/*

-----------------------------------------------------------------------------

This source file is part of OGRE

(Object-oriented Graphics Rendering Engine)

For the latest info, see http://www.ogre3d.org

Copyright (c) 2000-2014 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in

all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

THE SOFTWARE.

-----------------------------------------------------------------------------

*/

#ifndef __OGREPLUGIN_H__

#define __OGREPLUGIN_H__

#include "OgrePrerequisites.h"

namespace Ogre

{

    /** \addtogroup Core

    *  @{

    */

    /** \addtogroup General

    *  @{

    */

    /** Class defining a generic OGRE plugin.

        OGRE is very plugin-oriented and you can customise much of its behaviour

        by registering new plugins, dynamically if you are using dynamic linking.

        This class abstracts the generic interface that all plugins must support.

        Within the implementations of this interface, the plugin must call other

        OGRE classes in order to register the detailed customisations it is

        providing, e.g. registering a new SceneManagerFactory, a new

        MovableObjectFactory, or a new RenderSystem.

    @par

        Plugins can be linked statically or dynamically. If they are linked

        dynamically (ie the plugin is in a DLL or Shared Object file), then you

        load the plugin by calling the Root::loadPlugin method (or some other

        mechanism which leads to that call, e.g. plugins.cfg), passing the name of

        the DLL. OGRE will then call a global init function on that DLL, and it

        will be expected to register one or more Plugin implementations using

        Root::installPlugin. The procedure is very similar if you use a static

        linked plugin, except that you simply instantiate the Plugin implementation

        yourself and pass it to Root::installPlugin.

    @note

        Lifecycle of a Plugin instance is very important. The Plugin instance must

        remain valid until the Plugin is uninstalled. Here are the things you

        must bear in  mind:

        <ul><li>If your plugin is in a DLL:

        <ul><li>Create the Plugin instance and call Root::installPlugin in dllStartPlugin</li>

        <li>Call Root::uninstallPlugin, then delete it in dllStopPlugin</li></ul>

        <li>If your plugin is statically linked in your app:

        <ul><li>Create the Plugin anytime you like</li>

        <li>Call Root::installPlugin any time whilst Root is valid</li>

        <li>Call Root::uninstallPlugin if you like so long as Root is valid. However,

            it will be done for you when Root is destroyed, so the Plugin instance must

            still be valid at that point if you haven't manually uninstalled it.</li></ul>

        </ul>

        The install and uninstall methods will be called when the plugin is

        installed or uninstalled. The initialise and shutdown will be called when

        there is a system initialisation or shutdown, e.g. when Root::initialise 

        or Root::shutdown are called.

    */

    class _OgreExport Plugin : public PluginAlloc

    {

    public:

        Plugin() {}

        virtual ~Plugin() {}

        /** Get the name of the plugin. 

        @remarks An implementation must be supplied for this method to uniquely

            identify the plugin.

        */

        virtual const String& getName() const = 0;

        /** Perform the plugin initial installation sequence. 

        @remarks An implementation must be supplied for this method. It must perform

        the startup tasks necessary to install any rendersystem customisations 

        or anything else that is not dependent on system initialisation, ie

        only dependent on the core of Ogre. It must not perform any

        operations that would create rendersystem-specific objects at this stage,

        that should be done in initialise().

        */

        virtual void install() = 0;

        /** Perform any tasks the plugin needs to perform on full system

            initialisation.

        @remarks An implementation must be supplied for this method. It is called 

            just after the system is fully initialised (either after Root::initialise

            if a window is created then, or after the first window is created)

            and therefore all rendersystem functionality is available at this

            time. You can use this hook to create any resources which are 

            dependent on a rendersystem or have rendersystem-specific implementations.

        */

        virtual void initialise() = 0;

        /** Perform any tasks the plugin needs to perform when the system is shut down.

        @remarks An implementation must be supplied for this method.

        This method is called just before key parts of the system are unloaded, 

        such as rendersystems being shut down. You should use this hook to free up 

        resources and decouple custom objects from the OGRE system, whilst all the

        instances of other plugins (e.g. rendersystems) still exist.

        */

        virtual void shutdown() = 0;

        /** Perform the final plugin uninstallation sequence. 

        @remarks An implementation must be supplied for this method. It must perform

        the cleanup tasks which haven't already been performed in shutdown()

        (e.g. final deletion of custom instances, if you kept them around in case

        the system was reinitialised). At this stage you cannot be sure what other

        plugins are still loaded or active. It must therefore not perform any

        operations that would reference any rendersystem-specific objects - those

        should have been sorted out in the 'shutdown' method.

        */

        virtual void uninstall() = 0;

    };

    /** @} */

    /** @} */

}

#endif