/// <summary>
/// Floodfill heightfield to get 2D height data, starting at vertex locations
/// </summary>
/// <param name="compactField">Original heightfield data</param>
/// <param name="poly">Polygon in PolyMesh</param>
/// <param name="polyCount">Number of vertices per polygon</param>
/// <param name="verts">PolyMesh Vertices</param>
/// <param name="borderSize">Heightfield border size</param>
/// <param name="hp">HeightPatch which extracts heightfield data</param>
/// <param name="stack">Temporary stack of CompactSpanReferences</param>
private void GetHeightDataSeedsFromVertices(CompactHeightfield compactField, PolyMesh.Polygon poly, int polyCount, PolyVertex[] verts, int borderSize, HeightPatch hp, List<CompactSpanReference> stack)
{
hp.SetAll(0);
//use poly vertices as seed points
for (int j = 0; j < polyCount; j++)
{
var csr = new CompactSpanReference(0, 0, -1);
int dmin = int.MaxValue;
var v = verts[poly.Vertices[j]];
for (int k = 0; k < 9; k++)
{
//get vertices and offset x and z coordinates depending on current drection
int ax = v.X + VertexOffset[k * 2 + 0];
int ay = v.Y;
int az = v.Z + VertexOffset[k * 2 + 1];
//skip if out of bounds
if (ax < hp.X || ax >= hp.X + hp.Width || az < hp.Y || az >= hp.Y + hp.Length)
continue;
//get new cell
CompactCell c = compactField.Cells[(az + borderSize) * compactField.Width + (ax + borderSize)];
//loop through all the spans
for (int i = c.StartIndex, end = c.StartIndex + c.Count; i < end; i++)
{
CompactSpan s = compactField.Spans[i];
//find minimum y-distance
int d = Math.Abs(ay - s.Minimum);
if (d < dmin)
{
csr = new CompactSpanReference(ax, az, i);
dmin = d;
}
}
}
//only add if something new found
if (csr.Index != -1)
{
stack.Add(csr);
}
}
//find center of polygon using flood fill
int pcx = 0, pcz = 0;
for (int j = 0; j < polyCount; j++)
{
var v = verts[poly.Vertices[j]];
pcx += v.X;
pcz += v.Z;
}
pcx /= polyCount;
pcz /= polyCount;
//stack groups 3 elements as one part
foreach (var cell in stack)
{
int idx = (cell.Y - hp.Y) * hp.Width + (cell.X - hp.X);
hp[idx] = 1;
}
//process the entire stack
while (stack.Count > 0)
{
var cell = stack[stack.Count - 1];
stack.RemoveAt(stack.Count - 1);
//check if close to center of polygon
if (Math.Abs(cell.X - pcx) <= 1 && Math.Abs(cell.Y - pcz) <= 1)
{
//clear the stack and add a new group
stack.Clear();
stack.Add(cell);
break;
}
CompactSpan cs = compactField[cell];
//check all four directions
for (var dir = Direction.West; dir <= Direction.South; dir++)
{
//skip if disconnected
if (!cs.IsConnected(dir))
continue;
//get neighbor
int ax = cell.X + dir.GetHorizontalOffset();
int ay = cell.Y + dir.GetVerticalOffset();
//skip if out of bounds
if (ax < hp.X || ax >= (hp.X + hp.Width) || ay < hp.Y || ay >= (hp.Y + hp.Length))
continue;
if (hp[(ay - hp.Y) * hp.Width + (ax - hp.X)] != 0)
continue;
//get the new index
int ai = compactField.Cells[(ay + borderSize) * compactField.Width + (ax + borderSize)].StartIndex + CompactSpan.GetConnection(ref cs, dir);
//save data
int idx = (ay - hp.Y) * hp.Width + (ax - hp.X);
hp[idx] = 1;
//push to stack
stack.Add(new CompactSpanReference(ax, ay, ai));
}
}
//clear the heightpatch
hp.Clear();
//mark start locations
for (int i = 0; i < stack.Count; i++)
{
var c = stack[i];
//set new heightpatch data
int idx = (c.Y - hp.Y) * hp.Width + (c.X - hp.X);
CompactSpan cs = compactField.Spans[c.Index];
hp[idx] = cs.Minimum;
stack[i] = new CompactSpanReference(c.X + borderSize, c.Y + borderSize, c.Index);
}
}
private void GetHeightData(CompactHeightfield compactField, PolyMesh.Polygon poly, int polyCount, PolyVertex[] verts, int borderSize, HeightPatch hp)
{
var stack = new List<CompactSpanReference>();
bool empty = true;
hp.Clear();
for (int y = 0; y < hp.Length; y++)
{
int hy = hp.Y + y + borderSize;
for (int x = 0; x < hp.Width; x++)
{
int hx = hp.X + x + borderSize;
var cells = compactField.Cells[hy * compactField.Width + hx];
for (int i = cells.StartIndex, end = cells.StartIndex + cells.Count; i < end; i++)
{
var span = compactField.Spans[i];
if (span.Region == poly.RegionId)
{
hp[x, y] = span.Minimum;
empty = false;
bool border = false;
for (var dir = Direction.West; dir <= Direction.South; dir++)
{
if (span.IsConnected(dir))
{
int ax = hx + dir.GetHorizontalOffset();
int ay = hy + dir.GetVerticalOffset();
int ai = compactField.Cells[ay * compactField.Width + ax].StartIndex + CompactSpan.GetConnection(ref span, dir);
if (compactField.Spans[ai].Region != poly.RegionId)
{
border = true;
break;
}
}
}
if (border)
stack.Add(new CompactSpanReference(hx, hy, i));
break;
}
}
}
}
if (empty)
GetHeightDataSeedsFromVertices(compactField, poly, polyCount, verts, borderSize, hp, stack);
const int RetractSize = 256;
int head = 0;
while (head < stack.Count)
{
var cell = stack[head++];
var cs = compactField[cell];
if (head >= RetractSize)
{
head = 0;
if (stack.Count > RetractSize)
{
for (int i = 0; i < stack.Count - RetractSize; i++)
stack[i] = stack[i + RetractSize];
}
int targetSize = stack.Count % RetractSize;
while (stack.Count > targetSize)
stack.RemoveAt(stack.Count - 1);
}
//loop in all four directions
for (var dir = Direction.West; dir <= Direction.South; dir++)
{
//skip
if (!cs.IsConnected(dir))
continue;
int ax = cell.X + dir.GetHorizontalOffset();
int ay = cell.Y + dir.GetVerticalOffset();
int hx = ax - hp.X - borderSize;
int hy = ay - hp.Y - borderSize;
if (hx < 0 || hx >= hp.Width || hy < 0 || hy >= hp.Length)
continue;
//only continue if height is unset
if (hp.IsSet(hy * hp.Width + hx))
continue;
//get new span
int ai = compactField.Cells[ay * compactField.Width + ax].StartIndex + CompactSpan.GetConnection(ref cs, dir);
CompactSpan ds = compactField.Spans[ai];
hp[hx, hy] = ds.Minimum;
stack.Add(new CompactSpanReference(ax, ay, ai));
}
}
}