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, 230 insertions, 0 deletions

diff --git a/source/blender/editors/physics/rigidbody_constraint.c b/source/blender/editors/physics/rigidbody_constraint.c
new file mode 100644
index 00000000000..e4db1c91c2b
--- /dev/null
+++ b/source/blender/editors/physics/rigidbody_constraint.c
@@ -0,0 +1,230 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2013 Blender Foundation
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): Sergej Reich
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file rigidbody_constraint.c
+ *  \ingroup editor_physics
+ *  \brief Rigid Body constraint editing operators
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_group_types.h"
+#include "DNA_object_types.h"
+#include "DNA_rigidbody_types.h"
+#include "DNA_scene_types.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_math.h"
+
+#include "BKE_context.h"
+#include "BKE_depsgraph.h"
+#include "BKE_group.h"
+#include "BKE_object.h"
+#include "BKE_report.h"
+#include "BKE_rigidbody.h"
+
+#include "RNA_access.h"
+#include "RNA_define.h"
+#include "RNA_enum_types.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "ED_physics.h"
+#include "ED_screen.h"
+
+#include "physics_intern.h"
+
+/* ********************************************** */
+/* Helper API's for RigidBody Constraint Editing */
+
+static int ED_operator_rigidbody_con_active_poll(bContext *C)
+{
+	if (ED_operator_object_active_editable(C)) {
+		Object *ob = CTX_data_active_object(C);
+		return (ob && ob->rigidbody_constraint);
+	}
+	else
+		return 0;
+}
+
+
+void ED_rigidbody_con_add(wmOperator *op, Scene *scene, Object *ob, int type)
+{
+	/* check that object doesn't already have a constraint */
+	if (ob->rigidbody_constraint) {
+		BKE_reportf(op->reports, RPT_INFO, "Object '%s' already has a Rigid Body Constraint", ob->id.name + 2);
+		return;
+	}
+
+	/* make rigidbody constraint settings */
+	ob->rigidbody_constraint = BKE_rigidbody_create_constraint(scene, ob, type);
+	ob->rigidbody_constraint->flag |= RBC_FLAG_NEEDS_VALIDATE;
+}
+
+void ED_rigidbody_con_remove(Scene *scene, Object *ob)
+{
+	BKE_rigidbody_remove_constraint(scene, ob);
+	DAG_id_tag_update(&ob->id, OB_RECALC_OB);
+}
+
+/* ********************************************** */
+/* Active Object Add/Remove Operators */
+
+/* ************ Add Rigid Body Constraint ************** */
+
+static int rigidbody_con_add_exec(bContext *C, wmOperator *op)
+{
+	Scene *scene = CTX_data_scene(C);
+	Object *ob = (scene) ? OBACT : NULL;
+	int type = RNA_enum_get(op->ptr, "type");
+
+	/* apply to active object */
+	ED_rigidbody_con_add(op, scene, ob, type);
+
+	/* send updates */
+	DAG_ids_flush_update(CTX_data_main(C), 0);
+
+	WM_event_add_notifier(C, NC_OBJECT | ND_TRANSFORM, NULL);
+	WM_event_add_notifier(C, NC_GROUP | NA_EDITED, NULL);
+
+	/* done */
+	return OPERATOR_FINISHED;
+}
+
+void RIGIDBODY_OT_constraint_add(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->idname = "RIGIDBODY_OT_constraint_add";
+	ot->name = "Add Rigid Body Constraint";
+	ot->description = "Add Rigid Body Constraint to active object";
+
+	/* callbacks */
+	ot->exec = rigidbody_con_add_exec;
+	ot->poll = ED_operator_object_active_editable;
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+	/* properties */
+	ot->prop = RNA_def_enum(ot->srna, "type", rigidbody_con_type_items, RBC_TYPE_FIXED, "Rigid Body Constraint Type", "");
+}
+
+static int rigidbody_con_group_add_exec(bContext *C, wmOperator *op)
+{
+	Scene *scene = CTX_data_scene(C);
+	RigidBodyWorld *rbw = BKE_rigidbody_get_world(scene);
+	Object *ob = (scene) ? OBACT : NULL;
+	int type = RNA_enum_get(op->ptr, "type");
+
+	/* sanity checks */
+	if (ELEM(NULL, scene, rbw)) {
+		BKE_report(op->reports, RPT_ERROR, "No Rigid Body World to add Rigid Body Constraint to");
+		return OPERATOR_CANCELLED;
+	}
+	if (rbw->constraints == NULL) {
+		rbw->constraints = add_group("RigidBodyConstraints");
+	}
+	/* apply to active object */
+	ED_rigidbody_con_add(op, scene, ob, type);
+	add_to_group(rbw->constraints, ob, scene, NULL);
+
+	/* send updates */
+	DAG_ids_flush_update(CTX_data_main(C), 0);
+
+	WM_event_add_notifier(C, NC_OBJECT | ND_TRANSFORM, NULL);
+	WM_event_add_notifier(C, NC_GROUP | NA_EDITED, NULL);
+
+	/* done */
+	return OPERATOR_FINISHED;
+}
+
+void RIGIDBODY_OT_constraint_group_add(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->idname = "RIGIDBODY_OT_constraint_group_add";
+	ot->name = "Add Rigid Body Constraint";
+	ot->description = "Add Rigid Body Constraint to active object and world's group";
+
+	/* callbacks */
+	ot->exec = rigidbody_con_group_add_exec;
+	ot->poll = ED_operator_object_active_editable;
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+	/* properties */
+	ot->prop = RNA_def_enum(ot->srna, "type", rigidbody_con_type_items, RBC_TYPE_FIXED, "Rigid Body Constraint Type", "");
+}
+
+/* ************ Remove Rigid Body Constraint ************** */
+
+static int rigidbody_con_remove_exec(bContext *C, wmOperator *op)
+{
+	Scene *scene = CTX_data_scene(C);
+	Object *ob = (scene) ? OBACT : NULL;
+
+	/* sanity checks */
+	if (scene == NULL)
+		return OPERATOR_CANCELLED;
+
+	/* apply to active object */
+	if (ELEM(NULL, ob, ob->rigidbody_constraint)) {
+		BKE_report(op->reports, RPT_ERROR, "Object has no Rigid Body Constraint to remove");
+		return OPERATOR_CANCELLED;
+	}
+	else {
+		ED_rigidbody_con_remove(scene, ob);
+	}
+
+	/* send updates */
+	DAG_ids_flush_update(CTX_data_main(C), 0);
+
+	WM_event_add_notifier(C, NC_OBJECT | ND_TRANSFORM, NULL);
+	WM_event_add_notifier(C, NC_GROUP | NA_EDITED, NULL);
+
+	/* done */
+	return OPERATOR_FINISHED;
+}
+
+void RIGIDBODY_OT_constraint_remove(wmOperatorType *ot)
+{
+	/* identifiers */
+	ot->idname = "RIGIDBODY_OT_constraint_remove";
+	ot->name = "Remove Rigid Body Constraint";
+	ot->description = "Remove Rigid Body Constraint from Object";
+
+	/* callbacks */
+	ot->exec = rigidbody_con_remove_exec;
+	ot->poll = ED_operator_rigidbody_con_active_poll;
+
+	/* flags */
+	ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+}