colmathobbox.cpp

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/*
**  Command & Conquer Generals Zero Hour(tm)
**  Copyright 2025 Electronic Arts Inc.
**
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**  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.
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**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
**  GNU General Public License for more details.
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*/
 
/***********************************************************************************************
 ***              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/colmathobbox.cpp                      $*
 *                                                                                             *
 *                   Org Author:: Greg Hjelstrom                                               *
 *                                                                                             *
 *                       Author : Kenny Mitchell                                               * 
 *                                                                                             *
 *                     $Modtime:: 06/26/02 4:04p                                             $*
 *                                                                                             *
 *                    $Revision:: 9                                                           $*
 *                                                                                             *
 * 06/26/02 KM Matrix name change to avoid MAX conflicts                                       *
 *---------------------------------------------------------------------------------------------*
 * Functions:                                                                                  *
 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
 
#include "colmath.h"
#include "aaplane.h"
#include "plane.h"
#include "lineseg.h"
#include "tri.h"
#include "sphere.h"
#include "aabox.h"
#include "obbox.h"
#include "wwdebug.h"
 
 
 
// OBBox functions, where is operand B with respect to the OBBox
CollisionMath::OverlapType
CollisionMath::Overlap_Test(const OBBoxClass & box,const Vector3 & point)
{
    // transform point into box coordinate system
    Vector3 localpoint;
    Matrix3x3::Transpose_Rotate_Vector(box.Basis,(point - box.Center),&localpoint);
 
    // if the point is outside any of the extents, it is outside the box
    if (WWMath::Fabs(localpoint.X) > box.Extent.X) {
        return OUTSIDE;
    }
    if (WWMath::Fabs(localpoint.Y) > box.Extent.Y) {
        return OUTSIDE;
    }
    if (WWMath::Fabs(localpoint.Z) > box.Extent.Z) {
        return OUTSIDE;
    }
    return INSIDE;
}
 
CollisionMath::OverlapType
CollisionMath::Overlap_Test(const OBBoxClass & box,const LineSegClass & line)
{
    CastResultStruct res;
    Collide(line,box,&res);
    return eval_overlap_collision(res);
}
 
CollisionMath::OverlapType
CollisionMath::Overlap_Test(const OBBoxClass & box,const TriClass & tri)
{
    CastResultStruct res;
    Collide(box,Vector3(0,0,0),tri,Vector3(0,0,0),&res);
    return eval_overlap_collision(res);
}
 
CollisionMath::OverlapType 
CollisionMath::Overlap_Test(const AABoxClass & aabox,const OBBoxClass & obbox)
{
    if (CollisionMath::Intersection_Test(aabox,obbox)) {
        return BOTH;    // inside or overlapping
    } else {
        return OUTSIDE;
    }
}
 
CollisionMath::OverlapType 
CollisionMath::Overlap_Test(const OBBoxClass & obbox,const AABoxClass & aabox)
{
    if (CollisionMath::Intersection_Test(obbox,aabox)) {
        return BOTH;    // inside or overlapping
    } else {
        return OUTSIDE;
    }
}
 
 
CollisionMath::OverlapType
CollisionMath::Overlap_Test(const OBBoxClass & box,const OBBoxClass & box2)
{
    CastResultStruct res;
    Collide(box,Vector3(0,0,0),box2,Vector3(0,0,0),&res);
    return eval_overlap_collision(res);
}
 
bool CollisionMath::Collide
(
    const OBBoxClass &        box,
    const Vector3 &          move_vector,
    const PlaneClass &        plane,
    CastResultStruct *      result
)
{
    float frac;
 
    float extent = box.Project_To_Axis(plane.N);
    float dist = Vector3::Dot_Product(plane.N,box.Center) + plane.D;
    float move = Vector3::Dot_Product(plane.N,move_vector);
 
    if (dist > extent) {
        if (dist + move > extent) {
            // entire move ok!
            frac = 1.0f;
        } else {
            // partial move allowed
            frac = (extent - dist) / move;
        }
 
    } else if (dist < -extent) {
        if (dist + move < -extent) {
            // entire move ok!
            frac = 1.0f;
        } else {
            // partial move allowed
            frac = (-extent - dist) / move;
        }
    } else {
        result->StartBad = true;
        result->Normal = plane.N;
        return true;
    }
 
    if (frac < result->Fraction) {
        result->Fraction = frac;
        result->Normal = plane.N;
        if (result->ComputeContactPoint) {
 
            Vector3 move_dir(move_vector);
            move_dir.Normalize();
            float move_extent = Vector3::Dot_Product(move_dir,box.Extent);
            result->ContactPoint = box.Center + result->Fraction*move_vector  + move_extent*move_dir;
 
        }
        return true;
    }
    return false;
}