rigidbody: Avoid unnecessary simulation updates

Now we flag the world for update on frame change and only call
BKE_rigidbody_do_simulation() when needed.

3 files changed, 18 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/rigidbody.c b/source/blender/blenkernel/intern/rigidbody.c
index 055ada33867..9ae82422ca2 100644
--- a/source/blender/blenkernel/intern/rigidbody.c
+++ b/source/blender/blenkernel/intern/rigidbody.c
@@ -1223,6 +1223,8 @@ void BKE_rigidbody_do_simulation(Scene *scene, float ctime)
 	BKE_ptcache_id_time(&pid, scene, ctime, &startframe, &endframe, NULL);
 	cache = rbw->pointcache;
 
+	rbw->flag &= ~RBW_FLAG_FRAME_UPDATE;
+
 	/* flag cache as outdated if we don't have a world or number of objects in the simulation has changed */
 	if (rbw->physics_world == NULL || rbw->numbodies != BLI_countlist(&rbw->group->gobject)) {
 		cache->flag |= PTCACHE_OUTDATED;
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index 13e050f12b7..269751e79d4 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -1089,6 +1089,15 @@ static void scene_depsgraph_hack(Scene *scene, Scene *scene_parent)
 
 }
 
+static void scene_flag_rbw_recursive(Scene *scene)
+{
+	if (scene->set)
+		scene_flag_rbw_recursive(scene->set);
+
+	if (BKE_scene_check_rigidbody_active(scene))
+		scene->rigidbody_world->flag |= RBW_FLAG_FRAME_UPDATE;
+}
+
 static void scene_update_tagged_recursive(Main *bmain, Scene *scene, Scene *scene_parent)
 {
 	Base *base;
@@ -1106,8 +1115,7 @@ static void scene_update_tagged_recursive(Main *bmain, Scene *scene, Scene *scen
 	 */
 	// XXX: this position may still change, objects not being updated correctly before simulation is run
 	// NOTE: current position is so that rigidbody sim affects other objects
-	// FIXME: this now gets executed on every update, not just frame change now!!!
-	if (BKE_scene_check_rigidbody_active(scene)) {
+	if (BKE_scene_check_rigidbody_active(scene) && scene->rigidbody_world->flag & RBW_FLAG_FRAME_UPDATE) {
 		/* we use frame time of parent (this is "scene" itself for top-level of sets recursion), 
 		 * as that is the active scene controlling all timing in file at the moment
 		 */
@@ -1230,6 +1238,9 @@ void BKE_scene_update_for_newframe(Main *bmain, Scene *sce, unsigned int lay)
 	tag_main_idcode(bmain, ID_MA, FALSE);
 	tag_main_idcode(bmain, ID_LA, FALSE);
 
+	/* flag rigid body worlds for update */
+	scene_flag_rbw_recursive(sce);
+
 	/* BKE_object_handle_update() on all objects, groups and sets */
 	scene_update_tagged_recursive(bmain, sce, sce);
 
diff --git a/source/blender/makesdna/DNA_rigidbody_types.h b/source/blender/makesdna/DNA_rigidbody_types.h
index ca703130edc..1636f2f4e4b 100644
--- a/source/blender/makesdna/DNA_rigidbody_types.h
+++ b/source/blender/makesdna/DNA_rigidbody_types.h
@@ -80,7 +80,9 @@ typedef enum eRigidBodyWorld_Flag {
 	/* sim data needs to be rebuilt */
 	RBW_FLAG_NEEDS_REBUILD		= (1 << 1),
 	/* usse split impulse when stepping the simulation */
-	RBW_FLAG_USE_SPLIT_IMPULSE	= (1 << 2)
+	RBW_FLAG_USE_SPLIT_IMPULSE	= (1 << 2),
+	/* need to step simulation after frame update */
+	RBW_FLAG_FRAME_UPDATE		= (1 << 3)
 } eRigidBodyWorld_Flag;
 
 /* ******************************** */