SceneContext.h

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/*********************************************************\
 *  File: SceneContext.h                                 *
 *
 *  Copyright (C) 2002-2012 The PixelLight Team (http://www.pixellight.org/)
 *
 *  This file is part of PixelLight.
 *
 *  PixelLight is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  PixelLight 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 Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with PixelLight. If not, see <http://www.gnu.org/licenses/>.
\*********************************************************/


#ifndef __PLSCENE_SCENECONTEXT_H__
#define __PLSCENE_SCENECONTEXT_H__
#pragma once


//[-------------------------------------------------------]
//[ Includes                                              ]
//[-------------------------------------------------------]
#include <PLCore/Container/Array.h>
#include <PLCore/Base/Event/Event.h>
#include <PLCore/Core/AbstractContext.h>
#include "PLScene/PLScene.h"


//[-------------------------------------------------------]
//[ Forward declarations                                  ]
//[-------------------------------------------------------]
namespace PLMath {
    class GraphPathManager;
}
namespace PLRenderer {
    class RendererContext;
}
namespace PLMesh {
    class MeshManager;
}
namespace PLScene {
    class SceneNode;
    class VisManager;
    class SceneContainer;
    class SceneNodeHandler;
    class SceneRendererManager;
}


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
namespace PLScene {


//[-------------------------------------------------------]
//[ Classes                                               ]
//[-------------------------------------------------------]
/**
*  @brief
*    Scene context
*
*  @note
*    - There should be only one scene context instance per application
*/
class SceneContext : public PLCore::AbstractContext {


    //[-------------------------------------------------------]
    //[ Friends                                               ]
    //[-------------------------------------------------------]
    friend class SceneNode;


    //[-------------------------------------------------------]
    //[ Public events                                         ]
    //[-------------------------------------------------------]
    public:
        PLCore::Event<> EventUpdate;    /**< Scene context update event */


    //[-------------------------------------------------------]
    //[ Public functions                                      ]
    //[-------------------------------------------------------]
    public:
        /**
        *  @brief
        *    Constructor
        *
        *  @param[in] cRendererContext
        *    Renderer context to use
        */
        PLS_API SceneContext(PLRenderer::RendererContext &cRendererContext);

        /**
        *  @brief
        *    Destructor
        */
        PLS_API ~SceneContext();

        /**
        *  @brief
        *    Returns the used renderer context
        *
        *  @return
        *    The used renderer context
        */
        PLS_API PLRenderer::RendererContext &GetRendererContext() const;

        /**
        *  @brief
        *    Returns the mesh manager
        *
        *  @return
        *    The mesh manager
        */
        PLS_API PLMesh::MeshManager &GetMeshManager();

        /**
        *  @brief
        *    Returns the graph path manager
        *
        *  @return
        *    The graph path manager
        */
        PLS_API PLMath::GraphPathManager &GetGraphPathManager();

        /**
        *  @brief
        *    Returns the root of the scene graph
        *
        *  @return
        *    The root of the scene graph, a null pointer on (terrible) error
        *
        *  @see
        *    - SceneNode and SceneContainer for more information
        */
        PLS_API SceneContainer *GetRoot();

        /**
        *  @brief
        *    Performs a cleanup-operation (garbage collection)
        *
        *  @remarks
        *    If SceneNode::Delete() is called, scene nodes are not destroyed immediately,
        *    instead they register them self into a 'to delete' list of the scene graph. As
        *    soon this function is called, the scene nodes are destroyed. Normally this function
        *    is called once per frame automatically.
        */
        PLS_API void Cleanup();

        /**
        *  @brief
        *    Method that is called once per update loop
        *
        *  @param[in] bRespectPause
        *    Respect pause? ("PLCore::Timing::GetInstance()->IsPaused()")
        *
        *  @remarks
        *    You can use this method to do work you have to to within each frame. It's
        *    recommended to keep the work done within the implementation as compact as possible.
        *    Don't use this method to perform 'polling'-everything, use events or if required
        *    for example timers instead.
        */
        PLS_API void Update(bool bRespectPause = true);

        /**
        *  @brief
        *    Returns the scene renderer manager
        *
        *  @return
        *    The scene renderer manager
        */
        PLS_API SceneRendererManager &GetSceneRendererManager();

        /**
        *  @brief
        *    Returns the visibility manager
        *
        *  @return
        *    The visibility manager
        */
        PLS_API VisManager &GetVisManager();


        //[-------------------------------------------------------]
        //[ Processing                                            ]
        //[-------------------------------------------------------]
        /**
        *  @brief
        *    Starts a scene process
        *
        *  @remarks
        *    During scene traversal using for instance the hierarchy of a scene container, a scene node can
        *    be processed multiple times. If this is NOT desired, a scene node must be 'marked' as already
        *    processed so it isn't touched multiple times. The scene graph class offers 3 functions for this
        *    purpose: StartProcess(), TouchNode() and EndProcess(). If a scene process starts, StartProcess()
        *    is called with internally increases a counter. If a node should be processes TouchNode() is called,
        *    if 'true' is returned the node was already processed. After the whole scene process is finished, call
        *    EndProcess(). This is NOT 'multi threading save' and only ONE scene process can be performed at the
        *    same time, but this technique is incredible fast because internally only counters are compared!
        *
        *  @return
        *    'true' if all went fine, else 'false' (there's already a process running)
        */
        PLS_API bool StartProcess();

        /**
        *  @brief
        *    Checks whether a scene node was touched
        *
        *  @param[in] cSceneNode
        *    Scene node to check
        *
        *  @return
        *    'true' if the scene node was touched, else 'false'
        *
        *  @see
        *    - StartProcess()
        */
        PLS_API bool IsNodeTouched(SceneNode &cSceneNode) const;

        /**
        *  @brief
        *    Touches a scene node
        *
        *  @param[in] cSceneNode
        *    Scene node to touch
        *
        *  @return
        *    'true' if all went fine and the scene node was touched the first time during the
        *    current process, else 'false' if the scene node was already touched during the current
        *    process or there's currently no active process or the given scene node is invalid
        *
        *  @see
        *    - StartProcess()
        */
        PLS_API bool TouchNode(SceneNode &cSceneNode);

        /**
        *  @brief
        *    Ends a scene process
        *
        *  @see
        *    - StartProcess()
        *
        *  @return
        *    'true' if all went fine, else 'false' (there's currently no process running)
        */
        PLS_API bool EndProcess();


    //[-------------------------------------------------------]
    //[ Private data                                          ]
    //[-------------------------------------------------------]
    private:
        PLRenderer::RendererContext  *m_pRendererContext;       /**< The used renderer context, not destroyed by the scene context (always valid!) */
        PLMesh::MeshManager          *m_pMeshManager;           /**< The mesh manager, can be a null pointer */
        PLMath::GraphPathManager     *m_pGraphPathManager;      /**< The graph path manager, can be a null pointer */
        SceneNodeHandler             *m_pRoot;                  /**< The root of the scene graph (always valid!) */
        PLCore::Array<SceneNode*>     m_lstDeleteNodes;         /**< List of scene nodes to delete */
        SceneRendererManager         *m_pSceneRendererManager;  /**< Scene renderer manager, can be a null pointer */
        VisManager                   *m_pVisManager;            /**< Visibility manager, can be a null pointer */
        bool                          m_bProcessActive;         /**< Is there currently an active process? */
        PLCore::uint32                m_nProcessCounter;        /**< Internal process counter */


};


//[-------------------------------------------------------]
//[ Namespace                                             ]
//[-------------------------------------------------------]
} // PLScene


#endif // __PLSCENE_SCENECONTEXT_H__