Bugfix #19616: vertex group select as IK target cause crash in Blender2.5

Thanks to Masahito Takahashi (mato)  for the report and patch to fix this!

source/blender/blenkernel/BKE_constraint.h

@@ -131,7 +131,7 @@ void constraints_clear_evalob(struct bConstraintOb *cob);
 
 void constraint_mat_convertspace(struct Object *ob, struct bPoseChannel *pchan, float mat[][4], short from, short to);
 
-void get_constraint_target_matrix(struct bConstraint *con, int n, short ownertype, void *ownerdata, float mat[][4], float ctime);
+void get_constraint_target_matrix(struct Scene *scene, struct bConstraint *con, int n, short ownertype, void *ownerdata, float mat[][4], float ctime);
 void solve_constraints(struct ListBase *conlist, struct bConstraintOb *cob, float ctime);
 
 #ifdef __cplusplus

source/blender/blenkernel/intern/constraint.c

@@ -3553,7 +3553,7 @@ short proxylocked_constraints_owner (Object *ob, bPoseChannel *pchan)
  * None of the actual calculations of the matricies should be done here! Also, this function is 
  * not to be used by any new constraints, particularly any that have multiple targets.
  */
-void get_constraint_target_matrix (bConstraint *con, int n, short ownertype, void *ownerdata, float mat[][4], float ctime)
+void get_constraint_target_matrix (struct Scene *scene, bConstraint *con, int n, short ownertype, void *ownerdata, float mat[][4], float ctime)
 {
 	bConstraintTypeInfo *cti= constraint_get_typeinfo(con);
 	ListBase targets = {NULL, NULL};
@@ -3564,6 +3564,7 @@ void get_constraint_target_matrix (bConstraint *con, int n, short ownertype, voi
 		/* make 'constraint-ob' */
 		cob= MEM_callocN(sizeof(bConstraintOb), "tempConstraintOb");
 		cob->type= ownertype;
+		cob->scene = scene;
 		switch (ownertype) {
 			case CONSTRAINT_OBTYPE_OBJECT: /* it is usually this case */
 			{

source/blender/editors/object/object_relations.c

@@ -618,7 +618,7 @@ static int parent_set_exec(bContext *C, wmOperator *op)
 					
 					add_constraint_to_object(con, ob);
 					
-					get_constraint_target_matrix(con, 0, CONSTRAINT_OBTYPE_OBJECT, NULL, cmat, scene->r.cfra - give_timeoffset(ob));
+					get_constraint_target_matrix(scene, con, 0, CONSTRAINT_OBTYPE_OBJECT, NULL, cmat, scene->r.cfra - give_timeoffset(ob));
 					VecSubf(vec, ob->obmat[3], cmat[3]);
 					
 					ob->loc[0] = vec[0];

source/blender/ikplugin/intern/iksolver_plugin.c

@@ -210,7 +210,7 @@ static void where_is_ik_bone(bPoseChannel *pchan, float ik_mat[][3])   // nr = t
 
 /* called from within the core where_is_pose loop, all animsystems and constraints
 were executed & assigned. Now as last we do an IK pass */
-static void execute_posetree(Object *ob, PoseTree *tree)
+static void execute_posetree(struct Scene *scene, Object *ob, PoseTree *tree)
 {
 	float R_parmat[3][3], identity[3][3];
 	float iR_parmat[3][3];
@@ -347,7 +347,7 @@ static void execute_posetree(Object *ob, PoseTree *tree)
 		/* 1.0=ctime, we pass on object for auto-ik (owner-type here is object, even though
 		 * strictly speaking, it is a posechannel)
 		 */
-		get_constraint_target_matrix(target->con, 0, CONSTRAINT_OBTYPE_OBJECT, ob, rootmat, 1.0);
+		get_constraint_target_matrix(scene, target->con, 0, CONSTRAINT_OBTYPE_OBJECT, ob, rootmat, 1.0);
 		
 		/* and set and transform goal */
 		Mat4MulMat4(goal, rootmat, goalinv);
@@ -357,7 +357,7 @@ static void execute_posetree(Object *ob, PoseTree *tree)
 		
