Initial source commit

minorGems/graphics/3d/Object3DFactory.h

@@ -0,0 +1,129 @@
+/*
+ * Modification History
+ *
+ * 2001-March-14   Jason Rohrer
+ * Created.
+ *
+ * 2001-March-17   Jason Rohrer
+ * Finished implementation.
+ *
+ * 2001-April-1   Jason Rohrer
+ * Fixed flag name.
+ */
+
+#ifndef OBJECT_3D_FACTORY_INCLUDED
+#define OBJECT_3D_FACTORY_INCLUDED 
+
+#include "Object3D.h"
+
+// Run-time type identification interface (RTTI)
+#include <typeinfo>
+
+
+// include these objects only if we are part of subreal
+#ifdef SUBREAL
+#include "subreal/entity/EntityObject3D.h"
+#define FACTORY_ENTITY_OBJECT_FLAG 1
+
+#endif
+
+// the default flag
+#define FACTORY_DEFAULT_OBJECT_FLAG 0
+
+
+/**
+ * Class that maps Object3D integer subclass type flags to Object3D
+ * subclass instances.
+ *
+ * Motivation for this class:
+ * We have Object3D instances that exist simultaneously on opposite
+ * sides of the network (at both the client and server ends).  Initially,
+ * we just let the objects get sent to the server via the base class
+ * Object3D serialization function.  At that time, subclasses of Object3D
+ * did nothing more than init an Object3D in a particular way.  This
+ * worked fine when we didn't have animations associated with various
+ * Object3D subclasses, but doesn't work now that we have animation
+ * code in various subclasses.  During serialization (if the object
+ * is sent as a generic Object3D), the animation code is lost on
+ * the client end.  We need a way for the client to pick the correct
+ * subclass to construct for deserialization.  We can encode the
+ * various subtypes by integers, and then this factory class can
+ * be used to construct a class of appropriate subtype before
+ * deserialization.
+ *
+ * @author Jason Rohrer
+ */
+class Object3DFactory {
+	public:
+
+		/**
+		 * Finds an integer subclass type flag for an object instance.
+		 *
+		 * @param inObject the object to determine a flag for.  Must
+		 *   be destroyed by the caller.
+		 *
+		 * @return a type flag for inObject.  0 (the defautl Object3D
+		 *   baseclass flag) will be returned if subclass determination fails.
+		 */
+		static int object3DToInt( Object3D *inObject );
+
+		
+		/**
+		 * Constructs a new, unitialized Object3D (in other words,
+		 * an Object3D ready for deserialization) of a subclass
+		 * type matching inTypeFlag.
+		 *
+		 * @param inTypeFlag the type flag specifying the class
+		 *   of the returned object.
+		 *
+		 * @return an (unitialized) Object3D class instance with a
+		 *   subclass type corresponding to inTypeFlag.  If no
+		 *   matching class is found, a default Object3D baseclass
+		 *   instance is returned.  Must be destroyed by the caller. 
+		 */
+		static Object3D *intToObject3D( int inTypeFlag );
+		
+	};
+
+
+
+inline int Object3DFactory::object3DToInt( Object3D *inObject ) {
+
+	// use RTTI to determine type of inObject
+	
+#ifdef SUBREAL
+	if( typeid( *inObject ) == typeid( EntityObject3D ) ) {
+		return FACTORY_ENTITY_OBJECT_FLAG;
+		}
+#endif
+	// else return the default flag
+	return FACTORY_DEFAULT_OBJECT_FLAG;
+	}
+
+
+
+inline Object3D *Object3DFactory::intToObject3D( int inTypeFlag ) {
+	switch( inTypeFlag ) {
+		case FACTORY_DEFAULT_OBJECT_FLAG:
+			return new Object3D();
+			break;
+
+			/* these objects are only defined if
+			 * we are part of subreal
+			 */
+#ifdef SUBREAL
+		case FACTORY_ENTITY_OBJECT_FLAG:
+			return new EntityObject3D();
+			break;
+#endif
+
+		default:
+			// unknown object flag type
+			return new Object3D();
+			break;
+		}
+			
+	}
+
+
+#endif