Implemented sound effect delay in the situation where multiple instances of the same sound are started on a single frame

engine/Quake/snd_fmod.c

@@ -36,6 +36,10 @@ typedef struct entsounds_s
 
 static entsounds_t entsounds[MAX_CHANNELS];
 
+// Keep track of all the sounds started each frame
+static sfx_t *sfxThisFrame[16];
+static int numSfxThisFrame;
+
 void S_Startup(void)
 {
 	FMOD_RESULT result;
@@ -114,6 +118,8 @@ void S_Startup(void)
 	FMOD_System_Set3DRolloffCallback(fmod_system, &SND_FMOD_Attenuation);
 
 	memset(entsounds, 0, sizeof(entsounds));
+	memset(sfxThisFrame, 0, sizeof(sfxThisFrame));
+	numSfxThisFrame = 0;
 
 	sound_started = true;
 }
@@ -252,10 +258,12 @@ static soundslot_t *SND_PickSoundSlot(int entnum, int entchannel)
 
 void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float fvol, float attenuation)	// Note: volume and attenuation are properly normalized here
 {
+	int i;
 	FMOD_CHANNEL *channel;
 	FMOD_VECTOR position;
 	FMOD_RESULT result;
 	soundslot_t *userdata;
+	unsigned long long dspclock;
 
 	if (!fmod_system || !sfx)
 		return;
@@ -304,7 +312,20 @@ void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float f
 		FMOD_Channel_SetPriority(channel, 64);	// Ensure local sounds always get priority over other entities
 	}
 	
-	// TODO: Use ChannelControl::setDelay and ChannelControl::getDSPClock to add a delay to move sounds out of phase if necessary
+	for (i = 0; i < numSfxThisFrame; i++)
+	{
+		// if an identical sound has also been started this frame, offset the pos
+		// a bit to keep it from just making the first one louder
+		if (sfxThisFrame[i] == sfx)
+		{
+			FMOD_ChannelGroup_GetDSPClock(sfx_channelGroup, &dspclock, NULL);
+			FMOD_Channel_SetDelay(channel, dspclock + SND_GetDelay(sfx, 0.1f), 0, 0);
+			break;
+		}
+	}
+
+	if (numSfxThisFrame < 16)
+		sfxThisFrame[numSfxThisFrame++] = sfx;
 
 	FMOD_Channel_SetPaused(channel, 0);
 }
@@ -416,6 +437,10 @@ void S_Update(vec3_t origin, vec3_t forward, vec3_t right, vec3_t up)
 	FMOD_ChannelGroup_SetVolume(sfx_channelGroup, sfxvolume.value);
 
 	FMOD_System_Update(fmod_system);
+
+	// Reset sounds played for the next frame
+	memset(sfxThisFrame, 0, sizeof(sfxThisFrame));
+	numSfxThisFrame = 0;
 }
 
 void S_ExtraUpdate(void)