public HydraulicErosionCell getCopy()
{
HydraulicErosionCell copy = new HydraulicErosionCell();
copy.Altitude = Altitude;
copy.Water = Water;
copy.Sediment = Sediment;
return(copy);
}
private static HydraulicErosionCell[][] createHydraulicErosionCells(float?[][] heightMap)
{
int side = heightMap.Length;
HydraulicErosionCell[][] hydraulicErosionCells = new HydraulicErosionCell[side][];
for (int i = 0; i < side; i++)
{
hydraulicErosionCells[i] = new HydraulicErosionCell[side];
}
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
HydraulicErosionCell cell = new HydraulicErosionCell();
cell.Altitude = (float)heightMap[x][y];
hydraulicErosionCells[x][y] = cell;
}
}
return(hydraulicErosionCells);
}
private static HydraulicErosionCell[][] hydraulicErosionIteration(HydraulicErosionCell[][] hydraulicErosionCells)
{
int side = hydraulicErosionCells.Length;
//HydraulicErosionCell[][] resultHydraulicErosionCells = new HydraulicErosionCell[side][side];
// Step1 Rain water added
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
hydraulicErosionCells[x][y].Water = hydraulicErosionCells[x][y].Water + Kr;
}
}
// Step2 Create sediment
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
hydraulicErosionCells[x][y].Altitude = hydraulicErosionCells[x][y].Altitude - Ks * hydraulicErosionCells[x][y].Water;
hydraulicErosionCells[x][y].Sediment = hydraulicErosionCells[x][y].Sediment + Ks * hydraulicErosionCells[x][y].Water;
}
}
// Step3 water and sediment transport
HydraulicErosionCell[][] resultHydraulicErosionCells = new HydraulicErosionCell[side][];
for (int i = 0; i < side; i++)
{
resultHydraulicErosionCells[i] = new HydraulicErosionCell[side];
}
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
resultHydraulicErosionCells[x][y] = hydraulicErosionCells[x][y].getCopy();
}
}
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
HydraulicErosionCell current = hydraulicErosionCells[x][y];
HydraulicErosionCell resultCurrent = resultHydraulicErosionCells[x][y];
List <HydraulicErosionCell> neighbours = new List <HydraulicErosionCell>();
List <HydraulicErosionCell> resultNeighbours = new List <HydraulicErosionCell>();
if (x > 0 && y > 0)
{
neighbours.Add(hydraulicErosionCells[x - 1][y - 1]);
}
if (y > 0)
{
neighbours.Add(hydraulicErosionCells[x][y - 1]);
}
if (x < side - 1 && y > 0)
{
neighbours.Add(hydraulicErosionCells[x + 1][y - 1]);
}
if (x < side - 1)
{
neighbours.Add(hydraulicErosionCells[x + 1][y]);
}
if (x < side - 1 && y < side - 1)
{
neighbours.Add(hydraulicErosionCells[x + 1][y + 1]);
}
if (y < side - 1)
{
neighbours.Add(hydraulicErosionCells[x][y + 1]);
}
if (x > 0 && y < side - 1)
{
neighbours.Add(hydraulicErosionCells[x - 1][y + 1]);
}
if (x > 0)
{
neighbours.Add(hydraulicErosionCells[x - 1][y]);
}
if (x > 0 && y > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x - 1][y - 1]);
}
if (y > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x][y - 1]);
}
if (x < side - 1 && y > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x + 1][y - 1]);
}
if (x < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x + 1][y]);
}
if (x < side - 1 && y < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x + 1][y + 1]);
}
if (y < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x][y + 1]);
}
if (x > 0 && y < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x - 1][y + 1]);
}
if (x > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x - 1][y]);
}
transportWater(neighbours, resultNeighbours, current, resultCurrent);
}
}
hydraulicErosionCells = resultHydraulicErosionCells;
// Step4 Evaporation and deposition
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
hydraulicErosionCells[x][y].Water = hydraulicErosionCells[x][y].Water * (1 - Ke);
float mmax = Kc * hydraulicErosionCells[x][y].Water;
float dm = Math.Max(0, hydraulicErosionCells[x][y].Sediment - mmax);
hydraulicErosionCells[x][y].Sediment = hydraulicErosionCells[x][y].Sediment - dm;
hydraulicErosionCells[x][y].Altitude = hydraulicErosionCells[x][y].Altitude + dm;
