From 3f45d2cbd8775be352929c169c7ae2e5d77ca404 Mon Sep 17 00:00:00 2001
From: Andrew Pan <a@tny.town>
Date: Thu, 14 Aug 2025 00:27:46 -0400
Subject: [PATCH 1/3] opencascade-occt: add optional vtk dependency

---
 pkgs/by-name/op/opencascade-occt/package.nix  | 28 ++++++++++++++++---
 .../vtk-draw-conditional-glx.patch            | 14 ++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 pkgs/by-name/op/opencascade-occt/vtk-draw-conditional-glx.patch

diff --git a/pkgs/by-name/op/opencascade-occt/package.nix b/pkgs/by-name/op/opencascade-occt/package.nix
index 6295a0c98e38..a542df3d95d4 100644
--- a/pkgs/by-name/op/opencascade-occt/package.nix
+++ b/pkgs/by-name/op/opencascade-occt/package.nix
@@ -13,8 +13,12 @@
   libXext,
   libXmu,
   libXi,
-}:
+  vtk,
+  withVtk ? false,
 
+  # used in passthru.tests
+  opencascade-occt,
+}:
 stdenv.mkDerivation rec {
   pname = "opencascade-occt";
   version = "7.8.1";
@@ -33,6 +37,10 @@ stdenv.mkDerivation rec {
       url = "https://github.com/Open-Cascade-SAS/OCCT/commit/7236e83dcc1e7284e66dc61e612154617ef715d6.diff";
       hash = "sha256-NoC2mE3DG78Y0c9UWonx1vmXoU4g5XxFUT3eVXqLU60=";
     })
+
+    # patch does not apply against 7.9+, it was submitted upstream for future
+    # inclusion: https://github.com/Open-Cascade-SAS/OCCT/pull/683
+    ./vtk-draw-conditional-glx.patch
   ];
 
   nativeBuildInputs = [
@@ -49,10 +57,23 @@ stdenv.mkDerivation rec {
     libXmu
     libXi
     rapidjson
-  ];
+  ]
+  ++ lib.optional withVtk vtk;
 
   NIX_CFLAGS_COMPILE = [ "-fpermissive" ];
-  cmakeFlags = [ "-DUSE_RAPIDJSON=ON" ];
+  cmakeFlags = [
+    "-DUSE_RAPIDJSON=ON"
+  ]
+  ++ lib.optionals withVtk [
+    (lib.cmakeBool "USE_VTK" true)
+    (lib.cmakeFeature "3RDPARTY_VTK_INCLUDE_DIR" "${lib.getDev vtk}/include/vtk")
+  ];
+
+  passthru = {
+    tests = {
+      withVtk = opencascade-occt.override ({ withVtk = true; });
+    };
+  };
 
   meta = with lib; {
     description = "Open CASCADE Technology, libraries for 3D modeling and numerical simulation";
@@ -63,5 +84,4 @@ stdenv.mkDerivation rec {
     maintainers = with maintainers; [ amiloradovsky ];
     platforms = platforms.all;
   };
-
 }
diff --git a/pkgs/by-name/op/opencascade-occt/vtk-draw-conditional-glx.patch b/pkgs/by-name/op/opencascade-occt/vtk-draw-conditional-glx.patch
new file mode 100644
index 000000000000..76993ae6046f
--- /dev/null
+++ b/pkgs/by-name/op/opencascade-occt/vtk-draw-conditional-glx.patch
@@ -0,0 +1,14 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 86905287dc..19214e8f2d 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -623,5 +623,9 @@ if (USE_VTK)
+   add_definitions (-DHAVE_VTK)
+   set (OCCT_VTK_USED_TARGETS "" CACHE INTERNAL "" FORCE)
+   OCCT_INCLUDE_CMAKE_FILE ("adm/cmake/vtk")
++  if (DEFINED VTK_USE_X AND NOT VTK_USE_X)
++      message (STATUS "Info: TKIVtkDraw toolkits excluded due to VTK has no glx support")
++      list (REMOVE_ITEM BUILD_TOOLKITS TKIVtkDraw)
++  endif()
+ else()
+   OCCT_CHECK_AND_UNSET_GROUP ("3RDPARTY_VTK")

From 6b353e084d1999f2dfcecf3e1367111b562f536f Mon Sep 17 00:00:00 2001
From: Andrew Pan <a@tny.town>
Date: Mon, 1 Sep 2025 23:41:06 -0400
Subject: [PATCH 2/3] opencascade-occt: enable exceptions

---
 pkgs/by-name/op/opencascade-occt/package.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/pkgs/by-name/op/opencascade-occt/package.nix b/pkgs/by-name/op/opencascade-occt/package.nix
index a542df3d95d4..6314c6bb4105 100644
--- a/pkgs/by-name/op/opencascade-occt/package.nix
+++ b/pkgs/by-name/op/opencascade-occt/package.nix
@@ -63,6 +63,8 @@ stdenv.mkDerivation rec {
   NIX_CFLAGS_COMPILE = [ "-fpermissive" ];
   cmakeFlags = [
     "-DUSE_RAPIDJSON=ON"
+    # Enable exception handling for release builds.
+    (lib.cmakeBool "BUILD_RELEASE_DISABLE_EXCEPTIONS" false)
   ]
   ++ lib.optionals withVtk [
     (lib.cmakeBool "USE_VTK" true)

From 205d89f72385833f9b4312babbdac9b8b4fd0a31 Mon Sep 17 00:00:00 2001
From: Andrew Pan <a@tny.town>
Date: Mon, 1 Sep 2025 23:41:34 -0400
Subject: [PATCH 3/3] opencascade-occt: use cmakeBool for all bool flags

---
 pkgs/by-name/op/opencascade-occt/package.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/by-name/op/opencascade-occt/package.nix b/pkgs/by-name/op/opencascade-occt/package.nix
index 6314c6bb4105..5e0edc8a9ade 100644
--- a/pkgs/by-name/op/opencascade-occt/package.nix
+++ b/pkgs/by-name/op/opencascade-occt/package.nix
@@ -62,7 +62,7 @@ stdenv.mkDerivation rec {
 
   NIX_CFLAGS_COMPILE = [ "-fpermissive" ];
   cmakeFlags = [
-    "-DUSE_RAPIDJSON=ON"
+    (lib.cmakeBool "USE_RAPIDJSON" true)
     # Enable exception handling for release builds.
     (lib.cmakeBool "BUILD_RELEASE_DISABLE_EXCEPTIONS" false)
   ]