by AI/LLM usage will typically be closed and locked without further discussion.
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.