public MazePath Branch()
{
if (points.Count < 3)
{
return(null);
}
var index = rand.Next(points.Count - 2) + 1;
var nx = points[index].x;
var ny = points[index].y;
while (nx % 2 == 1 || ny % 2 == 1)
{
index = rand.Next(points.Count - 2) + 1;
nx = points[index].x;
ny = points[index].y;
}
var dirNew = Direction.UP;
var gUp = new GridPoint(nx, ny - 1);
var gDown = new GridPoint(nx, ny + 1);
var gLeft = new GridPoint(nx - 1, ny);
var gRight = new GridPoint(nx + 1, ny);
// Path is vertical
if ((gUp.Equals(points[index - 1]) && gDown.Equals(points[index + 1])) ||
(gUp.Equals(points[index + 1]) && gDown.Equals(points[index - 1])))
{
var roll = rand.Next(2);
nx = (roll == 0 ? nx + 1 : nx - 1);
dirNew = (roll == 0 ? Direction.RIGHT : Direction.LEFT);
return(new MazePath(nx, ny, dirNew));
}
// Path is horizontal
if ((gLeft.Equals(points[index - 1]) && gRight.Equals(points[index + 1])) ||
(gLeft.Equals(points[index + 1]) && gRight.Equals(points[index - 1])))
{
var roll = rand.Next(2);
ny = (roll == 0 ? ny + 1 : ny - 1);
dirNew = (roll == 0 ? Direction.DOWN : Direction.UP);
return(new MazePath(nx, ny, dirNew));
}
// Corner, upper right
if ((gUp.Equals(points[index - 1]) && gRight.Equals(points[index + 1])) ||
(gUp.Equals(points[index + 1]) && gRight.Equals(points[index - 1])))
{
var roll = rand.Next(2);
nx = (roll == 0 ? nx - 1 : nx);
ny = (roll == 0 ? ny : ny + 1);
dirNew = (roll == 0 ? Direction.LEFT : Direction.DOWN);
return(new MazePath(nx, ny, dirNew));
}
// Corner, upper left
if ((gUp.Equals(points[index - 1]) && gLeft.Equals(points[index + 1])) ||
(gUp.Equals(points[index + 1]) && gLeft.Equals(points[index - 1])))
{
var roll = rand.Next(2);
nx = (roll == 0 ? nx + 1 : nx);
ny = (roll == 0 ? ny : ny + 1);
dirNew = (roll == 0 ? Direction.RIGHT : Direction.DOWN);
return(new MazePath(nx, ny, dirNew));
}
// Corner, lower right
if ((gDown.Equals(points[index - 1]) && gRight.Equals(points[index + 1])) ||
(gDown.Equals(points[index + 1]) && gRight.Equals(points[index - 1])))
{
var roll = rand.Next(2);
nx = (roll == 0 ? nx - 1 : nx);
ny = (roll == 0 ? ny : ny - 1);
dirNew = (roll == 0 ? Direction.LEFT : Direction.UP);
return(new MazePath(nx, ny, dirNew));
}
// Corner, lower left
if ((gDown.Equals(points[index - 1]) && gLeft.Equals(points[index + 1])) ||
(gDown.Equals(points[index + 1]) && gLeft.Equals(points[index - 1])))
{
var roll = rand.Next(2);
nx = (roll == 0 ? nx + 1 : nx);
ny = (roll == 0 ? ny : ny - 1);
dirNew = (roll == 0 ? Direction.RIGHT : Direction.UP);
return(new MazePath(nx, ny, dirNew));
}
return(null);
}