BetterVR is a VR mod/hook that adds a PC-VR mode for BotW using the Wii U emulator called Cemu.
It currently supports the following features:
- Fully stereo-rendered with 6DOF, with full roomscale support. No alternated eye rendering is used.
- Full hands and arms support. You can deck yourself out in all the fanciest clothes.
- Wield weapons, torches and bokoblin arms into combat.
- Gestures to equip and throw weapons.
- Use motion controls to interact with the world to solve puzzles or start fires.
- Large mod compatibility. BetterVR only modifies the code and no game data. Most other mods should be compatible.
- Optional third-person mode.
Requirements
Supported VR headsets:
The app currently utilizes OpenXR, which is supported on all the major headsets (Valve Index, HTC Vive, Oculus Rift, Meta Quest,
Windows Mixed Reality etc.). However, controller bindings are currently only provided for Oculus Touch controllers.
While more integrated solutions are being found out, there's probably ways to setup OpenXR mappings through SteamVR or other applications.
Other Requirements:
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A gaming PC with a CPU that is good at single-threaded workloads (a recent Intel i5 or Ryzen 5 are recommended at least)! The GPU matters a bit, but the CPU is the bottleneck here.
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A legal copy of BotW for the Wii U.
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Windows OS. It doesn't work under Linux (even with Wine/Proton) for now.
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A properly set up Cemu emulator that's able to run at 60FPS or higher. See this guide for more info.
- Before reporting issues, make sure that you have a WORKING version of the game that can go in-game on your PC before you install this mod!
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A recent Cemu version. Only Cemu 2.6 is tested to work.
Current Limitations & Known Issues
- There's a small chance that the screen stays black after exiting any menus, which requires restarting the game to continue.
- Climbing ladders require jumping up the ladder to go up and you have to look at the ladder.
- You can get stuck behind ladders sometimes, especially when you stop moving at the very top of the ladder while climbing down. So keep moving at the start!
- It'll lack some comfort options for now, like a left-handed mode
or snap turning (added).
Mod Installation
[!TIP]
Meta/Oculus Link has terrible frame interpolation that will make game appear to run much worse while also making the grass and arms glitchy, even while using a cable.
Its HIGHLY recommended to use ALVR (free, both wired and wireless), Virtual Desktop (paid, wireless, most performant) or Steam Link (free, wireless) instead for Meta Quest headsets.
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Download the latest BetterVR_Launcher.exe release from the Releases page.
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Move BetterVR_Launcher.exe into the same folder as Cemu.exe.
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Modify the general Cemu settings first by launching the Cemu.exe and looking for the following things.
- Cemu's window title says your Cemu is version 2.6 or newer.
- Breath of the Wild is inside your game list, and lists update
V208 in the update column.
- Go to
Debug -> Accurate Barriers (Vulkan) and make sure it is disabled for better performance.
- Go to
Options -> General Settings -> Graphics. Make sure that the Renderer is set to Vulkan, that the correct GPU is selected, and VSync is off. Close the settings window.
- Go to
Options -> Graphic Packs and click the Download Community Graphic Packs button to make sure that your graphic packs are up to date.
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Close Cemu, connect your VR headset to your PC, start Virtual Desktop, SteamVR and and make sure that it has its OpenXR runtime set properly:
- For Virtual Desktop users: https://github.com/mbucchia/VirtualDesktop-OpenXR/wiki#download--installation
- For SteamVR, ALVR and Meta Quest Link users: https://academy.vrex.no/knowledge-base/openxr/
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Run BetterVR by using the BetterVR_Launcher.exe, then go to Options -> Graphic packs -> The Legend of Zelda: Breath of the Wild and make sure:
BetterVR is enabled.Mods -> FPS++ is enabled. The game will crash without it.
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Besides those, there's some other recommended graphic pack settings to make your game run properly and look better in VR:
Graphics:
- Set the VR Resolution Multiplier to change the resolution of the game when you're in VR. The mod is not very GPU intensive, so using a higher multiplier might not cost any performance.
- Set the Anti-Aliasing to
Nvidia FXAA or None (if you are using 2x resolution multiplier or higher).
- Use the optional recording mode above the VR Resolution Multiplier to render pixels outside of your VR headset's field-of-view to fit a 16:9 aspect ratio.
FPS++: Set the FPS limit to at least 120 or 144. Your headset/runtime will still control the actual VR framerate.Enhancements: Set anisotropic filtering to 16x, and optionally set a Clarity preset to make the colors less washed out.
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[Optional] To avoid some heavy stutters when you first start the game, download the shader caches from https://chriztr.github.io/cemu_shader_and_pipeline_caches/ and follow the How to install the caches section on that page.
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Double click the game in Cemu's game list while your VR headset is turned on and connected. If things went correctly, you should now be playing the game in VR!
Use the in-game BetterVR menu to see the BetterVR settings and controls guide (hold the X or equivalent button on your left VR controller, or long press the Menu button on your Xbox controller).
In the settings you can also enable an option to immediately start the game when you start the BetterVR_Launcher.exe. You can also add this executable to Virtual Desktop, SteamVR etc. as a non-official Steam game.
Troubleshooting
Here's some steps to help you debug issues when the game fails to launch:
- Verify that you've got a working game copy. Use Cemu.exe and launch the game normally. If you can load the game normally, it should work.
- Make sure that if you're using a laptop, both your integrated graphics card and your dedicated graphics card drivers are updated. Make sure that its also plugged into a wall outlet and that its NOT using a power saving setting.
- Unfortunately, some older AMD GPUs might have issues. See contact options below to help us squash these.
- Uninstall any Vulkan overlays or layers that might cause issues. Programs like Overwolf, RTSS and other things CAN cause issues, though certainly not guaranteed.
