void btGImpactCollisionAlgorithm::gimpacttrimeshpart_vs_plane_collision(
btDispatcher* dispatcher,
const btCollider* body0,
const btCollider* body1,
const btGImpactMeshShapePart* shape0,
const btStaticPlaneShape* shape1,
bool swapped
)
{
btTransform orgtrans0 = body0->getWorldTransform();
btTransform orgtrans1 = body1->getWorldTransform();
const btPlaneShape * planeshape = static_cast<const btPlaneShape *>(shape1);
btVector4 plane;
planeshape->get_plane_equation_transformed(orgtrans1,plane);
//test box against plane
btAABB tribox;
shape0->getAabb(orgtrans0,tribox.m_min,tribox.m_max);
tribox.increment_margin(planeshape->getMargin());
if( tribox.plane_classify(plane)!= BT_CONST_COLLIDE_PLANE) return;
shape0->lockChildShapes();
btScalar margin = shape0->getMargin() + planeshape->getMargin();
btVector3 vertex;
int vi = shape0->getVertexCount();
while(vi--)
{
shape0->getVertex(vi,vertex);
vertex = orgtrans0(vertex);
btScalar distance = vertex.dot(plane) - plane[3] - margin;
if(distance<0.0)//add contact
{
if(swapped)
{
addContactPoint(dispatcher, body1, body0,
vertex,
-plane,
distance);
}
else
{
addContactPoint(dispatcher, body0, body1,
vertex,
plane,
distance);
}
}
}
shape0->unlockChildShapes();
}
// This one is complicated and gross. Just don't go there...
// TODO: Comment me!
static int
seg2poly(cpShape *shape1, cpShape *shape2, cpContact **arr)
{
cpSegmentShape *seg = (cpSegmentShape *)shape1;
cpPolyShape *poly = (cpPolyShape *)shape2;
cpPolyShapeAxis *axes = poly->tAxes;
cpFloat segD = cpvdot(seg->tn, seg->ta);
cpFloat minNorm = cpPolyShapeValueOnAxis(poly, seg->tn, segD) - seg->r;
cpFloat minNeg = cpPolyShapeValueOnAxis(poly, cpvneg(seg->tn), -segD) - seg->r;
if(minNeg > 0.0f || minNorm > 0.0f) return 0;
int mini = 0;
cpFloat poly_min = segValueOnAxis(seg, axes->n, axes->d);
if(poly_min > 0.0f) return 0;
for(int i=0; i<poly->numVerts; i++){
cpFloat dist = segValueOnAxis(seg, axes[i].n, axes[i].d);
if(dist > 0.0f){
return 0;
} else if(dist > poly_min){
poly_min = dist;
mini = i;
}
}
int max = 0;
int num = 0;
cpVect poly_n = cpvneg(axes[mini].n);
cpVect va = cpvadd(seg->ta, cpvmult(poly_n, seg->r));
cpVect vb = cpvadd(seg->tb, cpvmult(poly_n, seg->r));
if(cpPolyShapeContainsVert(poly, va))
cpContactInit(addContactPoint(arr, &max, &num), va, poly_n, poly_min, CP_HASH_PAIR(seg, 0));
if(cpPolyShapeContainsVert(poly, vb))
cpContactInit(addContactPoint(arr, &max, &num), vb, poly_n, poly_min, CP_HASH_PAIR(seg, 1));
// Floating point precision problems here.
// This will have to do for now.
poly_min -= cp_collision_slop;
if(minNorm >= poly_min || minNeg >= poly_min) {
if(minNorm > minNeg)
findPointsBehindSeg(arr, &max, &num, seg, poly, minNorm, 1.0f);
else
findPointsBehindSeg(arr, &max, &num, seg, poly, minNeg, -1.0f);
}
return num;
}
// Add contacts for penetrating vertexes.
