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matt-s-clark / godot-gdextension-opencv

GDExtension project for OpenCV
MIT License
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Godot GDExtension for OpenCV

This project has been updated and tested on Linux, Windows and MacOS. It is still very early in development, but it may provide a good template for anyone adding OpenCV to their GDExtensions. Go to the "Godot T5 OpenCV" YouTube channel for updates and news - https://www.youtube.com/channel/UC1Bt3NJuaLWa0KqJt91Bh4A

For a basic example of how to create a GDExtension, see the Godot documentation: https://docs.godotengine.org/en/4.2/tutorials/scripting/gdextension/gdextension_cpp_example.html#

For great videos on GDExtensions with C++, take a look at Mosen Zare's YouTube Tutorials: https://www.youtube.com/playlist?list=PLhixpuPeRv9aDdsZbhTpsXguYRvMgyVQ-

Please be aware that OpenCV may contain patents that require licensing or credit. Please do your own research before using it in a commercial scenario.

If you're not already on the "Godot Engine" Discord channel I recommend you go and join it.

You can go to this Discord thread to get involved with the project (the link will only work if you have joined the "Godot Engine" Discord channel): https://discord.com/channels/212250894228652034/1232670118702485584

Prequisites

You will need to install the following (version numbers are the ones I have working correctly):

Copy the opencv.gdextension file to demo/bin.

Windows (x64)

You will need to manually copy the OpenCV files into the src folder of this project and make sure SConstruct references everything correctly. Pay particular attention to the following lines:

env.Append(CPPPATH=["src/", "src/opencv2/include"])
env.Append(LIBPATH=['src/opencv2/x64/vc16/lib'])
env.Append(LIBS=['opencv_world490', 'opencv_world490d'])

Make sure you include the godot-cpp git submodule:

git submodule update --init

If a basic init doesn't work, you may need to do the following in the project root folder:

git submodule add -b 4.2 https://github.com/godotengine/godot-cpp
cd godot-cpp
git submodule update --init

Compilation and Running

To compile, make sure you are in the project root folder:

scons platform=windows disable_exceptions=false

To clean your build folder, use the --clean argument, i.e.

scons platform=windows --clean

Run the extension from Godot. It is best to run Godot from the command line to capture any potential error messages that would normally be missed. For example, C++ cout only outputs to the command line and not the Godot terminal.

Follow the Godot C++ GDExtension tutorial for details on how to test the GDExample component.

MacOS (ARM)

Download OpenCV from the releases page and unpack.

Create a soft link src/opencv2 to the library folder opencv2.framework/Versions/Current/Header.

Compilation and Running

Set the opencv_library_path to point to your OpenCV library files (*.dylib).

To compile, make sure you are in the project root folder:

scons platform=macos arch=arm64 disable_exceptions=false

To run, make sure you include the DYLD_LIBRARY_PATH to your opencv dylib files if they are not in a system Library folder (i.e. you built them from source). On the command line where you will run Godot from:

export DYLD_LIBRARY_PATH='/Users/matt/vscode/gto/build_opencv/lib'

If you don't, you may experience Error: dlopen messages where the linker looks for files in the wrong place.

Start Godot from the command line:

cd demo
/Applications/Godot.app/Contents/MacOS/Godot -e

You may want to set some extra Godot parameters to start the editor somewhere convenient. For example:

/Applications/Godot\ 4.2.2.app/Contents/MacOS/Godot -e --screen 1 --position 0,0 -w --resolution 3240x2160

MacOS (Intel)

Intel setup is the same as for ARM, except the scons arch parameter when compiling.

To compile, make sure you are in the project root folder:

scons platform=macos arch=x86_64 disable_exceptions=false

Troubleshooting

If you have trouble compiling or running the gdextension, here are some suggestions: