/// <summary>
/// The return type is a bit conf
/// </summary>
/// <param name="column"></param>
private static bool ApplyGravity(SandColumn column)
{
var sandMoved = false;
var noPressureLowerNeighbours = new Queue <SandColumn>();
Shuffle(column.Neighbours);
foreach (var neighbour in column.Neighbours)
{
noPressureLowerNeighbours.Enqueue(neighbour);
}
while (noPressureLowerNeighbours.Count > 0)
{
var neighbour = noPressureLowerNeighbours.Dequeue();
if (neighbour.Height + 1 < column.Height && neighbour.NumExcessRoom > 0)
{
MoveSand(column, neighbour);
sandMoved = true;
if (neighbour.Height + 1 < column.Height && neighbour.NumExcessRoom > 0)
{
noPressureLowerNeighbours.Enqueue(neighbour);
}
}
}
return(sandMoved);
}
public static SandColumn[,] CreateSandTable(int height, int width, int defaultSandHeight, int defaultHeightLimit = int.MaxValue)
{
var sand = new SandColumn[width, height];
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
sand[x, y] = new SandColumn
{
HeightLimit = defaultHeightLimit,
Height = defaultSandHeight,
Location = new Point {
X = x, Y = y
}
};
}
}
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
sand[x, y].Neighbours = GetNeighbours(sand, new Point {
X = x, Y = y
});
Shuffle(sand[x, y].Neighbours);
}
}
return(sand);
}
private static bool SettleColumn(SandColumn column)
{
var columnChangedOnce = false; //if the column changed at all
bool columnChanged; //if the column changed in this iteration
do
{
columnChanged = false;
var lowerPressureNeighbours = new List <SandColumn>();
var equalPressureLowerHeightNeighbours = new List <SandColumn>();
foreach (var neighbour in column.Neighbours)
{
if (column.Pressure > 0 && column.DecreasedPressure >= neighbour.IncreasedPressure)
{
lowerPressureNeighbours.Add(neighbour);
}
else if (column.Pressure <= 0 && neighbour.Pressure <= 0 && column.DecreasedHeight >= neighbour.IncreasedHeight)
{
equalPressureLowerHeightNeighbours.Add(neighbour);
}
}
if (lowerPressureNeighbours.Count > 0)
{
var lowestPressure = lowerPressureNeighbours.Min(n => n.IncreasedPressure);
lowerPressureNeighbours.RemoveAll(n => n.Pressure > lowestPressure);
SandColumn chosenNeighbour = lowerPressureNeighbours[Rnd.Next(lowerPressureNeighbours.Count)];
MoveSand(column, chosenNeighbour);
columnChanged = true;
}
else if (equalPressureLowerHeightNeighbours.Count > 0)
{
MoveSand(column, equalPressureLowerHeightNeighbours[Rnd.Next(equalPressureLowerHeightNeighbours.Count)]);
columnChanged = true;
}
columnChangedOnce = columnChanged || columnChangedOnce;
} while (columnChanged);
return(columnChangedOnce);
}
private static bool SettlePressuredSand(SandColumn column)
{
//This is a basic breadth first search using a queue
if (column.Pressure <= 0)
{
return(false);
}
var sandMoved = false;
var neighbourQueue = new Queue <SandColumn>();
var visitedNeighbours = new HashSet <SandColumn>();
neighbourQueue.Enqueue(column);
while (column.Pressure > 0)
{
var currentNeighbour = neighbourQueue.Dequeue();
visitedNeighbours.Add(currentNeighbour);
var emptySpace = currentNeighbour.NumExcessRoom;
if (emptySpace > 0)
{
MoveSand(column, currentNeighbour, Math.Min(column.NumExcessSand, emptySpace));
sandMoved = true;
}
foreach (var currentNeighbourNeighbour in currentNeighbour.Neighbours)
{
if (!visitedNeighbours.Contains(currentNeighbourNeighbour))
{
neighbourQueue.Enqueue(currentNeighbourNeighbour);
}
}
}
return(sandMoved);
}
private static void MoveSand(SandColumn source, SandColumn dest, int amount = 1)
{
source.Height -= amount;
dest.Height += amount;
}
