Implemented ambient sounds, did some refactoring and added explanations about the different types of sounds

engine/Quake/snd_fmod.c

@@ -15,8 +15,11 @@ static float old_volume = -1.0f;
 
 static FMOD_CHANNELGROUP *sfx_channelGroup = NULL;
 
+vec3_t listener_origin;
+
 static const char *FMOD_SpeakerModeString(FMOD_SPEAKERMODE speakermode);
 static float SND_FMOD_Attenuation(FMOD_CHANNELCONTROL *channelControl, float distance);
+static void SND_StartAmbientSounds();
 
 // Copy and convert coordinate system
 #define FMOD_VectorCopy(a, b)	{(b).x=(a)[0];(b).y=(a)[2];(b).z=(a)[1];}
@@ -35,6 +38,7 @@ typedef struct entsounds_s
 } entsounds_t;
 
 static entsounds_t entsounds[MAX_CHANNELS];
+static FMOD_CHANNEL *ambients[NUM_AMBIENTS];
 
 // Keep track of all the sounds started each frame
 static sfx_t *sfxThisFrame[16];
@@ -130,7 +134,7 @@ void S_Shutdown(void)
 
 	Con_DPrintf("[FMOD] Shutdown\n");
 
-	S_StopAllSounds(true);
+	S_StopAllSounds(false);
 
 	// Release all sounds that were loaded and attached to sfx_t's
 	for (i = 0; i < num_sfx; i++)
@@ -228,6 +232,26 @@ static FMOD_RESULT SND_FMOD_Callback(FMOD_CHANNELCONTROL *channelcontrol, FMOD_C
 	return FMOD_OK;
 }
 
+static void SND_FMOD_SetChannelAttributes(FMOD_CHANNEL *channel, sfx_t *sfx, vec3_t origin, float vol)
+{
+	FMOD_VECTOR position;
+
+	FMOD_VectorCopy(origin, position);
+	FMOD_Channel_Set3DAttributes(channel, &position, NULL);
+	FMOD_Channel_SetVolume(channel, vol);
+	FMOD_Channel_SetVolumeRamp(channel, 1);	// This *might* help somewhat with slight audio pops (esp. noticable on the Nailgun)
+
+	if (sfx->loopstart >= 0)
+	{
+		FMOD_Channel_SetMode(channel, FMOD_LOOP_NORMAL);
+		FMOD_Channel_SetLoopPoints(channel, sfx->loopstart, FMOD_TIMEUNIT_MS, sfx->loopend, FMOD_TIMEUNIT_MS);
+	}
+	else
+	{
+		FMOD_Channel_SetMode(channel, FMOD_LOOP_OFF);
+	}
+}
+
 static soundslot_t *SND_PickSoundSlot(int entnum, int entchannel)
 {
 	soundslot_t *slot;
@@ -255,11 +279,107 @@ static soundslot_t *SND_PickSoundSlot(int entnum, int entchannel)
 	return slot;
 }
 
+/*
+==============
+Ambient sounds
+
+These are sounds that are always present and always playing. They are unaffected by distance or orientation.
+Instead they are modulated in volume based on whether the player is inside a world volume that has ambient sound levels set.
+==============
+*/
+static FMOD_CHANNEL *SND_StartAmbientSound(const char *samplename)
+{
+	sfx_t *sfx;
+	FMOD_CHANNEL *channel;
+	FMOD_RESULT result;
+
+	sfx = S_PrecacheSound(samplename);
+	if (!sfx)
+		return NULL;
+
+	S_LoadSound(sfx);
+	if (!sfx->sound)
+		return NULL;
+
+	result = FMOD_System_PlaySound(fmod_system, sfx->sound, sfx_channelGroup, 1, &channel);
+	if (result != FMOD_OK)
+	{
+		Con_Printf("Failed to play ambient FMOD sound: %s\n", FMOD_ErrorString(result));
+		return NULL;
+	}
+
+	SND_FMOD_SetChannelAttributes(channel, sfx, vec3_origin, 0.0f);
+	FMOD_Channel_Set3DLevel(channel, 0.0f);
+	FMOD_Channel_SetPaused(channel, 0);
+
+	return channel;
+}
+
+static void SND_StartAmbientSounds()
+{
+	memset(ambients, 0, sizeof(ambients));
+	ambients[AMBIENT_WATER] = SND_StartAmbientSound("ambience/water1.wav");
+	ambients[AMBIENT_SKY] = SND_StartAmbientSound("ambience/wind2.wav");
+}
+
+static void S_UpdateAmbientSounds()
+{
+	FMOD_CHANNEL *channel;
+	mleaf_t *leaf;
+	float vol, channel_vol;
+
+	if (cl.worldmodel && cl.worldmodel->nodes)
+		leaf = Mod_PointInLeaf(listener_origin, cl.worldmodel);
+	else
+		leaf = NULL;
+
+	for (int i = 0; i < NUM_AMBIENTS; i++)
+	{
+		channel = ambients[i];
+		if (!channel)
+			continue;
+
+		if (!leaf || !ambient_level.value)
+		{
+			FMOD_Channel_SetVolume(channel, 0.0f);
+			continue;
+		}
+
+		vol = (ambient_level.value * (float)leaf->ambient_sound_level[i]) / 255;
+		if (vol < 0.03f)
+			vol = 0.0f;
+
+		// don't adjust volume too fast
+		FMOD_Channel_GetVolume(channel, &channel_vol);
+		if (channel_vol < vol)
+		{
+			channel_vol += host_frametime * (ambient_fade.value / 255);
+			if (channel_vol > vol)
+				channel_vol = vol;
+		}
+		else if (channel_vol > vol)
+		{
+			channel_vol -= host_frametime * (ambient_fade.value / 255);
+			if (channel_vol < vol)
+				channel_vol = vol;
+		}
+
+		FMOD_Channel_SetVolume(channel, channel_vol);
+	}
+}
+
+/*
+=============
+Entity sounds
+
+These are your typical 3D sounds generated by entities in the world, including the player.
+Each entity has a number of preset voice channels, each of which can only play one sound at a time.
+=============
+*/
 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;
@@ -285,26 +405,14 @@ void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float f
 		return;
 	}
 
