output/openal: use alGetSourcei(AL_BUFFER) to force-unqueue buffers

The implementation of cancel() did not work well: you cannot use alSourceUnqueueBuffers() to unqueue queued buffers, and our function openal_unqueue_buffers() left the OpenAL library in a rather undefined state; nothing was supposed to be queued, but the "filled" variable was not reset.

output/openal: use alGetSourcei(AL_BUFFER) to force-unqueue buffers
e735abe3 · Max Kellermann · c0070b2f · e735abe3 · e735abe3
Commit e735abe3 authored Dec 13, 2011 by Max Kellermann
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Showing with 5 additions and 14 deletions

NEWS NEWS +1 -0

openal_output_plugin.c src/output/openal_output_plugin.c +4 -14

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--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,7 @@ ver 0.17 (2011/??/??)
  - dsdiff: new decoder plugin
 * output:
  - httpd: support for streaming to a DLNA client
+  - openal: improve buffer cancellation
  - osx: allow user to specify other audio devices
  - raop: new output plugin
  - shout: add possibility to set url

--- a/src/output/openal_output_plugin.c
+++ b/src/output/openal_output_plugin.c
@@ -109,19 +109,6 @@ openal_setup_context(struct openal_data *od,
 	return true;
 }

-static void
-openal_unqueue_buffers(struct openal_data *od)
-{
-	ALint num;
-	ALuint buffer;
-
-	alGetSourcei(od->source, AL_BUFFERS_QUEUED, &num);
-
-	while (num--) {
-		alSourceUnqueueBuffers(od->source, 1, &buffer);
-	}
-}
-
 static struct audio_output *
 openal_init(const struct config_param *param, GError **error_r)
 {
@@ -256,7 +243,10 @@ openal_cancel(struct audio_output *ao)
 	od->filled = 0;
 	alcMakeContextCurrent(od->context);
 	alSourceStop(od->source);
-	openal_unqueue_buffers(od);
+
+	/* force-unqueue all buffers */
+	alSourcei(od->source, AL_BUFFER, 0);
+	od->filled = 0;
 }

 const struct audio_output_plugin openal_output_plugin = {