Add support for flatpak steam

[EchoEllet]

The location of steam and wallpaper engine is different if we use steam Flatpak version

./linux-wallpaperengine 2804817823
Cannot find workshop directory for steam app 431960 and content 2804817823
terminate called after throwing an instance of 'std::runtime_error'
  what():  Cannot find workshop directory for steam app 431960 and content 2804817823
Aborted (core dumped)
[ahmedhnewa@ahmedhnewas-desktop build]$ ./linux-wallpaperengine /home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960
Cannot find directory for steam app wallpaper_engine: assets
No "scene.pkg" file found at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/scene.pkg". Defaulting to normal folder storage
No "gifscene.pkg" file found at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/gifscene.pkg". Defaulting to normal folder storage
Cannot find "". This folder is required for wallpaper engine to work
terminate called after throwing an instance of 'std::runtime_error'
  what():  Cannot find "". This folder is required for wallpaper engine to work
Aborted (core dumped)
[ahmedhnewa@ahmedhnewas-desktop build]$ ./linux-wallpaperengine /home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553
Cannot find directory for steam app wallpaper_engine: assets
Detected "scene.pkg" file at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/scene.pkg". Adding to list of searchable paths
No "gifscene.pkg" file found at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/gifscene.pkg". Defaulting to normal folder storage
Cannot find "". This folder is required for wallpaper engine to work
terminate called after throwing an instance of 'std::runtime_error'
  what():  Cannot find "". This folder is required for wallpaper engine to work
Aborted (core dumped)
[ahmedhnewa@ahmedhnewas-desktop build]$ ./linux-wallpaperengine /home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/
Cannot find directory for steam app wallpaper_engine: assets
Detected "scene.pkg" file at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/scene.pkg". Adding to list of searchable paths
No "gifscene.pkg" file found at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/gifscene.pkg". Defaulting to normal folder storage
Cannot find "". This folder is required for wallpaper engine to work
terminate called after throwing an instance of 'std::runtime_error'
  what():  Cannot find "". This folder is required for wallpaper engine to work
Aborted (core dumped)

./linux-wallpaperengine /home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/
Cannot find directory for steam app wallpaper_engine: assets
Detected "scene.pkg" file at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/scene.pkg". Adding to list of searchable paths
No "gifscene.pkg" file found at "/home/ahmedhnewa/.var/app/com.valvesoftware.Steam/.local/share/Steam/steamapps/workshop/content/431960/2536545553/gifscene.pkg". Defaulting to normal folder storage
Cannot find "". This folder is required for wallpaper engine to work
terminate called after throwing an instance of 'std::runtime_error'
  what():  Cannot find "". This folder is required for wallpaper engine to work
Aborted (core dumped)

At least add a way to change the default steam library location so everyone can test this project easily

[jabuxas]

having same problem, any fixes?

[EchoEllet]

having same problem, any fixes?

I don't think I have any. The support is dead

We need to forgot about it and move on

[Almamu]

If your steam installation is in a different path, use --assets-dir to change where the app looks for the wallpaper engine assets (right now it only looks for the installation path from repos). This is somewhat related to #177. I'll add the flatpak path to the folder where it looks for the files too.

[MomentQYC]

And snap Steam

[Almamu]

added two commits with snap and flatpak directories. I cannot validate them, but please feel free to re-open this issue if the problem persists after updating to the last version