diff -r 000000000000 -r 2f259fa3e83a ode/src/collision_util.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ode/src/collision_util.cpp Tue Feb 02 01:00:49 2010 +0200 @@ -0,0 +1,638 @@ +/************************************************************************* + * * + * 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 +#include +#include +#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] = dMUL((p1[0]-p2[0]),d1); + c->normal[1] = dMUL((p1[1]-p2[1]),d1); + c->normal[2] = dMUL((p1[2]-p2[2]),d1); + dReal k = dMUL(REAL(0.5),(r2 - r1 - d)); + c->pos[0] = p1[0] + dMUL(c->normal[0],k); + c->pos[1] = p1[1] + dMUL(c->normal[1],k); + c->pos[2] = p1[2] + dMUL(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-dMUL(uaub,uaub); + if (d <= REAL(0.0001)) { + // @@@ this needs to be made more robust + *alpha = 0; + *beta = 0; + } + else { + d = dRecip(d); + *alpha = dMUL((q1 + dMUL(uaub,q2)),d); + *beta = dMUL((dMUL(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. + +EXPORT_C 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 = dDIV(da1,la); + a1a2[0] = dMUL(k,a1a2[0]); + a1a2[1] = dMUL(k,a1a2[1]); + a1a2[2] = dMUL(k,a1a2[2]); + SET3 (n,a1b1,-,a1a2); + if (dDOT(b1b2,n) >= 0) { + a1a2[0] = dMUL(k,a1a2[0]); + a1a2[1] = dMUL(k,a1a2[1]); + a1a2[2] = dMUL(k,a1a2[2]); + SET3 (cp1,a1,+,a1a2); + SET2 (cp2,b1); + return; + } + } + + if (da2 >= 0 && da4 <= 0) { + k = dDIV(da2,la); + a1a2[0] = dMUL(k,a1a2[0]); + a1a2[1] = dMUL(k,a1a2[1]); + a1a2[2] = dMUL(k,a1a2[2]); + SET3 (n,a1b2,-,a1a2); + if (dDOT(b1b2,n) <= 0) { + a1a2[0] = dMUL(k,a1a2[0]); + a1a2[1] = dMUL(k,a1a2[1]); + a1a2[2] = dMUL(k,a1a2[2]); + SET3 (cp1,a1,+,a1a2); + SET2 (cp2,b2); + return; + } + } + + lb = dDOT(b1b2,b1b2); + if (db1 <= 0 && db2 >= 0) { + k = -dDIV(db1,lb); + b1b2[0] = dMUL(k,b1b2[0]); + b1b2[1] = dMUL(k,b1b2[1]); + b1b2[2] = dMUL(k,b1b2[2]); + SET3 (n,-a1b1,-,b1b2); + if (dDOT(a1a2,n) >= 0) { + b1b2[0] = dMUL(k,b1b2[0]); + b1b2[1] = dMUL(k,b1b2[1]); + b1b2[2] = dMUL(k,b1b2[2]); + SET2 (cp1,a1); + SET3 (cp2,b1,+,b1b2); + return; + } + } + + if (db3 <= 0 && db4 >= 0) { + k = -dDIV(db3,lb); + b1b2[0] = dMUL(k,b1b2[0]); + b1b2[1] = dMUL(k,b1b2[1]); + b1b2[2] = dMUL(k,b1b2[2]); + SET3 (n,-a2b1,-,b1b2); + if (dDOT(a1a2,n) <= 0) { + b1b2[0] = dMUL(k,b1b2[0]); + b1b2[1] = dMUL(k,b1b2[1]); + b1b2[2] = dMUL(k,b1b2[2]); + SET2 (cp1,a2); + SET3 (cp2,b1,+,b1b2); + return; + } + } + + // it must be edge-edge + + k = dDOT(a1a2,b1b2); + det = dMUL(la,lb) - dMUL(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 = dMUL((dMUL(lb,da1) - dMUL(k,db1)),det); + a1a2[0] = dMUL(alpha,a1a2[0]); + a1a2[1] = dMUL(alpha,a1a2[1]); + a1a2[2] = dMUL(alpha,a1a2[2]); + dReal beta = dMUL(( dMUL(k,da1) - dMUL(la,db1)),det); + b1b2[0] = dMUL(beta,b1b2[0]); + b1b2[1] = dMUL(beta,b1b2[1]); + b1b2[2] = dMUL(beta,b1b2[2]); + SET3 (cp1,a1,+,a1a2); + SET3 (cp2,b1,+,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] = REAL(-1.0); + } + else