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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. *
* *
*************************************************************************/
/*
standard ODE geometry primitives: public API and pairwise collision functions.
the rule is that only the low level primitive collision functions should set
dContactGeom::g1 and dContactGeom::g2.
*/
#include <ode/common.h>
#include <ode/collision.h>
#include <ode/matrix.h>
#include <ode/rotation.h>
#include <ode/odemath.h>
#include "collision_kernel.h"
#include "collision_std.h"
#include "collision_util.h"
#ifdef _MSC_VER
#pragma warning(disable:4291) // for VC++, no complaints about "no matching operator delete found"
#endif
//****************************************************************************
// box public API
dxBox::dxBox (dSpaceID space, dReal lx, dReal ly, dReal lz) : dxGeom (space,1)
{
dAASSERT (lx >= 0 && ly >= 0 && lz >= 0);
type = dBoxClass;
side[0] = lx;
side[1] = ly;
side[2] = lz;
}
void dxBox::computeAABB()
{
const dMatrix3& R = final_posr->R;
const dVector3& pos = final_posr->pos;
dReal xrange = REAL(0.5) * (dFabs (R[0] * side[0]) +
dFabs (R[1] * side[1]) + dFabs (R[2] * side[2]));
dReal yrange = REAL(0.5) * (dFabs (R[4] * side[0]) +
dFabs (R[5] * side[1]) + dFabs (R[6] * side[2]));
dReal zrange = REAL(0.5) * (dFabs (R[8] * side[0]) +
dFabs (R[9] * side[1]) + dFabs (R[10] * side[2]));
aabb[0] = pos[0] - xrange;
aabb[1] = pos[0] + xrange;
aabb[2] = pos[1] - yrange;
aabb[3] = pos[1] + yrange;
aabb[4] = pos[2] - zrange;
aabb[5] = pos[2] + zrange;
}
dGeomID dCreateBox (dSpaceID space, dReal lx, dReal ly, dReal lz)
{
return new dxBox (space,lx,ly,lz);
}
void dGeomBoxSetLengths (dGeomID g, dReal lx, dReal ly, dReal lz)
{
dUASSERT (g && g->type == dBoxClass,"argument not a box");
dAASSERT (lx > 0 && ly > 0 && lz > 0);
dxBox *b = (dxBox*) g;
b->side[0] = lx;
b->side[1] = ly;
b->side[2] = lz;
dGeomMoved (g);
}
void dGeomBoxGetLengths (dGeomID g, dVector3 result)
{
dUASSERT (g && g->type == dBoxClass,"argument not a box");
dxBox *b = (dxBox*) g;
result[0] = b->side[0];
result[1] = b->side[1];
result[2] = b->side[2];
}
dReal dGeomBoxPointDepth (dGeomID g, dReal x, dReal y, dReal z)
{
dUASSERT (g && g->type == dBoxClass,"argument not a box");
g->recomputePosr();
dxBox *b = (dxBox*) g;
// Set p = (x,y,z) relative to box center
//
// This will be (0,0,0) if the point is at (side[0]/2,side[1]/2,side[2]/2)
dVector3 p,q;
p[0] = x - b->final_posr->pos[0];
p[1] = y - b->final_posr->pos[1];
p[2] = z - b->final_posr->pos[2];
// Rotate p into box's coordinate frame, so we can
// treat the OBB as an AABB
dMULTIPLY1_331 (q,b->final_posr->R,p);
// Record distance from point to each successive box side, and see
// if the point is inside all six sides
dReal dist[6];
int i;
bool inside = true;
for (i=0; i < 3; i++) {
dReal side = b->side[i] * REAL(0.5);
dist[i ] = side - q[i];
dist[i+3] = side + q[i];
if ((dist[i] < 0) || (dist[i+3] < 0)) {
inside = false;
}
}
// If point is inside the box, the depth is the smallest positive distance
// to any side
if (inside) {
dReal smallest_dist = (dReal) (unsigned) -1;
for (i=0; i < 6; i++) {
if (dist[i] < smallest_dist) smallest_dist = dist[i];
}
return smallest_dist;
}
// Otherwise, if point is outside the box, the depth is the largest
// distance to any side. This is an approximation to the 'proper'
// solution (the proper solution may be larger in some cases).
dReal largest_dist = 0;
for (i=0; i < 6; i++) {
if (dist[i] > largest_dist) largest_dist = dist[i];
}
return -largest_dist;
}
//****************************************************************************
// box-box collision utility
// find all the intersection points between the 2D rectangle with vertices
// at (+/-h[0],+/-h[1]) and the 2D quadrilateral with vertices (p[0],p[1]),
// (p[2],p[3]),(p[4],p[5]),(p[6],p[7]).
