|Source code:||Closed source|
Cemu is a closed-source Wii U emulator for Windows. System requirements are pretty high if you want games to run at full speed, although there are numerous bugs that can crash games due to unimplemented features. It emulates the GamePad, Classic, and Pro controllers. A compatibility list can be found here.
Before updates are publicly released, they're accessible to backers over at their Patreon.
You will also need enough storage for the Wii U games. Running Cemu on WINE has been reported to work just as well as Windows.
- Windows 7 (64-bit)
- Graphics Card: Supports at least OpenGL 4.0
- Memory: 4 GB
- Windows 10 (64-bit)
- Graphics Card: Supports OpenGL 4.0 or newer (avoid integrated graphics)
- Memory: 6 GB or more
Cemu's directory needs proper values in the "keys.txt" file. The example line can be deleted.
You need yours to have many lines like this; one for the Wii U Common Key, and one line each for Game Keys. Note that for games that use the Loadiine format, you don't need a Game Key at all, only the latest version of Cemu.
Formats supported are uncompressed, WUD compressed, and Loadiine ISOs.
CEMU can read binary dumps from NFC tags by going to NFC -> Scan NFC Tag from file. Support is incomplete, and not all figurines may be compatible yet due to potentially bad reads.
The Wiimote still isn't emulated yet, but you can have up to 8 GamePads set in the menu.
Wii U GamePad bindings:
- Touch Controls: Mouse left click.
- Tilting and Gyro Controls: Holding the mouse right-click and dragging. It's lacking Z-axis key binding at the moment.
- Switch Screens between TV and GamePad: "TAB" key, "Ctrl+TAB" to keep focus. TV by default.
- Microphone: Spoofed, a configurable key simulates blowing on the mic.
Cemu cannot go online or connect to a real (or emulated) 3DS.
Shaders are normally cached as you play the game. This can cause a lot of stutter and slow the game down.
Cemu accepts other shader caches that can be traded online. You can go to /r/CEMUcaches and search for the ones you want. It's often very difficult to generate a complete cache for large games, and will not completely eliminate stuttering.
Some games' transferable caches may cause slowdowns on some graphics cards like the GeForce GTX 970. If this is the case, you will have to generate your own shaders and delete the ones you downloaded. In the case of the GeForce, also consider deleting the .bin and /toc file in your GLCache at
Native H.264 Decoder
MP4 videos are often encoded for Wii U games with the expectation that the hardware plays it back on-the-fly, but because the x86 architecture is not PowerPC, this is resource-intensive for Cemu since it has to run the PowerPC video decoder. An unofficial utility called CEMUhook bypasses this by playing H.264 video directly from Windows codecs that are programmed for x86.
Cemu may not be programmed well with hyperthreading. To disable it, go into the Task Manager, right click cemu.exe and then set these affinities:
To work around emulation bugs and other problems the way Dolphin does, "Graphic Packs" are title-specific property sheets which defines advanced settings you might not be able to change in the interface. Basic rendering options including shadow resolution and quality, post-processing effects like bloom, lighting and godrays, custom anti-aliasing, and such can be applied here. You can even use them to reduce the internal resolution for an increase in the framerate. This is not to be confused with Texture Packs, which are replacement textures; CEMU doesn't support that, but it is planned.
The "Graphic Packs" themselves are folders under the
graphicPacks directory. They can be named anything, but they should contain the "
rules.txt" file. A bare-bones example of a "Graphics Pack", called "Bayo_1080p", would look like this:
[Definition] titleIds = 0005000010172600,0005000010172700,000500001011b900,000500001014db00,0005000010157e00,0005000010157f00 name = "Bayonetta 1 + 2 - 1080p" [TextureRedefine] width = 1280 height = 720 overwriteWidth = 1920 overwriteHeight = 1080
Whenever the titleId matches the current one, Cemu will show the Graphics Pack under Options -> Graphics Pack. If you don't know what the titleId of the game you want is, check the
logs.txt file. You can safely delete it in the event that it gets too big for a text editor to parse.
The overwriteWidth and overwriteHeight properties used in this example will upscale the game from 720p to 1080p. But if the game doesn't have all of its textures in the specified resolution, they won't be upscaled and could look messy as a result. In this case, this problem is seen in some FMVs in the game. This is the purpose of the TextureRedefine rule.
See some of the community graphics packs at this page.
- Save states aren't getting implemented any time soon. This has a lot to do with the complexity of the Wii U memory layout and architecture, as well as the huge file size. As a result, the current developers are not interested in implementing them.
- The emulator is still unfinished and unoptimised, as noted in the lack of efficient and stable H.264 video decoding, causing glitchy videos. This is worked around with Cemuhook entirely, but its approach to video decoding is unlikely to be taken into the emulator.
There are anti-piracy measures on the Patreon early-access builds that are put behind the $5 tier. Backers putting out these builds can get banned if they're caught, and when the program fails verification, it locks down some features that impact performance.
Until 1.7.5 was released, one developer from Team Cemu, mudlord, spun off the project out of creative differences with the team, and in protest he put out cracked versions of early builds on his personal blog. These were also used to expose people breaching licenses for other emulators. A subreddit and Discord server was made to discuss Cemu piracy.
The official subreddit for Cemu advises against downloading unofficial "builds", saying they could be traced with malware, and it is part of their rules not to counterargue. The Cemu piracy subreddit has encountered malware authors taking advantage of this.