/// <summary>
/// - set the first element of the stack (LIFO) as the current grid
/// - while there are adjacent valid cell we get a random direction and try to build a path
/// - if the while condition isn't true we call the funcion again to check the previous element of the path
/// </summary>
public void RecursiveBacktracking()
{
grid[currentRow, currentColumn] = cellsStack.Pop();
currentColumn = grid[currentRow, currentColumn].column;
currentRow = grid[currentRow, currentColumn].row;
while (utilities.AreThereUnvisitedNeighbors(currentRow, currentColumn))
{
int direction = Random.Range(0, 4);
switch (direction)
{
case 0: //check up
if (utilities.IsCellValidAndUnvisited(currentRow - 1, currentColumn))
{
if (grid[currentRow, currentColumn].upWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].upWall);
}
currentRow--;
//Set the next cell to check
SetNextCell();
if (grid[currentRow, currentColumn].downWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].downWall);
}
}
break;
case 1: //check down
if (utilities.IsCellValidAndUnvisited(currentRow + 1, currentColumn))
{
if (grid[currentRow, currentColumn].downWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].downWall);
}
currentRow++;
SetNextCell();
if (grid[currentRow, currentColumn].upWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].upWall);
}
}
break;
case 2: //check left
if (utilities.IsCellValidAndUnvisited(currentRow, currentColumn - 1))
{
if (grid[currentRow, currentColumn].leftWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].leftWall);
}
currentColumn--;
SetNextCell();
if (grid[currentRow, currentColumn].rightWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].rightWall);
}
}
break;
case 3: //check right
if (utilities.IsCellValidAndUnvisited(currentRow, currentColumn + 1))
{
if (grid[currentRow, currentColumn].rightWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].rightWall);
}
currentColumn++;
SetNextCell();
if (grid[currentRow, currentColumn].leftWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].leftWall);
}
}
break;
default:
break;
}
}
if (cellsStack.Count > 0)
{
RecursiveBacktracking();
}
else
{
return;
}
}
/// <summary>
/// Method to create a path in the maze
/// + while there are valid adjacent cells and unvisited:
/// - we take a random direction and we destroy the walls between the two cells
/// - we set the current row/column on the new cell (we move on the new cell)
/// - we repeat this operation until the while condition is true
/// </summary>
void Walk()
{
while (utilities.AreThereUnvisitedNeighbors(currentRow, currentColumn))
{
int direction = Random.Range(0, 4);
switch (direction)
{
case 0: //check up
if (utilities.IsCellValidAndUnvisited(currentRow - 1, currentColumn))
{
if (grid[currentRow, currentColumn].upWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].upWall);
}
currentRow--;
grid[currentRow, currentColumn].visited = true;
if (grid[currentRow, currentColumn].downWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].downWall);
}
}
break;
case 1: //check down
if (utilities.IsCellValidAndUnvisited(currentRow + 1, currentColumn))
{
if (grid[currentRow, currentColumn].downWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].downWall);
}
currentRow++;
grid[currentRow, currentColumn].visited = true;
if (grid[currentRow, currentColumn].upWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].upWall);
}
}
break;
case 2: //check left
if (utilities.IsCellValidAndUnvisited(currentRow, currentColumn - 1))
{
if (grid[currentRow, currentColumn].leftWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].leftWall);
}
currentColumn--;
grid[currentRow, currentColumn].visited = true;
if (grid[currentRow, currentColumn].rightWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].rightWall);
}
}
break;
case 3: //check right
if (utilities.IsCellValidAndUnvisited(currentRow, currentColumn + 1))
{
if (grid[currentRow, currentColumn].rightWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].rightWall);
}
currentColumn++;
grid[currentRow, currentColumn].visited = true;
if (grid[currentRow, currentColumn].leftWall)
{
mazeBuilder.DestroyGameObject(grid[currentRow, currentColumn].leftWall);
}
}
break;
}
}
}