private TrackPlacementState CreateTunnel()
{
TrackSlope trackSlope = TrackSlope.Straight;
int num = 10;
TrackPlacementState trackPlacementState = TrackPlacementState.Invalid;
int x = _history[_length - 1].X;
int y = _history[_length - 1].Y;
for (TrackSlope trackSlope2 = TrackSlope.Up; trackSlope2 <= TrackSlope.Down; trackSlope2++)
{
TrackPlacementState trackPlacementState2 = TrackPlacementState.Invalid;
for (int i = 1; i < num; i++)
{
trackPlacementState2 = CalculateStateForLocation(x + i * _xDirection, y + i * (int)trackSlope2);
switch (trackPlacementState2)
{
default:
trackSlope = trackSlope2;
num = i;
trackPlacementState = trackPlacementState2;
break;
case TrackPlacementState.Obstructed:
continue;
case TrackPlacementState.Invalid:
break;
}
break;
}
if (trackPlacementState != 0 && trackPlacementState2 == TrackPlacementState.Obstructed && (trackPlacementState != TrackPlacementState.Obstructed || trackSlope != 0))
{
trackSlope = trackSlope2;
num = 10;
trackPlacementState = trackPlacementState2;
}
}
if (_length == 0 || !CanSlopesTouch(_history[_length - 1].Slope, trackSlope))
{
RewriteSlopeDirection(_length - 1, TrackSlope.Straight);
}
_history[_length - 1].Mode = TrackMode.Tunnel;
for (int j = 1; j < num; j++)
{
AppendToHistory(trackSlope, TrackMode.Tunnel);
}
return(trackPlacementState);
}
private TrackPlacementState TryRewriteHistoryToAvoidTiles()
{
int num = _length - 1;
int num2 = Math.Min(_length, _rewriteHistory.Length);
for (int i = 0; i < num2; i++)
{
_rewriteHistory[i] = _history[num - i];
}
while (num >= _length - num2)
{
if (_history[num].Slope == TrackSlope.Down)
{
TrackPlacementState historySegmentPlacementState = GetHistorySegmentPlacementState(num, _length - num);
if (historySegmentPlacementState == TrackPlacementState.Available)
{
return(historySegmentPlacementState);
}
RewriteSlopeDirection(num, TrackSlope.Straight);
}
num--;
}
if (GetHistorySegmentPlacementState(num + 1, _length - (num + 1)) == TrackPlacementState.Available)
{
return(TrackPlacementState.Available);
}
for (num = _length - 1; num >= _length - num2 + 1; num--)
{
if (_history[num].Slope == TrackSlope.Straight)
{
TrackPlacementState historySegmentPlacementState2 = GetHistorySegmentPlacementState(_length - num2, num2);
if (historySegmentPlacementState2 == TrackPlacementState.Available)
{
return(historySegmentPlacementState2);
}
RewriteSlopeDirection(num, TrackSlope.Up);
}
}
for (int j = 0; j < num2; j++)
{
_history[_length - 1 - j] = _rewriteHistory[j];
}
RewriteSlopeDirection(_length - 1, TrackSlope.Straight);
return(GetHistorySegmentPlacementState(num + 1, _length - (num + 1)));
}
private TrackPlacementState GetHistorySegmentPlacementState(int startIndex, int length)
{
TrackPlacementState result = TrackPlacementState.Available;
for (int i = startIndex; i < startIndex + length; i++)
{
TrackPlacementState trackPlacementState = CalculateStateForLocation(_history[i].X, _history[i].Y);
switch (trackPlacementState)
{
case TrackPlacementState.Invalid:
return(trackPlacementState);
case TrackPlacementState.Obstructed:
if (_history[i].Mode != TrackMode.Tunnel)
{
result = trackPlacementState;
}
break;
}
}
return(result);
}
private bool FindPath(int minLength, int maxLength)
{
int length = _length;
while (_length < _history.Length - 100)
{
TrackSlope slope = (_history[_length - 1].Slope != TrackSlope.Up) ? TrackSlope.Down : TrackSlope.Straight;
AppendToHistory(slope);
TrackPlacementState trackPlacementState = TryRewriteHistoryToAvoidTiles();
if (trackPlacementState == TrackPlacementState.Invalid)
{
break;
}
length = _length;
TrackPlacementState trackPlacementState2 = trackPlacementState;
while (trackPlacementState2 != 0)
{
trackPlacementState2 = CreateTunnel();
if (trackPlacementState2 == TrackPlacementState.Invalid)
{
break;
}
length = _length;
}
if (_length >= maxLength)
{
break;
}
}
_length = Math.Min(maxLength, length);
if (_length < minLength)
{
return(false);
}
SmoothTrack();
return(GetHistorySegmentPlacementState(0, _length) != TrackPlacementState.Invalid);
}