create .desktop file, pass parameters to hl2_launcher

build.nix

@@ -1,16 +1,46 @@
 { callPackage
 , symlinkJoin
+, fetchurl
+, makeDesktopItem
+, copyDesktopItems
 , hl2-unwrapped ? callPackage ./hl2-unwrapped.nix { }
 , hl2-wrapper ? callPackage ./hl2-wrapper.nix { inherit hl2-unwrapped; }
 }:
 
-symlinkJoin {
+let
   name = "hl2";
 
+  icon = fetchurl {
+    url = "https://upload.wikimedia.org/wikipedia/commons/1/14/Half-Life_2_Logo.svg";
+    hash = "sha256-/4GlYVAUSZiK7eLjM/HymcGphk5s2uCPOQuB1XOstuI=";
+  };
+in
+symlinkJoin rec{
+  inherit name;
+
   paths = [ 
     hl2-unwrapped
     hl2-wrapper
+  ] ++ desktopItems;
+
+  nativeBuildInputs = [
+    copyDesktopItems
   ];
 
-  postBuild = "ln -s $out/bin/hl2-wrapper $out/bin/hl2";
+  postBuild = ''
+    ln -s $out/bin/hl2-wrapper $out/bin/${name}
+
+    install -Dm444 ${icon} $out/share/icons/hicolor/scalable/apps/${name}.svg
+  '';
+
+  desktopItems = [
+    (makeDesktopItem {
+      name = "${name}";
+      exec = "${name}";
+      icon = "${name}";
+      desktopName = "Half-Life 2";
+      comment = "Built from the leaked source code";
+      categories = [ "Game" ];
+    })
+  ];
 }

hl2-unwrapped.nix

@@ -43,6 +43,6 @@ stdenv.mkDerivation {
   wafConfigureFlags = [
     "-T fastnative"
     "--disable-warns"
-    "--build-flags=-Wno-error=format-security,-O3"
+    "--build-flags=-Wno-error=format-security"
   ] ++ extraWafConfigureFlags;
 }

hl2-wrapper.nix

@@ -53,6 +53,10 @@ writeShellScriptBin "hl2-wrapper" ''
         resource_path="$2"
 	shift 2
         ;;
+      -p | --parameters)	# Sets parameters passed to hl2 launcher (encapsulated with quotes)
+        launcher_parameters="$2"
+        shift 2
+        ;;
       --impermanent) 		# Don't save newly created files that are not in symlimked folders (you probably don't want to use this)
         impermanent=true
 	shift 1
@@ -101,5 +105,5 @@ writeShellScriptBin "hl2-wrapper" ''
 
   trap cleanup EXIT
 
-  ( cd $tmp_dir ; ./hl2_launcher )
+  ( cd $tmp_dir ; ./hl2_launcher $launcher_parameters )
 ''