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This repository has been moved tohttps://github.com/kirides/go-d3d

I wanted to learn more aboutCOM interop with Go and create a somewhat usable screen sharing tool

This application uses D3D11IDXGIOutputDuplication to create a somewhatrealtime desktop presentation

• github.com/mattn/go-mjpeg for mjpeg streaming
• github.com/kbinani/screenshot for comparison with GDIBitBlt (slightly modified source, to support re-usingimage.RGBA)
• golang.org/x/exp/shiny/driver/internal/swizzle for faster BGRA -> RGBA conversion (seeshiny LICENSE)
• github.com/pixiv/go-libjpeg/jpeg for fast jpeg encoding
  • enable withgo build -tag jpegturbo

Just build the application and run it.It should serve all your monitors on an URL likehttp://127.0.0.1:8023/watch?screen=N
wherescreen=N <- N is the monitor index, starting at zero (0).

By changing the lines incmd/example/main.go regarding the streaming, you can switch between GDIBitBlt orIDXGIOutputDuplication

// ...framerate:=10fori:=0;i<n;i++ {// ...// streamDisplay(ctx, i, framerate, stream)  // <= USE GDI BitBltstreamDisplayDXGI(ctx,i,framerate,stream)// <= USE IDXGIOutputDuplication// captureScreenTranscode(ctx, i, desiredFps)http.HandleFunc(fmt.Sprintf("/mjpeg%d",i),stream.ServeHTTP)}// ...

The code contains the functioncaptureScreenTranscode which allows you to record theselected screen directly into ffmpeg and transcode it to h264 in an mp4 container.

Performanceis not optimized to 100%, there are still thing that could be improved.

• only copying the dirty-rectangles (less GPU<->CPU communication)
• faster swizzle implementation using AVX/2 (less time for converting the BGRA texture)
• profile ... profile ... profile

Overall the current implementation is about 2-5x faster than GDIBitBlt (depending on the resolution,the higher the bigger the difference) and uses a lot less resources for cases where there arent any changes to the screen.

To make use ofIDXGIOutput5::DuplicateOutput1, an application has to provide support forPerMonitorV2 DPI-Awareness (Windows 10 1703+)This is usually done by providing an my-executable.exe.manifest file either next to the executable, or as an embedded resource.

In this application there are calls toIsValidDpiAwarenessContext andSetThreadDpiAwarenessContext which circumvent the requirement.