Pre-fill playback-only output buffers with silence.

This simplifies the callback since the client does not need to worry
about silencing parts of the buffer that are not filled, such as the
end of a song or whatnot.

mini_al.h

@@ -2698,6 +2698,10 @@ mal_uint32 mal_get_default_buffer_size_in_milliseconds(mal_performance_profile p
 // Calculates a buffer size in frames for the specified performance profile and scale factor.
 mal_uint32 mal_get_default_buffer_size_in_frames(mal_performance_profile performanceProfile, mal_uint32 sampleRate);
 
+
+// Copies silent frames into the given buffer.
+void mal_zero_pcm_frames(void* p, mal_uint32 frameCount, mal_format format, mal_uint32 channels);
+
 #endif  // MAL_NO_DEVICE_IO
 
 
@@ -4629,6 +4633,11 @@ mal_uint32 mal_get_fragment_size_in_bytes(mal_uint32 bufferSizeInFrames, mal_uin
     return fragmentSizeInFrames * mal_get_bytes_per_frame(format, channels);
 }
 
+void mal_zero_pcm_frames(void* p, mal_uint32 frameCount, mal_format format, mal_uint32 channels)
+{
+    mal_zero_memory(p, frameCount * mal_get_bytes_per_frame(format, channels));
+}
+
 
 const char* mal_log_level_to_string(mal_uint32 logLevel)
 {
@@ -4707,6 +4716,8 @@ mal_uint32 mal_device__on_read_from_client(mal_pcm_converter* pDSP, void* pFrame
     mal_device* pDevice = (mal_device*)pUserData;
     mal_assert(pDevice != NULL);
 
+    mal_zero_pcm_frames(pFramesOut, frameCount, pDevice->playback.format, pDevice->playback.channels);
+
     mal_device_callback_proc onData = pDevice->onData;
     if (onData) {
         onData(pDevice, pFramesOut, NULL, frameCount);
@@ -4763,22 +4774,14 @@ mal_uint32 mal_device__pcm_converter__on_read_from_buffer_playback(mal_pcm_conve
 
 
 
-// A helper function for reading sample data from the client. Returns the number of samples read from the client. Remaining samples
-// are filled with silence.
-static MAL_INLINE mal_uint32 mal_device__read_frames_from_client(mal_device* pDevice, mal_uint32 frameCount, void* pSamples)
+// A helper function for reading sample data from the client.
+static MAL_INLINE void mal_device__read_frames_from_client(mal_device* pDevice, mal_uint32 frameCount, void* pSamples)
 {
     mal_assert(pDevice != NULL);
     mal_assert(frameCount > 0);
     mal_assert(pSamples != NULL);
 
-    mal_uint32 framesRead     = (mal_uint32)mal_pcm_converter_read(&pDevice->playback.converter, pSamples, frameCount);
-    mal_uint32 samplesRead    = framesRead * pDevice->playback.internalChannels;
-    mal_uint32 sampleSize     = mal_get_bytes_per_sample(pDevice->playback.internalFormat);
-    mal_uint32 consumedBytes  = samplesRead*sampleSize;
-    mal_uint32 remainingBytes = ((frameCount * pDevice->playback.internalChannels) - samplesRead)*sampleSize;
-    mal_zero_memory((mal_uint8*)pSamples + consumedBytes, remainingBytes);
-
-    return samplesRead;
+    mal_pcm_converter_read(&pDevice->playback.converter, pSamples, frameCount);
 }
 
 // A helper for sending sample data to the client.