Simple hacky test of using cl-autowrap and cffi to load fmod with Lisp and get a song to play

fmod-test.lisp

;; Public domain example of using cl-autowrap and cffi to follow using the core api documented at
;; https://fmod.com/resources/documentation-api?version=2.0&page=white-papers-getting-started.html
;; to load and play a sound file with fmod.
;; This file assumes it's in the downloaded fmodstudioapi20009linux/ folder,
;; which contains the C includes and pre-built dynamic libraries.
;; Try it out, evaluating step by step!

(ql:quickload :cl-autowrap)

(defpackage :fmod-test
  (:use :cl))
(in-package :fmod-test)

(defparameter *fmod.h* (merge-pathnames #p"api/core/inc/fmod.h"))
(ensure-directories-exist (merge-pathnames #p"spec/"))
(autowrap:c-include *fmod.h* :spec-path (merge-pathnames #p"spec/"))

(defparameter *fmod.so* (merge-pathnames #p"api/core/lib/x86_64/libfmod.so"))
(cffi:load-foreign-library *fmod.so*)

(defparameter *system-ptr* (cffi:foreign-alloc :pointer))
(fmod-system-create *system-ptr*)
; (= * +fmod-ok+) ; 0 -- see fmod_errors.h for explanations
(defparameter *system* (cffi:mem-ref *system-ptr* :pointer))
(fmod-system-init *system* 512 +fmod-init-normal+ nil)
; (= * +fmod-ok+) ; 0

(defparameter *test-sound-path*
  (merge-pathnames (uiop:parse-unix-namestring "../Desktop/muZn_HnTnL.mp3")))

(defparameter *sound-ptr* (cffi:foreign-alloc :pointer))
(fmod-system-create-sound *system* (namestring *test-sound-path*) +fmod-default+ nil *sound-ptr*)
; (= * +fmod-ok+) ; 0

; play immediately:

;(fmod-system-play-sound *system* (cffi:mem-ref *sound-ptr* :pointer) nil 0 nil)
; (= * +fmod-ok+) ; 0 -- should return immediately, i.e. sound playing does not block

; if we want, we can monitor the sound with a channel object
(defparameter *channel-ptr* (cffi:foreign-alloc :pointer))
(fmod-system-play-sound *system* (cffi:mem-ref *sound-ptr* :pointer) nil 0 *channel-ptr*)

; e.g. check if it's playing:
(defun is-playing? ()
  (cffi:with-foreign-object (is-playing? :pointer)
    (fmod-channel-is-playing (cffi:mem-ref *channel-ptr* :pointer) is-playing?)
    (cffi:mem-ref is-playing? :bool)))
(is-playing?)

; could also know this by seeing +fmod-err-invalid-handle+ (30)
; returned when calling any channel methods after it's done playing
; btw, you can know what enum key the value 30 corresponds to with:
; (autowrap:enum-key '(:enum (fmod-result)) 30)

(sleep 5)
(format t "Pausing 5 seconds...~%")
(fmod-channel-set-paused (cffi:mem-ref *channel-ptr* :pointer) 1)
(sleep 5)
(fmod-channel-set-paused (cffi:mem-ref *channel-ptr* :pointer) 0)

(loop while (is-playing?) do
      (sleep 1)
      (fmod-system-update *system*)) ; should be called once per 'game' tick, not needed here but see its doc for what it is needed for

(fmod-sound-release (cffi:mem-ref *sound-ptr* :pointer))
(fmod-system-release *system*)

(cffi:foreign-free *channel-ptr*)
(cffi:foreign-free *sound-ptr*)
(cffi:foreign-free *system-ptr*)