private Line CreateIntersectedLine(Line newLine,Point ip, ref bool flipped)
{
var start = newLine.Start;
var end = newLine.End;
//Check if the new line will not be too small
//if it is too small switch the start point with the previous end point
var totalDistance = MathHelpers.DistanceBetweenPoints(start, end);
var newDistance = MathHelpers.DistanceBetweenPoints(start, ip);
//Create the new line
//swap occurs when the new distance is smaller than 1/3 of the original distance
flipped = newDistance < (totalDistance*0.33);
var line = flipped? new Line(ip,end) : new Line(start, ip);
return line;
}
private void HandlePossibleRoadIntersections(Line line, Road startLine, Road endLine,List<Road> borders,List<Road> innerRoads )
{
bool flipped = false;
//check for possible intersection,
//if an intersection happens the end point becomes the point of intersection
//has to be reverse because otherwise the lines will intersect with the edges
for (var i = 0; i < innerRoads.Count; i++)
{
var l = innerRoads[i];
//if the line intersects
if (!line.IntersectsWith(l)) continue;
//find the intersection point
bool parallel = false;
var ip = line.FindIntersectionPoint(l, ref parallel);
//parrallel lines don't intersect so ignore
if (parallel) continue;
//Create the new line from the intersection
line = CreateIntersectedLine(line, ip, ref flipped);
//Split the line that is intersected with in 2 new lines
if (flipped)
{
startLine = innerRoads[i];
}
else
{
endLine = innerRoads[i];
}
//stop at the first intersection
break;
}
//Because of the new line the start and end line will have to be split in 2 new lines
//the total of new lines will be 3
//Adjust the borders
borders.Remove(startLine);
borders.Remove(endLine);
//create the split lines
borders.Add(new Road(startLine.Start,line.Start));
borders.Add(new Road(line.Start, startLine.End));
borders.Add( new Road(endLine.Start, line.End));
borders.Add(new Road(line.End, endLine.End));
//Add the new road to the inner roads
innerRoads.Add(Road.FromLine(line));
innerRoads.Remove(startLine);
innerRoads.Remove(endLine);
}
private SplitLine SplitLine(Line line, Point ip)
{
var start = line.Start;
var end = line.End;
return new SplitLine(new Line(start,ip),new Line(ip,end));
}
public static Road FromLine(Line l)
{
var r = new Road(l.Start, l.End)
{
CellLeft = l.CellLeft,
CellRight = l.CellRight
};
return r;
}