Add SDL2_mixer bindings.

* sdl2/bindings.scm: Add "AUDIO_*" constants.
* sdl2/bindings/mixer.scm: New file.
* sdl2/mixer.scm: New file.
* Makefile.am (SOURCES): Add new files.

3 files changed, 470 insertions, 0 deletions

diff --git a/sdl2/bindings.scm b/sdl2/bindings.scm
index 7edd7b2..1672b0d 100644
--- a/sdl2/bindings.scm
+++ b/sdl2/bindings.scm
@@ -855,3 +855,23 @@ RETURN-TYPE and accept arguments of ARG-TYPES."
 
 (define-foreign sdl-load-bmp-rw
   '* "SDL_LoadBMP_RW" (list '* int))
+
+
+;;;
+;;; Audio
+;;;
+
+(define-public AUDIO_U8     #x0008)
+(define-public AUDIO_S8     #x8008)
+(define-public AUDIO_U16LSB #x0010)
+(define-public AUDIO_S16LSB #x8010)
+(define-public AUDIO_U16MSB #x1010)
+(define-public AUDIO_S16MSB #x9010)
+(define-public AUDIO_U16    AUDIO_U16LSB)
+(define-public AUDIO_S16    AUDIO_S16LSB)
+(define-public AUDIO_S32LSB #x8020)
+(define-public AUDIO_S32MSB #x9020)
+(define-public AUDIO_S32    AUDIO_S32LSB)
+(define-public AUDIO_F32LSB #x8120)
+(define-public AUDIO_F32MSB #x9120)
+(define-public AUDIO_F32    AUDIO_F32LSB)
diff --git a/sdl2/bindings/mixer.scm b/sdl2/bindings/mixer.scm
new file mode 100644
index 0000000..638b409
--- /dev/null
+++ b/sdl2/bindings/mixer.scm
@@ -0,0 +1,131 @@
+;;; guile-sdl2 --- FFI bindings for SDL2
+;;; Copyright © 2015 David Thompson <davet@gnu.org>
+;;;
+;;; This file is part of guile-sdl2.
+;;;
+;;; Guile-sdl2 is free software; you can redistribute it and/or modify
+;;; it under the terms of the GNU Lesser General Public License as
+;;; published by the Free Software Foundation; either version 3 of the
+;;; License, or (at your option) any later version.
+;;;
+;;; Guile-sdl2 is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with guile-sdl2.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Low-level FFI bindings for SDL2_mixer.
+;;
+;;; Code:
+
+(define-module (sdl2 bindings mixer)
+  #:use-module (rnrs bytevectors)
+  #:use-module (system foreign)
+  #:use-module (sdl2 config)
+  #:use-module (sdl2 bindings))
+
+(define sdl-mixer-func
+  (let ((lib (dynamic-link %libsdl2-mixer)))
+    (lambda (return-type function-name arg-types)
+      "Return a procedure for the foreign function FUNCTION-NAME in
+the SDL2_mixer shared library.  That function must return a value of
+RETURN-TYPE and accept arguments of ARG-TYPES."
+      (pointer->procedure return-type
+                          (dynamic-func function-name lib)
+                          arg-types))))
+
+(define-syntax-rule (define-foreign name return-type func-name arg-types)
+  (define-public name
+    (sdl-mixer-func return-type func-name arg-types)))
+
+(define-public MIX_INIT_FLAC       #x00000001)
+(define-public MIX_INIT_MOD        #x00000002)
+(define-public MIX_INIT_MODPLUG    #x00000004)
+(define-public MIX_INIT_MP3        #x00000008)
+(define-public MIX_INIT_OGG        #x00000010)
+(define-public MIX_INIT_FLUIDSYNTH #x00000020)
+
+(define-public MIX_CHANNELS 8)
+(define-public MIX_DEFAULT_FREQUENCY 22050)
+(define-public MIX_MAX_VOLUME 128)
+(define-public MIX_DEFAULT_FORMAT
+  (if (eq? (native-endianness) 'little)
+      AUDIO_S16LSB
+      AUDIO_S16MSB))
+
+(define-foreign mix-init
+  int "Mix_Init" (list int))
+
+(define-foreign mix-quit
+  void "Mix_Quit" '())
+
+(define-foreign mix-open-audio
+  int "Mix_OpenAudio" (list int uint16 int int))
+
+(define-foreign mix-close-audio
