Add audio output volume control

iNDS/AppDelegate.m

@@ -596,7 +596,9 @@ - (WCEasySettingsViewController *)getSettingsViewController
 
         // Audio
         WCEasySettingsSection *audioSection = [[WCEasySettingsSection alloc] initWithTitle:@"Audio" subTitle:@""];
-        audioSection.items = @[[[WCEasySettingsSwitch alloc] initWithIdentifier:@"disableSound"
+        audioSection.items = @[[[WCEasySettingsSlider alloc] initWithIdentifier:@"outputVolume"
+                                                                          title:@"Output Volume"],
+                               [[WCEasySettingsSwitch alloc] initWithIdentifier:@"disableSound"
                                                                           title:@"Disable Sound"],
                                [[WCEasySettingsSwitch alloc] initWithIdentifier:@"allowExternalAudio"
                                                                           title:@"Allow External Audio"],

iNDS/core/emu.cpp

@@ -301,14 +301,20 @@ void EMU_enableSound(bool enabled)
 /*
  SPU seems to need to be kickstarted. If left disabled when initializing the ROM,
  then we can't expect to magically enable it partway through. To solve this, we
- just let it run for a cycle if we disable sound.
+ just let it run for a cycle if we disable sound. We only kick the SPU when soundEnabled has changed, to prevent unnecessarily kickstarting the SPU.
 
  More information see iNDS-Team/iNDS#35
  */
-    if (!enabled) SPU_Emulate_user(true);
+    if(!enabled && soundEnabled != enabled) SPU_Emulate_user(true);
     soundEnabled = enabled;
 }
 
+void EMU_setAudioOutputVolume(double volume)
+{
+    int vol = volume * 100;
+    SPU_SetVolume(vol);
+}
+
 void EMU_setFrameSkip(int skip)
 {
     if (skip == -1) {

iNDS/core/emu.h

@@ -37,6 +37,7 @@ bool EMU_doRomLoad(const char* path, const char* logical);
 bool EMU_loadRom(const char* path);
 void EMU_change3D(int type);
 void EMU_changeSound(int type);
+void EMU_setAudioOutputVolume(double volume);
 void EMU_enableSound(bool enable);
 bool EMU_frameSkip(bool force);
 void EMU_setFrameSkip(int skip);

iNDS/core/sndcoreaudio.mm

@@ -41,6 +41,7 @@
 static bool audioQueueStarted = false;
 static AudioQueueBufferRef aqBuffer[NUM_BUFFERS];
 static AudioQueueRef audioQueue;
+static float volume = 1.0;
 
 void SNDCoreAudioCallback(void *data, AudioQueueRef mQueue, AudioQueueBufferRef mBuffer) {
     mBuffer->mAudioDataByteSize = sndBufferSize;
@@ -119,14 +120,11 @@ void SNDCoreAudioMuteAudio() {
 }
 
 void SNDCoreAudioUnMuteAudio() {
-    AudioQueueSetParameter(audioQueue, kAudioQueueParam_Volume, 1.0);
+    AudioQueueSetParameter(audioQueue, kAudioQueueParam_Volume, volume);
 }
 
 void SNDCoreAudioSetVolume(int volume) {
-    /*
-     This function was not implemented, but if it was implemented,
-     this is how to do it.
     float scaled = volume / 100.0;
+    ::volume = scaled;
     AudioQueueSetParameter(audioQueue, kAudioQueueParam_Volume, scaled);
-     */
 }

iNDS/iNDSEmulatorViewController.mm

@@ -373,6 +373,10 @@ - (void)defaultsChanged:(NSNotification*)notification
         // (Mute on && don't ignore it) or user has sound disabled
         BOOL muteSound = [defaults boolForKey:@"disableSound"];
         EMU_enableSound(!muteSound);
+
+        double outputVolume = [defaults doubleForKey:@"outputVolume"];
+        EMU_setAudioOutputVolume(outputVolume);
+
         AVAudioSessionCategoryOptions opts = AVAudioSessionCategoryOptionDefaultToSpeaker | AVAudioSessionCategoryOptionAllowBluetoothA2DP;
         if([defaults boolForKey:@"allowExternalAudio"]){
             opts |= AVAudioSessionCategoryOptionMixWithOthers;

iNDS/settings/Defaults.plist

@@ -16,6 +16,8 @@
 	<true/>
 	<key>frameSkip</key>
 	<integer>-1</integer>
+	<key>outputVolume</key>
+	<integer>1</integer>
 	<key>disableSound</key>
 	<false/>
 	<key>allowExternalAudio</key>