//
// the intersection points are returned as x,y pairs in the 'ret' array.
// the number of intersection points is returned by the function (this will
// be in the range 0 to 8).
static int intersectRectQuad (dReal h[2], dReal p[8], dReal ret[16])
{
// q (and r) contain nq (and nr) coordinate points for the current (and
// chopped) polygons
int nq=4,nr;
dReal buffer[16];
dReal *q = p;
dReal *r = ret;
for (int dir=0; dir <= 1; dir++) {
// direction notation: xy[0] = x axis, xy[1] = y axis
for (int sign=-1; sign <= 1; sign += 2) {
// chop q along the line xy[dir] = sign*h[dir]
dReal *pq = q;
dReal *pr = r;
nr = 0;
for (int i=nq; i > 0; i--) {
// go through all points in q and all lines between adjacent points
if (sign*pq[dir] < h[dir]) {
// this point is inside the chopping line
pr[0] = pq[0];
pr[1] = pq[1];
pr += 2;
nr++;
if (nr & 8) {
q = r;
goto done;
}
}
dReal *nextq = (i > 1) ? pq+2 : q;
if ((sign*pq[dir] < h[dir]) ^ (sign*nextq[dir] < h[dir])) {
// this line crosses the chopping line
pr[1-dir] = pq[1-dir] + (nextq[1-dir]-pq[1-dir]) /
(nextq[dir]-pq[dir]) * (sign*h[dir]-pq[dir]);
pr[dir] = sign*h[dir];
pr += 2;
nr++;
if (nr & 8) {
q = r;
goto done;
}
}
pq += 2;
}
q = r;
r = (q==ret) ? buffer : ret;
nq = nr;
}
}
done:
if (q != ret) memcpy (ret,q,nr*2*sizeof(dReal));
return nr;
}
// given n points in the plane (array p, of size 2*n), generate m points that
// best represent the whole set. the definition of 'best' here is not
// predetermined - the idea is to select points that give good box-box
// collision detection behavior. the chosen point indexes are returned in the
// array iret (of size m). 'i0' is always the first entry in the array.
// n must be in the range [1..8]. m must be in the range [1..n]. i0 must be
// in the range [0..n-1].
void cullPoints (int n, dReal p[], int m, int i0, int iret[])
{
// compute the centroid of the polygon in cx,cy
int i,j;
dReal a,cx,cy,q;
if (n==1) {
cx = p[0];
cy = p[1];
}
else if (n==2) {
cx = REAL(0.5)*(p[0] + p[2]);
cy = REAL(0.5)*(p[1] + p[3]);
}
else {
a = 0;
cx = 0;
cy = 0;
for (i=0; i<(n-1); i++) {
q = p[i*2]*p[i*2+3] - p[i*2+2]*p[i*2+1];
a += q;
cx += q*(p[i*2]+p[i*2+2]);
cy += q*(p[i*2+1]+p[i*2+3]);
}
q = p[n*2-2]*p[1] - p[0]*p[n*2-1];
a = dRecip(REAL(3.0)*(a+q));
cx = a*(cx + q*(p[n*2-2]+p[0]));
cy = a*(cy + q*(p[n*2-1]+p[1]));
}
// compute the angle of each point w.r.t. the centroid
dReal A[8];
for (i=0; i<n; i++) A[i] = dAtan2(p[i*2+1]-cy,p[i*2]-cx);
// search for points that have angles closest to A[i0] + i*(2*pi/m).
