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source/gameengine/SceneGraph/SG_ParentRelation.h

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+/**
+ * @mainpage SG_ParentRelation   
+
+ * @section 
+ * 
+ * This is an abstract interface class to the Scene Graph library. 
+ * It allows you to specify how child nodes react to parent nodes.
+ * Normally a child will use it's parent's transforms to compute
+ * it's own global transforms. How this is performed depends on
+ * the type of relation. For example if the parent is a vertex 
+ * parent to this child then the child should not inherit any 
+ * rotation information from the parent. Or if the parent is a
+ * 'slow parent' to this child then the child should react 
+ * slowly to changes in the parent's position. The exact relation
+ * is left for you to implement by filling out this interface 
+ * with concrete examples. 
+ * 
+ * There is exactly one SG_ParentRelation per SG_Node. Subclasses
+ * should not be value types and should be allocated on the heap.
+ *
+ * $Id$
+ *
+ * ***** BEGIN GPL/BL DUAL 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. The Blender
+ * Foundation also sells licenses for use in proprietary software under
+ * the Blender License.  See http://www.blender.org/BL/ for information
+ * about this.
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ *
+ * The Original Code is: all of this file.
+ *
+ * Contributor(s): none yet.
+ *
+ * ***** END GPL/BL DUAL LICENSE BLOCK *****
+ * 
+ */
+
+#ifndef __SG_ParentRelation_h
+#define __SG_ParentRelation_h
+
+class SG_Spatial;
+
+class SG_ParentRelation {
+
+public :
+
+	/**
+	 * Update the childs local and global coordinates
+	 * based upon the parents global coordinates. 
+	 * You must also handle the case when this node has no
+	 * parent (parent == NULL). Usually you should just 
+	 * copy the local coordinates of the child to the 
+	 * world coordinates.
+	 */ 
+	
+	virtual
+		void
+	UpdateChildCoordinates(
+		SG_Spatial * child,
+		const SG_Spatial * parent
+	) = 0;
+
+	virtual 
+	~SG_ParentRelation(
+	){
+	};
+
+	/** 
+	 * You must provide a way of duplicating an
+	 * instance of an SG_ParentRelation. This should
+	 * return a pointer to a new duplicate allocated
+	 * on the heap. Responsibilty for deleting the 
+	 * duplicate resides with the caller of this method.
+	 */
+
+	virtual 
+		SG_ParentRelation *
+	NewCopy(
+	) = 0;
+
+protected :
+
+	/** 
+	 * Protected constructors 
+	 * this class is not meant to be instantiated.
+	 */
+
+	SG_ParentRelation(
+	) {	
+	};
+
+	/**
+	 * Copy construction should not be implemented
+	 */
+
+	SG_ParentRelation(
+		const SG_ParentRelation &
+	); 
+};	
+
+#endif