README.md

BehaviorTreeFlatBuffer

A wrapper for BehaviorTree.CPP for the purpose of writing FlatBuffers. Pass a javascript callback and a valid Groot xml file. A log in FlatBuffer format will be written via the callback in Int8Array Buffers.

Dependencies

• emscripten compiler (I'm using) 1.39.11
• https://github.com/BehaviorTree/BehaviorTree.CPP (included via submodule)

Publish notes to myself

• Publish with:

nvm use 14
source emsdk/emsdk_env.sh
make wasm build
npm publish

Quirks about WASM

• Not sure if I know how to shutdown the wasm properly. It may be better to only have one instance
  • This stems from how I am including the .js file output by emscripten. Not sure how to fix this.
• My test has the wasm file in the path of /out where it is built, but publish requires a different path
  • Thus I patch the .js file

Quirks about wrapper

• BehaviorTree.CPP is well written and throws many errors during the operations I need. Thus I patched out some error checking. I generated the patch with:

cd lib/BehaviorTree.CPP/src
diff xml_parsing.cpp xml_parsing2.cpp > ../../../patch/xml_parsing.patch

or

cd lib/BehaviorTree.CPP/src
cp tree_node.cpp tree_node2.cpp
git checkout tree_node.cpp
diff tree_node.cpp tree_node2.cpp > ../../../patch/tree_node.patch

See Also Emscripten

• https://github.com/Planeshifter/emscripten-examples/tree/master/01_PassingArrays Arrays js->C
• https://stackoverflow.com/questions/28904273/struct-operations-in-javascript-through-emscripten Arrays c->js
• https://stackoverflow.com/questions/47248045/webassembly-calling-javascript-methods-from-wasm-i-e-within-c-code Arrays c->js
• https://stackoverflow.com/questions/55446258/emscripten-pass-uint8-t-array-to-javascript Arrays c->js
• https://emscripten.org/docs/porting/connecting_cpp_and_javascript/Interacting-with-code.html#calling-javascript-functions-as-function-pointers-from-c Types for c->js

See Also Make/patch

• https://stackoverflow.com/questions/7394290/how-to-check-return-value-from-the-shell-directive deal with exit codes from make
• https://unix.stackexchange.com/questions/55780/check-if-a-file-or-folder-has-been-patched-already only patch if not patched