Nla Sound Strips + Add Speaker

Second part of previous commit. Now, when speaker objects are created,
they are created by default with an NLA sound strip so that it is easy
to just start immediately using this to do cool stuff (i.e. timing
when you want the sound to start).

source/blender/editors/object/object_add.c

@@ -35,6 +35,7 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "DNA_anim_types.h"
 #include "DNA_curve_types.h"
 #include "DNA_group_types.h"
 #include "DNA_lamp_types.h"
@@ -69,6 +70,7 @@
 #include "BKE_mball.h"
 #include "BKE_mesh.h"
 #include "BKE_modifier.h"
+#include "BKE_nla.h"
 #include "BKE_object.h"
 #include "BKE_particle.h"
 #include "BKE_report.h"
@@ -778,6 +780,25 @@ static int object_speaker_add_exec(bContext *C, wmOperator *op)
 		return OPERATOR_CANCELLED;
 
 	ob= ED_object_add_type(C, OB_SPEAKER, loc, rot, FALSE, layer);
+	
+	/* to make it easier to start using this immediately in NLA, a default sound clip is created
+	 * ready to be moved around to retime the sound and/or make new sound clips
+	 */
+	{
+		/* create new data for NLA hierarchy */
+		AnimData *adt = BKE_id_add_animdata(&ob->id);
+		NlaTrack *nlt = add_nlatrack(adt, NULL);
+		NlaStrip *strip = add_nla_soundstrip(CTX_data_scene(C), ob->data);
+		
+		/* hook them up */
+		BKE_nlatrack_add_strip(nlt, strip);
+		
+		/* auto-name the strip, and give the track an interesting name  */
+		strcpy(nlt->name, "SoundTrack");
+		BKE_nlastrip_validate_name(adt, strip);
+		
+		WM_event_add_notifier(C, NC_ANIMATION|ND_NLA|NA_EDITED, NULL);
+	}
 
 	return OPERATOR_FINISHED;
 }