see, Arisotura, was it that hard?

src/SPU.cpp

@@ -738,6 +738,16 @@ void Mix(u32 samples)
 }
 
 
+void TrimOutput()
+{
+    const int halflimit = (OutputBufferSize / 2);
+
+    int readpos = OutputWriteOffset - (halflimit*2);
+    if (readpos < 0) readpos += (OutputBufferSize*2);
+
+    OutputReadOffset = readpos;
+}
+
 void DrainOutput()
 {
     OutputReadOffset = 0;

src/SPU.h

@@ -35,6 +35,7 @@ void SetBias(u16 bias);
 
 void Mix(u32 samples);
 
+void TrimOutput();
 void DrainOutput();
 void InitOutput();
 int GetOutputSize();

src/libui_sdl/DlgVideoSettings.cpp

@@ -94,7 +94,7 @@ void RevertSettings()
     if (old_vsync != Config::ScreenVSync)
     {
         Config::ScreenVSync = old_vsync;
-        ApplyNewSettings(4);
+        //ApplyNewSettings(4);
     }
     if (old_usegl != new_usegl)
     {
@@ -161,7 +161,7 @@ void OnGLDisplayChanged(uiCheckbox* cb, void* blarg)
 void OnVSyncChanged(uiCheckbox* cb, void* blarg)
 {
     Config::ScreenVSync = uiCheckboxChecked(cb);
-    ApplyNewSettings(4);
+    //ApplyNewSettings(4);
 }
 
 void OnThreaded3DChanged(uiCheckbox* cb, void* blarg)

src/libui_sdl/main.cpp

@@ -130,6 +130,8 @@ bool GL_ScreenSizeDirty;
 
 int GL_3DScale;
 
+bool GL_VSyncStatus;
+
 int ScreenGap = 0;
 int ScreenLayout = 0;
 int ScreenSizing = 0;
@@ -163,6 +165,9 @@ int AudioFreq;
 float AudioSampleFrac;
 SDL_AudioDeviceID AudioDevice, MicDevice;
 
+SDL_cond* AudioSync;
+SDL_mutex* AudioSyncLock;
+
 u32 MicBufferLength = 2048;
 s16 MicBuffer[2048];
 u32 MicBufferReadPos, MicBufferWritePos;
@@ -239,6 +244,8 @@ bool GLScreen_InitOSDShader(GLuint* shader)
 
 bool GLScreen_Init()
 {
+    GL_VSyncStatus = Config::ScreenVSync;
+
     // TODO: consider using epoxy?
     if (!OpenGL_Init())
         return false;
@@ -301,6 +308,13 @@ void GLScreen_DeInit()
 
 void GLScreen_DrawScreen()
 {
+    bool vsync = Config::ScreenVSync && !HotkeyDown(HK_FastForward);
+    if (vsync != GL_VSyncStatus)
+    {
+        GL_VSyncStatus = vsync;
+        uiGLSetVSync(vsync);
+    }
+
     float scale = uiGLGetFramebufferScale(GLContext);
 
     glBindFramebuffer(GL_FRAMEBUFFER, uiGLGetFramebuffer(GLContext));
@@ -575,9 +589,14 @@ void AudioCallback(void* data, Uint8* stream, int len)
     s16 buf_in[1024*2];
     s16* buf_out = (s16*)stream;
 
-    int num_in = SPU::ReadOutput(buf_in, len_in);
+    int num_in;
     int num_out = len;
 
+    SDL_LockMutex(AudioSyncLock);
+    num_in = SPU::ReadOutput(buf_in, len_in);
+    SDL_CondSignal(AudioSync);
+    SDL_UnlockMutex(AudioSyncLock);
+
     if (num_in < 1)
     {
         memset(stream, 0, len*sizeof(s16)*2);
@@ -920,6 +939,7 @@ int EmuThreadFunc(void* burp)
             Config::LimitFPS = !Config::LimitFPS;
             uiQueueMain(UpdateFPSLimit, NULL);
         }
+        // TODO: similar hotkeys for video/audio sync?
 
         if (HotkeyPressed(HK_Pause)) uiQueueMain(TogglePause, NULL);
         if (HotkeyPressed(HK_Reset)) uiQueueMain(Reset, NULL);
@@ -988,9 +1008,23 @@ int EmuThreadFunc(void* burp)
             }
             uiAreaQueueRedrawAll(MainDrawArea);
 
-            bool limitfps = Config::LimitFPS && !HotkeyDown(HK_FastForward);
+            bool fastforward = HotkeyDown(HK_FastForward);
-            bool vsync = Config::ScreenVSync && Screen_UseGL;
+
-            SPU::Sync(limitfps || vsync);
+            if (Config::AudioSync && !fastforward)
+            {
+                SDL_LockMutex(AudioSyncLock);
+                while (SPU::GetOutputSize() > 1024)
+                {
+                    int ret = SDL_CondWaitTimeout(AudioSync, AudioSyncLock, 500);
+                    if (ret == SDL_MUTEX_TIMEDOUT) break;
+                }
+                SDL_UnlockMutex(AudioSyncLock);
+            }
+            else
+            {
+                // ensure the audio FIFO doesn't overflow
+                //SPU::TrimOutput();
+            }
 
             float framerate = (1000.0f * nlines) / (60.0f * 263.0f);
 
@@ -998,6 +1032,7 @@ int EmuThreadFunc(void* burp)
                 u32 curtick = SDL_GetTicks();
                 u32 delay = curtick - lasttick;
 
+                bool limitfps = Config::LimitFPS && !fastforward;
                 if (limitfps)
                 {
                     float wantedtickF = starttick + (framerate * (fpslimitcount+1));
@@ -2269,7 +2304,7 @@ void ApplyNewSettings(int type)
         GPU3D::InitRenderer(Screen_UseGL);
         if (Screen_UseGL) uiGLMakeContextCurrent(NULL);
     }
-    else if (type == 4) // vsync
+    /*else if (type == 4) // vsync
     {
         if (Screen_UseGL)
         {
@@ -2281,7 +2316,7 @@ void ApplyNewSettings(int type)
         {
             // TODO eventually: VSync for non-GL screen?
         }
-    }
+    }*/
 
     EmuRunning = prevstatus;
 }
@@ -2704,6 +2739,9 @@ int main(int argc, char** argv)
     uiMenuItemSetChecked(MenuItem_AudioSync, Config::AudioSync==1);
     uiMenuItemSetChecked(MenuItem_ShowOSD, Config::ShowOSD==1);
 
+    AudioSync = SDL_CreateCond();
+    AudioSyncLock = SDL_CreateMutex();
+
     AudioFreq = 48000; // TODO: make configurable?
     SDL_AudioSpec whatIwant, whatIget;
     memset(&whatIwant, 0, sizeof(SDL_AudioSpec));
@@ -2779,6 +2817,9 @@ int main(int argc, char** argv)
     if (AudioDevice) SDL_CloseAudioDevice(AudioDevice);
     if (MicDevice)   SDL_CloseAudioDevice(MicDevice);
 
+    SDL_DestroyCond(AudioSync);
+    SDL_DestroyMutex(AudioSyncLock);
+
     if (MicWavBuffer) delete[] MicWavBuffer;
 
     if (ScreenBitmap[0]) uiDrawFreeBitmap(ScreenBitmap[0]);