Great thanks to reitowo for this magnificent work. There is a proper README for lovely expert beginers.

Example

Share Electron's offscreen window's frame to Spout output.

It listens to paint event and copies the frame data, sends to native module, copies to D3D11Texture2D and share.

1. Visual Studio (tested on 2022) with C++ core desktop enviroment
2. cmake
3. vcpkg Install and use packages with CMake

   setting VCPKG_ROOT env variable is important

1. clone the repo and go to directory,

2. Update the info in package.json according to your electron version.

   Set arch to x86 if your project is targeting 32-bit.

   {
     "cmake-js": {
       "runtime": "electron",
       "runtimeVersion": "30.0.1",
       "arch": "x64"
     }
   }

3. Run npx cmake-js print-configure to get CMake configuration.

   

4. Copy these arguments and set these variables to CMake options.

   Warning: You must change -DCMAKE_MSVC_RUNTIME_LIBRARY to MultiThreaded$<$<CONFIG:Debug>:Debug>DLL because we link Spout statically.

   -G "Visual Studio 17 2022" -A x64
   -DCMAKE_BUILD_TYPE=Release
   -DCMAKE_JS_VERSION=7.2.1
   -DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded$<$<CONFIG:Debug>:Debug>DLL
   -DCMAKE_JS_INC=C:/Users/reito/.cmake-js/electron-x64/v25.8.0/include/node
   -DCMAKE_JS_SRC=C:/Users/reito/AppData/Roaming/npm/node_modules/cmake-js/lib/cpp/win_delay_load_hook.cc
   -DNODE_RUNTIME=electron
   -DNODE_RUNTIMEVERSION=25.8.0
   -DNODE_ARCH=x64
   -DCMAKE_JS_LIB=C:/Users/reito/.cmake-js/electron-x64/v25.8.0/x64/node.lib
   -DCMAKE_SHARED_LINKER_FLAGS=/DELAYLOAD:NODE.EXE
   

   There are environment dependent values, do not directly copy the text above, and always use the value provided by the command.

5. To configure cmake acording to configuration set the CMAkeLists.txt if there is any difference

6. Run npx cmake-js print-configure to compile the project.

   Warning: If you see the error "could not find toolchain file: /scripts/buildsystems/vcpkg.cmake", set your $ENV{VCPKG_ROOT} manually at PreLoad.cmake

7. Build and use the .node file in your project

let win = new BrowserWindow({
  title: "MyWindow",
  webPreferences: {
    preload,
    offscreen: true,
    offscreenUseSharedTexture: true,
  },
  show: false,
  transparent: true,
});

const { SpoutOutput } = require("electron_spout.node");
const osr = new SpoutOutput("Electron Output");

win.webContents.setFrameRate(60);
win.webContents.on("paint", (event, dirty, image, texture) => {
  if (texture) {
    // when offscreenUseSharedTexture = true
    osr.updateTexture(texture);
  } else {
    osr.updateFrame(image.getBitmap(), image.getSize());
  }
});