This fixes #2, added SDL_AUDIO_ALLOW_CHANGES config flag and added pa…

…use and unpause functions

README.md

@@ -8,11 +8,22 @@
 ## How to use
 
 * Include audio.c and audio.h into your project
-* test.c shows how to simply load wave files as music or sound
+* test.c shows how to simply load wave files as music or sound, and a simple pause and unpause function
+
+## API Functions:
+
+```c
+void initAudio(void);
+void endAudio(void);
+void playSound(const char * filename, int volume);
+void playMusic(const char * filename, int volume);
+void pauseAudio(void);
+void unpauseAudio(void);
+```
 
 ## Music vs Sound
 
-* Only one music can play at a time, and it loops (to close music you can just run endAudio() lazily, or write your own pause function which is not difficult).
+* Only one music can play at a time, and it loops (to close music you can just run `endAudio()`, or use `pauseAudio()` and `unpauseAudio()`).
    * If you add another music when one is playing, the first one fades out before ending, and then playing the second.
    * If you play more than 2 music at once, the first fades as expected, only the last music queued before the first fade out is used
 
@@ -22,7 +33,16 @@
 
 * This implementation uses SDL_MixAudioFormat for mixing for simplicity. It's noted "Do not use this function for mixing together more than two streams of sample data". While only playing 1 music removes a lot of these issues, if you need something more powerful you should write your own mixing function.
 * Multiple Music cannot be mixed together, only music and sound
-* This implementation ONLY plays WAV files, and they must all be of the same format, see the top of audio.c to set the format, stereo vs mono etc... No conversion
+* This implementation ONLY plays WAV files, and they should all be the same format, but can have differing formats if you play around with `SDL_AUDIO_ALLOW_CHANGES` in `audio.c`, see the top of audio.c to set the format, stereo vs mono etc... No conversion
+
+## Features to add
+
+- Pause / unpause only music, only sound or ~~both~~
+- Current implementation uses callback method, however in SDL 2.0.4 there exists `SDL_QueueAudio()` (no callback)
+
+## Emscripten Compatibility
+
+* [Github Issue - Solution](https://github.com/jakebesworth/Simple-SDL2-Audio/issues/2)
 
 ## Resources
 
@@ -34,3 +54,4 @@
 
 * [Jake Besworth](https://github.com/jakebesworth)
 * [Lorenzo Mancini](https://github.com/lmancini)
+* [Ted](https://github.com/claimred)

src/audio.c

@@ -43,6 +43,18 @@
 /* Specifies a unit of audio data to be used at a time. Must be a power of 2 */
 #define AUDIO_SAMPLES 4096
 
+/* Flags OR'd together, which specify how SDL should behave when a device cannot offer a specific feature
+ * If flag is set, SDL will change the format in the actual audio file structure (as opposed to gDevice->want)
+ *
+ * Note: If you're having issues with Emscripten / EMCC play around with these flags
+ *
+ * 0                                    Allow no changes
+ * SDL_AUDIO_ALLOW_FREQUENCY_CHANGE     Allow frequency changes (e.g. AUDIO_FREQUENCY is 48k, but allow files to play at 44.1k
+ * SDL_AUDIO_ALLOW_FORMAT_CHANGE        Allow Format change (e.g. AUDIO_FORMAT may be S32LSB, but allow wave files of S16LSB to play)
+ * SDL_AUDIO_ALLOW_CHANNELS_CHANGE      Allow any number of channels (e.g. AUDIO_CHANNELS being 2, allow actual 1)
+ * SDL_AUDIO_ALLOW_ANY_CHANGE           Allow all changes above
+ */
+#define SDL_AUDIO_ALLOW_CHANGES SDL_AUDIO_ALLOW_ANY_CHANGE
 /*
  * Queue structure for all loaded sounds
  *
@@ -184,20 +196,17 @@ void initAudio(void)
     Sound * global;
     gDevice = calloc(1, sizeof(PrivateAudioDevice));
 
