dNewtonCollision* dNewtonContactMaterial::GetShape1 (const void* const contact)
{
NewtonBody* const body = NewtonJointGetBody1 ((NewtonJoint*)m_materialHandle);
NewtonMaterial* const material = NewtonContactGetMaterial (contact);
NewtonCollision* const collision = NewtonMaterialGetBodyCollidingShape (material, body);
return (dNewtonCollision*)NewtonCollisionGetUserData(collision);
}
static void GetCollisionSubShape(const NewtonJoint* const contactJoint, NewtonBody* const body)
{
NewtonCollisionInfoRecord collisionInfo;
NewtonCollision* const collision = NewtonBodyGetCollision(body);
NewtonCollisionGetInfo (collision, &collisionInfo);
int count = 0;
NewtonCollision* collidingSubShapeArrar[32];
// see if this is a compound collision or any other collision with sub collision shapes
if (collisionInfo.m_collisionType == SERIALIZE_ID_COMPOUND) {
// to get the torque we need the center of gravity in global space
dVector origin;
dMatrix bodyMatrix;
NewtonBodyGetMatrix(body, &bodyMatrix[0][0]);
NewtonBodyGetCentreOfMass(body, &origin[0]);
origin = bodyMatrix.TransformVector(origin);
for (void* contact = NewtonContactJointGetFirstContact (contactJoint); contact; contact = NewtonContactJointGetNextContact (contactJoint, contact)) {
// get the material of this contact,
// this part contain all contact information, the sub colliding shape,
NewtonMaterial* const material = NewtonContactGetMaterial (contact);
NewtonCollision* const subShape = NewtonMaterialGetBodyCollidingShape (material, body);
int i = count - 1;
for (; i >= 0; i --) {
if (collidingSubShapeArrar[i] == subShape) {
break;
}
}
if (i < 0) {
collidingSubShapeArrar[count] = subShape;
count ++;
dAssert (count < int (sizeof (collidingSubShapeArrar) / sizeof (collidingSubShapeArrar[0])));
// you can also get the forces here, however when tho function is call form a contact material
// we can only get resting forces, impulsive forces can not be read here since they has no being calculated yet.
// whoever if this function function is call after the NetwonUpdate they the application can read the contact force, that was applied to each contact point
dVector force;
dVector posit;
dVector normal;
NewtonMaterialGetContactForce (material, body, &force[0]);
NewtonMaterialGetContactPositionAndNormal (material, body, &posit[0], &normal[0]);
// the torque on this contact is
dVector torque ((origin - posit) * force);
// do what ever you want wit this
}
}
}
// here we should have an array of all colling sub shapes
if (count) {
// do what you need with this sub shape list
}
}
