[workflow][Nix] initial packaging & flake (sofa-framework#5059)

* [Nix] initial packaging & flake

* [Nix] setup CI

* [CMake] FindQGLViewer: fix include dir computation

we use `#include <QGLViewer/qglviewer.h>`, so `QGLViewer_INCLUDE_DIR`
must not include `QGLViewer` component.

Also, on darwin, headers are installed in Headers dir, not include, ref:
https://github.com/GillesDebunne/libQGLViewer/blob/ba9a875784afbb7ee73088fe0e8701c31bc7277d/QGLViewer/QGLViewer.pro#L138

* [Nix] fix build on macos

This require fixes in upstream nixpkgs:
NixOS/nixpkgs#348549

So we can use the source of that PR for now

* [CMake] FindQGLViewer: fix for Qt6

ref. https://github.com/GillesDebunne/libQGLViewer/blob/ba9a875784afbb7ee73088fe0e8701c31bc7277d/QGLViewer/QGLViewer.pro#L176

* [Nix] Qt5 -> Qt6

* [CMake] fix typo for Qt6

* [CMake] fix SOFA_GUI_QT_HAVE_QT6 definition

without this, `lib/cmake/Sofa.GUI.Qt/Sofa.GUI.QtConfig.cmake` has:
> `set(SOFA_GUI_QT_HAVE_QT6 0)`

and therefore, in SofaPython3, `find_package(QGLViewer QUIET REQUIRED)`
is not called, and build ends up with:
> [ 98%] Linking CXX shared library ../../lib/python3/site-packages/Sofa/Gui.cpython-312-x86_64-linux-gnu.so
> […]/ld: cannot find -lQGLViewer: No such file or directory

* [Nix] fixup lib path on Darwin

TODO: This should be fixed in CMake instead, but I have no clue.

error was:
> dyld[61665]: Library not loaded: /nix/store/aalbn4pznxwy18ydjmb15c3y4izj8isi-sofa-24.06.00/lib/libSceneChecking.24.12.99.dylib
>   Referenced from: <8B75C775-7FE5-3755-A190-B11A3F4F6666> /nix/store/aalbn4pznxwy18ydjmb15c3y4izj8isi-sofa-24.06.00/bin/.runSofa-24.12.99-wrapped
>   Reason: tried: '/nix/store/aalbn4pznxwy18ydjmb15c3y4izj8isi-sofa-24.06.00/lib/libSceneChecking.24.12.99.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/nix/store/aalbn4pznxwy18ydjmb15c3y4izj8isi-sofa-24.06.00/lib/libSceneChecking.24.12.99.dylib' (no such file), '/nix/store/aalbn4pznxwy18ydjmb15c3y4izj8isi-sofa-24.06.00/lib/libSceneChecking.24.12.99.dylib' (no such file), '/usr/local/lib/libSceneChecking.24.12.99.dylib' (no such file), '/usr/lib/libSceneChecking.24.12.99.dylib' (no such file, not in dyld cache)
> zsh: abort      ./result/bin/runSofa

* [Nix] CI on macos too

* nix: add nixGL

* [Nix] fix package description

Co-authored-by: Hugo <[email protected]>

* Apply suggestions from code review

---------

Co-authored-by: Hugo <[email protected]>

.github/workflows/nix.yml

@@ -0,0 +1,21 @@
+name: "CI - Nix"
+
+on:
+  push:
+
+jobs:
+  nix:
+    runs-on: "${{ matrix.os }}-latest"
+    if: ${{ github.repository_owner == 'sofa-framework' }}
+    strategy:
+      matrix:
+        os: [ubuntu, macos]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v27
+      # TODO: the "sofa" account on cachix does not exist yet
+      #- uses: cachix/cachix-action@v15
+        #with:
+          #name: sofa
+          #authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+      - run: nix build -L

Sofa/GUI/Qt/CMakeLists.txt

@@ -24,8 +24,11 @@ endif()
 
 if (Qt6Core_FOUND)
     message("${PROJECT_NAME}: will use Qt6")
-    sofa_find_package(Qt6 COMPONENTS Gui GuiTools Widgets WidgetsTools OpenGLWidgets REQUIRED)
-    set(SOFA_GUI_QT_TARETS ${SOFA_GUI_QT_TARGETS} Qt::Core Qt::Gui Qt::Widgets Qt::OpenGLWidgets )
+    find_package(Qt6 COMPONENTS Gui GuiTools Widgets WidgetsTools OpenGLWidgets REQUIRED)
+    # GuiTools & WidgetsTools does not define a Qt6::component CMake target
+    # So we can't look for those target to know how we should define SOFA_GUI_QT_HAVE_QT6
+    sofa_find_package(Qt6 COMPONENTS Gui Widgets OpenGLWidgets REQUIRED)
+    set(SOFA_GUI_QT_TARGETS ${SOFA_GUI_QT_TARGETS} Qt::Core Qt::Gui Qt::Widgets Qt::OpenGLWidgets )
 elseif (Qt5Core_FOUND)
     message("${PROJECT_NAME}: will use Qt5 (deprecated)")
     sofa_find_package(Qt5 COMPONENTS Core Gui OpenGL REQUIRED)

