WIP FMOD sound system:

- Quick hack channel userdata for attenuation to test normal entity sounds
- Always set full volume for sounds coming from the view entity (i.e. the player)
- It's starting to sound like Quake!

engine/Quake/snd_fmod.c

@@ -22,7 +22,6 @@ static float SND_FMOD_Attenuation(FMOD_CHANNELCONTROL *channelControl, float dis
 
 typedef struct entchannel_s
 {
-	sfx_t *sfx;
 	int entnum;
 	int entchannel;
 	float dist_mult;
@@ -134,6 +133,12 @@ static float SND_FMOD_Attenuation(FMOD_CHANNELCONTROL *channelcontrol, float dis
 		return 1.0f;
 	}
 
+	// Anything coming from the view entity will always be full volume
+	if (userdata->entnum == cl.viewentity)
+	{
+		return 1.0f;
+	}
+
 	scale = 1.0f - (distance * userdata->dist_mult);
 	if (scale < 0.0f)
 		scale = 0.0f;
@@ -190,7 +195,7 @@ static float SND_FMOD_Attenuation(FMOD_CHANNELCONTROL *channelcontrol, float dis
 //	return channel;
 //}
 
-void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float fvol, float attenuation)
+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
 {
 	FMOD_CHANNEL *channel;
 	FMOD_VECTOR position;
@@ -200,7 +205,7 @@ void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float f
 		return;
 
 	// TODO: check nosound cvar
-	return;	// HACK play no entity sfx for now
+	//return;	// HACK play no entity sfx for now
 
 	S_LoadSound(sfx);
 	if (!sfx->sound)
@@ -208,12 +213,13 @@ void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float f
 
 	// Find channel group for entity number (or create) => note entnum can also be some random hash value
 		// ChannelControl::setMode => set to 3D
+		// Can use channel group per entity to store entity-specific userdata, with maybe 16 fixed channel slots
 	
 	// Pre-define channels for each entity (could be an array of ints, probably array of entchannel_t structs)
 	// For entchannel 0, dynamically select a free channel (or just play without doing anything, let FMOD handle it)
 	// If channel at index entchannel >0 is already playing: stop
 	//		Set userdata pointer to entchannel_t so we can check if the FMOD channel still belongs to this entity & entchannel, before checking if it's already playing
-	// Special case entchannel -1 => just play locally on listener, no 3D
+	// Special case entchannel -1 => just play locally on listener, no 3D (also override any sound already playing on entity)
 
 	// System::playSound with paused = true
 	result = FMOD_System_PlaySound(fmod_system, sfx->sound, sfx_channelGroup, 1, &channel);
@@ -229,7 +235,14 @@ void S_StartSound(int entnum, int entchannel, sfx_t *sfx, vec3_t origin, float f
 	FMOD_Channel_SetMode(channel, FMOD_LOOP_OFF);	// TODO: some entity sounds do need to loop, e.g. moving elevators. How is this done?
 	FMOD_Channel_SetVolume(channel, fvol);
 	FMOD_Channel_Set3DLevel(channel, entchannel < 0 ? 0.0f : 1.0f);	// entchannel -1 is used for local sounds
-	// TODO: attenuation
+	
+	// TODO: attenuation (this is just a quick hack to test)
+	entchannel_t *userdata = (entchannel_t*)malloc(sizeof(entchannel_t));	// TODO: we REALLY need to allocate this properly, this is now a memory leak!!
+	userdata->entnum = entnum;
+	userdata->entchannel = entchannel;
+	userdata->channel = channel;
+	userdata->dist_mult = attenuation / sound_nominal_clip_dist;
+	FMOD_Channel_SetUserData(channel, userdata);
 
 	// TODO: use ChannelControl Callback to detect when the sound ends, then clear it from the entchannel_t list
 
@@ -249,9 +262,6 @@ void S_StaticSound(sfx_t *sfx, vec3_t origin, float vol, float attenuation)	// N
 	FMOD_RESULT result;
 	unsigned long long dspclock;
 
-	// Similar to above, but without the per-entity channel group song and dance
-	// Check if sound is looped (should be) and FMOD_Channel_SetMode to looped
-	// Set Channel::setLoopPoints if the sfxcache specifies something non-standard
 	if (!fmod_system || !sfx)
 		return;
 
@@ -271,14 +281,15 @@ void S_StaticSound(sfx_t *sfx, vec3_t origin, float vol, float attenuation)	// N
 	FMOD_Channel_SetMode(channel, FMOD_LOOP_NORMAL);
 	FMOD_Channel_SetVolume(channel, vol / 255);
 	
-	// TODO: attenuation (which is pre-multiplied by 64)
+	// Set up attenuation info for use by the rolloff callback
 	entchannel_t *userdata = (entchannel_t*)malloc(sizeof(entchannel_t));	// This is rather convenient. Can we use Z_Malloc here perhaps?
-	userdata->sfx = sfx;
+	userdata->entnum = -1;
 	userdata->channel = channel;
 	userdata->dist_mult = (attenuation / 64) / sound_nominal_clip_dist;
 	FMOD_Channel_SetUserData(channel, userdata);
 
-	// Add a random delay so that similar sounds don't phase together (note: this isn't really authentic to original Quake, but it improves the sense of directionality)
+	// Add a random delay so that similar sounds don't phase together
+	// Note: this isn't really authentic to the original Quake sound system, but it does improve the sense of directionality
 	FMOD_ChannelGroup_GetDSPClock(sfx_channelGroup, &dspclock, NULL);
 	FMOD_Channel_SetDelay(channel, dspclock + SND_GetDelay(sfx), 0, 0);
 
@@ -302,7 +313,7 @@ void S_StopAllSounds(qboolean clear)
 
 void S_ClearBuffer(void)
 {
-
+	// TODO Use this to remove per-entity channel group and clear all userdata?
 }
 
 void S_Update(vec3_t origin, vec3_t forward, vec3_t right, vec3_t up)