Work on sound driver levels.

apu/resampler.h

@@ -91,6 +91,29 @@ class Resampler
         r_right[0] = r_right[1] = r_right[2] = r_right[3] = 0;
     }
 
+    inline void dump(unsigned int num_samples)
+    {
+        if (space_filled() >= num_samples)
+            start = (start + num_samples) % buffer_size;
+    }
+
+    inline void add_silence(unsigned int num_samples)
+    {
+        if (space_empty() <= num_samples)
+        {
+            int new_end = (end + num_samples) % buffer_size;
+
+            if (new_end < end)
+            {
+                memset(buffer + end, 0, 2 * (buffer_size - end));
+                memset(buffer, 0, 2 * (num_samples - (buffer_size - end)));
+            }
+
+            memset(buffer + end, 0, 2 * num_samples);
+            end = new_end;
+        }
+    }
+
     inline bool pull(int16_t *dst, int num_samples)
     {
         if (space_filled() < num_samples)

common/audio/s9x_sound_driver_cubeb.cpp

@@ -10,11 +10,13 @@
 bool S9xCubebSoundDriver::write_samples(int16_t *data, int samples)
 {
     bool retval = true;
-    if (samples > buffer.space_empty())
+    auto empty = buffer.space_empty();
+    if (samples > empty)
     {
         retval = false;
-        samples = buffer.space_empty();
+        buffer.dump(buffer.buffer_size / 2 - empty);
     }
+
     buffer.push(data, samples);
 
     return retval;
@@ -83,6 +85,7 @@ long S9xCubebSoundDriver::data_callback(cubeb_stream *stream, void const *input_
         auto zeroed_samples = nframes * 2 - avail;
         memset(output_buffer, 0, zeroed_samples);
         buffer.read((int16_t *)output_buffer + zeroed_samples, nframes * 2 - zeroed_samples);
+        buffer.add_silence(buffer.buffer_size / 2);
     }
     else
     {

common/audio/s9x_sound_driver_pulse.cpp

@@ -111,10 +111,10 @@ bool S9xPulseSoundDriver::open_device(int playback_rate, int buffer_size_ms)
     ss.rate = playback_rate;
 
     pa_buffer_attr buffer_attr;
-    buffer_attr.tlength = pa_usec_to_bytes(buffer_size_ms * 1000, &ss);
+    buffer_attr.tlength = 2 * pa_usec_to_bytes(buffer_size_ms * 1000, &ss);
     buffer_attr.maxlength = buffer_attr.tlength * 2;
     buffer_attr.minreq = pa_usec_to_bytes(3000, &ss);
-    buffer_attr.prebuf = -1;
+    buffer_attr.prebuf = buffer_attr.tlength / 2;
 
     printf("PulseAudio sound driver initializing...\n");
 
@@ -189,8 +189,23 @@ bool S9xPulseSoundDriver::write_samples(int16_t *data, int samples)
     size_t bytes = pa_stream_writable_size(stream);
     unlock();
 
-    if (samples * 2 > bytes)
+    if (draining)
+    {
+        if (bytes > buffer_size / 2)
+        {
             return false;
+        }
+        else
+        {
+            draining = false;
+        }
+    }
+
+    if (samples * 2 > bytes)
+    {
+        draining = true;
+        return false;
+    }
 
     if (samples * 2 < bytes)
         bytes = samples * 2;

common/audio/s9x_sound_driver_pulse.hpp

@@ -32,6 +32,7 @@ class S9xPulseSoundDriver : public S9xSoundDriver
     void wait();
 
     int buffer_size;
+    bool draining = false;
 };
 
 #endif /* __S9X_SOUND_DRIVER_PULSE_HPP */

common/audio/s9x_sound_driver_sdl.cpp

@@ -10,10 +10,11 @@
 bool S9xSDLSoundDriver::write_samples(int16_t *data, int samples)
 {
     bool retval = true;
-    if (samples > buffer.space_empty())
+    auto empty = buffer.space_empty();
+    if (samples > empty)
     {
         retval = false;
-        samples = buffer.space_empty();
+        buffer.dump(buffer.buffer_size / 2 - empty);
     }
     buffer.push(data, samples);
 
@@ -24,6 +25,11 @@ void S9xSDLSoundDriver::mix(unsigned char *output, int bytes)
 {
     if (buffer.avail() >= bytes >> 1)
         buffer.read((int16_t *)output, bytes >> 1);
+    else
+    {
+        buffer.read((int16_t *)output, buffer.avail());
+        buffer.add_silence(buffer.buffer_size / 2);
+    }
 }
 
 S9xSDLSoundDriver::S9xSDLSoundDriver()

qt/src/EmuApplication.cpp

@@ -84,8 +84,14 @@ static void trackBufferLevel(int percent, QWidget *parent)
         ticks = 0;
     }
 
+    dialog->setFocusPolicy(Qt::FocusPolicy::NoFocus);
+
     if (!dialog->isVisible())
+    {
+        dialog->setDisabled(true);
         dialog->show();
+        dialog->setModal(false);
+    }
 }
 #endif