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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-Plane collider by Christoph Beyer ( boernerb@web.de )
*
* This testing basically comes down to testing the intersection
* of the cylinder caps (discs) with the plane.
*
*/
#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 dCollideCylinderPlane(dxGeom *Cylinder, dxGeom *Plane, int flags, dContactGeom *contact, int skip)
{
dIASSERT (skip >= (int)sizeof(dContactGeom));
dIASSERT (Cylinder->type == dCylinderClass);
dIASSERT (Plane->type == dPlaneClass);
dIASSERT ((flags & NUMC_MASK) >= 1);
int GeomCount = 0; // count of used contactgeoms
#ifdef dSINGLE
const dReal toleranz = REAL(0.0001);
#endif
#ifdef dDOUBLE
const dReal toleranz = REAL(0.0000001);
#endif
// Get the properties of the cylinder (length+radius)
dReal radius, length;
dGeomCylinderGetParams(Cylinder, &radius, &length);
dVector3 &cylpos = Cylinder->final_posr->pos;
// and the plane
dVector4 planevec;
dGeomPlaneGetParams(Plane, planevec);
dVector3 PlaneNormal = {planevec[0],planevec[1],planevec[2]};
dVector3 PlanePos = {planevec[0] * planevec[3],planevec[1] * planevec[3],planevec[2] * planevec[3]};
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);
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;
// parallel-check
s = vDir1[0] * PlaneNormal[0] + vDir1[1] * PlaneNormal[1] + vDir1[2] * PlaneNormal[2];
if(s < 0)
s += REAL(1.0); // is ca. 0, if vDir1 and PlaneNormal are parallel
else
s -= REAL(1.0); // is ca. 0, if vDir1 and PlaneNormal are parallel
if(s < toleranz && s > (-toleranz))
{
// discs are parallel to the plane
// 1.compute if, and where contacts are
dVector3 P;
s = planevec[3] - dVector3Dot(planevec, G1Pos1);
dReal t;
t = planevec[3] - dVector3Dot(planevec, G1Pos2);
if(s >= t) // s == t does never happen,
{
if(s >= 0)
{
// 1. Disc
dVector3Copy(G1Pos1, P);
}
else
return GeomCount; // no contacts
}
else
{
if(t >= 0)
{
// 2. Disc
dVector3Copy(G1Pos2, P);
}
else
return GeomCount; // no contacts
}
// 2. generate a coordinate-system on the disc
dVector3 V1, V2;
if(vDir1[0] < toleranz && vDir1[0] > (-toleranz))
{
// not x-axis
V1[0] = vDir1[0] + REAL(1.0); // random value
V1[1] = vDir1[1];
V1[2] = vDir1[2];
}
else
{
// maybe x-axis
V1[0] = vDir1[0];
V1[1] = vDir1[1] + REAL(1.0); // random value
V1[2] = vDir1[2];
}
// V1 is now another direction than vDir1
// Cross-product
dVector3Cross(V1, vDir1, V2);
// make unit V2
t = dVector3Length(V2);
t = radius / t;
dVector3Scale(V2, t);
// cross again
dVector3Cross(V2, vDir1, V1);
// |V2| is 'radius' and vDir1 unit, so |V1| is 'radius'
// V1 = first axis
// V2 = second axis
// 3. generate contactpoints
// Potential contact 1
dVector3Add(P, V1, contact->pos);
contact->depth = planevec[3] - dVector3Dot(planevec, contact->pos);
if(contact->depth > 0)
{
dVector3Copy(PlaneNormal, contact->normal);
contact->g1 = Cylinder;
contact->g2 = Plane;
GeomCount++;
if( GeomCount >= (flags & NUMC_MASK))
return GeomCount; // enough contactgeoms
contact = (dContactGeom *)((char *)contact + skip);
}
// Potential contact 2
dVector3Subtract(P, V1, contact->pos);
contact->depth = planevec[3] - dVector3Dot(planevec, contact->pos);
if(contact->depth > 0)
{
dVector3Copy(PlaneNormal, contact->normal);
contact->g1 = Cylinder;
contact->g2 = Plane;
GeomCount++;
if( GeomCount >= (flags & NUMC_MASK))
return GeomCount; // enough contactgeoms
contact = (dContactGeom *)((char *)contact + skip);
}
// Potential contact 3
dVector3Add(P, V2, contact->pos);
contact->depth = planevec[3] - dVector3Dot(planevec, contact->pos);
if(contact->depth > 0)
{
dVector3Copy(PlaneNormal, contact->normal);
contact->g1 = Cylinder;
contact->g2 = Plane;
GeomCount++;
if( GeomCount >= (flags & NUMC_MASK))
return GeomCount; // enough contactgeoms
contact = (dContactGeom *)((char *)contact + skip);
}
// Potential contact 4
dVector3Subtract(P, V2, contact->pos);
contact->depth = planevec[3] - dVector3Dot(planevec, contact->pos);
if(contact->depth > 0)
{
dVector3Copy(PlaneNormal, contact->normal);
contact->g1 = Cylinder;
contact->g2 = Plane;
GeomCount++;
if( GeomCount >= (flags & NUMC_MASK))
return GeomCount; // enough contactgeoms
contact = (dContactGeom *)((char *)contact + skip);
}
}
else
{
dReal t = dVector3Dot(PlaneNormal, vDir1);
C[0] = vDir1[0] * t - PlaneNormal[0];
C[1] = vDir1[1] * t - PlaneNormal[1];
C[2] = vDir1[2] * t - PlaneNormal[2];
s = dVector3Length(C);
// move C onto the circle
s = radius / s;
dVector3Scale(C, s);
// deepest point of disc 1
dVector3Add(C, G1Pos1, contact->pos);
// depth of the deepest point
contact->depth = planevec[3] - dVector3Dot(planevec, contact->pos);
if(contact->depth >= 0)
{
dVector3Copy(PlaneNormal, contact->normal);
contact->g1 = Cylinder;
contact->g2 = Plane;
GeomCount++;
if( GeomCount >= (flags & NUMC_MASK))
return GeomCount; // enough contactgeoms
contact = (dContactGeom *)((char *)contact + skip);
}
// C is still computed
// deepest point of disc 2
dVector3Add(C, G1Pos2, contact->pos);
// depth of the deepest point
contact->depth = planevec[3] - planevec[0] * contact->pos[0] - planevec[1] * contact->pos[1] - planevec[2] * contact->pos[2];
if(contact->depth >= 0)
{
dVector3Copy(PlaneNormal, contact->normal);
contact->g1 = Cylinder;
contact->g2 = Plane;
GeomCount++;
if( GeomCount >= (flags & NUMC_MASK))
return GeomCount; // enough contactgeoms
contact = (dContactGeom *)((char *)contact + skip);
}
}
return GeomCount;
}
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