//----------------------------------------------------------------------------
SpatialPtr Node::SetChild(UInt i, Spatial* pChild)
{
// Some folks are under the impression that a node can have multiple
// parents, the scene graph therefore being a DAG. That is not the case.
// The parent-child relationships form a tree. This assertion is to let
// folks know this and to warn them that a child is being kidnapped from
// another parent. To be safe, you should really call DetachChild before
// you reattach somewhere else with AttachChild or SetChild. If you do
// call DetachChild first, be aware that the child might self-destruct.
// If you want this not to happen, hang onto the child via a smart
// pointer. For example,
//
// Node* pNode0 = WIRE_NEW Node;
// Spatial* pChild0 = <...>;
// pNode0->AttachChild(pChild0); // child at index 0
// Node* pNode1 = <...>;
//
// // This asserts because pChild0 already has a parent (pNode0).
// pNode1->AttachChild(pChild0);
//
// // Instead do this and avoid the potential self-destruction of
// // pChild0).
// SpatialPtr spSaveChild = pNode0->GetChild(0);
// pNode0->DetachChild(spSaveChild);
// pNode1->AttachChild(spSaveChild);
if (pChild)
{
WIRE_ASSERT(!pChild->GetParent());
}
if (i < GetQuantity())
{
// detach child currently in slot
SpatialPtr spPreviousChild = mChildren[i];
if (spPreviousChild)
{
spPreviousChild->SetParent(0);
}
// attach new child to slot
if (pChild)
{
pChild->SetParent(this);
}
mChildren[i] = pChild;
return spPreviousChild;
}
// index out of range, increase array size and attach new child
pChild->SetParent(this);
mChildren.Append(pChild);
return NULL;
}
//----------------------------------------------------------------------------
SpatialPtr Node::DetachChildAt (int i)
{
if (0 <= i && i < m_kChild.GetQuantity())
{
SpatialPtr spkChild = m_kChild[i];
if ( spkChild )
{
// child exists in slot, detach it
spkChild->SetParent(0);
m_kChild[i] = 0;
m_iUsed--;
}
return spkChild;
}
return 0;
}
//----------------------------------------------------------------------------
SpatialPtr Node::DetachChildAt(UInt i)
{
if (i < GetQuantity())
{
SpatialPtr spChild = mChildren[i];
if (spChild)
{
// child exists in slot, detach it
spChild->SetParent(NULL);
mChildren[i] = NULL;
}
return spChild;
}
return NULL;
}
//----------------------------------------------------------------------------
SpatialPtr Node::SetChild (int i, Spatial* pkChild)
{
// Some folks are of the impression that a node can have multiple parents,
// the scene graph therefore being a DAG. That is not the case. The
// parent-child relationships form a tree. This assertion is to let folks
// know this and to warn them that a child is being kidnapped from another
// parent. To be safe, you should really call DetachChild before you
// reattach somewhere else with AttachChild or SetChild.
if (pkChild)
{
assert(!pkChild->GetParent());
}
if (0 <= i && i < m_kChild.GetQuantity())
{
// detach child currently in slot
SpatialPtr spkPreviousChild = m_kChild[i];
if (spkPreviousChild)
{
spkPreviousChild->SetParent(0);
m_iUsed--;
}
// attach new child to slot
if (pkChild)
{
pkChild->SetParent(this);
m_iUsed++;
}
m_kChild[i] = pkChild;
return spkPreviousChild;
}
// index out of range, increase array size and attach new child
pkChild->SetParent(this);
m_kChild.SetElement(i,pkChild);
m_iUsed++;
return 0;
}
