ProjectM on RetroPie

[appas]

Hi,
I quite like the Milkdrop/ProjectM music visualizer, so I thought it'd be nice to run it from the same Raspberry Pi 3+ as my RetroPie.
First, I compiled projectM on the RetroPie box. Then I compiled the SDL2 Frontend. I then used ChatGPT to build a custom launcher:
Under /home/pi/RetroPie/roms/projectm I created this file by the name of projectm.sh:

#!/bin/bash
xrandr -s 1920x1080
sudo xinit /usr/local/bin/projectm-sdl2 --width 1920 --height 1080 --presetPath /home/pi/presets-cream-of-the-crop-master -- -f

Then in /etc/emulationstation/es_systems.cfg I put

<system>
  <name>projectm</name>
  <fullname>projectm</fullname>
  <path>/home/pi/RetroPie/roms/projectm</path>
  <extension>.sh .SH</extension>
  <command>/bin/bash %ROM%</command>
  <platform>projectm</platform>
  <theme>projectm</theme>
</system>

As part of the systemlist element.

Then under /etc/emulationstation/themes/projectm add the file theme.xml with the contents

<theme>
  <systemView>
    <image>art/systems/projectm.svg</image>
    <textColor>#FFFFFF</textColor>
  </systemView>
  <homeMenu>
    <image>art/screens/projectm.svg</image>
    <textColor>#FFFFFF</textColor>
  </homeMenu>
</theme>

I needed to put the projectm.svg in

/etc/emulationstation/themes/carbon-2021/art/systems/projectm.svg
/etc/emulationstation/themes/carbon-2021/art/controllers/projectm.svg

so that it was picked up correctly.

After that, I have a ProjectM entry in my EmulationStation. There is 1 "game" under it, which launches the projectM SDL2 Frontend. It works - but it's very slow.

I remember running MilkDrop full framerate on lesser hardware, so if anyone could help me speed up the visualizer, that'd be great. I think it has to do with the GL driver: I built projectM with GL ES enabled, but I have the "Legacy" GL Driver selected, because EmulationStation won't start with either the "Fake" or the "Full" GL Driver. See here: https://retropie.org.uk/forum/topic/33764/unable-to-start-emulationstation/2?_=1673488951007

I tried installing xserver-xorg-video-fbturbo to get accelerated framebuffers, but it's still slow.
How can I get a GL driver and still be able to use EmulationStation?

[appas]

@appas
Here are a few images to show the progress so far.

Never mind the source text glitching on top of the menu; that's an artifact of raspi2png which I'm using to take screenshots, and it doesn't actually look like that.