int avail[8];
for (i=0; i<n; i++) avail[i] = 1;
avail[i0] = 0;
iret[0] = i0;
iret++;
for (j=1; j<m; j++) {
a = dReal(j)*(2*M_PI/m) + A[i0];
if (a > M_PI) a -= 2*M_PI;
dReal maxdiff=1e9,diff;
#ifndef dNODEBUG
*iret = i0; // iret is not allowed to keep this value
#endif
for (i=0; i<n; i++) {
if (avail[i]) {
diff = dFabs (A[i]-a);
if (diff > M_PI) diff = 2*M_PI - diff;
if (diff < maxdiff) {
maxdiff = diff;
*iret = i;
}
}
}
#ifndef dNODEBUG
dIASSERT (*iret != i0); // ensure iret got set
#endif
avail[*iret] = 0;
iret++;
}
}
// given two boxes (p1,R1,side1) and (p2,R2,side2), collide them together and
// generate contact points. this returns 0 if there is no contact otherwise
// it returns the number of contacts generated.
// `normal' returns the contact normal.
// `depth' returns the maximum penetration depth along that normal.
// `return_code' returns a number indicating the type of contact that was
// detected:
// 1,2,3 = box 2 intersects with a face of box 1
// 4,5,6 = box 1 intersects with a face of box 2
// 7..15 = edge-edge contact
// `maxc' is the maximum number of contacts allowed to be generated, i.e.
// the size of the `contact' array.
// `contact' and `skip' are the contact array information provided to the
// collision functions. this function only fills in the position and depth
// fields.
int dBoxBox (const dVector3 p1, const dMatrix3 R1,
const dVector3 side1, const dVector3 p2,
const dMatrix3 R2, const dVector3 side2,
dVector3 normal, dReal *depth, int *return_code,
int maxc, dContactGeom *contact, int skip)
{
const dReal fudge_factor = REAL(1.05);
dVector3 p,pp,normalC;
const dReal *normalR = 0;
dReal A[3],B[3],R11,R12,R13,R21,R22,R23,R31,R32,R33,
Q11,Q12,Q13,Q21,Q22,Q23,Q31,Q32,Q33,s,s2,l;
int i,j,invert_normal,code;
// 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
A[0] = side1[0]*REAL(0.5);
A[1] = side1[1]*REAL(0.5);
A[2] = side1[2]*REAL(0.5);
B[0] = side2[0]*REAL(0.5);
B[1] = side2[1]*REAL(0.5);
B[2] = side2[2]*REAL(0.5);
// Rij is R1'*R2, i.e. the relative rotation between R1 and R2
R11 = dDOT44(R1+0,R2+0); R12 = dDOT44(R1+0,R2+1); R13 = dDOT44(R1+0,R2+2);
R21 = dDOT44(R1+1,R2+0); R22 = dDOT44(R1+1,R2+1); R23 = dDOT44(R1+1,R2+2);
R31 = dDOT44(R1+2,R2+0); R32 = dDOT44(R1+2,R2+1); R33 = dDOT44(R1+2,R2+2);
Q11 = dFabs(R11); Q12 = dFabs(R12); Q13 = dFabs(R13);
Q21 = dFabs(R21); Q22 = dFabs(R22); Q23 = dFabs(R23);
Q31 = dFabs(R31); Q32 = dFabs(R32); Q33 = dFabs(R33);
// for all 15 possible separating axes:
// * see if the axis separates the boxes. if so, return 0.
// * find the depth of the penetration along the separating axis (s2)
// * if this is the largest depth so far, record it.
// the normal vector will be set to the separating axis with the smallest
// depth. note: normalR is set to point to a column of R1 or R2 if that is
// the smallest depth normal so far. otherwise normalR is 0 and normalC is
// set to a vector relative to body 1. invert_normal is 1 if the sign of
// the normal should be flipped.
#define TST(expr1,expr2,norm,cc) \
s2 = dFabs(expr1) - (expr2); \
if (s2 > 0) return 0; \
if (s2 > s) { \
s = s2; \
normalR = norm; \
invert_normal = ((expr1) < 0); \
code = (cc); \
}
s = -dInfinity;
invert_normal = 0;
code = 0;
// separating axis = u1,u2,u3
TST (pp[0],(A[0] + B[0]*Q11 + B[1]*Q12 + B[2]*Q13),R1+0,1);
TST (pp[1],(A[1] + B[0]*Q21 + B[1]*Q22 + B[2]*Q23),R1+1,2);
TST (pp[2],(A[2] + B[0]*Q31 + B[1]*Q32 + B[2]*Q33),R1+2,3);
// separating axis = v1,v2,v3
TST (dDOT41(R2+0,p),(A[0]*Q11 + A[1]*Q21 + A[2]*Q31 + B[0]),R2+0,4);
TST (dDOT41(R2+1,p),(A[0]*Q12 + A[1]*Q22 + A[2]*Q32 + B[1]),R2+1,5);
TST (dDOT41(R2+2,p),(A[0]*Q13 + A[1]*Q23 + A[2]*Q33 + B[2]),R2+2,6);
// note: cross product axes need to be scaled when s is computed.
