/*************************************************************************
* *
* Open Dynamics Engine, Copyright (C) 2001,2002 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. *
* *
*************************************************************************/
/*
some useful collision utility stuff. this includes some API utility
functions that are defined in the public header files.
*/
#include <ode/common.h>
#include <ode/collision.h>
#include <ode/odemath.h>
#include "collision_util.h"
//****************************************************************************
int dCollideSpheres (dVector3 p1, dReal r1,
dVector3 p2, dReal r2, dContactGeom *c)
{
// printf ("d=%.2f (%.2f %.2f %.2f) (%.2f %.2f %.2f) r1=%.2f r2=%.2f\n",
// d,p1[0],p1[1],p1[2],p2[0],p2[1],p2[2],r1,r2);
dReal d = dDISTANCE (p1,p2);
if (d > (r1 + r2)) return 0;
if (d <= 0) {
c->pos[0] = p1[0];
c->pos[1] = p1[1];
c->pos[2] = p1[2];
c->normal[0] = 1;
c->normal[1] = 0;
c->normal[2] = 0;
c->depth = r1 + r2;
}
else {
dReal d1 = dRecip (d);
c->normal[0] = (p1[0]-p2[0])*d1;
c->normal[1] = (p1[1]-p2[1])*d1;
c->normal[2] = (p1[2]-p2[2])*d1;
dReal k = REAL(0.5) * (r2 - r1 - d);
c->pos[0] = p1[0] + c->normal[0]*k;
c->pos[1] = p1[1] + c->normal[1]*k;
c->pos[2] = p1[2] + c->normal[2]*k;
c->depth = r1 + r2 - d;
}
return 1;
}
void dLineClosestApproach (const dVector3 pa, const dVector3 ua,
const dVector3 pb, const dVector3 ub,
dReal *alpha, dReal *beta)
{
dVector3 p;
p[0] = pb[0] - pa[0];
p[1] = pb[1] - pa[1];
p[2] = pb[2] - pa[2];
dReal uaub = dDOT(ua,ub);
dReal q1 = dDOT(ua,p);
dReal q2 = -dDOT(ub,p);
dReal d = 1-uaub*uaub;
if (d <= REAL(0.0001)) {
// @@@ this needs to be made more robust
*alpha = 0;
*beta = 0;
}
else {
d = dRecip(d);
*alpha = (q1 + uaub*q2)*d;
*beta = (uaub*q1 + q2)*d;
}
}
// given two line segments A and B with endpoints a1-a2 and b1-b2, return the
// points on A and B that are closest to each other (in cp1 and cp2).
// in the case of parallel lines where there are multiple solutions, a
// solution involving the endpoint of at least one line will be returned.
// this will work correctly for zero length lines, e.g. if a1==a2 and/or
// b1==b2.
//
// the algorithm works by applying the voronoi clipping rule to the features
// of the line segments. the three features of each line segment are the two
// endpoints and the line between them. the voronoi clipping rule states that,
// for feature X on line A and feature Y on line B, the closest points PA and
// PB between X and Y are globally the closest points if PA is in V(Y) and
// PB is in V(X), where V(X) is the voronoi region of X.
void dClosestLineSegmentPoints (const dVector3 a1, const dVector3 a2,
const dVector3 b1, const dVector3 b2,
dVector3 cp1, dVector3 cp2)
{
dVector3 a1a2,b1b2,a1b1,a1b2,a2b1,a2b2,n;
dReal la,lb,k,da1,da2,da3,da4,db1,db2,db3,db4,det;
#define SET2(a,b) a[0]=b[0]; a[1]=b[1]; a[2]=b[2];
#define SET3(a,b,op,c) a[0]=b[0] op c[0]; a[1]=b[1] op c[1]; a[2]=b[2] op c[2];
// check vertex-vertex features
SET3 (a1a2,a2,-,a1);
SET3 (b1b2,b2,-,b1);
SET3 (a1b1,b1,-,a1);
da1 = dDOT(a1a2,a1b1);
db1 = dDOT(b1b2,a1b1);
if (da1 <= 0 && db1 >= 0) {
SET2 (cp1,a1);
SET2 (cp2,b1);
return;
}
SET3 (a1b2,b2,-,a1);
da2 = dDOT(a1a2,a1b2);
db2 = dDOT(b1b2,a1b2);
if (da2 <= 0 && db2 <= 0) {
SET2 (cp1,a1);
SET2 (cp2,b2);
return;
}
SET3 (a2b1,b1,-,a2);
da3 = dDOT(a1a2,a2b1);
db3 = dDOT(b1b2,a2b1);
if (da3 >= 0 && db3 >= 0) {
SET2 (cp1,a2);
SET2 (cp2,b1);
return;
}
SET3 (a2b2,b2,-,a2);
da4 = dDOT(a1a2,a2b2);
db4 = dDOT(b1b2,a2b2);
if (da4 >= 0 && db4 <= 0) {
SET2 (cp1,a2);
SET2 (cp2,b2);
return;
}
// check edge-vertex features.