 		/* same for pole vector target */
 		if(data->poletar) {
-			get_constraint_target_matrix(target->con, 1, CONSTRAINT_OBTYPE_OBJECT, ob, rootmat, 1.0);
+			get_constraint_target_matrix(scene, target->con, 1, CONSTRAINT_OBTYPE_OBJECT, ob, rootmat, 1.0);
 			
 			if(data->flag & CONSTRAINT_IK_SETANGLE) {
 				/* don't solve IK when we are setting the pole angle */
@@ -511,7 +511,7 @@ void iksolver_execute_tree(struct Scene *scene, struct Object *ob,  struct bPose
 			tree->pchan[a]->flag |= POSE_CHAIN;
 		}
 		/* 5. execute the IK solver */
-		execute_posetree(ob, tree);
+		execute_posetree(scene, ob, tree);
 		
 		/* 6. apply the differences to the channels, 
 			  we need to calculate the original differences first */

source/blender/ikplugin/intern/itasc_plugin.cpp

@@ -89,6 +89,7 @@ void KDL::SetToZero(JntArray& array);
 // one structure for each target in the scene
 struct IK_Target
 {
+	struct Scene			*blscene;
 	iTaSC::MovingFrame*		target;
 	iTaSC::ConstraintSet*	constraint;
 	struct bConstraint*		blenderConstraint;
@@ -105,6 +106,7 @@ struct IK_Target
 	float					eeRest[4][4];	//end effector initial pose relative to armature
 
 	IK_Target() {
+		blscene = NULL;
 		target = NULL;
 		constraint = NULL;
 		blenderConstraint = NULL;
@@ -155,6 +157,7 @@ struct IK_Channel {
 
 struct IK_Scene
 {
+	struct Scene		*blscene;
 	IK_Scene*			next;
 	int					numchan;	// number of channel in pchan
 	int					numjoint;	// number of joint in jointArray
@@ -172,6 +175,7 @@ struct IK_Scene
 	std::vector<IK_Target*>		targets;
 
 	IK_Scene() {
+		blscene = NULL;
 		next = NULL;
 		channels = NULL;
 		armature = NULL;
@@ -533,7 +537,7 @@ static bool target_callback(const iTaSC::Timestamp& timestamp, const iTaSC::Fram
 	bConstraint* constraint = (bConstraint*)target->blenderConstraint;
 	float tarmat[4][4];
 
-	get_constraint_target_matrix(constraint, 0, CONSTRAINT_OBTYPE_OBJECT, target->owner, tarmat, 1.0);
+	get_constraint_target_matrix(target->blscene, constraint, 0, CONSTRAINT_OBTYPE_OBJECT, target->owner, tarmat, 1.0);
 
 	// rootmat contains the target pose in world coordinate
 	// if enforce is != 1.0, blend the target position with the end effector position
@@ -601,7 +605,7 @@ static bool base_callback(const iTaSC::Timestamp& timestamp, const iTaSC::Frame&
 		IK_Channel &rootchan = ikscene->channels[0];
 
 		// get polar target matrix in world space
-		get_constraint_target_matrix(ikscene->polarConstraint, 1, CONSTRAINT_OBTYPE_OBJECT, ikscene->blArmature, mat, 1.0);
+		get_constraint_target_matrix(ikscene->blscene, ikscene->polarConstraint, 1, CONSTRAINT_OBTYPE_OBJECT, ikscene->blArmature, mat, 1.0);
 		// convert to armature space
 		Mat4MulMat4(polemat, mat, imat);
 		// get the target in world space (was computed before as target object are defined before base object)
@@ -1050,6 +1054,7 @@ static IK_Scene* convert_tree(Scene *blscene, Object *ob, bPoseChannel *pchan)
 		return NULL;
 
 	ikscene = new IK_Scene;
+	ikscene->blscene = blscene;
 	arm = new iTaSC::Armature();
 	scene = new iTaSC::Scene();
 	ikscene->channels = new IK_Channel[tree->totchannel];
@@ -1382,6 +1387,7 @@ static IK_Scene* convert_tree(Scene *blscene, Object *ob, bPoseChannel *pchan)
 	// finally add the constraint
 	for (t=0; t<ikscene->targets.size(); t++) {
 		IK_Target* iktarget = ikscene->targets[t];
+		iktarget->blscene = blscene;
 		condata= (bKinematicConstraint*)iktarget->blenderConstraint->data;
 		pchan = tree->pchan[iktarget->channel];
 		unsigned int controltype, bonecnt;