ballerburg: include desktop file and icon

pkgs/games/ballerburg/default.nix

@@ -1,6 +1,14 @@
-{ lib, stdenv, fetchurl, cmake, SDL }:
+{ lib, stdenv, fetchurl, cmake, SDL, makeDesktopItem, copyDesktopItems
+, imagemagick }:
 
-stdenv.mkDerivation rec {
+let
+
+  icon = fetchurl {
+    url = "https://baller.tuxfamily.org/king.png";
+    sha256 = "1xq2h87s648wjpjl72ds3xnnk2jp8ghbkhjzh2g4hpkq2zdz90hy";
+  };
+
+in stdenv.mkDerivation rec {
   pname = "ballerburg";
   version = "1.2.0";
 
@@ -9,10 +17,32 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-BiX0shPBGA8sshee8rxs41x+mdsrJzBqhpDDic6sYwA=";
   };
 
-  nativeBuildInputs = [ cmake ];
+  nativeBuildInputs = [ cmake copyDesktopItems imagemagick ];
 
   buildInputs = [ SDL ];
 
+  desktopItems = [
+    (makeDesktopItem {
+      name = "Ballerburg";
+      desktopName = "Ballerburg SDL";
+      type = "Application";
+      exec = "_NET_WM_ICON=ballerburg ballerburg";
+      comment = meta.description;
+      icon = "ballerburg";
+      categories = "Game;";
+    })
+  ];
+
+  postInstall = ''
+    # Generate and install icon files
+    for size in 16 32 48 64 72 96 128 192 512 1024; do
+      mkdir -p $out/share/icons/hicolor/"$size"x"$size"/apps
+      convert ${icon} -sample "$size"x"$size" \
+        -background white -gravity south -extent "$size"x"$size" \
+        $out/share/icons/hicolor/"$size"x"$size"/apps/ballerburg.png
+    done
+  '';
+
   meta = with lib; {
     description = "Classic cannon combat game";
     longDescription = ''