KX_RayCast.cpp

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/*
 * $Id: KX_RayCast.cpp 35171 2011-02-25 13:35:59Z jesterking $
 *
 * ***** 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;
}