cullsys.h

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/*
**  Command & Conquer Generals Zero Hour(tm)
**  Copyright 2025 Electronic Arts Inc.
**
**  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/>.
*/
 
/***********************************************************************************************
 ***              C O N F I D E N T I A L  ---  W E S T W O O D  S T U D I O S               ***
 ***********************************************************************************************
 *                                                                                             *
 *                 Project Name : WWMath                                                       *
 *                                                                                             *
 *                     $Archive:: /Commando/Code/wwmath/cullsys.h                             $*
 *                                                                                             *
 *                       Author:: Greg Hjelstrom                                               *
 *                                                                                             *
 *                     $Modtime:: 5/08/01 6:33p                                               $*
 *                                                                                             *
 *                    $Revision:: 5                                                           $*
 *                                                                                             *
 *---------------------------------------------------------------------------------------------*
 * Functions:                                                                                  *
 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 
#if defined(_MSC_VER)
#pragma once
#endif
 
#ifndef CULLSYS_H
#define CULLSYS_H
 
#include "wwdebug.h"
#include "stdlib.h"
#include "refcount.h"
#include "aabox.h"
 
class CullableClass;
class CullSystemClass;
class FrustumClass;
 
/*
** CullLinkClass
** This class will serve as a base class for the various types of linkage information
** that the Cullable instances will need.  Each CullableClass will have a pointer to
** a class derived from CullLinkClass where the different culling systems can store
** things.
*/
class CullLinkClass
{
public:
    WWINLINE CullLinkClass(CullSystemClass * system)                                { System = system; WWASSERT(System); }
    virtual ~CullLinkClass(void)                                              { WWASSERT(System == NULL); }
    
    WWINLINE void                   Set_Culling_System(CullSystemClass * sys)      { System = sys; } 
    WWINLINE CullSystemClass * Get_Culling_System(void)                            { return System; }
 
protected:
    CullSystemClass * System;
};
 
 
/*
** CullableClass
** This is the base class for any object that can be inserted into a culling system
** This class provides an axis aligned bounding box and some linkage variables which
** allow it to be processed by any culling system.
*/
class CullableClass : public RefCountClass
{
public:
    
    CullableClass(void);
    virtual ~CullableClass(void);
    
    /*
    ** Access to the culling box for this object.  When you set the cull box, you are
    ** basically guaranteeing that the object is contained within the given box.  The
    ** object will automatically be updated in whatever culling system it is currently
    ** contained in (if any)
    */
    WWINLINE const AABoxClass & Get_Cull_Box(void) const                          { return CullBox; }
    void                                Set_Cull_Box(const AABoxClass & box,bool just_loaded = false);
 
    /*
    ** These functions are used by various culling systems to manage the linkage 
    ** pointers.  *The average user should NEVER call these*
    */
    void                                Set_Culling_System(CullSystemClass * sys);
    CullSystemClass *                Get_Culling_System(void) const;
    WWINLINE void                   Set_Cull_Link(CullLinkClass * c)                  { CullLink = c; }
    WWINLINE CullLinkClass *   Get_Cull_Link(void) const                          { return CullLink; }
 
private:
 
    WWINLINE void                   Set_Next_Collected(CullableClass * c)          { NextCollected = c; }
    WWINLINE CullableClass *   Get_Next_Collected(void)                            { return NextCollected; }
 
    /*
    ** Culling Data
    ** Each object can be linked into various types of culling systems.
    ** Each culling system can use its own linkage data structure (derived
    ** from CullLinkClass) to keep track of the object.  The CullData pointer 
    ** will point to one of the culling link objects and NULL
    ** if its not in any system.
    */
    CullLinkClass *             CullLink;
 
    /*
    ** Bounding Box
    ** Any objects derived from Cullable should update the bounding box
    ** whenever the object moves or changes size.  In order to do this,
    ** call Set_Cull_Box...
    */
    AABoxClass                      CullBox;
 
    /*
    ** NextCollected
    ** This pointer is used by the culling system to keep a singly linked 
    ** list of cullable object that have been "collected". 
    */
    CullableClass *                NextCollected;
 
    // Not Implemented:
    CullableClass(const CullableClass & src);
    CullableClass & operator = (const CullableClass & src);
 
    friend class CullSystemClass;
};
 
 
 
 
/*
** CullSystemClass
** Base class of any culling system.  This interface exists so that things can
** be shuffled around without having explicit knowledge of what system they are in.
*/
class CullSystemClass
{
public:
 
    CullSystemClass(void);
    virtual ~CullSystemClass(void);
 
    /*
    ** Collect_Objects.  Updates the internal collection list with the
    ** objects that overlap the given primitive. 
    ** WARNING: This builds an internal list that is only valid until
    ** another list is built, only one list can be valid at any time.
    ** WARNING: Always call Reset_Collection if you want to start a 
    ** fresh collection!
    */
    void                    Reset_Collection(void);
    virtual void        Collect_Objects(const Vector3 & point)                    = 0;
    virtual void        Collect_Objects(const AABoxClass & box)                = 0;
    virtual void        Collect_Objects(const OBBoxClass & box)                = 0;
    virtual void        Collect_Objects(const FrustumClass & frustum)        = 0;
 
    /*
    ** This object has moved or changed size, update it
    */
    virtual void        Update_Culling(CullableClass * obj)                      = 0;
 
protected:
 
    /*
    ** Iterate through the collected objects
    */
    CullableClass *    Get_First_Collected_Object_Internal(void);
    CullableClass *    Get_Next_Collected_Object_Internal(CullableClass * obj);
    CullableClass *    Peek_First_Collected_Object_Internal(void);
    CullableClass *    Peek_Next_Collected_Object_Internal(CullableClass * obj);
 
    /*
    ** Build the list of collected objects
    */
    void                    Add_To_Collection(CullableClass * obj);
 
    /*
    ** Pointer to the head of the current collection of objects
    */
    CullableClass *    CollectionHead;
 
    friend class CullableClass;
};
 
 
#endif