Fix underwater breathing sounds when player not fully in the water. Same as https://github.com/ValveSoftware/halflife/issues/3110.

dlls/player.cpp

@@ -1198,23 +1198,26 @@ void CBasePlayer::WaterMove()
 	}
 
 	// make bubbles
-	air = (int)( pev->air_finished - gpGlobals->time );
-	if( !RANDOM_LONG( 0, 0x1f ) && RANDOM_LONG( 0, AIRTIME - 1 ) >= air )
+	if( pev->waterlevel == 3 )
 	{
-		switch( RANDOM_LONG( 0, 3 ) )
+		air = (int)( pev->air_finished - gpGlobals->time );
+		if( !RANDOM_LONG( 0, 0x1f ) && RANDOM_LONG( 0, AIRTIME - 1 ) >= air )
 		{
-			case 0:
-				EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim1.wav", 0.8, ATTN_NORM );
-				break;
-			case 1:
-				EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim2.wav", 0.8, ATTN_NORM );
-				break;
-			case 2:
-				EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim3.wav", 0.8, ATTN_NORM );
-				break;
-			case 3:
-				EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim4.wav", 0.8, ATTN_NORM );
-				break;
+			switch( RANDOM_LONG( 0, 3 ) )
+			{
+				case 0:
+					EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim1.wav", 0.8, ATTN_NORM );
+					break;
+				case 1:
+					EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim2.wav", 0.8, ATTN_NORM );
+					break;
+				case 2:
+					EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim3.wav", 0.8, ATTN_NORM );
+					break;
+				case 3:
+					EMIT_SOUND( ENT( pev ), CHAN_BODY, "player/pl_swim4.wav", 0.8, ATTN_NORM );
+					break;
+			}
 		}
 	}