// normal (n1,n2,n3) is relative to box 1.
#undef TST
#define TST(expr1,expr2,n1,n2,n3,cc) \
s2 = dFabs(expr1) - (expr2); \
if (s2 > 0) return 0; \
l = dSqrt ((n1)*(n1) + (n2)*(n2) + (n3)*(n3)); \
if (l > 0) { \
s2 /= l; \
if (s2*fudge_factor > s) { \
s = s2; \
normalR = 0; \
normalC[0] = (n1)/l; normalC[1] = (n2)/l; normalC[2] = (n3)/l; \
invert_normal = ((expr1) < 0); \
code = (cc); \
} \
}
// separating axis = u1 x (v1,v2,v3)
TST(pp[2]*R21-pp[1]*R31,(A[1]*Q31+A[2]*Q21+B[1]*Q13+B[2]*Q12),0,-R31,R21,7);
TST(pp[2]*R22-pp[1]*R32,(A[1]*Q32+A[2]*Q22+B[0]*Q13+B[2]*Q11),0,-R32,R22,8);
TST(pp[2]*R23-pp[1]*R33,(A[1]*Q33+A[2]*Q23+B[0]*Q12+B[1]*Q11),0,-R33,R23,9);
// separating axis = u2 x (v1,v2,v3)
TST(pp[0]*R31-pp[2]*R11,(A[0]*Q31+A[2]*Q11+B[1]*Q23+B[2]*Q22),R31,0,-R11,10);
TST(pp[0]*R32-pp[2]*R12,(A[0]*Q32+A[2]*Q12+B[0]*Q23+B[2]*Q21),R32,0,-R12,11);
TST(pp[0]*R33-pp[2]*R13,(A[0]*Q33+A[2]*Q13+B[0]*Q22+B[1]*Q21),R33,0,-R13,12);
// separating axis = u3 x (v1,v2,v3)
TST(pp[1]*R11-pp[0]*R21,(A[0]*Q21+A[1]*Q11+B[1]*Q33+B[2]*Q32),-R21,R11,0,13);
TST(pp[1]*R12-pp[0]*R22,(A[0]*Q22+A[1]*Q12+B[0]*Q33+B[2]*Q31),-R22,R12,0,14);
TST(pp[1]*R13-pp[0]*R23,(A[0]*Q23+A[1]*Q13+B[0]*Q32+B[1]*Q31),-R23,R13,0,15);
#undef TST
if (!code) return 0;
// if we get to this point, the boxes interpenetrate. compute the normal
// in global coordinates.
if (normalR) {
normal[0] = normalR[0];
normal[1] = normalR[4];
normal[2] = normalR[8];
}
else {
dMULTIPLY0_331 (normal,R1,normalC);
}
if (invert_normal) {
normal[0] = -normal[0];
normal[1] = -normal[1];
normal[2] = -normal[2];
}
*depth = -s;
// compute contact point(s)
if (code > 6) {
// an edge from box 1 touches an edge from box 2.
