//------------------------------------------------------------------------------
private void InsertLocalMinima(LocalMinima newLm)
{
if( m_MinimaList == null )
{
m_MinimaList = newLm;
}
else if( newLm.Y >= m_MinimaList.Y )
{
newLm.next = m_MinimaList;
m_MinimaList = newLm;
} else
{
LocalMinima tmpLm = m_MinimaList;
while( tmpLm.next != null && ( newLm.Y < tmpLm.next.Y ) )
tmpLm = tmpLm.next;
newLm.next = tmpLm.next;
tmpLm.next = newLm;
}
}
//------------------------------------------------------------------------------
private void DisposeLocalMinimaList()
{
while( m_MinimaList != null )
{
LocalMinima tmpLm = m_MinimaList.next;
m_MinimaList = null;
m_MinimaList = tmpLm;
}
m_CurrentLM = null;
}
//---------------------------------------------------------------------------
TEdge4 AddBoundsToLML(TEdge4 e)
{
//Starting at the top of one bound we progress to the bottom where there's
//a local minima. We then go to the top of the next bound. These two bounds
//form the left and right (or right and left) bounds of the local minima.
e.nextInLML = null;
e = e.next;
for (;;)
{
if ( e.dx == horizontal )
{
//nb: proceed through horizontals when approaching from their right,
// but break on horizontal minima if approaching from their left.
// This ensures 'local minima' are always on the left of horizontals.
if (e.next.ytop < e.ytop && e.next.xbot > e.prev.xbot) break;
if (e.xtop != e.prev.xbot) SwapX(e);
e.nextInLML = e.prev;
}
else if (e.ycurr == e.prev.ycurr) break;
else e.nextInLML = e.prev;
e = e.next;
}
//e and e.prev are now at a local minima ...
LocalMinima newLm = new LocalMinima();
newLm.next = null;
newLm.Y = e.prev.ybot;
if ( e.dx == horizontal ) //horizontal edges never start a left bound
{
if (e.xbot != e.prev.xbot) SwapX(e);
newLm.leftBound = e.prev;
newLm.rightBound = e;
} else if (e.dx < e.prev.dx)
{
newLm.leftBound = e.prev;
newLm.rightBound = e;
} else
{
newLm.leftBound = e;
newLm.rightBound = e.prev;
}
newLm.leftBound.side = EdgeSide.esLeft;
newLm.rightBound.side = EdgeSide.esRight;
InsertLocalMinima( newLm );
for (;;)
{
if ( e.next.ytop == e.ytop && e.next.dx != horizontal ) break;
e.nextInLML = e.next;
e = e.next;
if ( e.dx == horizontal && e.xbot != e.prev.xtop) SwapX(e);
}
return e.next;
}
//------------------------------------------------------------------------------
protected virtual bool Reset()
{
m_CurrentLM = m_MinimaList;
if ( m_CurrentLM == null ) return false; //ie nothing to process
//reset all edges ...
LocalMinima lm = m_MinimaList;
while (lm != null)
{
TEdge4 e = lm.leftBound;
while (e != null)
{
e.xcurr = e.xbot;
e.ycurr = e.ybot;
e.side = EdgeSide.esLeft;
e.outIdx = -1;
e = e.nextInLML;
}
e = lm.rightBound;
while (e != null)
{
e.xcurr = e.xbot;
e.ycurr = e.ybot;
e.side = EdgeSide.esRight;
e.outIdx = -1;
e = e.nextInLML;
}
lm = lm.next;
}
return true;
}
//------------------------------------------------------------------------------
protected void PopLocalMinima()
{
if (m_CurrentLM == null) return;
m_CurrentLM = m_CurrentLM.next;
}
//constructor (nb: no external instantiation)
//------------------------------------------------------------------------------
internal ClipperBase()
{
m_MinimaList = null;
m_CurrentLM = null;
}