rigidbody: Add rigid body constraints

Constraints connect two rigid bodies.
Depending on which constraint is used different degrees of freedom
are limited, e.g. a hinge constraint only allows the objects to rotate
around a common axis.

Constraints are implemented as individual objects and bahave similar to
rigid bodies in terms of adding/removing/validating.

The position and orientation of the constraint object is the pivot point
of the constraint.

Constraints have their own group in the rigid body world.

To make connecting rigid bodies easier, there is a "Connect" operator that
creates an empty objects with a rigid body constraint connecting the selected
objects to active.

Currently the following constraints are implemented:
* Fixed
* Point
* Hinge
* Slider
* Piston
* Generic

Note: constraint limits aren't animatable yet).

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/editors/physics/physics_intern.h b/source/blender/editors/physics/physics_intern.h
index b4b4b5e54f5..4b4855c9922 100644
--- a/source/blender/editors/physics/physics_intern.h
+++ b/source/blender/editors/physics/physics_intern.h
@@ -115,6 +115,11 @@ void RIGIDBODY_OT_objects_remove(struct wmOperatorType *ot);
 void RIGIDBODY_OT_shape_change(struct wmOperatorType *ot);
 void RIGIDBODY_OT_mass_calculate(struct wmOperatorType *ot);
 
+/* rigidbody_constraint.c */
+void RIGIDBODY_OT_constraint_add(struct wmOperatorType *ot);
+void RIGIDBODY_OT_constraint_group_add(struct wmOperatorType *ot);
+void RIGIDBODY_OT_constraint_remove(struct wmOperatorType *ot);
+
 /*rigidbody_world.c */
 void RIGIDBODY_OT_world_add(struct wmOperatorType *ot);
 void RIGIDBODY_OT_world_remove(struct wmOperatorType *ot);