- Go over all the installation steps one more time and make sure that you didn't diverge from any of the steps. If you're seeing a green screen, it means that the Vulkan layer isn't enabled. This is likely due to using OpenGL in Cemu's settings.
- If Cemu shows a Vulkan error like -13, these issues are likely GPU driver related.
If none of these steps helped, check the BotW support channel on the Flat2VR Discord server (recommended) or make a GitHub issue. Me and other people will try to help you in our spare time.
Controls
You can now view the controls in-game now by opening the BetterVR menu by holding the X button on your left VR controller.
With Valve Index Controllers you can use the A button.
For Xbox/Playstation etc. controllers, long press the Start button and use the mouse for changing settings.
You can find the controller image here (click to enlarge):
Technical Overview
Rendering an image to the VR headset
This mod ships with no game files, so you might ask how it works.
The game starts with the BetterVR Vulkan layer enabled. The Vulkan layer, which comes in the form of the .DLL file, is then able to intercept the Vulkan commands that Cemu submits so that we can get the final frame to render to the VR headset and draw the debugging tools.
A technical hurdle here was that due to OpenXR frameworks not being designed to be instantiated inside something that is intercepting Vulkan commands, this mod utilizes Vulkan <-> D3D12 interop to pipe the rendered output from Vulkan to a D3D12 application that's just used for rendering the captured image to the VR headset. That way the OpenXR framework is just interacting with root-level rendering handles, instead of what'd occur in the Vulkan hook.
Using an external DLL originally made a lot of sense when Cemu wasn't open-sourced (though it also makes it slightly less tied to a specific emulator or version of Cemu, and prevents a VR specific version of Cemu that'll quickly become outdated). In hindsight, it probably would've saved a lot of time spent trying to get the mod to work without using D3D12.
How to make it VR
However, while drawing the game's rendered output to the VR headset is one thing, getting a native game to render a 3D image is a whole other thing. For that, the mod has a bunch of PowerPC assembly patches (the Wii U has a PowerPC CPU) to modify the game's code. For example, an important patch is to make it so that the game renders two frames before updating all of the game's systems and objects that are on-screen. Then, among many other patches, you'll also find patches that change the camera or player model positions each frame, or trigger an attack.
Usually the assembly code will call into the C++ code if it wants to do complicated algebra to specify where the camera or Link's hands should be for example. And some assembly patches use a clearing instruction for the Wii U's GPU which, after being translated, will signal the Vulkan hook to send the almost-finished final game image to the D3D12 code where it can present it inside the VR headset.
Additionally, since combat is a large part of the original game, there's also a new swing and stab detection system that allows the player to cut trees and enemies down when they execute proper swings and stabbing motions. This prevents a situation where weapon hitboxes are abused to instantly stagger an enemy. There's plans for an even deeper integration, but as of today that's about it. This is fully optional since the mod still features an attack button, but the latter will offer a lot more immersion.
Understanding how the game works, finding and patching the exact parts inside the game's executable is by far the most difficult part and it took thousands of hours of reverse-engineering. Its without a doubt the most time consuming task of this VR mod, especially since this game uses a custom C++ engine of which is not much known about other then the good work of the (largely unfinished, but still very helpful) decompilation project.
If you want to know more about the technical details, feel free to ask in the BetterVR related channels in the Flat2VR Discord server.
There's enough that was skipped over or left out in this explanation.
Build Instructions (For Developers)
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Install the latest Vulkan SDK from https://vulkan.lunarg.com/sdk/home#windows and make sure that VULKAN_SDK was added
to your environment variables.
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Install vcpkg (make sure to run the bootstrap and install commands it mentions) and use the following command to install the required dependencies:
vcpkg install openxr-loader:x64-windows-static-md glm:x64-windows-static-md vulkan-headers:x64-windows-static-md imgui:x64-windows-static-md
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Change the CMakeUserPresets.json file to contain the directory where you've stored vcpkg. Its currently hardcoded.
If you want to use Meta XR Simulator (which is quite helpful during debugging), you should change its path now too.
Meta XR Simulator doesn't work unless you edit the [install folder]/config/sim_core_configuration.json file from "disable_interop": false, to "disable_interop": true,.
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[Optional] Download and extract a new Cemu installation to the Cemu folder that's included.
This step is technically not required, but it's the default install location and makes debugging much easier.
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Use Visual Studio (Recommended) or Clion to open the CMake project. Make sure that it's compiling a x64 build.
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For direct Visual Studio debugging, its recommended that instead of launching the BetterVR_Launcher, you set-up a launch.vs.json that launches Cemu.exe with the .dll loaded.
Once the CMake project is open in VS (make sure its not ran as admin), go to Debug->Debug and Launch Settings for BetterVR_Layer.
With that open, copy the configuration from launch.vs.json and replace the placeholder paths.
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If step 6 doesn't work, you can also just launch the BetterVR_Project by debugging the BetterVR_Launcher target (make sure to pick the Install option). You might have to manually attach or install a multi-process debugging extension.
Credits
Crementif: Main Developer
Acudofy: Sword & stab analysis system
Holydh: Developed the input systems
leoetlino: For the BotW Decomp project, which was very useful
Exzap: Technical support and optimization help
Mako Marci: Edited the trailer, made the logo and controller guide
Tim, Mako Marci, Solarwolf07, Elliott Tate & Derra: Helped with testing, recording, feedback and support
Licenses
This project is licensed under the MIT license.
BetterVR also uses the following libraries:
- vkroots (MIT licensed)
- imgui (MIT licensed)
- ImPlot (MIT licensed)
Crementif/BotW-BetterVR