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/*************************************************************************
* *
* Open Dynamics Engine, Copyright (C) 2001-2003 Russell L. Smith. *
* All rights reserved. Email: russ@q12.org Web: www.q12.org *
* *
* This library is free software; you can redistribute it and/or *
* modify it under the terms of EITHER: *
* (1) The GNU Lesser General Public License as published by the Free *
* Software Foundation; either version 2.1 of the License, or (at *
* your option) any later version. The text of the GNU Lesser *
* General Public License is included with this library in the *
* file LICENSE.TXT. *
* (2) The BSD-style license that is included with this library in *
* the file LICENSE-BSD.TXT. *
* *
* This library 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 files *
* LICENSE.TXT and LICENSE-BSD.TXT for more details. *
* *
*************************************************************************/
/*******************************************************************
* *
* cylinder-sphere collider by Christoph Beyer (boernerb@web.de) *
* *
* In Cylinder/Sphere-collisions, there are three possibilies: *
* 1. collision with the cylinder's nappe *
* 2. collision with one of the cylinder's disc *
* 3. collision with one of the disc's border *
* *
* This collider computes two distances (s, t) and based on them, *
* it decides, which collision we have. *
* This collider always generates 1 (or 0, if we have no collison) *
* contacts. *
* It is able to "separate" cylinder and sphere in all *
* configurations, but it never pays attention to velocity. *
* So, in extrem situations, "tunneling-effect" is possible. *
* *
*******************************************************************/
#include <ode/collision.h>
#include <ode/matrix.h>
#include <ode/rotation.h>
#include <ode/odemath.h>
#include <ode/objects.h>
#include "collision_kernel.h" // for dxGeom
#include "collision_util.h"
int dCollideCylinderSphere(dxGeom* Cylinder, dxGeom* Sphere,
int flags, dContactGeom *contact, int skip)
{
dIASSERT (skip >= (int)sizeof(dContactGeom));
dIASSERT (Cylinder->type == dCylinderClass);
dIASSERT (Sphere->type == dSphereClass);
dIASSERT ((flags & NUMC_MASK) >= 1);
unsigned char* pContactData = (unsigned char*)contact;
int GeomCount = 0; // count of used contacts
#ifdef dSINGLE
const dReal toleranz = REAL(0.0001);
#endif
#ifdef dDOUBLE
const dReal toleranz = REAL(0.0000001);
#endif
// get the data from the geoms
dReal radius, length;
dGeomCylinderGetParams(Cylinder, &radius, &length);
dVector3 &cylpos = Cylinder->final_posr->pos;
const dReal* pfRot1 = dGeomGetRotation(Cylinder);
dReal radius2;
radius2 = dGeomSphereGetRadius(Sphere);
const dReal* SpherePos = dGeomGetPosition(Sphere);
// G1Pos1 is the middle of the first disc
// G1Pos2 is the middle of the second disc
// vDir1 is the unit direction of the cylinderaxis
dVector3 G1Pos1, G1Pos2, vDir1;
vDir1[0] = Cylinder->final_posr->R[2];
vDir1[1] = Cylinder->final_posr->R[6];
vDir1[2] = Cylinder->final_posr->R[10];
dReal s;
s = length * REAL(0.5); // just a precomputed factor
G1Pos2[0] = vDir1[0] * s + cylpos[0];
G1Pos2[1] = vDir1[1] * s + cylpos[1];
G1Pos2[2] = vDir1[2] * s + cylpos[2];
G1Pos1[0] = vDir1[0] * -s + cylpos[0];
G1Pos1[1] = vDir1[1] * -s + cylpos[1];
G1Pos1[2] = vDir1[2] * -s + cylpos[2];
dVector3 C;
dReal t;
// Step 1: compute the two distances 's' and 't'
// 's' is the distance from the first disc (in vDir1-/Zylinderaxis-direction), the disc with G1Pos1 in the middle
s = (SpherePos[0] - G1Pos1[0]) * vDir1[0] - (G1Pos1[1] - SpherePos[1]) * vDir1[1] - (G1Pos1[2] - SpherePos[2]) * vDir1[2];
if(s < (-radius2) || s > (length + radius2) )
{
// Sphere is too far away from the discs
// no collision
return 0;
}
// C is the direction from Sphere-middle to the cylinder-axis (vDir1); C is orthogonal to the cylinder-axis
C[0] = s * vDir1[0] + G1Pos1[0] - SpherePos[0];
C[1] = s * vDir1[1] + G1Pos1[1] - SpherePos[1];
C[2] = s * vDir1[2] + G1Pos1[2] - SpherePos[2];
// t is the distance from the Sphere-middle to the cylinder-axis!
t = dVector3Length(C);
if(t > (radius + radius2) )
{
// Sphere is too far away from the cylinder axis!
