KX_RayCast.cpp

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/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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 2
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 * KX_MouseFocusSensor determines mouse in/out/over events.
 */

#include <stdlib.h>
#include <stdio.h>

#include "KX_RayCast.h"

#include "MT_Point3.h"
#include "MT_Vector3.h"

#include "KX_IPhysicsController.h"
#include "PHY_IPhysicsEnvironment.h"
#include "PHY_IPhysicsController.h"

KX_RayCast::KX_RayCast(KX_IPhysicsController* ignoreController, bool faceNormal, bool faceUV)
    :PHY_IRayCastFilterCallback(dynamic_cast<PHY_IPhysicsController*>(ignoreController), faceNormal, faceUV) 
{
}

void KX_RayCast::reportHit(PHY_RayCastResult* result)
{
    m_hitFound = true;
    m_hitPoint.setValue((const float*)result->m_hitPoint);
    m_hitNormal.setValue((const float*)result->m_hitNormal);
    m_hitUVOK = result->m_hitUVOK;
    m_hitUV.setValue((const float*)result->m_hitUV);
    m_hitMesh = result->m_meshObject;
    m_hitPolygon = result->m_polygon;
}

bool KX_RayCast::RayTest(PHY_IPhysicsEnvironment* physics_environment, const MT_Point3& _frompoint, const MT_Point3& topoint, KX_RayCast& callback)
{
    if(physics_environment==NULL) return false; /* prevents crashing in some cases */
    
    // Loops over all physics objects between frompoint and topoint,
    // calling callback.RayHit for each one.
    //
    // callback.RayHit should return true to stop looking, or false to continue.
    //
    // returns true if an object was found, false if not.
    
    MT_Point3 frompoint(_frompoint);
    const MT_Vector3 todir( (topoint - frompoint).safe_normalized() );
    MT_Point3 prevpoint(_frompoint+todir*(-1.f));
    
    PHY_IPhysicsController* hit_controller;

    while((hit_controller = physics_environment->rayTest(callback,
            frompoint.x(),frompoint.y(),frompoint.z(),
            topoint.x(),topoint.y(),topoint.z())) != NULL) 
    {
        KX_ClientObjectInfo* info = static_cast<KX_ClientObjectInfo*>(hit_controller->getNewClientInfo());
        
        if (!info)
        {
            printf("no info!\n");
            MT_assert(info && "Physics controller with no client object info");
            break;
        }
        
        // The biggest danger to endless loop, prevent this by checking that the
        // hit point always progresses along the ray direction..
        prevpoint -= callback.m_hitPoint;
        if (prevpoint.length2() < MT_EPSILON)
            break;

        if (callback.RayHit(info))
            // caller may decide to stop the loop and still cancel the hit
            return callback.m_hitFound;

        // Skip past the object and keep tracing.
        // Note that retrieving in a single shot multiple hit points would be possible 
        // but it would require some change in Bullet.
        prevpoint = callback.m_hitPoint;
        /* We add 0.001 of fudge, so that if the margin && radius == 0., we don't endless loop. */
        MT_Scalar marg = 0.001 + hit_controller->GetMargin();
        marg *= 2.f;
        /* Calculate the other side of this object */
        MT_Scalar h = MT_abs(todir.dot(callback.m_hitNormal));
        if (h <= 0.01)
            // the normal is almost orthogonal to the ray direction, cannot compute the other side
            break;
        marg /= h; 
        frompoint = callback.m_hitPoint + marg * todir;
        // verify that we are not passed the to point
        if ((topoint - frompoint).dot(todir) < 0.f)
            break;
    }
    return false;
}