-    if(!(SDL_WasInit(SDL_INIT_AUDIO) & SDL_INIT_AUDIO))
+    if(gDevice == NULL)
     {
-        fprintf(stderr, "[%s: %d]Error: SDL_INIT_AUDIO not initialized\n", __FILE__, __LINE__);
-        gDevice->audioEnabled = 0;
+        fprintf(stderr, "[%s: %d]Fatal Error: Memory c-allocation error\n", __FILE__, __LINE__);
         return;
     }
-    else
-    {
-        gDevice->audioEnabled = 1;
-    }
 
-    if(gDevice == NULL)
+    gDevice->audioEnabled = 0;
+
+    if(!(SDL_WasInit(SDL_INIT_AUDIO) & SDL_INIT_AUDIO))
     {
-        fprintf(stderr, "[%s: %d]Fatal Error: Memory c-allocation error\n", __FILE__, __LINE__);
+        fprintf(stderr, "[%s: %d]Error: SDL_INIT_AUDIO not initialized\n", __FILE__, __LINE__);
         return;
     }
 
@@ -222,22 +231,25 @@ void initAudio(void)
     global->next = NULL;
 
     /* want.userdata = new; */
-    if((gDevice->device = SDL_OpenAudioDevice(NULL, 0, &(gDevice->want), NULL, SDL_AUDIO_ALLOW_ANY_CHANGE)) == 0)
+    if((gDevice->device = SDL_OpenAudioDevice(NULL, 0, &(gDevice->want), NULL, SDL_AUDIO_ALLOW_CHANGES)) == 0)
     {
         fprintf(stderr, "[%s: %d]Warning: failed to open audio device: %s\n", __FILE__, __LINE__, SDL_GetError());
     }
     else
     {
+        /* Set audio device enabled global flag */
+        gDevice->audioEnabled = 1;
+
         /* Unpause active audio stream */
-        SDL_PauseAudioDevice(gDevice->device, 0);
+        unpauseAudio();
     }
 }
 
 void endAudio(void)
 {
     if(gDevice->audioEnabled)
     {
-        SDL_PauseAudioDevice(gDevice->device, 1);
+        pauseAudio();
 
         freeSound((Sound *) (gDevice->want).userdata);
 
@@ -248,6 +260,22 @@ void endAudio(void)
     free(gDevice);
 }
 
+void pauseAudio(void)
+{
+    if(gDevice->audioEnabled)
+    {
+        SDL_PauseAudioDevice(gDevice->device, 1);
+    }
+}
+
+void unpauseAudio(void)
+{
+    if(gDevice->audioEnabled)
+    {
+        SDL_PauseAudioDevice(gDevice->device, 0);
+    }
+}
+
 static Sound * createSound(const char * filename, uint8_t loop, int volume)
 {
     Sound * new = calloc(1, sizeof(Sound));

src/audio.h

@@ -51,6 +51,7 @@ void playMusic(const char * filename, int volume);
 
 /*
  * Free all audio related variables
+ * Note, this needs to be run even if initAudio fails, because it frees the global audio device
  *
  */
 void endAudio(void);
@@ -61,6 +62,18 @@ void endAudio(void);
  */
 void initAudio(void);
 
+/*
+ * Pause audio from playing
+ *
+ */
+void pauseAudio(void);
+
+/*
+ * Unpause audio from playing
+ *
+ */
+void unpauseAudio(void);
+
 #ifdef __cplusplus
 }
 #endif

src/test.c

@@ -23,6 +23,10 @@ int main(void)
     playMusic("music/road.wav", SDL_MIX_MAXVOLUME);
     SDL_Delay(2000);
 
+    pauseAudio();
+    SDL_Delay(2000);
+    unpauseAudio();
+
     playSound("sounds/door2.wav", SDL_MIX_MAXVOLUME / 2);
     SDL_Delay(7000);