// if one or both of the lines has zero length, we will never get to here,
// so we do not have to worry about the following divisions by zero.
la = dDOT(a1a2,a1a2);
if (da1 >= 0 && da3 <= 0) {
k = da1 / la;
SET3 (n,a1b1,-,k*a1a2);
if (dDOT(b1b2,n) >= 0) {
SET3 (cp1,a1,+,k*a1a2);
SET2 (cp2,b1);
return;
}
}
if (da2 >= 0 && da4 <= 0) {
k = da2 / la;
SET3 (n,a1b2,-,k*a1a2);
if (dDOT(b1b2,n) <= 0) {
SET3 (cp1,a1,+,k*a1a2);
SET2 (cp2,b2);
return;
}
}
lb = dDOT(b1b2,b1b2);
if (db1 <= 0 && db2 >= 0) {
k = -db1 / lb;
SET3 (n,-a1b1,-,k*b1b2);
if (dDOT(a1a2,n) >= 0) {
SET2 (cp1,a1);
SET3 (cp2,b1,+,k*b1b2);
return;
}
}
if (db3 <= 0 && db4 >= 0) {
k = -db3 / lb;
SET3 (n,-a2b1,-,k*b1b2);
if (dDOT(a1a2,n) <= 0) {
SET2 (cp1,a2);
SET3 (cp2,b1,+,k*b1b2);
return;
}
}
// it must be edge-edge
k = dDOT(a1a2,b1b2);
det = la*lb - k*k;
if (det <= 0) {
// this should never happen, but just in case...
SET2(cp1,a1);
SET2(cp2,b1);
return;
}
det = dRecip (det);
dReal alpha = (lb*da1 - k*db1) * det;
dReal beta = ( k*da1 - la*db1) * det;
SET3 (cp1,a1,+,alpha*a1a2);
SET3 (cp2,b1,+,beta*b1b2);
# undef SET2
# undef SET3
}
// a simple root finding algorithm is used to find the value of 't' that
// satisfies:
// d|D(t)|^2/dt = 0
// where:
// |D(t)| = |p(t)-b(t)|
// where p(t) is a point on the line parameterized by t:
// p(t) = p1 + t*(p2-p1)
// and b(t) is that same point clipped to the boundary of the box. in box-
// relative coordinates d|D(t)|^2/dt is the sum of three x,y,z components
// each of which looks like this:
//
// t_lo /
// ______/ -->t
// / t_hi
// /
//
// t_lo and t_hi are the t values where the line passes through the planes
// corresponding to the sides of the box. the algorithm computes d|D(t)|^2/dt
// in a piecewise fashion from t=0 to t=1, stopping at the point where
// d|D(t)|^2/dt crosses from negative to positive.
void dClosestLineBoxPoints (const dVector3 p1, const dVector3 p2,
const dVector3 c, const dMatrix3 R,
const dVector3 side,
dVector3 lret, dVector3 bret)
{
int i;
// compute the start and delta of the line p1-p2 relative to the box.
// we will do all subsequent computations in this box-relative coordinate
// system. we have to do a translation and rotation for each point.
dVector3 tmp,s,v;
tmp[0] = p1[0] - c[0];
tmp[1] = p1[1] - c[1];
tmp[2] = p1[2] - c[2];
dMULTIPLY1_331 (s,R,tmp);
tmp[0] = p2[0] - p1[0];
tmp[1] = p2[1] - p1[1];
tmp[2] = p2[2] - p1[2];
dMULTIPLY1_331 (v,R,tmp);
// mirror the line so that v has all components >= 0
dVector3 sign;
for (i=0; i<3; i++) {
if (v[i] < 0) {
s[i] = -s[i];
v[i] = -v[i];
sign[i] = -1;
}
else sign[i] = 1;
}
// compute v^2
dVector3 v2;
v2[0] = v[0]*v[0];
v2[1] = v[1]*v[1];
v2[2] = v[2]*v[2];
// compute the half-sides of the box
dReal h[3];
h[0] = REAL(0.5) * side[0];
h[1] = REAL(0.5) * side[1];
h[2] = REAL(0.5) * side[2];
// region is -1,0,+1 depending on which side of the box planes each
// coordinate is on. tanchor is the next t value at which there is a
// transition, or the last one if there are no more.