sign[i] = REAL(1.0); + } + + // compute v^2 + dVector3 v2; + v2[0] = dMUL(v[0],v[0]); + v2[1] = dMUL(v[1],v[1]); + v2[2] = dMUL(v[2],v[2]); + + // compute the half-sides of the box + dReal h[3]; + h[0] = dMUL(REAL(0.5),side[0]); + h[1] = dMUL(REAL(0.5),side[1]); + h[2] = dMUL(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]; + + // Denormals are a problem, because we divide by v[i], and then + // multiply that by 0. Alas, infinity times 0 is infinity (!) + // We also use v2[i], which is v[i] squared. Here's how the epsilons + // are chosen: + // float epsilon = 1.175494e-038 (smallest non-denormal number) + // double epsilon = 2.225074e-308 (smallest non-denormal number) + // For single precision, choose an epsilon such that v[i] squared is + // not a denormal; this is for performance. + // For double precision, choose an epsilon such that v[i] is not a + // denormal; this is for correctness. (Jon Watte on mailinglist) + + const dReal tanchor_eps = REAL(2e-5f); + + // find the region and tanchor values for p1 + for (i=0; i<3; i++) { + if (v[i] > tanchor_eps) { + if (s[i] < -h[i]) { + region[i] = -1; + tanchor[i] = dDIV((-h[i]-s[i]),v[i]); + } + else { + region[i] = (s[i] > h[i]); + tanchor[i] = dDIV((h[i]-s[i]),v[i]); + } + } + else { + region[i] = 0; + tanchor[i] = REAL(2.0); // 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 -= dMUL((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 = REAL(1.0); + 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 = REAL(0.0); + for (i=0; i<3; i++) { + next_dd2dt += dMUL((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 = dDIV((next_dd2dt-dd2dt),(next_t - t)); + t -= dDIV(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] = dDIV((h[i]-s[i]),v[i]); + region[i]++; + } + } + t = next_t; + dd2dt = next_dd2dt; + } + while (t < REAL(1.0)); + t = REAL(1.0); + + got_answer: + + // compute closest point on the line + for (i=0; i<3; i++) lret[i] = p1[i] + dMUL(t,tmp[i]); // note: tmp=p2-p1 + + // compute closest point on the box + for (i=0; i<3; i++) { + tmp[i] = dMUL(sign[i],(s[i] + dMUL(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. + +EXPORT_C 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 = dMUL(side1[0],REAL(0.5)); A2 = dMUL(side1[1],REAL(0.5)); A3 = dMUL(side1[2],REAL(0.5)); + B1 = dMUL(side2[0],REAL(0.5)); B2 = dMUL(side2[1],REAL(0.5)); B3 = dMUL(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 + dMUL(B1,Q11) + dMUL(B2,Q12) + dMUL(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 + dMUL(B1,Q21) + dMUL(B2,Q22) + dMUL(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 + dMUL(B1,Q31) + dMUL(B2,Q32) + dMUL(B3,Q33))) return 0; + + // separating axis = v1,v2,v3 + if (dFabs(dDOT41(R2+0,p)) > (dMUL(A1,Q11) + dMUL(A2,Q21) + dMUL(A3,Q31) + B1)) return 0; + if (dFabs(dDOT41(R2+1,p)) > (dMUL(A1,Q12) + dMUL(A2,Q22) + dMUL(A3,Q32) + B2)) return 0; + if (dFabs(dDOT41(R2+2,p)) > (dMUL(A1,Q13) + dMUL(A2,Q23) + dMUL(A3,Q33) + B3)) return 0; + + // separating axis = u1 x (v1,v2,v3) + if (dFabs(dMUL(pp[2],R21)-dMUL(pp[1],R31)) > dMUL(A2,Q31) + dMUL(A3,Q21) + dMUL(B2,Q13) + dMUL(B3,Q12)) return 0; + if (dFabs(dMUL(pp[2],R22)-dMUL(pp[1],R32)) > dMUL(A2,Q32) + dMUL(A3,Q22) + dMUL(B1,Q13) + dMUL(B3,Q11)) return 0; + if (dFabs(dMUL(pp[2],R23)-dMUL(pp[1],R33)) > dMUL(A2,Q33) + dMUL(A3,Q23) + dMUL(B1,Q12) + dMUL(B2,Q11)) return 0; + + // separating axis = u2 x (v1,v2,v3) + if (dFabs(dMUL(pp[0],R31)-dMUL(pp[2],R11)) > dMUL(A1,Q31) + dMUL(A3,Q11) + dMUL(B2,Q23) + dMUL(B3,Q22)) return 0; + if (dFabs(dMUL(pp[0],R32)-dMUL(pp[2],R12)) > dMUL(A1,Q32) + dMUL(A3,Q12) + dMUL(B1,Q23) + dMUL(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(dMUL(pp[1],R11)-dMUL(pp[0],R21)) > dMUL(A1,Q21) + dMUL(A2,Q11) + dMUL(B2,Q33) + dMUL(B3,Q32)) return 0; + if (dFabs(dMUL(pp[1],R12)-dMUL(pp[0],R22)) > dMUL(A1,Q22) + dMUL(A2,Q12) + dMUL(B1,Q33) + dMUL(B3,Q31)) return 0; + if (dFabs(dMUL(pp[1],R13)-dMUL(pp[0],R23)) > dMUL(A1,Q23) + dMUL(A2,Q13) + dMUL(B1,Q32) + dMUL(B2,Q31)) return 0; + + return 1; +} + +//**************************************************************************** +// other utility functions + +EXPORT_C 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 + +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]-dMUL((vEpnt0[0]-vEpnt1[0]),dDIV(fDistance0,(fDistance0-fDistance1))); + vIntersectionPoint[1]= vEpnt0[1]-dMUL((vEpnt0[1]-vEpnt1[1]),dDIV(fDistance0,(fDistance0-fDistance1))); + vIntersectionPoint[2]= vEpnt0[2]-dMUL((vEpnt0[2]-vEpnt1[2]),dDIV(fDistance0,(fDistance0-fDistance1))); + + // clamp correct edge to intersection point + if ( fDistance0 < REAL(0.0) ) + { + 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= 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] - + dMUL((avArrayIn[i0][0]-avArrayIn[i1][0]),dDIV(fDistance0,(fDistance0-fDistance1))); + vIntersectionPoint[1]= avArrayIn[i0][1] - + dMUL((avArrayIn[i0][1]-avArrayIn[i1][1]),dDIV(fDistance0,(fDistance0-fDistance1))); + vIntersectionPoint[2]= avArrayIn[i0][2] - + dMUL((avArrayIn[i0][2]-avArrayIn[i1][2]),dDIV(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= 0 ) + { + // emit point + if (dVector3Length2(avArrayIn[i0]) <= dMUL(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] - + dMUL((avArrayIn[i0][0]-avArrayIn[i1][0]),dDIV(fDistance0,(fDistance0-fDistance1))); + vIntersectionPoint[1]= avArrayIn[i0][1] - + dMUL((avArrayIn[i0][1]-avArrayIn[i1][1]),dDIV(fDistance0,(fDistance0-fDistance1))); + vIntersectionPoint[2]= avArrayIn[i0][2] - + dMUL((avArrayIn[i0][2]-avArrayIn[i1][2]),dDIV(fDistance0,(fDistance0-fDistance1))); + + // emit intersection point + if (dVector3Length2(avArrayIn[i0]) <= dMUL(fRadius,fRadius)) + { + avArrayOut[ctOut][0] = vIntersectionPoint[0]; + avArrayOut[ctOut][1] = vIntersectionPoint[1]; + avArrayOut[ctOut][2] = vIntersectionPoint[2]; + ctOut++; + } + } + } +} +