static inline int
findVerts(cpContact **arr, cpPolyShape *poly1, cpPolyShape *poly2, cpVect n, cpFloat dist)
{
int max = 0;
int num = 0;
for(int i=0; i<poly1->numVerts; i++){
cpVect v = poly1->tVerts[i];
if(cpPolyShapeContainsVertPartial(poly2, v, cpvneg(n)))
cpContactInit(addContactPoint(arr, &max, &num), v, n, dist, CP_HASH_PAIR(poly1->shape.hashid, i));
}
for(int i=0; i<poly2->numVerts; i++){
cpVect v = poly2->tVerts[i];
if(cpPolyShapeContainsVertPartial(poly1, v, n))
cpContactInit(addContactPoint(arr, &max, &num), v, n, dist, CP_HASH_PAIR(poly2->shape.hashid, i));
}
// if(!num)
// addContactPoint(arr, &size, &num, cpContactNew(shape1->body->p, n, dist, 0));
return num;
}
// Identify vertexes that have penetrated the segment.
static inline void
findPointsBehindSeg(cpContact **arr, int *max, int *num, cpSegmentShape *seg, cpPolyShape *poly, cpFloat pDist, cpFloat coef)
{
cpFloat dta = cpvcross(seg->tn, seg->ta);
cpFloat dtb = cpvcross(seg->tn, seg->tb);
cpVect n = cpvmult(seg->tn, coef);
for(int i=0; i<poly->numVerts; i++){
cpVect v = poly->tVerts[i];
if(cpvdot(v, n) < cpvdot(seg->tn, seg->ta)*coef + seg->r){
cpFloat dt = cpvcross(seg->tn, v);
if(dta >= dt && dt >= dtb){
cpContactInit(addContactPoint(arr, max, num), v, n, pDist, CP_HASH_PAIR(poly->shape.hashid, i));
}
}
}
}
void btGImpactCollisionAlgorithm::collide_sat_triangles(btCollisionObject * body0,
btCollisionObject * body1,
btGImpactMeshShapePart * shape0,
btGImpactMeshShapePart * shape1,
const int * pairs, int pair_count)
{
btTransform orgtrans0 = body0->getWorldTransform();
btTransform orgtrans1 = body1->getWorldTransform();
btPrimitiveTriangle ptri0;
btPrimitiveTriangle ptri1;
GIM_TRIANGLE_CONTACT contact_data;
shape0->lockChildShapes();
shape1->lockChildShapes();
const int * pair_pointer = pairs;
while(pair_count--)
{
m_triface0 = *(pair_pointer);
m_triface1 = *(pair_pointer+1);
pair_pointer+=2;
shape0->getPrimitiveTriangle(m_triface0,ptri0);
shape1->getPrimitiveTriangle(m_triface1,ptri1);
#ifdef TRI_COLLISION_PROFILING
bt_begin_gim02_tri_time();
#endif
ptri0.applyTransform(orgtrans0);
ptri1.applyTransform(orgtrans1);
//build planes
ptri0.buildTriPlane();
ptri1.buildTriPlane();
// test conservative
if(ptri0.overlap_test_conservative(ptri1))
{
if(ptri0.find_triangle_collision_clip_method(ptri1,contact_data))
{
int j = contact_data.m_point_count;
while(j--)
{
addContactPoint(body0, body1,
contact_data.m_points[j],
contact_data.m_separating_normal,
-contact_data.m_penetration_depth);
}
}
}
#ifdef TRI_COLLISION_PROFILING
bt_end_gim02_tri_time();
#endif
}
shape0->unlockChildShapes();
shape1->unlockChildShapes();
}
int dBoxBox2 (const btVector3 p1, const dMatrix3 R1,
const btVector3 side1, const btVector3 p2,
const dMatrix3 R2, const btVector3 side2,
BoxBoxResults *results)
{
const btScalar fudge_factor = 1.05;
btVector3 p,pp,normalC;
normalC[0] = 0.f;
normalC[1] = 0.f;
normalC[2] = 0.f;
const btScalar *normalR = 0;
btScalar 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,normal[3],depth;
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 (already specified as half lengths)
A[0] = side1[0];
A[1] = side1[1];
A[2] = side1[2];
B[0] = side2[0];
B[1] = side2[1];
B[2] = side2[2];
// 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 = btFabs(R11); Q12 = btFabs(R12); Q13 = btFabs(R13);
Q21 = btFabs(R21); Q22 = btFabs(R22); Q23 = btFabs(R23);
