Prevent copying too much in the Rigid Body simulation

To prevent the pointcache from being copied-on-write too (and requiring
copying back), the cache is now shared between the original and
evaluated scenes. Reading from the cache is always allowed; running the
sim and writing to the cache is only allowed when the depsgraph is
active.

Some pointers have moved from RigidBodyWorld (RBO) to
RigidBodyWorldShared (RBOS). writefile.c copies some pointers back from
RBOS to RBO so that the file can still be opened on older Blenders
without crashing on a segfault.

The RigidBodyWorldShared struct is written to the blend file, because it
refers to the PointCache ID block.

The RigidObjectShared struct is runtime-only, and thus not saved to the
blend file.

An RNA getter-function is used to hide the new 'shared' pointer. As a
result the Python API hasn't changed.

Reviewed by: campbellbarton

Differential Revision: https://developer.blender.org/D3508

1 files changed, 3 insertions, 4 deletions

diff --git a/source/blender/editors/physics/rigidbody_world.c b/source/blender/editors/physics/rigidbody_world.c
index 8d5258a7522..52a20ed7cf7 100644
--- a/source/blender/editors/physics/rigidbody_world.c
+++ b/source/blender/editors/physics/rigidbody_world.c
@@ -114,8 +114,7 @@ static int rigidbody_world_remove_exec(bContext *C, wmOperator *op)
 		return OPERATOR_CANCELLED;
 	}
 
-	BKE_rigidbody_free_world(rbw);
-	scene->rigidbody_world = NULL;
+	BKE_rigidbody_free_world(scene);
 
 	/* done */
 	return OPERATOR_FINISHED;
@@ -152,14 +151,14 @@ static int rigidbody_world_export_exec(bContext *C, wmOperator *op)
 		BKE_report(op->reports, RPT_ERROR, "No Rigid Body World to export");
 		return OPERATOR_CANCELLED;
 	}
-	if (rbw->physics_world == NULL) {
+	if (rbw->shared->physics_world == NULL) {
 		BKE_report(op->reports, RPT_ERROR, "Rigid Body World has no associated physics data to export");
 		return OPERATOR_CANCELLED;
 	}
 
 	RNA_string_get(op->ptr, "filepath", path);
 #ifdef WITH_BULLET
-	RB_dworld_export(rbw->physics_world, path);
+	RB_dworld_export(rbw->shared->physics_world, path);
 #endif
 	return OPERATOR_FINISHED;
 }