// no collision
return 0;
}
// decide which kind of collision we have:
if(t > radius && (s < 0 || s > length) )
{
// 3. collision
if(s <= 0)
{
contact->depth = radius2 - dSqrt( (s) * (s) + (t - radius) * (t - radius) );
if(contact->depth < 0)
{
// no collision!
return 0;
}
contact->pos[0] = C[0] / t * -radius + G1Pos1[0];
contact->pos[1] = C[1] / t * -radius + G1Pos1[1];
contact->pos[2] = C[2] / t * -radius + G1Pos1[2];
contact->normal[0] = (contact->pos[0] - SpherePos[0]) / (radius2 - contact->depth);
contact->normal[1] = (contact->pos[1] - SpherePos[1]) / (radius2 - contact->depth);
contact->normal[2] = (contact->pos[2] - SpherePos[2]) / (radius2 - contact->depth);
contact->g1 = Cylinder;
contact->g2 = Sphere;
GeomCount++;
return GeomCount;
}
else
{
// now s is bigger than length here!
contact->depth = radius2 - dSqrt( (s - length) * (s - length) + (t - radius) * (t - radius) );
if(contact->depth < 0)
{
// no collision!
return 0;
}
contact->pos[0] = C[0] / t * -radius + G1Pos2[0];
contact->pos[1] = C[1] / t * -radius + G1Pos2[1];
contact->pos[2] = C[2] / t * -radius + G1Pos2[2];
contact->normal[0] = (contact->pos[0] - SpherePos[0]) / (radius2 - contact->depth);
contact->normal[1] = (contact->pos[1] - SpherePos[1]) / (radius2 - contact->depth);
contact->normal[2] = (contact->pos[2] - SpherePos[2]) / (radius2 - contact->depth);
contact->g1 = Cylinder;
contact->g2 = Sphere;
GeomCount++;
return GeomCount;
}
}
else if( (radius - t) <= s && (radius - t) <= (length - s) )
{
// 1. collsision
if(t > (radius2 + toleranz))
{
// cylinder-axis is outside the sphere
contact->depth = (radius2 + radius) - t;
if(contact->depth < 0)
{
// should never happen, but just for safeness
return 0;
}
else
{
C[0] /= t;
C[1] /= t;
C[2] /= t;
contact->pos[0] = C[0] * radius2 + SpherePos[0];
contact->pos[1] = C[1] * radius2 + SpherePos[1];
contact->pos[2] = C[2] * radius2 + SpherePos[2];
contact->normal[0] = C[0];
contact->normal[1] = C[1];
contact->normal[2] = C[2];
contact->g1 = Cylinder;
contact->g2 = Sphere;
GeomCount++;
return GeomCount;
}
}
else
{
// cylinder-axis is outside of the sphere
contact->depth = (radius2 + radius) - t;
if(contact->depth < 0)
{
// should never happen, but just for safeness
return 0;
}
else
{
contact->pos[0] = C[0] + SpherePos[0];
contact->pos[1] = C[1] + SpherePos[1];
contact->pos[2] = C[2] + SpherePos[2];
contact->normal[0] = C[0] / t;
contact->normal[1] = C[1] / t;
contact->normal[2] = C[2] / t;
contact->g1 = Cylinder;
contact->g2 = Sphere;
GeomCount++;
return GeomCount;
}
}
}
else
{
// 2. collision
if(s <= (length * REAL(0.5)) )
{
// collsision with the first disc
contact->depth = s + radius2;
if(contact->depth < 0)
{
// should never happen, but just for safeness
return 0;
}
contact->pos[0] = radius2 * vDir1[0] + SpherePos[0];
contact->pos[1] = radius2 * vDir1[1] + SpherePos[1];
contact->pos[2] = radius2 * vDir1[2] + SpherePos[2];
contact->normal[0] = vDir1[0];
contact->normal[1] = vDir1[1];
contact->normal[2] = vDir1[2];
contact->g1 = Cylinder;
contact->g2 = Sphere;
GeomCount++;
return GeomCount;
}
else
{
// collsision with the second disc
contact->depth = (radius2 + length - s);
if(contact->depth < 0)
{
// should never happen, but just for safeness
return 0;
}
contact->pos[0] = radius2 * -vDir1[0] + SpherePos[0];
contact->pos[1] = radius2 * -vDir1[1] + SpherePos[1];
contact->pos[2] = radius2 * -vDir1[2] + SpherePos[2];
contact->normal[0] = -vDir1[0];
contact->normal[1] = -vDir1[1];
contact->normal[2] = -vDir1[2];
contact->g1 = Cylinder;
contact->g2 = Sphere;
GeomCount++;
return GeomCount;
}
}
return GeomCount;
}
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