HID device communication

Development
1

I’ve written some code for a Teensy which allows communcation with an HID device for the display of a MIDI controller. I’m thinking about porting this code to a module for Rack.
Has anyone done a Makefile for building/linking the necessary dependencies for making the API available within a module?

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stoermelder's Idea und Development Thread
2

For reference, I finally spent time on figuring this out, and it is more easy than expected:

  • Add hidapi as dependency under dep/hidapi to your project.
  • Add to your Makefile:
FLAGS += -Idep/hidapi/hidapi

and after include $(RACK_DIR)/arch.mk:

ifdef ARCH_MAC
	SOURCES += dep/hidapi/mac/hid.c
endif
ifdef ARCH_WIN
	SOURCES += dep/hidapi/windows/hid.c
	CFLAGS += -DHID_API_NO_EXPORT_DEFINE
endif
ifdef ARCH_LIN
	SOURCES += dep/hidapi/linux/hid.c
endif
  • If you are using a GitHub workflow to build your plugin, add this before the “Build plugin” step:
- name: Install required dependencies
  if: ${{ matrix.platform == 'lin-x64' }}
  run: |
    apt-get update
    apt-get install -y libudev-dev
    # Copy libudev headers to cross-compiler sysroot (find it dynamically)
    SYSROOT=$(find /home/build/rack-plugin-toolchain/local -type d -name 'sysroot' 2>/dev/null | grep ubuntu | head -1)
    mkdir -p $SYSROOT/usr/include
    cp /usr/include/libudev.h $SYSROOT/usr/include/
  shell: bash

I did not test it under Linux, but it builds without issues.

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