Interface and bindings to the Allegro 5 game programming library
- `al_*` becomes `al:*`
- `(al:rest secs)` is `(al:rest-time secs)` because of symbol interference with #’cl:rest.
- Enums/constants are shortened, check constants.lisp if you need help finding them.
- Type names have changed too, check types.lisp if you need help finding them.
- To access slots from a C struct, you can use CFFI:MEM-REF create a plist
(defcstruct display-mode (width :int) (height :int) (format :int) (refresh-rate :int)) (with-foreign-object (test '(:struct display-mode)) (let ((plist (mem-ref test '(:struct display-mode)))) (print plist) (print (getf plist 'width))))
- I’ve got a neat lispy interface here
- Everything else is pretty much 1-to-1
- Examples exist if you get lost
Feel free to raise an issue to request a feature or for me to work on something
Complete but missing haptic, touch input, shader, and the video streaming addon.
I won’t work on the following sections because Common Lisp has more suitable implementations. (Might eventually do it for completeness though) Feel free to explain otherwise and I’ll listen.
Why can’t my program find the DLL in Windows?
There are path problems in Windows because the DLL files (which contain all the functions the CFFI calls upon) doesn’t have a default location unlike in Unix environments. When the library loads in Windows, it will look for the DLL in the current folder of the FILE.LISP that evaluates (ql:quickload “cl-liballegro”) This means you must have a copy of the DLL file in the directory of FILE.LISP, not in the cl-liballegro directory unless the FILE.LISP is in there. SLIME however, likes to change the default search folder to the one Emacs is in when it starts.
;; Open command prompt in the folder that contains both the DLL and game.lisp` > sbcl > (load "game.lisp") ; File contains (ql:quickload "cl-liballegro")
With Emacs + SLIME
game.lisp contains (ql:quickload :cl-liballegro)
;; Looks for the DLL at /path/to/Desktop/allegro.dll C-x C-f /path/to/Desktop/file9.lisp M-x slime C-x C-f /path/to/Desktop/game/game.lisp C-c C-l
;; Looks for the DLL at /path/to/Desktop/game/allegro.dll C-x C-f /path/to/Desktop/file9.lisp C-x C-f /path/to/Desktop/game/game.lisp M-x slime C-c C-l
;; Looks for the DLL at /whatever/default/emacs/directory/allegro.dll M-x slime C-x C-f /path/to/Desktop/game/game.lisp C-c C-l