// find a point pa on the intersecting edge of box 1
dVector3 pa;
dReal sign;
for (i=0; i<3; i++) pa[i] = p1[i];
for (j=0; j<3; j++) {
sign = (dDOT14(normal,R1+j) > 0) ? REAL(1.0) : REAL(-1.0);
for (i=0; i<3; i++) pa[i] += sign * A[j] * R1[i*4+j];
}
// find a point pb on the intersecting edge of box 2
dVector3 pb;
for (i=0; i<3; i++) pb[i] = p2[i];
for (j=0; j<3; j++) {
sign = (dDOT14(normal,R2+j) > 0) ? REAL(-1.0) : REAL(1.0);
for (i=0; i<3; i++) pb[i] += sign * B[j] * R2[i*4+j];
}
dReal alpha,beta;
dVector3 ua,ub;
for (i=0; i<3; i++) ua[i] = R1[((code)-7)/3 + i*4];
for (i=0; i<3; i++) ub[i] = R2[((code)-7)%3 + i*4];
dLineClosestApproach (pa,ua,pb,ub,&alpha,&beta);
for (i=0; i<3; i++) pa[i] += ua[i]*alpha;
for (i=0; i<3; i++) pb[i] += ub[i]*beta;
for (i=0; i<3; i++) contact[0].pos[i] = REAL(0.5)*(pa[i]+pb[i]);
contact[0].depth = *depth;
*return_code = code;
return 1;
}
// okay, we have a face-something intersection (because the separating
// axis is perpendicular to a face). define face 'a' to be the reference
// face (i.e. the normal vector is perpendicular to this) and face 'b' to be
// the incident face (the closest face of the other box).
const dReal *Ra,*Rb,*pa,*pb,*Sa,*Sb;
if (code <= 3) {
Ra = R1;
Rb = R2;
pa = p1;
pb = p2;
Sa = A;
Sb = B;
}
else {
Ra = R2;
Rb = R1;
pa = p2;
pb = p1;
Sa = B;
Sb = A;
}
// nr = normal vector of reference face dotted with axes of incident box.
// anr = absolute values of nr.
dVector3 normal2,nr,anr;
if (code <= 3) {
normal2[0] = normal[0];
normal2[1] = normal[1];
normal2[2] = normal[2];
}
else {
normal2[0] = -normal[0];
normal2[1] = -normal[1];
normal2[2] = -normal[2];
}
dMULTIPLY1_331 (nr,Rb,normal2);
anr[0] = dFabs (nr[0]);
anr[1] = dFabs (nr[1]);
anr[2] = dFabs (nr[2]);
// find the largest compontent of anr: this corresponds to the normal
// for the indident face. the other axis numbers of the indicent face
// are stored in a1,a2.
int lanr,a1,a2;
if (anr[1] > anr[0]) {
if (anr[1] > anr[2]) {
a1 = 0;
lanr = 1;
a2 = 2;
}
else {
a1 = 0;
a2 = 1;
lanr = 2;
}
}
else {
if (anr[0] > anr[2]) {
lanr = 0;
a1 = 1;
a2 = 2;
}
else {
a1 = 0;
a2 = 1;
lanr = 2;
}
}
// compute center point of incident face, in reference-face coordinates
dVector3 center;
if (nr[lanr] < 0) {
for (i=0; i<3; i++) center[i] = pb[i] - pa[i] + Sb[lanr] * Rb[i*4+lanr];
}
else {
for (i=0; i<3; i++) center[i] = pb[i] - pa[i] - Sb[lanr] * Rb[i*4+lanr];
}
// find the normal and non-normal axis numbers of the reference box
int codeN,code1,code2;
if (code <= 3) codeN = code-1; else codeN = code-4;
if (codeN==0) {
code1 = 1;
code2 = 2;
}
else if (codeN==1) {
code1 = 0;
code2 = 2;
}
else {
code1 = 0;
code2 = 1;
}
// find the four corners of the incident face, in reference-face coordinates
dReal quad[8]; // 2D coordinate of incident face (x,y pairs)
dReal c1,c2,m11,m12,m21,m22;
c1 = dDOT14 (center,Ra+code1);
c2 = dDOT14 (center,Ra+code2);
// optimize this? - we have already computed this data above, but it is not
// stored in an easy-to-index format. for now it's quicker just to recompute
// the four dot products.
m11 = dDOT44 (Ra+code1,Rb+a1);
m12 = dDOT44 (Ra+code1,Rb+a2);
m21 = dDOT44 (Ra+code2,Rb+a1);
m22 = dDOT44 (Ra+code2,Rb+a2);
{
dReal k1 = m11*Sb[a1];
dReal k2 = m21*Sb[a1];
dReal k3 = m12*Sb[a2];
dReal k4 = m22*Sb[a2];
quad[0] = c1 - k1 - k3;
quad[1] = c2 - k2 - k4;
quad[2] = c1 - k1 + k3;
quad[3] = c2 - k2 + k4;
quad[4] = c1 + k1 + k3;
quad[5] = c2 + k2 + k4;
quad[6] = c1 + k1 - k3;
quad[7] = c2 + k2 - k4;
}
// find the size of the reference face
dReal rect[2];
rect[0] = Sa[code1];
rect[1] = Sa[code2];
// intersect the incident and reference faces
dReal ret[16];
int n = intersectRectQuad (rect,quad,ret);
if (n < 1) return 0; // this should never happen
// convert the intersection points into reference-face coordinates,
// and compute the contact position and depth for each point. only keep
// those points that have a positive (penetrating) depth. delete points in
// the 'ret' array as necessary so that 'point' and 'ret' correspond.