+  void "Mix_CloseAudio" '())
+
+(define-foreign mix-load-wav-rw
+  '* "Mix_LoadWAV_RW" (list '* int))
+
+(define-foreign mix-free-chunk
+  void "Mix_FreeChunk" '(*))
+
+(define-foreign mix-volume-chunk
+  int "Mix_VolumeChunk" (list '* int))
+
+(define-foreign mix-volume
+  int "Mix_Volume" (list int int))
+
+(define-foreign mix-play-channel-timed
+  int "Mix_PlayChannelTimed" (list int '* int int))
+
+(define-foreign mix-pause
+  void "Mix_Pause" (list int))
+
+(define-foreign mix-resume
+  void "Mix_Resume" (list int))
+
+(define-foreign mix-halt-channel
+  void "Mix_HaltChannel" (list int))
+
+(define-foreign mix-playing
+  int "Mix_Playing" (list int))
+
+(define-foreign mix-paused
+  int "Mix_Paused" (list int))
+
+(define-foreign mix-load-mus
+  '* "Mix_LoadMUS" '(*))
+
+(define-foreign mix-free-music
+  void "Mix_FreeMusic" '(*))
+
+(define-foreign mix-play-music
+  int "Mix_PlayMusic" (list '* int))
+
+(define-foreign mix-volume-music
+  int "Mix_VolumeMusic" (list int))
+
+(define-foreign mix-pause-music
+  void "Mix_PauseMusic" '())
+
+(define-foreign mix-resume-music
+  void "Mix_ResumeMusic" '())
+
+(define-foreign mix-rewind-music
+  void "Mix_RewindMusic" '())
+
+(define-foreign mix-halt-music
+  void "Mix_HaltMusic" '())
+
+(define-foreign mix-playing-music
+  int "Mix_PlayingMusic" '())
+
+(define-foreign mix-paused-music
+  int "Mix_PausedMusic" '())
diff --git a/sdl2/mixer.scm b/sdl2/mixer.scm
new file mode 100644
index 0000000..c740d85
--- /dev/null
+++ b/sdl2/mixer.scm
@@ -0,0 +1,319 @@
+;;; guile-sdl2 --- FFI bindings for SDL2
+;;; Copyright © 2015 David Thompson <davet@gnu.org>
+;;;
+;;; This file is part of guile-sdl2.
+;;;
+;;; Guile-sdl2 is free software; you can redistribute it and/or modify
+;;; it under the terms of the GNU Lesser General Public License as
+;;; published by the Free Software Foundation; either version 3 of the
+;;; License, or (at your option) any later version.
+;;;
+;;; Guile-sdl2 is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;;; General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with guile-sdl2.  If not, see
+;;; <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Font rendering.
+;;
+;;; Code:
+
+(define-module (sdl2 mixer)
+  #:use-module (ice-9 format)
+  #:use-module (ice-9 match)
+  #:use-module (system foreign)
+  #:use-module (sdl2)
+  #:use-module ((sdl2 bindings) #:prefix ffi:)
+  #:use-module ((sdl2 bindings mixer) #:prefix ffi:)
+  #:export (%default-frequency
+            %default-format
+            %default-chunk-size
+
+            mixer-init
+            mixer-quit
+            open-audio
+            close-audio
+
+            chunk?
+            load-chunk
+            delete-chunk!
+            set-chunk-volume!
+            play-chunk!
+
+            set-channel-volume!
+            pause-channel!
+            resume-channel!
+            stop-channel!
+            channel-playing?
+            playing-channels-count
+            channel-paused?
+            paused-channels-count
+
+            music?
+            load-music
+            delete-music!
+            play-music!
+            set-music-volume!
+            music-volume
+            pause-music!
+            resume-music!
+            rewind-music!
+            stop-music!
+            music-playing?
+            music-paused?))
