SDL2: fix mixer errors, mixer.init(..., allowchanges=0)

docs/reST/ref/mixer.rst

@@ -42,7 +42,7 @@ change the default buffer by calling :func:`pygame.mixer.pre_init` before
 .. function:: init
 
    | :sl:`initialize the mixer module`
-   | :sg:`init(frequency=22050, size=-16, channels=2, buffer=4096, devicename=None, allowedchanges=0) -> None`
+   | :sg:`init(frequency=22050, size=-16, channels=2, buffer=4096, devicename=None, allowedchanges=AUDIO_ALLOW_FREQUENCY_CHANGE | AUDIO_ALLOW_CHANNELS_CHANGE) -> None`
 
    Initialize the mixer module for Sound loading and playback. The default
    arguments can be overridden to provide specific audio mixing. Keyword
@@ -87,7 +87,9 @@ change the default buffer by calling :func:`pygame.mixer.pre_init` before
       - AUDIO_ALLOW_CHANNELS_CHANGE
       - AUDIO_ALLOW_ANY_CHANGE
 
-   .. versionadded:: 2 allowedchanges added for SDL2. Only allowedchanges=0 works with SDL1.
+   .. versionadded:: 2 allowedchanges added for SDL2.
+                     This has no effect with SDL1 (i.e. the requested format
+                     may always differ from the returned format).
 
 
    It is safe to call this more than once, but after the mixer is initialized

src_c/doc/mixer_doc.h

@@ -1,6 +1,6 @@
 /* Auto generated file: with makeref.py .  Docs go in docs/reST/ref/ . */
 #define DOC_PYGAMEMIXER "pygame module for loading and playing sounds"
-#define DOC_PYGAMEMIXERINIT "init(frequency=22050, size=-16, channels=2, buffer=4096, devicename=None, allowedchanges=0) -> None\ninitialize the mixer module"
+#define DOC_PYGAMEMIXERINIT "init(frequency=22050, size=-16, channels=2, buffer=4096, devicename=None, allowedchanges=AUDIO_ALLOW_FREQUENCY_CHANGE | AUDIO_ALLOW_CHANNELS_CHANGE) -> None\ninitialize the mixer module"
 #define DOC_PYGAMEMIXERPREINIT "pre_init(frequency=22050, size=-16, channels=2, buffersize=4096, devicename=None) -> None\npreset the mixer init arguments"
 #define DOC_PYGAMEMIXERQUIT "quit() -> None\nuninitialize the mixer"
 #define DOC_PYGAMEMIXERGETINIT "get_init() -> (frequency, format, channels)\ntest if the mixer is initialized"
@@ -46,7 +46,7 @@ pygame.mixer
 pygame module for loading and playing sounds
 
 pygame.mixer.init
- init(frequency=22050, size=-16, channels=2, buffer=4096, devicename=None, allowedchanges=0) -> None
+ init(frequency=22050, size=-16, channels=2, buffer=4096, devicename=None, allowedchanges=AUDIO_ALLOW_FREQUENCY_CHANGE | AUDIO_ALLOW_CHANNELS_CHANGE) -> None
 initialize the mixer module
 
 pygame.mixer.pre_init

src_c/mixer.c

@@ -65,7 +65,12 @@ const PG_sample_format_t PG_SAMPLE_CHAR_SIGN = (char)0xff > 0 ? 0 : 0x10000u;
 #define PYGAME_MIXER_DEFAULT_SIZE -16
 #define PYGAME_MIXER_DEFAULT_CHANNELS 2
 #define PYGAME_MIXER_DEFAULT_CHUNKSIZE 4096
-#define PYGAME_MIXER_DEFAULT_ALLOWEDCHANGES 0
+#if IS_SDLv2
+#define PYGAME_MIXER_DEFAULT_ALLOWEDCHANGES SDL_AUDIO_ALLOW_FREQUENCY_CHANGE | \
+                                            SDL_AUDIO_ALLOW_CHANNELS_CHANGE
+#else
+#define PYGAME_MIXER_DEFAULT_ALLOWEDCHANGES -1
+#endif
 
 static PyTypeObject pgSound_Type;
 static PyTypeObject pgChannel_Type;
@@ -346,28 +351,36 @@ _init(int freq, int size, int channels, int chunk, char *devicename, int allowed
         size = request_size;
     }
 
+    if (allowedchanges == -1) {
+        allowedchanges = request_allowedchanges;
+    }
+
     if (!channels) {
         channels = request_channels;
     }
 #if IS_SDLv1
-    switch (channels) {
-        case 1:
-        case 2:
-            break;
-        default:
-            PyErr_SetString(PyExc_ValueError, "'channels' must be 1 (mono) or 2 (stereo)");
-            return NULL;
-    }
+    channels = channels <= 1 ? 1 : 2;
 #else /* IS_SDLv2 */
-    switch (channels) {
-        case 1:
-        case 2:
-        case 4:
-        case 6:
-            break;
-        default:
-            PyErr_SetString(PyExc_ValueError, "'channels' must be 1, 2, 4, or 6");
-            return NULL;
+    if (allowedchanges & SDL_AUDIO_ALLOW_CHANNELS_CHANGE) {
+        if (channels <= 1)
+            channels = 1;
+        else if (channels <= 3)
+            channels = 2;
+        else if (channels <= 5)
+            channels = 4;
+        else
+            channels = 6;
+    } else {
+        switch (channels) {
+            case 1:
+            case 2:
+            case 4:
+            case 6:
+                break;
+            default:
+                PyErr_SetString(PyExc_ValueError, "'channels' must be 1, 2, 4, or 6");
+                return NULL;
+        }
     }
 #endif /* IS_SDLv2 */
 
@@ -378,9 +391,6 @@ _init(int freq, int size, int channels, int chunk, char *devicename, int allowed
     if (!devicename) {
         devicename = request_devicename;
     }
-    if (allowedchanges == -1) {
-        allowedchanges = request_allowedchanges;
-    }
 
     /* printf("size:%d:\n", size); */
 

test/mixer_test.py

@@ -78,7 +78,7 @@ def test_pre_init__zero_values(self):
     def test_init__zero_values(self):
         # Ensure that argument values of 0 are replaced with
         # preset values. No way to check buffer size though.
-        mixer.pre_init(44100, 8, 1)  # None default values
+        mixer.pre_init(44100, 8, 1, allowedchanges=0)  # None default values
         mixer.init(0, 0, 0)
         self.assertEqual(mixer.get_init(), (44100, 8, 1))
 
@@ -311,7 +311,7 @@ def _test_array_interface_fail(self, a):
         self.assertRaises(ValueError, mixer.Sound, array=a)
 
     def test_array_interface(self):
-        mixer.init(22050, -16, 1)
+        mixer.init(22050, -16, 1, allowedchanges=0)
         snd = mixer.Sound(buffer=as_bytes('\x00\x7f') * 20)
         d = snd.__array_interface__
         self.assertTrue(isinstance(d, dict))