dReal point[3*8]; // penetrating contact points
dReal dep[8]; // depths for those points
dReal det1 = dRecip(m11*m22 - m12*m21);
m11 *= det1;
m12 *= det1;
m21 *= det1;
m22 *= det1;
int cnum = 0; // number of penetrating contact points found
for (j=0; j < n; j++) {
dReal k1 = m22*(ret[j*2]-c1) - m12*(ret[j*2+1]-c2);
dReal k2 = -m21*(ret[j*2]-c1) + m11*(ret[j*2+1]-c2);
for (i=0; i<3; i++) point[cnum*3+i] =
center[i] + k1*Rb[i*4+a1] + k2*Rb[i*4+a2];
dep[cnum] = Sa[codeN] - dDOT(normal2,point+cnum*3);
if (dep[cnum] >= 0) {
ret[cnum*2] = ret[j*2];
ret[cnum*2+1] = ret[j*2+1];
cnum++;
}
}
if (cnum < 1) return 0; // this should never happen
// we can't generate more contacts than we actually have
if (maxc > cnum) maxc = cnum;
if (maxc < 1) maxc = 1;
if (cnum <= maxc) {
// we have less contacts than we need, so we use them all
for (j=0; j < cnum; j++) {
dContactGeom *con = CONTACT(contact,skip*j);
for (i=0; i<3; i++) con->pos[i] = point[j*3+i] + pa[i];
con->depth = dep[j];
}
}
else {
// we have more contacts than are wanted, some of them must be culled.
// find the deepest point, it is always the first contact.
int i1 = 0;
dReal maxdepth = dep[0];
for (i=1; i<cnum; i++) {
if (dep[i] > maxdepth) {
maxdepth = dep[i];
i1 = i;
}
}
int iret[8];
cullPoints (cnum,ret,maxc,i1,iret);
for (j=0; j < maxc; j++) {
dContactGeom *con = CONTACT(contact,skip*j);
for (i=0; i<3; i++) con->pos[i] = point[iret[j]*3+i] + pa[i];
con->depth = dep[iret[j]];
}
cnum = maxc;
}
*return_code = code;
return cnum;
}
int dCollideBoxBox (dxGeom *o1, dxGeom *o2, int flags,
dContactGeom *contact, int skip)
{
dIASSERT (skip >= (int)sizeof(dContactGeom));
dIASSERT (o1->type == dBoxClass);
dIASSERT (o2->type == dBoxClass);
dVector3 normal;
dReal depth;
int code;
dxBox *b1 = (dxBox*) o1;
dxBox *b2 = (dxBox*) o2;
int num = dBoxBox (o1->final_posr->pos,o1->final_posr->R,b1->side, o2->final_posr->pos,o2->final_posr->R,b2->side,
normal,&depth,&code,flags & NUMC_MASK,contact,skip);
for (int i=0; i<num; i++) {
CONTACT(contact,i*skip)->normal[0] = -normal[0];
CONTACT(contact,i*skip)->normal[1] = -normal[1];
CONTACT(contact,i*skip)->normal[2] = -normal[2];
CONTACT(contact,i*skip)->g1 = o1;
CONTACT(contact,i*skip)->g2 = o2;
}
return num;
}
int dCollideBoxPlane (dxGeom *o1, dxGeom *o2,
int flags, dContactGeom *contact, int skip)
{
dIASSERT (skip >= (int)sizeof(dContactGeom));
dIASSERT (o1->type == dBoxClass);
dIASSERT (o2->type == dPlaneClass);
dxBox *box = (dxBox*) o1;
dxPlane *plane = (dxPlane*) o2;
contact->g1 = o1;
contact->g2 = o2;
int ret = 0;
//@@@ problem: using 4-vector (plane->p) as 3-vector (normal).