+
+(define (audio-format->symbol n)
+  (cond
+   ((= n ffi:AUDIO_U8)     'u8)
+   ((= n ffi:AUDIO_S8)     's8)
+   ((= n ffi:AUDIO_U16LSB) 'u16lsb)
+   ((= n ffi:AUDIO_S16LSB) 's16lsb)
+   ((= n ffi:AUDIO_U16MSB) 'u16msb)
+   ((= n ffi:AUDIO_S16MSB) 's16msb)
+   ((= n ffi:AUDIO_U16)    'u16)
+   ((= n ffi:AUDIO_S16)    's16)
+   ((= n ffi:AUDIO_S32LSB) 's32lsb)
+   ((= n ffi:AUDIO_S32MSB) 's32msb)
+   ((= n ffi:AUDIO_S32)    's32)
+   ((= n ffi:AUDIO_F32LSB) 'f32lsb)
+   ((= n ffi:AUDIO_F32MSB) 'f32msb)
+   ((= n ffi:AUDIO_F32)    'f32)))
+
+(define symbol->audio-format
+  (match-lambda
+    ('u8     ffi:AUDIO_U8)
+    ('s8     ffi:AUDIO_S8)
+    ('u16lsb ffi:AUDIO_U16LSB)
+    ('s16lsb ffi:AUDIO_S16LSB)
+    ('u16msb ffi:AUDIO_U16MSB)
+    ('s16msb ffi:AUDIO_S16MSB)
+    ('u16    ffi:AUDIO_U16)
+    ('s16    ffi:AUDIO_S16)
+    ('s32lsb ffi:AUDIO_S32LSB)
+    ('s32msb ffi:AUDIO_S32MSB)
+    ('s32    ffi:AUDIO_S32)
+    ('f32lsb ffi:AUDIO_F32LSB)
+    ('f32msb ffi:AUDIO_F32MSB)
+    ('f32    ffi:AUDIO_F32)))
+
+(define %default-frequency ffi:MIX_DEFAULT_FREQUENCY)
+(define %default-format (audio-format->symbol ffi:MIX_DEFAULT_FORMAT))
+(define %default-chunk-size 4096)
+
+(define* (mixer-init #:optional
+                     (formats '(flac mod modplug mp3 ogg fluidsynth)))
+  "Initialize mixer library with support for FORMATS, a list of
+symbols representing audio file formats.  Possible formats are:
+
+- flac
+- mod
+- modplug
+- mp3
+- ogg
+- fluidsynth"
+  (define symbol->init-flag
+    (match-lambda
+      ('flac       ffi:MIX_INIT_FLAC)
+      ('mod        ffi:MIX_INIT_MOD)
+      ('modplug    ffi:MIX_INIT_MODPLUG)
+      ('mp3        ffi:MIX_INIT_MP3)
+      ('ogg        ffi:MIX_INIT_OGG)
+      ('fluidsynth ffi:MIX_INIT_FLUIDSYNTH)))
+
+  (let* ((mask (apply logior (map symbol->init-flag formats)))
+         (result (ffi:mix-init mask)))
+    (unless (= mask result)
+      (sdl-error "mixer-init" "failed to initialize mixer library"))))
+
+(define (mixer-quit)
+  "Shutdown mixer library."
+  (ffi:mix-quit))
+
+(define* (open-audio #:key (frequency %default-frequency)
+                     (format %default-format)
+                     (stereo? #t)
+                     (chunk-size %default-chunk-size))
+  "Initialize the mixer API.  FREQUENCY specificies the sample rate in
+hertz.  When STEREO? is #t, two output channels are used, otherwise
+mono output is used instead.  CHUNK-SIZE specifies the number of bytes
+used per output sample.  FORMAT is a symbol that specifies the output
+sample format.  Possible values are:
+
+- u8
+- s8
+- u16lsb
+- s16lsb
+- u16msb
+- s16msb
+- u16
+- s16
+- s32lsb
+- s32msb
+- s32
+- f32lsb
+- f32msb
+- f32"
+  (unless (zero? (ffi:mix-open-audio frequency
+                                     (symbol->audio-format format)
+                                     (if stereo? 2 1)
+                                     chunk-size))
+    (sdl-error "open-audio" "failed to open audio")))
+
+(define (close-audio)
+  "Shut down the mixer API."
+  (ffi:mix-close-audio))
+
+
+;;;
+;;; Chunks
+;;;
+
+(define-wrapped-pointer-type <chunk>
+  chunk?
+  wrap-chunk unwrap-chunk
+  (lambda (chunk port)
+    (format port "#<chunk ~x>"
+            (pointer-address (unwrap-chunk chunk)))))
+
+(define (load-chunk file)
+  "Load the audio data in FILE and return an audio chunk."
+  (let ((ptr (ffi:mix-load-wav-rw (ffi:sdl-rw-from-file (string->pointer file)
+                                                        (string->pointer "rb"))
+                                  1)))
+    (if (null-pointer? ptr)
+        (sdl-error "load-audio" "failed to load audio")
+        (wrap-chunk ptr))))
+
+(define (delete-chunk! chunk)
+  "Free the memory used for CHUNK."
