A Nintendo DS and DSi emulator for Android, built on top of melonDS and the melonDS Android port by rafaelvcaetano.

WatermelonDS is a fork that keeps up with upstream while adding RetroAchievements (including offline play), a Vulkan renderer, RetroArch shader presets and full external display support, wrapped in its own visual identity.

Everything from the upstream Android port, plus:

• Achievements, leaderboards and Hardcore mode, with a shared card style for the in-game popups
• Your profile and score are shown on load and in the settings screen
• Offline play: unlocks earned without a connection are stored and submitted later. Two providers are available the one built into WatermelonDS, or RAOfflineProxy if you prefer to run it yourself. Note that RAOfflineProxy does not support Hardcore mode
• Achievements can be disabled without logging out, and sessions start even for games that have no achievement set

• Software, OpenGL, Vulkan and compute renderers, with internal resolution scaling
• Vulkan gained a fastpath presentation profile, optimized texture uploads and dynamic scissor clipping
• RetroArch shader presets on every renderer, through librashader
• Adrenotools driver support on the gitHub flavor, for custom Adreno drivers

• Play on a second screen (TV, dock, devices such as the Odin 2), with the touch screen still usable on the handheld
• Per-ROM external screen and layout settings, screen rotation, backgrounds, video filtering and aspect ratio control
• Achievements are shown on the external display while you browse your ROM list

• DSiWare titles in the ROM list, box art on the "continue" shelf, and custom ROM names
• Layout editor with screen transparency, aspect ratio options and separate centering controls
• Settings backup and restore (requires a restart to apply), with internal and external layouts backed up separately
• Alternate input bindings and a hold-to-fast-forward button

The core is kept in sync with melonDS 1.0 and later upstream changes.

• Local Multiplayer
• DSi SD card support
• Customizable button skins

Performance is solid on 64 bit devices with thread rendering and JIT enabled, and should run at full speed on flagship devices. Performance on older devices, specially 32 bit devices, is very poor due to the lack of JIT support.

It's possible to launch WatermelonDS from third party frontends. For that, you will need to have the ROMs you want to launch already scanned by WatermelonDS. Then, you can configure your third-party frontend with the following configuration:

• Package name: me.magnum.melondualds (nightly builds use me.magnum.melondualds.nightly)
• Activity name: me.magnum.melonds.ui.emulator.EmulatorActivity
• Parameters (choose one):
  • Intent data (preferred) - a URI of the NDS ROM (ZIP and 7z files are supported). Ensure read permission is granted
  • uri (deprecated) - a string with the SAF URI of the NDS ROM (ZIP and 7z files are supported)
  • PATH (deprecated) - a string with the absolute path to the NDS ROM (ZIP and 7z files are supported)

When launching ROMs from third-party frontends, if WatermelonDS hasn't scanned that particular ROM previously, it won't be able to create the save file next to the ROM file if the option "Save next to ROM file" is enabled in the settings or the save file directory is not set. Instead, WatermelonDS will create a save file in Android/data/me.magnum.melondualds/files/saves

Builds are published here. Release candidates are marked as pre-releases; they can contain more bugs than usual and you may need to clear your app data to get them to work properly after an update.

To build the project you will need the Android SDK, NDK, CMake, a JDK 21 toolchain and a Rust toolchain (cargo and rustup), which is used to build librashader for each ABI.

1. Clone the project, including submodules with:

   git clone --recurse-submodules https://github.com/SapphireRhodonite/melonDS-android.git

2. Install the Android SDK, NDK (28.0.13004108) and CMake

3. Install Rust with rustup. If Android Studio does not inherit your shell PATH, set the CARGO and RUSTUP environment variables to the executable paths

4. Build with:

   1. Unix: ./gradlew :app:assembleGitHubProdDebug
   2. Windows: gradlew.bat :app:assembleGitHubProdDebug

5. The generated APK can be found at app/build/outputs/apk/gitHubProd/debug

There are two flavor dimensions, so build tasks combine both: gitHub or playStore (the former enables adrenotools) and prod or nightly. For example, :app:assembleGitHubNightlyDebug or :app:assembleGitHubProdRelease.

If you want to create a release build, you will need to modify your local.properties file to include the following fields:

• MELONDS_KEYSTORE=<path_to_your_keystore>
• MELONDS_KEYSTORE_PASSWORD=<keystore_password>
• MELONDS_KEY_ALIAS=<name_of_your_key_alias>
• MELONDS_KEY_PASSWORD=<key_alias_password>

• melonDS by Arisotura and contributors — the emulator core
• melonDS Android by rafaelvcaetano
• librashader — RetroArch shader preset support
• rcheevos — RetroAchievements support