Function S_AddLoopSounds

code/client/snd_dma.cpp:1967–2026

================== S_AddLoopSounds Spatialize all of the looping sounds. All sounds are on the same cycle, so any duplicates can just sum up the channel multipliers. ================== */

==================
*/
void S_AddLoopSounds (void)
{
	int			i, j;
	int			left, right, left_total, right_total;
	channel_t	*ch;
	loopSound_t	*loop, *loop2;
	static int	loopFrame;

	loopFrame++;
	for ( i = 0 ; i < numLoopSounds ; i++) {
		loop = &loopSounds[i];
		if ( loop->mergeFrame == loopFrame ) {
			continue;	// already merged into an earlier sound
		}

		// find the total contribution of all sounds of this type
		left_total = right_total = 0;

		for ( j = i ; j < numLoopSounds ; j++) {
			loop2 = &loopSounds[j];
			if ( loop2->sfx != loop->sfx ) {
				continue;
			}
			loop2->mergeFrame = loopFrame;	// don't check this again later

			S_SpatializeOrigin( loop2->origin, loop2->volume, &left, &right, loop2->entchan);

			left_total += left;
			right_total += right;
		}

		if (left_total == 0 && right_total == 0)
			continue;		// not audible

		// allocate a channel
		ch = S_PickChannel(0, 0);
		if (!ch)
			return;

		if (left_total > SOUND_MAXVOL)
			left_total = SOUND_MAXVOL;
		if (right_total > SOUND_MAXVOL)
			right_total = SOUND_MAXVOL;
		ch->leftvol = left_total;
		ch->rightvol = right_total;
		ch->loopSound = qtrue;	// remove next frame
		ch->thesfx = loop->sfx;

		// you cannot use MP3 files here because they offer only streaming access, not random
		//
		if (loop->sfx->pMP3StreamHeader)
		{
			Com_Error( ERR_DROP, "S_AddLoopSounds(): Cannot use streamed MP3 files here for random access (%s)\n",loop->sfx->sSoundName );
		}
		else
		{
			memset(&ch->MP3StreamHeader,0,						sizeof(ch->MP3StreamHeader));
		}