int region[3];
dReal tanchor[3];
// find the region and tanchor values for p1
for (i=0; i<3; i++) {
if (v[i] > 0) {
if (s[i] < -h[i]) {
region[i] = -1;
tanchor[i] = (-h[i]-s[i])/v[i];
}
else {
region[i] = (s[i] > h[i]);
tanchor[i] = (h[i]-s[i])/v[i];
}
}
else {
region[i] = 0;
tanchor[i] = 2; // this will never be a valid tanchor
}
}
// compute d|d|^2/dt for t=0. if it's >= 0 then p1 is the closest point
dReal t=0;
dReal dd2dt = 0;
for (i=0; i<3; i++) dd2dt -= (region[i] ? v2[i] : 0) * tanchor[i];
if (dd2dt >= 0) goto got_answer;
do {
// find the point on the line that is at the next clip plane boundary
dReal next_t = 1;
for (i=0; i<3; i++) {
if (tanchor[i] > t && tanchor[i] < 1 && tanchor[i] < next_t)
next_t = tanchor[i];
}
// compute d|d|^2/dt for the next t
dReal next_dd2dt = 0;
for (i=0; i<3; i++) {
next_dd2dt += (region[i] ? v2[i] : 0) * (next_t - tanchor[i]);
}
// if the sign of d|d|^2/dt has changed, solution = the crossover point
if (next_dd2dt >= 0) {
dReal m = (next_dd2dt-dd2dt)/(next_t - t);
t -= dd2dt/m;
goto got_answer;
}
// advance to the next anchor point / region
for (i=0; i<3; i++) {
if (tanchor[i] == next_t) {
tanchor[i] = (h[i]-s[i])/v[i];
region[i]++;
}
}
t = next_t;
dd2dt = next_dd2dt;
}
while (t < 1);
t = 1;
got_answer:
// compute closest point on the line
for (i=0; i<3; i++) lret[i] = p1[i] + t*tmp[i]; // note: tmp=p2-p1
// compute closest point on the box
for (i=0; i<3; i++) {
tmp[i] = sign[i] * (s[i] + t*v[i]);
if (tmp[i] < -h[i]) tmp[i] = -h[i];
else if (tmp[i] > h[i]) tmp[i] = h[i];
}
dMULTIPLY0_331 (s,R,tmp);
for (i=0; i<3; i++) bret[i] = s[i] + c[i];
}
// given boxes (p1,R1,side1) and (p1,R1,side1), return 1 if they intersect
// or 0 if not.
int dBoxTouchesBox (const dVector3 p1, const dMatrix3 R1,
const dVector3 side1, const dVector3 p2,
const dMatrix3 R2, const dVector3 side2)
{
// two boxes are disjoint if (and only if) there is a separating axis
// perpendicular to a face from one box or perpendicular to an edge from
// either box. the following tests are derived from:
// "OBB Tree: A Hierarchical Structure for Rapid Interference Detection",
// S.Gottschalk, M.C.Lin, D.Manocha., Proc of ACM Siggraph 1996.
// Rij is R1'*R2, i.e. the relative rotation between R1 and R2.
// Qij is abs(Rij)
dVector3 p,pp;
dReal A1,A2,A3,B1,B2,B3,R11,R12,R13,R21,R22,R23,R31,R32,R33,
Q11,Q12,Q13,Q21,Q22,Q23,Q31,Q32,Q33;
// get vector from centers of box 1 to box 2, relative to box 1
p[0] = p2[0] - p1[0];
p[1] = p2[1] - p1[1];
p[2] = p2[2] - p1[2];
dMULTIPLY1_331 (pp,R1,p); // get pp = p relative to body 1
// get side lengths / 2
A1 = side1[0]*REAL(0.5); A2 = side1[1]*REAL(0.5); A3 = side1[2]*REAL(0.5);
B1 = side2[0]*REAL(0.5); B2 = side2[1]*REAL(0.5); B3 = side2[2]*REAL(0.5);
// for the following tests, excluding computation of Rij, in the worst case,
// 15 compares, 60 adds, 81 multiplies, and 24 absolutes.
