Can play sound effect but music is not working yet.

core/Interfaces.carp

@@ -55,3 +55,9 @@
   (if (< a b) a b))
 
 (defn id [x] x)
+
+(defn null? [p]
+  (Pointer.eq NULL (the (Ptr t) p)))
+
+(defn not-null? [p]
+  (not (null? p)))

core/SDL_mixer.carp

@@ -7,13 +7,65 @@
 
 (defmodule Mixer
 
-  (register default-format
-            Int
-            "MIX_DEFAULT_FORMAT")
-
-  ;; freq format channels chunksize
+  ;; Setup
   (register open-audio
-            (Fn [Int Int Int Int] ())
+            ;; freq format channels chunksize
+            (Fn [Int Int Int Int] Int)
             "Mix_OpenAudio")
 
+  (register default-format Int "MIX_DEFAULT_FORMAT")
+
+  (register ogg-support Int "MIX_INIT_OGG")
+  (register mp3-support Int "MIX_INIT_MP3")
+  (register mod-support Int "MIX_INIT_MOD")
+  (register flac-support Int "MIX_INIT_FLAC")
+
+  (register init (Fn [Int] Int) "Mix_Init")
+  (register quit (Fn [Int] Int) "Mix_Quit")
+
+  ;; Loading
+  (register load-wav
+            (Fn [(Ptr Char)] (Ptr Mix_Chunk))
+            "Mix_LoadWAV")
+
+  (register load-music
+            (Fn [(Ptr Char)] (Ptr Mix_Music))
+            "Mix_LoadMUS")
+
+  ;; Playing samples (Mix_Chunk:s)
+  (register play-channel
+            ;; args: channel chunk loops
+            ;; ret: channel
+            (Fn [Int (Ptr Mix_Chunk) Int] Int)
+            "Mix_PlayChannel")
+
+  (register channel-playing?
+            (Fn [Int] Bool)
+            "Mix_Playing")
+
+  ;; Music
+  (register nr-of-music-decoders
+            (Fn [] Int)
+            "Mix_GetNumMusicDecoders")
+
+  ;; This function seems flakey, returns NULL?
+  (register get-music-decoder
+            (Fn [Int] (Ptr Char))
+            "Mix_GetMusicDecoder")
+
+  (register play-music
+            ;; args: music loops
+            ;; ret: ok-code
+            (Fn [(Ptr Mix_Music) Int] Int)
+            "Mix_PlayMusic")
+
+  ;; Helpers
+  (defn ok? [error-code]
+    (= 0 error-code))
+
+  (def any-free-channel -1)
+
+  (defn valid-channel? [ch]
+    (not (= ch -1)))
+
   )

examples/sounds.carp

@@ -1,12 +1,37 @@
 (load "SDL.carp")
 (load "SDL_mixer.carp")
 
-(defn draw [app rend state]
-  (SDL.bg rend &(SDL.rgb 255 0 0)))
+(def fx1 (the (Ptr Mix_Chunk) NULL))
+
+(defn play-sound-fx1 []
+  (ignore (Mixer.play-channel Mixer.any-free-channel fx1 0)))
+
+(defn event-handler [app]
+    (let [event (SDL.Event.init)]
+      (while (SDL.Event.poll (address event))
+        (let [et (SDL.Event.type &event)]
+          (cond (= et SDL.Event.quit)
+                (SDLApp.stop app)
+                (= et SDL.Event.key-down)
+                (let [key (SDL.Event.keycode &event)]
+                  (case key
+                    SDL.key-escape (SDLApp.stop app)
+                    SDL.key-return (play-sound-fx1)
+                    ()))
+                ())))))
 
 (defn main []
   (let [app (SDLApp.create "Sound Effects with SDL_mixer" 400 300)
         rend @(SDLApp.renderer &app)]
     (do
-      (SDLApp.run-with-callbacks &app SDLApp.default-event-handler id draw 0)
+      (if (Mixer.ok? (Mixer.open-audio 22050 Mixer.default-format 2 4096))
+        (println* "Audio initialized.")
+        (println* "Failed to initialize audio."))
+      (set! fx1 (Mixer.load-wav (cstr "resources/fx1.wav")))
+      (assert (not-null? fx1))
+      (let-do [n (Mixer.nr-of-music-decoders)]
+        (println* "Nr of music decoders: " n))
+      (let-do [music (Mixer.load-music (cstr "resources/song.aif"))]
+        (println* "Music null? " (null? music)))
+      (SDLApp.run-with-callbacks &app event-handler id SDLApp.default-draw 0)
       0)))