Require AudioStream::mix to return the number of frames successfully mixed

2 files changed, 6 insertions, 3 deletions

diff --git a/scene/resources/audio_stream_sample.cpp b/scene/resources/audio_stream_sample.cpp
index ef070589e4..2ab9b7b5a4 100644
--- a/scene/resources/audio_stream_sample.cpp
+++ b/scene/resources/audio_stream_sample.cpp
@@ -221,12 +221,12 @@ void AudioStreamPlaybackSample::do_resample(const Depth *p_src, AudioFrame *p_ds
 	}
 }
 
-void AudioStreamPlaybackSample::mix(AudioFrame *p_buffer, float p_rate_scale, int p_frames) {
+int AudioStreamPlaybackSample::mix(AudioFrame *p_buffer, float p_rate_scale, int p_frames) {
 	if (!base->data || !active) {
 		for (int i = 0; i < p_frames; i++) {
 			p_buffer[i] = AudioFrame(0, 0);
 		}
-		return;
+		return 0;
 	}
 
 	int len = base->data_bytes;
@@ -395,12 +395,15 @@ void AudioStreamPlaybackSample::mix(AudioFrame *p_buffer, float p_rate_scale, in
 	}
 
 	if (todo) {
+		int mixed_frames = p_frames - todo;
 		//bit was missing from mix
 		int todo_ofs = p_frames - todo;
 		for (int i = todo_ofs; i < p_frames; i++) {
 			p_buffer[i] = AudioFrame(0, 0);
 		}
+		return mixed_frames;
 	}
+	return p_frames;
 }
 
 AudioStreamPlaybackSample::AudioStreamPlaybackSample() {}
diff --git a/scene/resources/audio_stream_sample.h b/scene/resources/audio_stream_sample.h
index 70b8ba79ad..8bf3d29123 100644
--- a/scene/resources/audio_stream_sample.h
+++ b/scene/resources/audio_stream_sample.h
@@ -73,7 +73,7 @@ public:
 	virtual float get_playback_position() const override;
 	virtual void seek(float p_time) override;
 
-	virtual void mix(AudioFrame *p_buffer, float p_rate_scale, int p_frames) override;
+	virtual int mix(AudioFrame *p_buffer, float p_rate_scale, int p_frames) override;
 
 	AudioStreamPlaybackSample();
 };