+	SND_FMOD_SetChannelAttributes(channel, sfx, origin, fvol);
+
 	// Set up callback data for rolloff and cleanup
 	userdata->channel = channel;
 	userdata->dist_mult = attenuation / sound_nominal_clip_dist;
 	FMOD_Channel_SetUserData(channel, userdata);
 	FMOD_Channel_SetCallback(channel, &SND_FMOD_Callback);
 
-	FMOD_VectorCopy(origin, position);
-	FMOD_Channel_Set3DAttributes(channel, &position, NULL);
-	FMOD_Channel_SetVolume(channel, fvol);
-
-	if (sfx->loopstart >= 0)
-	{
-		FMOD_Channel_SetMode(channel, FMOD_LOOP_NORMAL);
-		FMOD_Channel_SetLoopPoints(channel, sfx->loopstart, FMOD_TIMEUNIT_MS, sfx->loopend, FMOD_TIMEUNIT_MS);
-	}
-	else
-	{
-		FMOD_Channel_SetMode(channel, FMOD_LOOP_OFF);
-	}
-	
 	// Anything coming from the view entity will always be full volume, and entchannel -1 is used for local sounds (e.g. menu sounds)
 	if (entchannel < 0 || entnum == cl.viewentity)
 	{
@@ -330,12 +438,17 @@ void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float f
 	FMOD_Channel_SetPaused(channel, 0);
 }
 
-// TODO: we're still missing Automatic Ambient sounds for water, lava, slime etc (see S_UpdateAmbientSounds)
+/*
+=============
+Static sounds
 
+These are sounds that have a fixed position in the world and loop continuously.
+They typically start playing immediately on level load.
+=============
+*/
 void S_StaticSound(sfx_t *sfx, vec3_t origin, float vol, float attenuation)	// Note: volume and attenuation are in 0-255 range here
 {
 	FMOD_CHANNEL *channel;
-	FMOD_VECTOR position;
 	FMOD_RESULT result;
 	soundslot_t *userdata;
 	unsigned long long dspclock;
@@ -354,11 +467,8 @@ void S_StaticSound(sfx_t *sfx, vec3_t origin, float vol, float attenuation)	// N
 		return;
 	}
 
-	FMOD_VectorCopy(origin, position);
-	FMOD_Channel_Set3DAttributes(channel, &position, NULL);
-	FMOD_Channel_SetMode(channel, FMOD_LOOP_NORMAL);
-	FMOD_Channel_SetVolume(channel, vol / 255);
-	
+	SND_FMOD_SetChannelAttributes(channel, sfx, origin, vol / 255);
+
 	// Set up attenuation info for use by the rolloff callback
 	userdata = SND_PickSoundSlot(-1, -1);
 	userdata->channel = channel;
@@ -402,7 +512,12 @@ void S_StopAllSounds(qboolean clear)
 	FMOD_ChannelGroup_Stop(sfx_channelGroup);
 
 	if (clear)
+	{
 		S_ClearBuffer();
+
+		// Ambient sounds need to be restarted, as they are always "playing"
+		SND_StartAmbientSounds();
+	}
 }
 
 void S_ClearBuffer(void)
@@ -426,6 +541,8 @@ void S_Update(vec3_t origin, vec3_t forward, vec3_t right, vec3_t up)
 		old_volume = sfxvolume.value;
 	}
 
+	VectorCopy(origin, listener_origin);
+
 	FMOD_VECTOR fmod_pos, fmod_forward, fmod_up;
 	FMOD_VectorCopy(origin, fmod_pos);
 	FMOD_VectorCopy(forward, fmod_forward);
@@ -436,6 +553,8 @@ void S_Update(vec3_t origin, vec3_t forward, vec3_t right, vec3_t up)
 
 	FMOD_ChannelGroup_SetVolume(sfx_channelGroup, sfxvolume.value);
 
+	S_UpdateAmbientSounds();
+
 	FMOD_System_Update(fmod_system);
 
 	// Reset sounds played for the next frame