}
}
return(hydraulicErosionCells);
}
private static void transportSediment(List <HydraulicErosionCell> neighbours, List <HydraulicErosionCell> resultNeighbours, HydraulicErosionCell current, HydraulicErosionCell resultCurrent)
{
float dtotal = 0;
float dmax = 0;
for (int i = 0; i < neighbours.Count; i++)
{
float di = current.Altitude - neighbours[i].Altitude;
if (di > T)
{
dtotal += di;
if (di > dmax)
{
dmax = di;
}
}
}
if (dtotal > 0)
{
for (int i = 0; i < neighbours.Count; i++)
{
float di = current.Altitude - neighbours[i].Altitude;
if (di > T)
{
float dh = C * (dmax - T) * (di / dtotal);
resultNeighbours[i].Altitude = resultNeighbours[i].Altitude + dh;
resultCurrent.Altitude = resultCurrent.Altitude - dh;
}
}
}
}
private static HydraulicErosionCell[][] thermalErosionIteration(HydraulicErosionCell[][] hydraulicErosionCells)
{
int side = hydraulicErosionCells.Length;
HydraulicErosionCell[][] resultHydraulicErosionCells = new HydraulicErosionCell[side][];
for (int i = 0; i < side; i++)
{
resultHydraulicErosionCells[i] = new HydraulicErosionCell[side];
}
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
resultHydraulicErosionCells[x][y] = hydraulicErosionCells[x][y].getCopy();
}
}
for (int x = 0; x < side; x++)
{
for (int y = 0; y < side; y++)
{
HydraulicErosionCell current = hydraulicErosionCells[x][y];
HydraulicErosionCell resultCurrent = resultHydraulicErosionCells[x][y];
List <HydraulicErosionCell> neighbours = new List <HydraulicErosionCell>();
List <HydraulicErosionCell> resultNeighbours = new List <HydraulicErosionCell>();
if (x > 0 && y > 0)
{
neighbours.Add(hydraulicErosionCells[x - 1][y - 1]);
}
if (y > 0)
{
neighbours.Add(hydraulicErosionCells[x][y - 1]);
}
if (x < side - 1 && y > 0)
{
neighbours.Add(hydraulicErosionCells[x + 1][y - 1]);
}
if (x < side - 1)
{
neighbours.Add(hydraulicErosionCells[x + 1][y]);
}
if (x < side - 1 && y < side - 1)
{
neighbours.Add(hydraulicErosionCells[x + 1][y + 1]);
}
if (y < side - 1)
{
neighbours.Add(hydraulicErosionCells[x][y + 1]);
}
if (x > 0 && y < side - 1)
{
neighbours.Add(hydraulicErosionCells[x - 1][y + 1]);
}
if (x > 0)
{
neighbours.Add(hydraulicErosionCells[x - 1][y]);
}
if (x > 0 && y > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x - 1][y - 1]);
}
if (y > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x][y - 1]);
}
if (x < side - 1 && y > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x + 1][y - 1]);
}
if (x < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x + 1][y]);
}
if (x < side - 1 && y < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x + 1][y + 1]);
}
if (y < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x][y + 1]);
}
if (x > 0 && y < side - 1)
{
resultNeighbours.Add(resultHydraulicErosionCells[x - 1][y + 1]);
}
if (x > 0)
{
resultNeighbours.Add(resultHydraulicErosionCells[x - 1][y]);
}
transportSediment(neighbours, resultNeighbours, current, resultCurrent);
}
}
return(resultHydraulicErosionCells);
}
private static void transportWater(List <HydraulicErosionCell> neighbours, List <HydraulicErosionCell> resultNeighbours, HydraulicErosionCell current, HydraulicErosionCell resultCurrent)
{
float a = current.Altitude + current.Water;
float aa = 0;
float dtotal = 0;
int validCount = 0;
for (int i = 0; i < neighbours.Count; i++)
{
float ai = neighbours[i].Altitude + neighbours[i].Water;
if (ai < a)
{
aa += ai;
dtotal += (a - ai);
validCount++;
}
}
aa /= (float)validCount;
float da = a - aa;
for (int i = 0; i < neighbours.Count; i++)
{
float ai = neighbours[i].Altitude + neighbours[i].Water;
if (ai < a)
{
float di = a - ai;
float dw = Math.Min(current.Water, da) * (di / dtotal);
float dm = current.Sediment * (dw / current.Water);
resultNeighbours[i].Water = resultNeighbours[i].Water + dw;
resultCurrent.Water = resultCurrent.Water - dw;
resultNeighbours[i].Sediment = resultNeighbours[i].Sediment + dm;
resultCurrent.Sediment = resultCurrent.Sediment - dm;
}
}
}
