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Getting Started With Common Lisp
Install libfreenect as described on the Installation page.
(ql:quickload :cffi) (ql:quickload :verrazano)
Verrazano depends on an external program, gccxml, to generate CFFI bindings, so you would need to install it too. On Ubuntu, it is available via apt-get:
sudo apt-get install gccxml
Generate CFFI bindings
Generate the CFFI bindings -- running verrazano:generate-binding will create the file libfreenect.lisp -- and load them.
(verrazano:generate-binding (list :cffi :package-name :libfreenect :input-files (list "libfreenect/libfreenect.h"))) (load (compile-file #p"libfreenect.lisp")) (use-package :libfreenect)
Load libfreenect in your Lisp image
On Linux, you would load libfreenect.so. Change the name accordingly for Mac and Windows. On the mac, You'll need to do (mapc #'cffi:load-foreign-library '((:framework "CoreFoundation") (:framework "IOKit"))) first.
Define a couple of globals which you would need to pass around for most calls to libfreenect:
(defvar *ctx*) ; freenect_context *ctx; (defvar *dev*) ; freenect_device *dev;
Initialize the library with a call to freenect_init:
(let ((ctx-ptr (cffi:foreign-alloc :pointer))) (freenect-init ctx-ptr (cffi:null-pointer)) (setf *ctx* (cffi:mem-ref ctx-ptr :pointer)))
The second arg to freenect_init is a libusb context, which we set to NULL since we are using only one context here (NULL refers to the default context).
If a Kinect is connected, you can confirm it with a call to freenect_num_devices (which should return 1):
(freenect-num-devices *ctx*) ; this should return 1
Now "open" the device with a call to freenect_open_device:
(let ((dev-ptr (cffi:foreign-alloc :pointer))) (freenect-open-device *ctx* dev-ptr 0) (setf *dev* (cffi:mem-ref dev-ptr :pointer)))
The last arg to freenect_open_device refers to the device number index, which is 0 in case a single device is connected.
Now you can confirm that you are able to work with the device with a call to freenect_set_led (see the LED colour change accordingly):
(freenect-set-led *dev* (cffi:foreign-enum-value 'freenect-led-options :led-blink-red-yellow))
When you are done with Kinect hacking, you should wrap things up cleanly:
(freenect-close-device *dev*) (freenect-shutdown *ctx*)