// notation: R1=[u1 u2 u3], R2=[v1 v2 v3]
// separating axis = u1,u2,u3
R11 = dDOT44(R1+0,R2+0); R12 = dDOT44(R1+0,R2+1); R13 = dDOT44(R1+0,R2+2);
Q11 = dFabs(R11); Q12 = dFabs(R12); Q13 = dFabs(R13);
if (dFabs(pp[0]) > (A1 + B1*Q11 + B2*Q12 + B3*Q13)) return 0;
R21 = dDOT44(R1+1,R2+0); R22 = dDOT44(R1+1,R2+1); R23 = dDOT44(R1+1,R2+2);
Q21 = dFabs(R21); Q22 = dFabs(R22); Q23 = dFabs(R23);
if (dFabs(pp[1]) > (A2 + B1*Q21 + B2*Q22 + B3*Q23)) return 0;
R31 = dDOT44(R1+2,R2+0); R32 = dDOT44(R1+2,R2+1); R33 = dDOT44(R1+2,R2+2);
Q31 = dFabs(R31); Q32 = dFabs(R32); Q33 = dFabs(R33);
if (dFabs(pp[2]) > (A3 + B1*Q31 + B2*Q32 + B3*Q33)) return 0;
// separating axis = v1,v2,v3
if (dFabs(dDOT41(R2+0,p)) > (A1*Q11 + A2*Q21 + A3*Q31 + B1)) return 0;
if (dFabs(dDOT41(R2+1,p)) > (A1*Q12 + A2*Q22 + A3*Q32 + B2)) return 0;
if (dFabs(dDOT41(R2+2,p)) > (A1*Q13 + A2*Q23 + A3*Q33 + B3)) return 0;
// separating axis = u1 x (v1,v2,v3)
if (dFabs(pp[2]*R21-pp[1]*R31) > A2*Q31 + A3*Q21 + B2*Q13 + B3*Q12) return 0;
if (dFabs(pp[2]*R22-pp[1]*R32) > A2*Q32 + A3*Q22 + B1*Q13 + B3*Q11) return 0;
if (dFabs(pp[2]*R23-pp[1]*R33) > A2*Q33 + A3*Q23 + B1*Q12 + B2*Q11) return 0;
// separating axis = u2 x (v1,v2,v3)
if (dFabs(pp[0]*R31-pp[2]*R11) > A1*Q31 + A3*Q11 + B2*Q23 + B3*Q22) return 0;
if (dFabs(pp[0]*R32-pp[2]*R12) > A1*Q32 + A3*Q12 + B1*Q23 + B3*Q21) return 0;
if (dFabs(pp[0]*R33-pp[2]*R13) > A1*Q33 + A3*Q13 + B1*Q22 + B2*Q21) return 0;
// separating axis = u3 x (v1,v2,v3)
if (dFabs(pp[1]*R11-pp[0]*R21) > A1*Q21 + A2*Q11 + B2*Q33 + B3*Q32) return 0;
if (dFabs(pp[1]*R12-pp[0]*R22) > A1*Q22 + A2*Q12 + B1*Q33 + B3*Q31) return 0;
if (dFabs(pp[1]*R13-pp[0]*R23) > A1*Q23 + A2*Q13 + B1*Q32 + B2*Q31) return 0;
return 1;
}
//****************************************************************************
// other utility functions
void dInfiniteAABB (dxGeom *geom, dReal aabb[6])
{
aabb[0] = -dInfinity;
aabb[1] = dInfinity;
aabb[2] = -dInfinity;
aabb[3] = dInfinity;
aabb[4] = -dInfinity;
aabb[5] = dInfinity;
}
//****************************************************************************
// Helpers for Croteam's collider - by Nguyen Binh
#ifdef dCYLINDER_ENABLED
int dClipEdgeToPlane( dVector3 &vEpnt0, dVector3 &vEpnt1, const dVector4& plPlane)
{
// calculate distance of edge points to plane
dReal fDistance0 = dPointPlaneDistance( vEpnt0 ,plPlane );
dReal fDistance1 = dPointPlaneDistance( vEpnt1 ,plPlane );
// if both points are behind the plane
if ( fDistance0 < 0 && fDistance1 < 0 )
{
// do nothing
return 0;
// if both points in front of the plane
}
else if ( fDistance0 > 0 && fDistance1 > 0 )
{
// accept them
return 1;
// if we have edge/plane intersection
} else if ((fDistance0 > 0 && fDistance1 < 0) || ( fDistance0 < 0 && fDistance1 > 0))
{
// find intersection point of edge and plane
dVector3 vIntersectionPoint;
vIntersectionPoint[0]= vEpnt0[0]-(vEpnt0[0]-vEpnt1[0])*fDistance0/(fDistance0-fDistance1);
vIntersectionPoint[1]= vEpnt0[1]-(vEpnt0[1]-vEpnt1[1])*fDistance0/(fDistance0-fDistance1);
vIntersectionPoint[2]= vEpnt0[2]-(vEpnt0[2]-vEpnt1[2])*fDistance0/(fDistance0-fDistance1);
// clamp correct edge to intersection point
