private void AddShallowBump(Point2I point, fieldT currFld,
LinkedList <bumpT> steepBumps, LinkedList <bumpT> shallowBumps)
{
// First, the far point of shallow is set to the new point.
currFld.m_Shallow.m_Far = point;
// Second, we need to add the new bump to the shallow bump list for
// future steep bump handling.
shallowBumps.AddLast(new bumpT());
shallowBumps.Last.Value.m_Location = point;
shallowBumps.Last.Value.m_Parent = currFld.m_ShallowBump;
currFld.m_ShallowBump = shallowBumps.Last.Value;
// Now we have too look through the list of steep bumps and see if
// any of them are below the line.
// If there are, we need to replace near point too.
bumpT currentBump = currFld.m_SteepBump;
while (currentBump != null)
{
if (currFld.m_Shallow.IsAbove(currentBump.m_Location))
{
currFld.m_Shallow.m_Near = currentBump.m_Location;
}
currentBump = currentBump.m_Parent;
}
}
public fieldT(fieldT f)
{
m_Steep = new Line2I(new Point2I(f.m_Steep.m_Near.m_X, f.m_Steep.m_Near.m_Y),
new Point2I(f.m_Steep.m_Far.m_X, f.m_Steep.m_Far.m_Y));
m_Shallow = new Line2I(
new Point2I(f.m_Shallow.m_Near.m_X, f.m_Shallow.m_Near.m_Y),
new Point2I(f.m_Shallow.m_Far.m_X, f.m_Shallow.m_Far.m_Y));
m_SteepBump = f.m_SteepBump;
m_ShallowBump = f.m_ShallowBump;
}
private bool CheckField(CLikeIterator <fieldT> currentField)
{
// If the two slopes are colinear, and if they pass through either
// extremity, remove the field of view.
fieldT currFld = currentField.GetCurrent();
bool ret = false;
if (currFld.m_Shallow.DoesContain(currFld.m_Steep.m_Near) &&
currFld.m_Shallow.DoesContain(currFld.m_Steep.m_Far) &&
(currFld.m_Shallow.DoesContain(new Point2I(0, 1)) || currFld.m_Shallow
.DoesContain(new Point2I(1, 0))))
{
currentField.RemoveCurrent();
ret = true;
}
return(ret);
}
private void AddSteepBump(Point2I point, fieldT currFld,
LinkedList <bumpT> steepBumps, LinkedList <bumpT> shallowBumps)
{
currFld.m_Steep.m_Far = point;
steepBumps.AddLast(new bumpT());
steepBumps.Last.Value.m_Location = point;
steepBumps.Last.Value.m_Parent = currFld.m_SteepBump;
currFld.m_SteepBump = steepBumps.Last.Value;
// Now look through the list of shallow bumps and see if any of them
// are below the line.
bumpT currentBump = currFld.m_ShallowBump;
while (currentBump != null)
{
if (currFld.m_Steep.IsBelow(currentBump.m_Location))
{
currFld.m_Steep.m_Near = currentBump.m_Location;
}
currentBump = currentBump.m_Parent;
}
}
private void VisitSquare(fovStateT state, Point2I dest,
CLikeIterator <fieldT> currentField, LinkedList <bumpT> steepBumps,
LinkedList <bumpT> shallowBumps, LinkedList <fieldT> activeFields)
{
// The top-left and bottom-right corners of the destination square.
Point2I topLeft = new Point2I(dest.m_X, dest.m_Y + 1);
Point2I bottomRight = new Point2I(dest.m_X + 1, dest.m_Y);
while (!currentField.IsAtEnd() &&
currentField.GetCurrent().m_Steep
.IsBelowOrContains(bottomRight))
{
// case ABOVE
// The square is in case 'above'. This means that it is ignored
// for the currentField. But the steeper fields might need it.
currentField.GotoNext();
}
if (currentField.IsAtEnd())
{
// The square was in case 'above' for all fields. This means that
// we no longer care about it or any squares in its diagonal rank.
return;
}
// Now we check for other cases.
if (currentField.GetCurrent().m_Shallow.IsAboveOrContains(topLeft))
{
// case BELOW
// The shallow line is above the extremity of the square, so that
// square is ignored.
return;
}
// The square is between the lines in some way. This means that we
// need to visit it and determine whether it is blocked.
bool isBlocked = ActIsBlocked(state, dest);
if (!isBlocked)
{
// We don't care what case might be left, because this square does
// not obstruct.
return;
}
if (currentField.GetCurrent().m_Shallow.IsAbove(bottomRight) &&
currentField.GetCurrent().m_Steep.IsBelow(topLeft))
{
// case BLOCKING
// Both lines intersect the square. This current field has ended.
currentField.RemoveCurrent();
}
else if (currentField.GetCurrent().m_Shallow.IsAbove(bottomRight))
{
// case SHALLOW BUMP
// The square intersects only the shallow line.
AddShallowBump(topLeft, currentField.GetCurrent(), steepBumps,
shallowBumps);
CheckField(currentField);
}
else if (currentField.GetCurrent().m_Steep.IsBelow(topLeft))
{
// case STEEP BUMP
// The square intersects only the steep line.
AddSteepBump(bottomRight, currentField.GetCurrent(), steepBumps,
shallowBumps);
CheckField(currentField);
}
else
{
// case BETWEEN
// The square intersects neither line. We need to split into two
// fields.
fieldT steeperField = currentField.GetCurrent();
fieldT shallowerField = new fieldT(currentField.GetCurrent());
currentField.InsertBeforeCurrent(shallowerField);
AddSteepBump(bottomRight, shallowerField, steepBumps, shallowBumps);
currentField.GotoPrevious();
if (!CheckField(currentField)) // did not remove
{
currentField.GotoNext(); // point to the original element
}
AddShallowBump(topLeft, steeperField, steepBumps, shallowBumps);
CheckField(currentField);
}
}
