OSR GPU Native Addon #

Native Node.js addon for handling Electron's Offscreen Rendering (OSR) GPU shared textures.

Overview #

When Electron's offscreen rendering is configured with useSharedTexture: true, the paint event provides a texture object containing a native GPU texture handle (IOSurface on macOS, D3D11 texture on Windows). This addon allows you to:

1. Import the texture into OpenGL (macOS)
2. Copy the texture data to a CPU buffer for use in WebGL

Building #

cd native/osr-gpu
npm install
npm run build

API #

initContext() #

Initialize the native graphics context (OpenGL on macOS, D3D11 on Windows).

copyTextureToBuffer(textureInfo) #

Copy the GPU texture data to a CPU buffer. This is the recommended approach for WebGL compatibility.

Parameters:

• textureInfo - The texture info object from Electron's paint event e.texture.textureInfo
  • sharedTextureHandle - Buffer containing the native handle

Returns:

• { data: Uint8Array, width: number, height: number } - RGBA pixel data

importTexture(textureInfo) (macOS only) #

Import the IOSurface directly as an OpenGL texture.

Returns:

• { textureId: number, width: number, height: number, target: string }

releaseTexture(textureId) #

Release an imported texture.

destroyContext() #

Clean up the native graphics context.

Usage in Electron #

const osrGpu = require('./native/osr-gpu');

// Initialize once
osrGpu.initContext();

// In your offscreen window
win.webContents.on('paint', async (e, dirty, image) => {
  if (e.texture) {
    // Option 1: Copy to buffer (recommended for WebGL)
    const { data, width, height } = osrGpu.copyTextureToBuffer(e.texture.textureInfo);
    // Use data as RGBA Uint8Array...
    
    // IMPORTANT: Always release the texture when done!
    e.texture.release();
  }
});

// Cleanup on exit
osrGpu.destroyContext();

Platform Support #

• macOS: Full support via IOSurface + OpenGL
• Windows: Full support via D3D11 shared textures
• Linux: Not yet implemented (TODO)

References #

• Electron OSR Documentation
• CEF OSR Implementation