+/*
+ * Copyright (C) 2008 Patrik Gornicz, Gornicz_P (at) hotmail (dot) com.
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "GravityWell.h"
+#include "../Entities/PhysicsEntity.h"
+
+
+/// ***** Constructors/Destructors *****
+
+GravityWell::GravityWell(const Vector2& pos)
+ : position(pos)
+{
+
+}
+GravityWell::~GravityWell()
+{
+
+}
+
+/// ***** Public Class Methods *****
+
+Vector2 GravityWell::forceDelta(const PhysicsEntity* e, float) const
+{
+ const Vector2& pos = e->positionRaw();
+ float mass = e->mass;
+
+ Vector2 delta = position - pos;
+ float sqrDist = delta.sqrLength();
+
+ Vector2 acc(0,0);
+
+ if( sqrDist > 0.5F )
+ acc += delta / sqrDist * mass;
+
+ return acc;
+}