In Development – RetroArch ANGLE support – OpenGL support for UWP and more

Libretro Team

ANGLE is middleware developed by Google that serves as an OpenGL compatibility layer on systems where OpenGL support is either spotty or missing entirely. It converts OpenGL calls to Direct3D 9/11.

In this video, you will see ANGLE being used on RetroArch UWP. In specific, it allows us to run OpenGL cores now on the Xbox One, where only Direct3D 11/12 are available as graphics APIs. Mupen64plus Next is shown running in this video on an Xbox One S with fairly acceptable results.

Will this be ready for the next version?

We don’t know yet if this will make it for version 1.8.2.

Let us tell you though what this will entail in the future –

  • There will likely be two binaries from now on for the desktop Win32 Windows version – one with ANGLE, one without. The non-ANGLE version will use your system-provided OpenGL driver, while the ANGLE version will use the ANGLE version of the OpenGL dynamic libraries.
  • ANGLE works over OpenGL ES. This means that ANGLE requires separately compiled cores targeting OpenGL ES 2/3 instead of desktop OpenGL. What this means is that 1) we need separate cores since the current OpenGL cores available for Windows assume that desktop OpenGL will be targeted, and 2) a libretro core has to have a working OpenGL ES 2 or 3 implementation in order for it to work. This will mean that currently, cores like Quake 2/3/Doom 3 won’t work since there are no working OpenGL ES 2 codepaths in those cores. However, Mupen64plus Next and Flycast do have OpenGLES 2 codepaths.

What usecases are there for using ANGLE instead of regular OpenGL?

There are several scenarios imaginable where you would want to use ANGLE. Here are some of them –

  • UWP (shorthand for Universal Windows Platform) allows you to make one binary that will work on Windows Mobile 10, Windows 10 and Xbox One. The only graphics API available for UWP programs is Direct3D 11 or 12. So for OpenGL cores to work, a middleware layer like ANGLE which converts OpenGL to Direct3D is our only option. Therefore, ANGLE allows us to run OpenGL ES 2 cores on the Xbox One.
  • Certain graphics cards might have nonexistent OpenGL support on Windows 10 and therefore fall back to Microsoft’s reference OpenGL 1.1 drivers. This is pretty much the worst case imaginable and really limits what you can do with OpenGL on such graphics cards. Intel HD 2000/3000 series integrated GPUs are pretty much in this position. For such GPUs, ANGLE might be your only option to get any kind of acceptable level of hardware accelerated graphics support with openGL-based cores.
  • OpenGL driver support might be stagnating for certain graphics cards, and therefore several bugs go unresolved in their OpenGL driver implementations. ANGLE is a good way to work around that assuming you are OK with an OpenGL ES 2/3 feature set.

We will fill you in as things develop how ANGLE will fit into RetroArch’s future releases. For now, the path seems clear – separate core versions for the emulators that have viable OpenGL ES 2/3 codepaths, and separate binaries at least on Windows desktop for an ANGLE-enabled and non-ANGLE enabled version. The redist (redistributable) will also need to be updated to include the extra dynamic library dependencies.

RetroArch 1.8.2 – Accessibility features for blind people

Libretro Team

RetroArch singlehandedly takes big strides to cater to an underrepresented group of people, opening up a whole new world of entertainment.

See here the perspective of a blind person talking about the new accessibility features available in the latest nightly versions of RetroArch. This and more will be available out of the box starting as of version 1.8.2.

Also read our version 1.8.2 release announcement post here.

Written by Devin Prater, Certified Assistive technology instructor
Edits by Barry Rowe, AI Service and Accessibility contributor

Background

For decades, video games have offered entertainment for many people. Childhoods were changed by iconic franchises like Super Mario, Zelda, Final Fantasy, and Castlevania. People can reasonably count on others to understand the meaning behind video game references.

For people who are blind, however, these games could only be enjoyed through their great music, or by reading novelizations or fanfiction. Audio games have been created, to fill the void of video games which could not be played, an some blind people braved fighting games by memorizing menus and special attacks, but audio games were few in number, and didn’t usually have much content.

Emulation

Emulation has helped many people who are blind relive their childhood playing fighting games. With the rise of machine learning, however, blind gamers now have another tool in their arsenal: optical character recognition, the extracting of text from images. With this being a part of many screen readers, blind people could use that to read menus, character select screens, and unspoken dialog.

RetroArch

RetroArch is the first “emulator” to now offer Accessibility to blind people by speaking the interface. Along with the text-to-speech AI service, RetroArch has not only become the first emulator to implement accessibility for blind people in menus, but also in reading game text as well.

This doesn’t, however, mean that all games are accessible. A blind person still cannot get Super mario into the castle in Super Mario 64, nor defeat Lavos in Chrono Trigger, although perhaps one could probably play Radical Dreamers now. Much more work will be needed to make video games completely accessible to blind people, even portraying health bars in fighting games through sound cues. Even so, the accessibility of RetroArch means that blind users of Windows, MacOS, and Linux can enjoy the state of the art in video game accessibility through emulation.

How to enable accessibility

Once you’ve downloaded and installed RetroArch, there are two ways to enabled accessibility. The first way is by turning it on via the menu. Once RetroArch is started press: right, then up seven times, then enter (on some systems this could be the x key), and then right. You should hear “Accessibility Accessibility Enable ON” at this point. If this doesn’t, restart RetroArch and try again. This method navigates the menu, which may change in later versions, so you should read the RetroArch Accessibility Docs for any updated key presses.

The second method is to enable it via the command line. This is done by running the RetroArch executable (for example: retroarch.exe) in the command line or terminal. On windows for instance, once you’ve opened the command line, navigate to the RetroArch folder, and run “retroarch.exe –accessibility” and you should hear “RetroArch Accessibility On. Main Menu Load Core.” From there you can navigate right to the settings submenu, and then down to the Accessibility option, and then turn set Accessibility Enable on. Now you’ll be able to start RetroArch with accessibility from outside the command line as usual.

If these options don’t work for you, it could be that your OS does not have the required speech libraries or voices that RetroArch needs. For windows, RetroArch uses the Windows Narrator, which you can read how to download additional voices for here. On MacOS, it uses the “say” command, which you can read how to download voices for here. And on Linux it uses Espeak. For Ubuntu, you can install espeak by running “sudo apt-get install espeak” and then “sudo apt-get install espeak-data” for the additional voices.

Using the AI Service with Accessibility

The AI Service can also use the Accessibility narrator for Text-to-Speech. This can be done by going to the AI Service settings section, and changing the AI Service Output to “Narrator Mode.” This handles the Text-To-Speech, but the AI Service still needs to process the game screen to get that text. You can follow the setup instructions for the AI Service here.

Conclusion

While people without disabilities have been able to play thousands of video games, both current and past, blind people have not had the ability to enjoy more than a handful of video games. Through
emulation, this is beginning to change. Games which were once only playable if one could memorize menus and selection screens are becoming accessible using OCR, and more will be possible through the hard work of developers who may build upon this foundation for accessible video game emulation.

RetroArch is the first emulation center to provide accessibility for the user interface, and an AI service to perform OCR on video games, allowing blind users of all three major desktop operating systems to enjoy playing fighting games now with knowledge of any text that appears onscreen. It is hoped that this is only the beginning of a great advancement in accessibility, with RetroArch paving the way to even greater video game accessibility for people who are blind.