+  (ffi:mix-free-chunk (unwrap-chunk chunk)))
+
+(define (set-chunk-volume! chunk volume)
+  "Set the loudness of CHUNK to VOLUME, an integer in the range [0,
+128].  Return the previous chunk volume setting."
+  (ffi:mix-volume-chunk (unwrap-chunk chunk) volume))
+
+(define* (play-chunk! chunk #:key (loops 0) channel)
+  "Play CHUNK on CHANNEL, an integer channel identifier or #f to use
+the first unreserved audio channel.  CHUNK will play LOOPS + 1 times.
+Return the channel identifier that CHUNK is played on."
+  (let ((ret (ffi:mix-play-channel-timed (if channel channel -1)
+                                         (unwrap-chunk chunk)
+                                         loops -1)))
+    (if (= -1 ret)
+        (sdl-error "play-chunk!" "failed to play audio")
+        ret)))
+
+
+;;;
+;;; Channels
+;;;
+
+(define (set-channel-volume! channel volume)
+  "Set the loudness of CHANNEL, an integer channel identifier or #f
+for all channels, to VOLUME, an integer in the range 0-128.  Return
+the previous volume of CHANNEL, or the average of all channels if
+CHANNEL is #f."
+  (ffi:mix-volume (if channel channel -1) volume))
+
+(define (pause-channel! channel)
+  "Pause playback on CHANNEL, an integer channel identifier, or #f to
+pause all channels."
+  (ffi:mix-pause (if channel channel -1)))
+
+(define (resume-channel! channel)
+  "Resume playback on CHANNEL, an integer channel identifier, or #f to
+pause all channels."
+  (ffi:mix-resume (if channel channel -1)))
+
+(define (stop-channel! channel)
+  "Halt playback on CHANNEL, an integer channel identifier, or #f to
+pause all channels."
+  (ffi:mix-halt-channel (if channel channel -1)))
+
+(define (channel-playing? channel)
+  "Return #t if CHANNEL is playing."
+  (= 1 (ffi:mix-playing channel)))
+
+(define (playing-channels-count)
+  "Return the number of channels currently playing."
+  (ffi:mix-playing -1))
+
+(define (channel-paused? channel)
+  "Return #t if CHANNEL is paused."
+  (= 1 (ffi:mix-paused channel)))
+
+(define (paused-channels-count)
+  "Return the number of channels that are paused."
+  (ffi:mix-paused -1))
+
+
+;;;
+;;; Music
+;;;
+
+(define-wrapped-pointer-type <music>
+  music?
+  wrap-music unwrap-music
+  (lambda (music port)
+    (format port "#<music ~x>"
+            (pointer-address (unwrap-music music)))))
+
+(define (load-music file)
+  "Load music from FILE."
+  (let ((ptr (ffi:mix-load-mus (string->pointer file))))
+    (if (null-pointer? ptr)
+        (sdl-error "load-music" "failed to load music")
+        (wrap-music ptr))))
+
+(define (delete-music! music)
+  "Delete the memory used for MUSIC."
+  (ffi:mix-free-music (unwrap-music music)))
+
+(define* (play-music! music #:optional (loops 1))
+  "Play MUSIC, repeated LOOPS times.  LOOPS may be #f, in which case
+the music loops indefinitely."
+  (unless (zero? (ffi:mix-play-music (unwrap-music music) (if loops loops -1)))
+    (sdl-error "play-music!" "failed to play music")))
+
+(define (set-music-volume! volume)
+  "Set music loudness to VOLUME, an integer in the range 0-128.
+Return the previous volume."
+  (if (>= volume 0)
+      (ffi:mix-volume-music volume)
+      (throw 'sdl-error "set-music-volume!"
+             "volume must be a non-negative integer")))
+
+(define (music-volume)
+  "Return the music volume."
+  (ffi:mix-volume-music -1))
+
+(define (pause-music!)
+  "Pause the music."
+  (ffi:mix-pause-music))
+
+(define (resume-music!)
+  "Resume music playback."
+  (ffi:mix-resume-music))
+
+(define (rewind-music!)
+  "Start music playback from the beginning.  Rewinding is only
+supported for MOD, OGG, MP3, and native MIDI music."
+  (ffi:mix-rewind-music))
+
+(define (stop-music!)
+  "Halt music playback."
+  (ffi:mix-halt-music))
+
+(define (music-playing?)
+  "Return #t if music is currently playing."
+  (= 1 (ffi:mix-playing-music)))
+
+(define (music-paused?)
+  "Return #t if music is currently paused."
+  (= 1 (ffi:mix-paused-music)))