public float[,] ErodeTerrain(float[,] heightMap, int seed)
{
rng = new System.Random(seed);
erosionInfo = InitializeErosionInfo();
erosionBrush = InitializeErosionBrush(heightMap);
depositionBrush = InitializeDepositionBrush(heightMap);
for (int i = 0; i < settings.iterations; i++)
{
Droplet droplet = new Droplet(heightMap, erosionInfo, erosionBrush, depositionBrush);
droplet.Update();
}
return(heightMap);
}
public Droplet(float[,] map, ErosionInfo info, ErosionBrush eBrush, DepositionBrush dBrush)
{
heightMap = map;
erosionInfo = info;
erosionBrush = eBrush;
depositionBrush = dBrush;
mapWidth = heightMap.GetLength(0);
mapHeight = heightMap.GetLength(1);
position = new Vector2(
erosionInfo.rng.Next(0, mapWidth - 1),
erosionInfo.rng.Next(0, mapHeight - 1)
);
direction = new Vector2(0f, 0f).normalized;
}
ErosionBrush InitializeErosionBrush(float[,] heightMap)
{
int width = heightMap.GetLength(0);
int height = heightMap.GetLength(1);
ErosionBrush erosionBrush = new ErosionBrush(width, height);
Vector2 position = new Vector2();
Vector2 v = new Vector2();
float[] xOffsets = new float[(int)settings.erosionRadius * (int)settings.erosionRadius * 4];
float[] yOffsets = new float[(int)settings.erosionRadius * (int)settings.erosionRadius * 4];
for (int x = 0; x < width; x++)
{
for (int y = 0; y < height; y++)
{
if (x < 0 || x >= width || y < 0 || y >= height)
{
continue;
}
int index = 0;
position.x = x;
position.y = y;
float weightSum = 0f;
int numVertices = 0;
for (int i = -(int)settings.erosionRadius; i <= settings.erosionRadius; i++)
{
int xCoord = x + i;
for (int j = -(int)settings.erosionRadius; j <= settings.erosionRadius; j++)
{
int yCoord = y + j;
v.x = xCoord;
v.y = yCoord;
if (xCoord < 0 || xCoord >= width || yCoord < 0 || yCoord >= height)
{
continue;
}
if ((v - position).magnitude <= settings.erosionRadius)
{
weightSum += Mathf.Max(0f, settings.erosionRadius - (v - position).magnitude);
numVertices++;
xOffsets[index] = i;
yOffsets[index] = j;
index++;
}
}
}
erosionBrush.erosionBrushWeights[y * width + x] = new float[numVertices];
erosionBrush.erosionBrushVertices[y * width + x] = new float[numVertices];
for (int n = 0; n < numVertices; n++)
{
v.x = x + xOffsets[n];
v.y = y + yOffsets[n];
float weight = Mathf.Max(0, settings.erosionRadius - (v - position).magnitude) / weightSum;
erosionBrush.erosionBrushVertices[y * width + x][n] = v.y * width + v.x;
erosionBrush.erosionBrushWeights[y * width + x][n] = weight;
}
}
}
return(erosionBrush);
}