Rope: Fix crash when a connected object is removed

src/game/C4Game.cpp

@@ -914,6 +914,7 @@ void C4Game::ClearPointers(C4Object * pObj)
 	TransferZones.ClearPointers(pObj);
 	if (pGlobalEffects)
 		pGlobalEffects->ClearPointers(pObj);
+	Ropes.ClearPointers(pObj);
 }
 
 bool C4Game::TogglePause()

src/object/C4Rope.cpp

@@ -262,7 +262,6 @@ void C4RopeElement::Execute(const C4Rope* rope, C4Real dt)
 					if(Target->Shape.GetVertexContact(i, dwCNATCheck, Target->GetX(), Target->GetY()))
 						iContactVertex = i;
 
-				// TODO: Check force redirection at the vertex which has contact
 				if(iContactVertex != -1)
 					SetForceRedirection(rope, Target->Shape.VtxX[iContactVertex], Target->Shape.VtxY[iContactVertex]);
 			}
@@ -590,6 +589,23 @@ void C4Rope::Execute()
 	}
 }
 
+void C4Rope::ClearPointers(C4Object* obj)
+{
+	for(C4RopeElement* cur = Front; cur != NULL; cur = cur->Next)
+	{
+		if(cur->GetObject() == obj)
+		{
+			cur->x = obj->fix_x;
+			cur->y = obj->fix_y;
+			cur->vx = obj->xdir;
+			cur->vy = obj->ydir;
+			cur->m = obj->Mass;
+
+			cur->Object = NULL;
+		}
+	}
+}
+
 // TODO: Move this to StdGL
 void C4Rope::Draw(C4TargetFacet& cgo, C4BltTransform* pTransform)
 {
@@ -769,3 +785,9 @@ void C4RopeList::Draw(C4TargetFacet& cgo, C4BltTransform* pTransform)
 
 	glPopMatrix();
 }
+
+void C4RopeList::ClearPointers(C4Object* obj)
+{
+	for(unsigned int i = 0; i < Ropes.size(); ++i)
+		Ropes[i]->ClearPointers(obj);
+}

src/object/C4Rope.h

@@ -72,6 +72,8 @@ public:
 	void Draw(C4TargetFacet& cgo, C4BltTransform* pTransform);
 	void Execute();
 
+	void ClearPointers(C4Object* obj);
+
 	C4Real GetSegmentLength() const { return l; }
 	C4Real GetOuterFriction() const { return mu; }
 
@@ -97,11 +99,6 @@ private:
 	C4DefGraphics* Graphics;
 	int32_t SegmentCount;
 
-	// TODO: Add a "dynlength" feature which adapts the spring length to the
-	// distance of the two ends, up to a maximum... and/or callbacks to script
-	// when the length should be changed so that script can do it (and maybe
-	// play an animation, such as for the lift tower).
-
 	C4Real l; // spring length in equilibrium
 	C4Real k; // spring constant
 	C4Real mu; // outer friction constant
@@ -141,6 +138,8 @@ public:
 
 	C4Rope* CreateRope(C4Object* first_obj, C4Object* second_obj, int32_t n_segments, C4DefGraphics* graphics);
 
+	void ClearPointers(C4Object* obj);
+
 private:
 	C4RopeAul RopeAul;
 	std::vector<C4Rope*> Ropes;