colmathfrustum.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/colmathfrustum.h                      $*
 *                                                                                             *
 *              Original Author:: Greg Hjelstrom                                               *
 *                                                                                             *
 *                      $Author:: Jani_p                                                      $*
 *                                                                                             *
 *                     $Modtime:: 5/04/01 8:25p                                               $*
 *                                                                                             *
 *                    $Revision:: 3                                                           $*
 *                                                                                             *
 *---------------------------------------------------------------------------------------------*
 * Functions:                                                                                  *
 *   CollisionMath::Overlap_Test -- test a frustum and an AABox for overlap                    *
 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
#if defined(_MSC_VER)
#pragma once
#endif
 
#ifndef COLMATHFRUSTUM_H
#define COLMATHFRUSTUM_H
 
#include "always.h"
#include "aabox.h"
#include "vector3.h"
#include "lineseg.h"
#include "frustum.h"
 
/*
** Inline collision functions dealing with frustums
*/
 
/***********************************************************************************************
 * CollisionMath::Overlap_Test -- test a frustum and an AABox for overlap                      *
 *                                                                                             *
 * INPUT:                                                                                      *
 *                                                                                             *
 * OUTPUT:                                                                                     *
 *                                                                                             *
 * WARNINGS:                                                                                   *
 *                                                                                             *
 * HISTORY:                                                                                    *
 *   3/29/2000  gth : Created.                                                                 *
 *=============================================================================================*/
inline 
CollisionMath::OverlapType
CollisionMath::Overlap_Test(const FrustumClass & frustum,const AABoxClass & box,int & planes_passed)
{
    int mask = 0;
 
    // TODO: doesn't catch all cases...
    for (int i = 0; i < 6; i++) {
 
        int plane_bit = (1<<i);
    
        // only check this plane if we have to  
        if ((planes_passed & plane_bit) == 0) {
        
            int result = CollisionMath::Overlap_Test(frustum.Planes[i],box);
            if (result == OUTSIDE) {
 
                return OUTSIDE;
            } else if (result == INSIDE) {
                planes_passed |= plane_bit;
            }
            mask |= result;
        
        } else {
        
            mask |= INSIDE;
        
        }
    }
 
    if (mask == INSIDE) {
        return INSIDE;
    }
    return OVERLAPPED;
}
 
#endif