cmake/Modules/FindQGLViewer.cmake

@@ -14,14 +14,14 @@ if(NOT TARGET QGLViewer)
 
   if(NOT QGLViewer_INCLUDE_DIR)
     find_path(QGLViewer_INCLUDE_DIR
-      NAMES qglviewer.h
-      PATH_SUFFIXES include/QGLViewer
+      NAMES QGLViewer/qglviewer.h
+      PATH_SUFFIXES include Headers
     )
   endif()
 
   if(NOT QGLViewer_LIBRARY)
   find_library(QGLViewer_LIBRARY
-    NAMES QGLViewer QGLViewer2 QGLViewer-qt5
+    NAMES QGLViewer QGLViewer2 QGLViewer-qt5 QGLViewer-qt6
     PATH_SUFFIXES lib
   )
   endif()

flake.nix

@@ -0,0 +1,37 @@
+{
+  description = "SOFA is an open-source framework for interactive physics simulation, with emphasis on biomechanical and robotic simulations";
+
+  inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    #nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    # ref. https://github.com/NixOS/nixpkgs/pull/348549
+    nixpkgs.url = "github:nim65s/nixpkgs/qt6-libqglviewer";
+    nixgl.url = "github:nix-community/nixGL";
+  };
+
+  outputs =
+    inputs@{ flake-parts, nixgl, nixpkgs, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = nixpkgs.lib.systems.flakeExposed;
+      perSystem =
+        { pkgs, self', system, ... }:
+        {
+          _module.args.pkgs = import nixpkgs {
+            inherit system;
+            overlays = [ nixgl.overlay ];
+          };
+          apps.nixgl = {
+            type = "app";
+            program = pkgs.writeShellApplication {
+              name = "nixgl-sofa";
+              text = "${pkgs.lib.getExe pkgs.nixgl.auto.nixGLDefault} ${pkgs.lib.getExe self'.packages.sofa}";
+            };
+          };
+          devShells.default = pkgs.mkShell { inputsFrom = [ self'.packages.default ]; };
+          packages = {
+            default = self'.packages.sofa;
+            sofa = pkgs.callPackage ./package.nix { };
+          };
+        };
+    };
+}

package.nix

@@ -0,0 +1,82 @@
+{
+  boost,
+  cmake,
+  cxxopts,
+  eigen,
+  #fetchFromGitHub,
+  glew,
+  gtest,
+  lib,
+  qt6Packages,
+  libGL,
+  metis,
+  stdenv,
+  tinyxml-2,
+  zlib,
+}:
+
+stdenv.mkDerivation {
+  pname = "sofa";
+  version = "24.06.00";
+
+  src = lib.fileset.toSource {
+    root = ./.;
+    fileset = lib.fileset.unions [
+      ./applications
+      ./Authors.txt
+      ./cmake
+      ./CHANGELOG.md
+      ./CMakeLists.txt
+      ./CMakePresets.json
+      ./examples
+      ./extlibs
+      ./LICENSE-LGPL.md
+      ./package.cmake
+      ./README.md
+      ./scripts
+      ./share
+      ./Sofa
+      ./tools
+    ];
+  };
+
+  propagatedNativeBuildInputs = [
+    cmake
+    qt6Packages.wrapQtAppsHook
+  ];
+  propagatedBuildInputs = [
+    boost
+    cxxopts
+    eigen
+    glew
+    gtest
+    qt6Packages.libqglviewer
+    qt6Packages.qtbase
+    libGL
+    metis
+    tinyxml-2
+    zlib
+  ];
+
+  cmakeFlags = [
+    (lib.cmakeBool "SOFA_ALLOW_FETCH_DEPENDENCIES" false)
+  ];
+
+  doCheck = true;
+
+  postFixup = lib.optionalString stdenv.hostPlatform.isDarwin ''
+    install_name_tool -change \
+      $out/lib/libSceneChecking.24.12.99.dylib \
+      $out/plugins/SceneChecking/lib/libSceneChecking.24.12.99.dylib \
+      $out/bin/.runSofa-24.12.99-wrapped
+  '';
+
+  meta = {
+    description = "SOFA is an open-source framework for interactive physics simulation, with emphasis on biomechanical and robotic simulations";
+    homepage = "https://github.com/sofa-framework/sofa";
+    license = lib.licenses.lgpl21Only;
+    maintainers = with lib.maintainers; [ nim65s ];
+    mainProgram = "runSofa";
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+}