void CollisionSpace::Collide(void (*callback)(CollisionContact*))
{
RebuildObjectTrees();
int mailboxMin = 0;
for (std::list<Geom*>::iterator i = m_geoms.begin(); i != m_geoms.end(); ++i) {
(*i)->SetMailboxIndex(mailboxMin++);
}
/* This mailbox nonsense is so: after collision(a,b), we will not
* attempt collision(b,a) */
mailboxMin = 1;
for (std::list<Geom*>::iterator i = m_geoms.begin(); i != m_geoms.end(); ++i, mailboxMin++) {
CollideGeoms(*i, mailboxMin, callback);
}
}
// This is the generic sweep test for all swept volumes, but not character-controller specific
bool SweepTest::DoSweepTest(void* user_data,
void* user_data2,
NxU32 nb_boxes, const NxExtendedBounds3* boxes, const void** box_user_data,
NxU32 nb_capsules, const NxExtendedCapsule* capsules, const void** capsule_user_data,
SweptVolume& swept_volume,
const NxVec3& direction, NxU32 max_iter, NxU32* nb_collisions,
NxU32 group_flags, float min_dist, const NxGroupsMask* groupsMask, bool down_pass)
{
// Early exit when motion is zero. Since the motion is decomposed into several vectors
// and this function is called for each of them, it actually happens quite often.
if(direction.isZero())
return false;
bool HasMoved = false;
mValidTri = false;
NxExtendedVec3 CurrentPosition = swept_volume.mCenter;
NxExtendedVec3 TargetPosition = swept_volume.mCenter;
TargetPosition += direction;
NxU32 NbCollisions = 0;
while(max_iter--)
{
gNbIters++;
// Compute current direction
NxVec3 CurrentDirection = TargetPosition - CurrentPosition;
// Make sure the new TBV is still valid
{
// Compute temporal bounding box. We could use a capsule or an OBB instead:
// - the volume would be smaller
// - but the query would be slower
// Overall it's unclear whether it's worth it or not.
// TODO: optimize this part ?
NxExtendedBounds3 TemporalBox;
swept_volume.ComputeTemporalBox(*this, TemporalBox, CurrentPosition, CurrentDirection);
// Gather touched geoms
UpdateTouchedGeoms(user_data, swept_volume,
nb_boxes, boxes, box_user_data,
nb_capsules, capsules, capsule_user_data,
group_flags, TemporalBox, groupsMask);
}
const float Length = CurrentDirection.magnitude();
if(Length<min_dist) break;
CurrentDirection /= Length;
// From Quake2: "if velocity is against the original velocity, stop dead to avoid tiny occilations in sloping corners"
if((CurrentDirection|direction) <= 0.0f) break;
// From this point, we're going to update the position at least once
HasMoved = true;
// Find closest collision
SweptContact C;
C.mDistance = Length + mSkinWidth;
if(!CollideGeoms(this, swept_volume, mGeomStream, CurrentPosition, CurrentDirection, C))
{
// no collision found => move to desired position
CurrentPosition = TargetPosition;
break;
}
ASSERT(C.mGeom); // If we reach this point, we must have touched a geom
if(C.mGeom->mType==TOUCHED_USER_BOX || C.mGeom->mType==TOUCHED_USER_CAPSULE)
{
// We touched a user object, typically another CCT
if(mValidateCallback) UserHitCallback(user_data2, C, CurrentDirection, Length);
// Trying to solve the following problem:
// - by default, the CCT "friction" is infinite, i.e. a CCT will not slide on a slope (this is by design)
// - this produces bad results when a capsule CCT stands on top of another capsule CCT, without sliding. Visually it looks
// like the character is standing on the other character's head, it looks bad. So, here, we would like to let the CCT
// slide away, i.e. we don't want friction.
// So here we simply increase the number of iterations (== let the CCT slide) when the first down collision is with another CCT.
if(down_pass && !NbCollisions)
max_iter += 9;
}
else
{
// We touched a normal object
#ifdef USE_CONTACT_NORMAL_FOR_SLOPE_TEST
mValidTri = true;
mCN = C.mWorldNormal;
#else
if(C.mIndex!=INVALID_ID)
{
mValidTri = true;
mTouched = mWorldTriangles[C.mIndex];
}
#endif
{
if(mValidateCallback) ShapeHitCallback(user_data2, C, CurrentDirection, Length);
}
}
NbCollisions++;
mContactPointHeight = (float)C.mWorldPos[mUpDirection]; // UBI
const float DynSkin = mSkinWidth;
if(C.mDistance>DynSkin/*+0.01f*/)
CurrentPosition += CurrentDirection*(C.mDistance-DynSkin);
NxVec3 WorldNormal = C.mWorldNormal;
if(mWalkExperiment)
{
// Make sure the auto-step doesn't bypass this !
WorldNormal[mUpDirection]=0.0f;
WorldNormal.normalize();
}
const float Bump = 0.0f; // ### doesn't work when !=0 because of Quake2 hack!
const float Friction = 1.0f;
CollisionResponse(TargetPosition, CurrentPosition, CurrentDirection, WorldNormal, Bump, Friction, mNormalizeResponse);
}
if(nb_collisions) *nb_collisions = NbCollisions;
// Final box position that should be reflected in the graphics engine
swept_volume.mCenter = CurrentPosition;
// If we didn't move, don't update the box position at all (keeping possible lazy-evaluated structures valid)
return HasMoved;
}
