Geant4 Qt Issues

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1

Hi,
I have been trying to get geant4 to work with Qt enabled (on wayland system). I am using the following shell:

{ pkgs ? import (fetchTarball "https://github.com/NixOS/nixpkgs/tarball/nixos-24.05") { } }:
let 
  geant4WithQt = pkgs.geant4.override {
      enableQt = true;
  };
in
pkgs.mkShellNoCC {
  packages = [
  pkgs.libsForQt5.full geant4WithQt pkgs.geant4.data.G4NDL pkgs.geant4.data.G4EMLOW pkgs.geant4.data.G4PhotonEvaporation pkgs.geant4.data.G4RadioactiveDecay pkgs.geant4.data.G4SAIDDATA pkgs.geant4.data.G4PARTICLEXS pkgs.geant4.data.G4ABLA pkgs.geant4.data.G4INCL pkgs.geant4.data.G4PII pkgs.geant4.data.G4ENSDFSTATE pkgs.geant4.data.G4RealSurface pkgs.geant4.data.G4TENDL ];
}

When I build and run example B1, I get the Qt viewer, but with a window that just shows my background:

2024-09-16T10:21:32,390470089-04:00
2024-09-16T10:21:32,390470089-04:001917×1037 200 KB

Prior to including Qt, I was able to see the viewer (but obviously not able to interact). Does anyone have any idea why this is happening? Also, if there is a better way to run geant4 with the datasets and qt included, I would suggestions.
Thanks!

2

The following shell.nix works:

{ pkgs ? import <nixpkgs> {} }:
let geant4WithQt = pkgs.geant4.override {
  enableQt = true;
};
in
pkgs.mkShell {
    buildInputs = [
      geant4WithQt
      pkgs.libsForQt5.full
      pkgs.geant4.data.G4ABLA
      pkgs.geant4.data.G4INCL 
      pkgs.geant4.data.G4PhotonEvaporation
      pkgs.geant4.data.G4RealSurface
      pkgs.geant4.data.G4EMLOW
      pkgs.geant4.data.G4NDL
      pkgs.geant4.data.G4PII
      pkgs.geant4.data.G4SAIDDATA
      pkgs.geant4.data.G4ENSDFSTATE
      pkgs.geant4.data.G4PARTICLEXS
      pkgs.geant4.data.G4RadioactiveDecay
    ];
    shellHook = ''
      export QT_QPA_PLATFORM="xcb"
    '';
}

Note the inclusion of the shellHook to set the QT_QPA_PLATFORM variable to xcb. This appears to be what fixes the previous issue.