const dReal *R = o1->final_posr->R; // rotation of box
const dReal *n = plane->p; // normal vector
// project sides lengths along normal vector, get absolute values
dReal Q1 = dDOT14(n,R+0);
dReal Q2 = dDOT14(n,R+1);
dReal Q3 = dDOT14(n,R+2);
dReal A1 = box->side[0] * Q1;
dReal A2 = box->side[1] * Q2;
dReal A3 = box->side[2] * Q3;
dReal B1 = dFabs(A1);
dReal B2 = dFabs(A2);
dReal B3 = dFabs(A3);
// early exit test
dReal depth = plane->p[3] + REAL(0.5)*(B1+B2+B3) - dDOT(n,o1->final_posr->pos);
if (depth < 0) return 0;
// find number of contacts requested
int maxc = flags & NUMC_MASK;
if (maxc < 1) maxc = 1;
if (maxc > 3) maxc = 3; // no more than 3 contacts per box allowed
// find deepest point
dVector3 p;
p[0] = o1->final_posr->pos[0];
p[1] = o1->final_posr->pos[1];
p[2] = o1->final_posr->pos[2];
#define FOO(i,op) \
p[0] op REAL(0.5)*box->side[i] * R[0+i]; \
p[1] op REAL(0.5)*box->side[i] * R[4+i]; \
p[2] op REAL(0.5)*box->side[i] * R[8+i];
#define BAR(i,iinc) if (A ## iinc > 0) { FOO(i,-=) } else { FOO(i,+=) }
BAR(0,1);
BAR(1,2);
BAR(2,3);
#undef FOO
#undef BAR
// the deepest point is the first contact point
contact->pos[0] = p[0];
contact->pos[1] = p[1];
contact->pos[2] = p[2];
contact->normal[0] = n[0];
contact->normal[1] = n[1];
contact->normal[2] = n[2];
contact->depth = depth;
ret = 1; // ret is number of contact points found so far
if (maxc == 1) goto done;
// get the second and third contact points by starting from `p' and going
// along the two sides with the smallest projected length.
#define FOO(i,j,op) \
CONTACT(contact,i*skip)->pos[0] = p[0] op box->side[j] * R[0+j]; \
CONTACT(contact,i*skip)->pos[1] = p[1] op box->side[j] * R[4+j]; \
CONTACT(contact,i*skip)->pos[2] = p[2] op box->side[j] * R[8+j];
#define BAR(ctact,side,sideinc) \
depth -= B ## sideinc; \
if (depth < 0) goto done; \
if (A ## sideinc > 0) { FOO(ctact,side,+) } else { FOO(ctact,side,-) } \
CONTACT(contact,ctact*skip)->depth = depth; \
ret++;
CONTACT(contact,skip)->normal[0] = n[0];
CONTACT(contact,skip)->normal[1] = n[1];
CONTACT(contact,skip)->normal[2] = n[2];
if (maxc == 3) {
CONTACT(contact,2*skip)->normal[0] = n[0];
CONTACT(contact,2*skip)->normal[1] = n[1];
CONTACT(contact,2*skip)->normal[2] = n[2];
}
if (B1 < B2) {
if (B3 < B1) goto use_side_3; else {
BAR(1,0,1); // use side 1
if (maxc == 2) goto done;
if (B2 < B3) goto contact2_2; else goto contact2_3;
}
}
else {
if (B3 < B2) {
use_side_3: // use side 3
BAR(1,2,3);
if (maxc == 2) goto done;
if (B1 < B2) goto contact2_1; else goto contact2_2;
}
else {
BAR(1,1,2); // use side 2
if (maxc == 2) goto done;
if (B1 < B3) goto contact2_1; else goto contact2_3;
}
}
contact2_1: BAR(2,0,1); goto done;
contact2_2: BAR(2,1,2); goto done;
contact2_3: BAR(2,2,3); goto done;
#undef FOO
#undef BAR
done:
for (int i=0; i<ret; i++) {
CONTACT(contact,i*skip)->g1 = o1;
CONTACT(contact,i*skip)->g2 = o2;
}
return ret;
}
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