Q31 = btFabs(R31); Q32 = btFabs(R32); Q33 = btFabs(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 = btFabs(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 = btFabs(expr1) - (expr2); \
if (s2 > SIMD_EPSILON) return 0; \
l = btSqrt((n1)*(n1) + (n2)*(n2) + (n3)*(n3)); \
if (l > SIMD_EPSILON) { \
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); \
} \
}
btScalar fudge2 = 1.0e-5f;
Q11 += fudge2;
Q12 += fudge2;
Q13 += fudge2;
Q21 += fudge2;
Q22 += fudge2;
Q23 += fudge2;
Q31 += fudge2;
Q32 += fudge2;
Q33 += fudge2;
// 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;
results->code = code;
// 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
btVector3 pa;
btScalar sign;
for (i=0; i<3; i++) pa[i] = p1[i];
for (j=0; j<3; j++) {
sign = (dDOT14(normal,R1+j) > 0) ? 1.0 : -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
btVector3 pb;
for (i=0; i<3; i++) pb[i] = p2[i];
for (j=0; j<3; j++) {
sign = (dDOT14(normal,R2+j) > 0) ? -1.0 : 1.0;
for (i=0; i<3; i++) pb[i] += sign * B[j] * R2[i*4+j];
}
btScalar alpha,beta;
btVector3 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;
{
btVector3 pointInWorld;
addContactPoint(results,normal,pb,depth);
}
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 btScalar *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.
btVector3 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] = btFabs (nr[0]);
anr[1] = btFabs (nr[1]);
anr[2] = btFabs (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
btVector3 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
btScalar quad[8]; // 2D coordinate of incident face (x,y pairs)
btScalar 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);
{
btScalar k1 = m11*Sb[a1];
btScalar k2 = m21*Sb[a1];
btScalar k3 = m12*Sb[a2];
btScalar 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
btScalar rect[2];
rect[0] = Sa[code1];
rect[1] = Sa[code2];
// intersect the incident and reference faces
btScalar ret[16];
int n = intersectRectQuad2 (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.
btScalar point[3*8]; // penetrating contact points
btScalar dep[8]; // depths for those points
btScalar det1 = 1.f/(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++) {
btScalar k1 = m22*(ret[j*2]-c1) - m12*(ret[j*2+1]-c2);
btScalar 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
int maxc = 4;
if (maxc > cnum) maxc = cnum;
if (maxc < 1) maxc = 1;
if (cnum <= maxc)
{
if (code<4)
{
// we have less contacts than we need, so we use them all
for (j=0; j < cnum; j++)
{
btVector3 pointInWorld;
for (i=0; i<3; i++)
pointInWorld[i] = point[j*3+i] + pa[i];
addContactPoint(results,normal,pointInWorld,dep[j]);
}
}
else
{
// we have less contacts than we need, so we use them all
for (j=0; j < cnum; j++)
{
btVector3 pointInWorld;
for (i=0; i<3; i++)
pointInWorld[i] = point[j*3+i] + pa[i]-normal[i]*dep[j];
addContactPoint(results,normal,pointInWorld,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;
btScalar maxdepth = dep[0];
for (i=1; i<cnum; i++)
{
if (dep[i] > maxdepth)
{
maxdepth = dep[i];
i1 = i;
}
}
int iret[8];
cullPoints2 (cnum,ret,maxc,i1,iret);
for (j=0; j < maxc; j++)
{
btVector3 posInWorld;
for (i=0; i<3; i++)
posInWorld[i] = point[iret[j]*3+i] + pa[i];
if (code<4)
{
addContactPoint(results, normal,posInWorld,dep[iret[j]]);
}
else
{
posInWorld[0] -= normal[0]*dep[iret[j]];
posInWorld[1] -= normal[1]*dep[iret[j]];
posInWorld[2] -= normal[2]*dep[iret[j]];
addContactPoint(results, normal,posInWorld,dep[iret[j]]);
}
}
cnum = maxc;
}
return cnum;
}