if ( fDistance0 < 0 )
{
dVector3Copy(vIntersectionPoint,vEpnt0);
} else
{
dVector3Copy(vIntersectionPoint,vEpnt1);
}
return 1;
}
return 1;
}
// clip polygon with plane and generate new polygon points
void dClipPolyToPlane( const dVector3 avArrayIn[], const int ctIn,
dVector3 avArrayOut[], int &ctOut,
const dVector4 &plPlane )
{
// start with no output points
ctOut = 0;
int i0 = ctIn-1;
// for each edge in input polygon
for (int i1=0; i1<ctIn; i0=i1, i1++) {
// calculate distance of edge points to plane
dReal fDistance0 = dPointPlaneDistance( avArrayIn[i0],plPlane );
dReal fDistance1 = dPointPlaneDistance( avArrayIn[i1],plPlane );
// if first point is in front of plane
if( fDistance0 >= 0 ) {
// emit point
avArrayOut[ctOut][0] = avArrayIn[i0][0];
avArrayOut[ctOut][1] = avArrayIn[i0][1];
avArrayOut[ctOut][2] = avArrayIn[i0][2];
ctOut++;
}
// if points are on different sides
if( (fDistance0 > 0 && fDistance1 < 0) || ( fDistance0 < 0 && fDistance1 > 0) ) {
// find intersection point of edge and plane
dVector3 vIntersectionPoint;
vIntersectionPoint[0]= avArrayIn[i0][0] -
(avArrayIn[i0][0]-avArrayIn[i1][0])*fDistance0/(fDistance0-fDistance1);
vIntersectionPoint[1]= avArrayIn[i0][1] -
(avArrayIn[i0][1]-avArrayIn[i1][1])*fDistance0/(fDistance0-fDistance1);
vIntersectionPoint[2]= avArrayIn[i0][2] -
(avArrayIn[i0][2]-avArrayIn[i1][2])*fDistance0/(fDistance0-fDistance1);
// emit intersection point
avArrayOut[ctOut][0] = vIntersectionPoint[0];
avArrayOut[ctOut][1] = vIntersectionPoint[1];
avArrayOut[ctOut][2] = vIntersectionPoint[2];
ctOut++;
}
}
}
void dClipPolyToCircle(const dVector3 avArrayIn[], const int ctIn,
dVector3 avArrayOut[], int &ctOut,
const dVector4 &plPlane ,dReal fRadius)
{
// start with no output points
ctOut = 0;
int i0 = ctIn-1;
// for each edge in input polygon
for (int i1=0; i1<ctIn; i0=i1, i1++)
{
// calculate distance of edge points to plane
dReal fDistance0 = dPointPlaneDistance( avArrayIn[i0],plPlane );
dReal fDistance1 = dPointPlaneDistance( avArrayIn[i1],plPlane );
// if first point is in front of plane
if( fDistance0 >= 0 )
{
// emit point
if (dVector3Length2(avArrayIn[i0]) <= fRadius*fRadius)
{
avArrayOut[ctOut][0] = avArrayIn[i0][0];
avArrayOut[ctOut][1] = avArrayIn[i0][1];
avArrayOut[ctOut][2] = avArrayIn[i0][2];
ctOut++;
}
}
// if points are on different sides
if( (fDistance0 > 0 && fDistance1 < 0) || ( fDistance0 < 0 && fDistance1 > 0) )
{
// find intersection point of edge and plane
dVector3 vIntersectionPoint;
vIntersectionPoint[0]= avArrayIn[i0][0] -
(avArrayIn[i0][0]-avArrayIn[i1][0])*fDistance0/(fDistance0-fDistance1);
vIntersectionPoint[1]= avArrayIn[i0][1] -
(avArrayIn[i0][1]-avArrayIn[i1][1])*fDistance0/(fDistance0-fDistance1);
vIntersectionPoint[2]= avArrayIn[i0][2] -
(avArrayIn[i0][2]-avArrayIn[i1][2])*fDistance0/(fDistance0-fDistance1);
// emit intersection point
if (dVector3Length2(avArrayIn[i0]) <= fRadius*fRadius)
{
avArrayOut[ctOut][0] = vIntersectionPoint[0];
avArrayOut[ctOut][1] = vIntersectionPoint[1];
avArrayOut[ctOut][2] = vIntersectionPoint[2];
ctOut++;
}
}
}
}
#endif
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