Add custom gamescope package

features/gaming.nix

@@ -2,10 +2,10 @@
     environment.systemPackages = with pkgs; [
         protonup-qt
         vesktop
+        localPackages.gamescope
     ];
 
     programs.steam = {
         enable = true;
-        gamescopeSession.enable = true;
     };
 }

flake.nix

@@ -64,6 +64,7 @@
             in
             {
                 kickoff-dot-desktop = pkgs.callPackage ./pkgs/kickoff-dot-desktop.nix { };
+                gamescope = pkgs.callPackage ./pkgs/gamescope {};
             }
         );
     };

pkgs/gamescope/default.nix

@@ -0,0 +1,155 @@
+{ stdenv
+, fetchFromGitHub
+, meson
+, pkg-config
+, ninja
+, xorg
+, libdrm
+, libei
+, vulkan-loader
+, vulkan-headers
+, wayland
+, wayland-protocols
+, libxkbcommon
+, glm
+, gbenchmark
+, libcap
+, libavif
+, SDL2
+, pipewire
+, pixman
+, libinput
+, glslang
+, hwdata
+, openvr
+, stb
+, wlroots
+, libliftoff
+, libdecor
+, libdisplay-info
+, lib
+, makeBinaryWrapper
+, patchelfUnstable
+, nix-update-script
+, enableExecutable ? true
+, enableWsi ? true
+}:
+let
+  joshShaders = fetchFromGitHub {
+    owner = "Joshua-Ashton";
+    repo = "GamescopeShaders";
+    rev = "v0.1";
+    hash = "sha256-gR1AeAHV/Kn4ntiEDUSPxASLMFusV6hgSGrTbMCBUZA=";
+  };
+in
+stdenv.mkDerivation (finalAttrs: {
+  pname = "gamescope";
+  version = "3.14.16";
+
+  src = fetchFromGitHub {
+    owner = "ValveSoftware";
+    repo = "gamescope";
+    rev = "refs/tags/${finalAttrs.version}";
+    fetchSubmodules = true;
+    hash = "sha256-tijFVOIMW+nkot/uRP0PNZBYZkZMMt1PcAN5+3SWzW4=";
+  };
+
+  patches = [
+    # Unvendor dependencies
+    ./use-pkgconfig.patch
+
+    # Make it look for shaders in the right place
+    ./shaders-path.patch
+  ];
+
+  # We can't substitute the patch itself because substituteAll is itself a derivation,
+  # so `placeholder "out"` ends up pointing to the wrong place
+  postPatch = ''
+    substituteInPlace src/reshade_effect_manager.cpp --replace "@out@" "$out"
+  '';
+
+  mesonFlags = [
+    (lib.mesonBool "enable_gamescope" enableExecutable)
+    (lib.mesonBool "enable_gamescope_wsi_layer" enableWsi)
+  ];
+
+  # don't install vendored vkroots etc
+  mesonInstallFlags = ["--skip-subprojects"];
+
+  strictDeps = true;
+
+  depsBuildBuild = [
+    pkg-config
+  ];
+
+  nativeBuildInputs = [
+    meson
+    pkg-config
+    ninja
+  ] ++ lib.optionals enableExecutable [
+    makeBinaryWrapper
+    glslang
+  ];
+
+  buildInputs = [
+    pipewire
+    hwdata
+    xorg.libX11
+    wayland
+    wayland-protocols
+    vulkan-loader
+    openvr
+    glm
+  ] ++ lib.optionals enableWsi [
+    vulkan-headers
+  ] ++ lib.optionals enableExecutable (wlroots.buildInputs ++ [  # gamescope uses a custom wlroots branch
+    xorg.libXcomposite
+    xorg.libXcursor
+    xorg.libXdamage
+    xorg.libXext
+    xorg.libXi
+    xorg.libXmu
+    xorg.libXrender
+    xorg.libXres
+    xorg.libXtst
+    xorg.libXxf86vm
+    libavif
+    libdrm
+    libei
+    libliftoff
+    SDL2
+    libdecor
+    libinput
+    libxkbcommon
+    gbenchmark
+    pixman
+    libcap
+    stb
+    libdisplay-info
+  ]);
+
+  postInstall = lib.optionalString enableExecutable ''
+    # using patchelf unstable because the stable version corrupts the binary
+    ${lib.getExe patchelfUnstable} $out/bin/gamescope \
+      --add-rpath ${vulkan-loader}/lib --add-needed libvulkan.so.1
+
+    # --debug-layers flag expects these in the path
+    wrapProgram "$out/bin/gamescope" \
+      --prefix PATH : ${with xorg; lib.makeBinPath [xprop xwininfo]}
+
+    # Install ReShade shaders
+    mkdir -p $out/share/gamescope/reshade
+    cp -r ${joshShaders}/* $out/share/gamescope/reshade/
+  '';
+
+  passthru.updateScript = nix-update-script {};
+
+  meta = with lib; {
+    description = "SteamOS session compositing window manager";
+    homepage = "https://github.com/ValveSoftware/gamescope";
+    license = licenses.bsd2;
+    maintainers = with maintainers; [ nrdxp pedrohlc Scrumplex zhaofengli k900 ];
+    platforms = platforms.linux;
+    mainProgram = "gamescope";
+  };
+})

pkgs/gamescope/shaders-patch.patch

@@ -0,0 +1,13 @@
+diff --git a/src/reshade_effect_manager.cpp b/src/reshade_effect_manager.cpp
+index 3597ca1..de45250 100644
+--- a/src/reshade_effect_manager.cpp
++++ b/src/reshade_effect_manager.cpp
+@@ -34,7 +34,7 @@ static std::string GetLocalUsrDir()
+
+ static std::string GetUsrDir()
+ {
+-    return "/usr";
++    return "@out@";
+ }
+
+ static LogScope reshade_log("gamescope_reshade");

pkgs/gamescope/use-pkgconfig.patch

@@ -0,0 +1,9 @@
+--- a/meson.build
++++ b/meson.build
+@@ -6,7 +6,6 @@ project(
+   default_options: [
+     'cpp_std=c++20',
+     'warning_level=2',
+-    'force_fallback_for=wlroots,libliftoff,vkroots',
+   ],
+ )