Guard OpenGL mode on native Wayland

MainForm.pas

@@ -35,6 +35,7 @@ uses
   CATEngine, CATSerial, CATTcp,
   SpectrumView, SpectrumViewOpengl,
   StatusBar,
+  PlatformUtils,
   WinFirewall;
 
 const
@@ -1469,6 +1470,22 @@ begin
   FSplitterDrag  := False;
 
   FUseOpenGLSpectrum := HasOpenGLSpectrumSwitch;
+  if FUseOpenGLSpectrum and (not QtPlatformAllowsOpenGLControls) then
+  begin
+    MessageDlg('OpenGL rendering disabled',
+      'OpenGL rendering is not available in the current Qt Wayland mode.' + LineEnding +
+      LineEnding +
+      'The Lazarus/LCL Qt6 OpenGL control used by EWSDR requires an X11 display handle, ' +
+      'but the native Wayland backend does not provide one. Using it here can cause an access violation during startup.' +
+      LineEnding +
+      LineEnding +
+      'To run EWSDR with OpenGL rendering, start it through XWayland:' + LineEnding +
+      'QT_QPA_PLATFORM=xcb ./ewsdr --opengl' + LineEnding +
+      LineEnding +
+      'OpenGL rendering will be disabled for this session.',
+      mtWarning, [mbOK], 0);
+    FUseOpenGLSpectrum := False;
+  end;
   if FUseOpenGLSpectrum then
     FWaterfallFrameInterval := 1;
   if FUseOpenGLSpectrum then

PlatformUtils.pas

@@ -0,0 +1,42 @@
+unit PlatformUtils;
+
+{
+  PlatformUtils.pas - small helpers for desktop/runtime platform checks.
+}
+
+{$IFDEF FPC}
+  {$MODE Delphi}
+{$ENDIF}
+
+interface
+
+function QtPlatformAllowsOpenGLControls: Boolean;
+
+implementation
+
+uses
+  SysUtils;
+
+function QtPlatformAllowsOpenGLControls: Boolean;
+var
+  Qpa, FirstQpa, SessionType: string;
+  Sep: Integer;
+begin
+  Result := True;
+  Qpa := LowerCase(Trim(GetEnvironmentVariable('QT_QPA_PLATFORM')));
+  SessionType := LowerCase(Trim(GetEnvironmentVariable('XDG_SESSION_TYPE')));
+
+  if Qpa <> '' then
+  begin
+    FirstQpa := Qpa;
+    Sep := Pos(';', FirstQpa);
+    if Sep > 0 then
+      FirstQpa := Copy(FirstQpa, 1, Sep - 1);
+    Result := FirstQpa <> 'wayland';
+    Exit;
+  end;
+
+  Result := SessionType <> 'wayland';
+end;
+
+end.

ewsdr.lpi

@@ -210,6 +210,10 @@
         <Filename Value="SpectrumView.pas"/>
         <IsPartOfProject Value="True"/>
       </Unit>
+      <Unit>
+        <Filename Value="PlatformUtils.pas"/>
+        <IsPartOfProject Value="True"/>
+      </Unit>
       <Unit>
         <Filename Value="SpectrumViewOpengl.pas"/>
         <IsPartOfProject Value="True"/>