/// <summary>
/// Gets the <see cref="CompactSpan"/> specified by the reference.
/// </summary>
/// <param name="spanRef">A reference to a span in this <see cref="CompactHeightfield"/>.</param>
/// <returns>The referenced span.</returns>
public CompactSpan this[CompactSpanReference spanRef]
{
get
{
return spans[spanRef.Index];
}
}
/// <summary>
/// Builds a set of <see cref="Contour"/>s around the generated regions. Must be called after regions are generated.
/// </summary>
/// <param name="maxError">The maximum allowed deviation in a simplified contour from a raw one.</param>
/// <param name="maxEdgeLength">The maximum edge length.</param>
/// <param name="buildFlags">Flags that change settings for the build process.</param>
/// <returns>A <see cref="ContourSet"/> containing one contour per region.</returns>
public ContourSet BuildContourSet(float maxError, int maxEdgeLength, ContourBuildFlags buildFlags)
{
BBox3 contourSetBounds = bounds;
if (borderSize > 0)
{
//remove offset
float pad = borderSize * cellSize;
contourSetBounds.Min.X += pad;
contourSetBounds.Min.Z += pad;
contourSetBounds.Max.X -= pad;
contourSetBounds.Max.Z -= pad;
}
int contourSetWidth = width - borderSize * 2;
int contourSetLength = length - borderSize * 2;
int maxContours = Math.Max(maxRegions, 8);
var contours = new List<Contour>(maxContours);
EdgeFlags[] flags = new EdgeFlags[spans.Length];
//Modify flags array by using the CompactHeightfield data
//mark boundaries
for (int z = 0; z < length; z++)
{
for (int x = 0; x < width; x++)
{
//loop through all the spans in the cell
CompactCell c = cells[x + z * width];
for (int i = c.StartIndex, end = c.StartIndex + c.Count; i < end; i++)
{
CompactSpan s = spans[i];
//set the flag to 0 if the region is a border region or null.
if (s.Region.IsNull || RegionId.HasFlags(s.Region, RegionFlags.Border))
{
flags[i] = 0;
continue;
}
//go through all the neighboring cells
for (var dir = Direction.West; dir <= Direction.South; dir++)
{
//obtain region id
RegionId r = RegionId.Null;
if (s.IsConnected(dir))
{
int dx = x + dir.GetHorizontalOffset();
int dz = z + dir.GetVerticalOffset();
int di = cells[dx + dz * width].StartIndex + CompactSpan.GetConnection(ref s, dir);
r = spans[di].Region;
}
//region ids are equal
if (r == s.Region)
{
//res marks all the internal edges
EdgeFlagsHelper.AddEdge(ref flags[i], dir);
}
}
//flags represents all the nonconnected edges, edges that are only internal
//the edges need to be between different regions
EdgeFlagsHelper.FlipEdges(ref flags[i]);
}
}
}
var verts = new List<ContourVertex>();
var simplified = new List<ContourVertex>();
for (int z = 0; z < length; z++)
{
for (int x = 0; x < width; x++)
{
CompactCell c = cells[x + z * width];
for (int i = c.StartIndex, end = c.StartIndex + c.Count; i < end; i++)
{
//flags is either 0000 or 1111
//in other words, not connected at all
//or has all connections, which means span is in the middle and thus not an edge.
if (flags[i] == EdgeFlags.None || flags[i] == EdgeFlags.All)
{
flags[i] = EdgeFlags.None;
continue;
}
var spanRef = new CompactSpanReference(x, z, i);
RegionId reg = this[spanRef].Region;
if (reg.IsNull || RegionId.HasFlags(reg, RegionFlags.Border))
continue;
//reset each iteration
verts.Clear();
simplified.Clear();
//Walk along a contour, then build it
WalkContour(spanRef, flags, verts);
Contour.Simplify(verts, simplified, maxError, maxEdgeLength, buildFlags);
Contour.RemoveDegenerateSegments(simplified);
Contour contour = new Contour(simplified, reg, areas[i], borderSize);
if (!contour.IsNull)
contours.Add(contour);
}
}
}
//Check and merge bad contours
for (int i = 0; i < contours.Count; i++)
{
Contour cont = contours[i];
//Check if contour is backwards
if (cont.Area2D < 0)
{
//Find another contour to merge with
int mergeIndex = -1;
for (int j = 0; j < contours.Count; j++)
{
if (i == j)
continue;
//Must have at least one vertex, the same region ID, and be going forwards.
Contour contj = contours[j];
if (contj.Vertices.Length != 0 && contj.RegionId == cont.RegionId && contj.Area2D > 0)
{
mergeIndex = j;
break;
}
}
//Merge if found.
if (mergeIndex != -1)
{
contours[mergeIndex].MergeWith(cont);
contours.RemoveAt(i);
i--;
}
}
}
return new ContourSet(contours, contourSetBounds, contourSetWidth, contourSetLength);
}
/// <summary>
/// Try to visit all the spans. May be needed in filtering small regions.
/// </summary>
/// <param name="regions">an array of region values</param>
/// <param name="spanRef">The span to start walking from.</param>
/// <param name="dir">The direction to start walking in.</param>
/// <param name="cont">A collection of regions to append to.</param>
private void WalkContour(RegionId[] regions, CompactSpanReference spanRef, Direction dir, List<RegionId> cont)
{
Direction startDir = dir;
int starti = spanRef.Index;
CompactSpan ss = spans[starti];
RegionId curReg = RegionId.Null;
if (ss.IsConnected(dir))
{
int dx = spanRef.X + dir.GetHorizontalOffset();
int dy = spanRef.Y + dir.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref ss, dir);
curReg = regions[di];
}
cont.Add(curReg);
int iter = 0;
while (++iter < 40000)
{
CompactSpan s = spans[spanRef.Index];
if (IsSolidEdge(regions, ref spanRef, dir))
{
//choose the edge corner
RegionId r = RegionId.Null;
if (s.IsConnected(dir))
{
int dx = spanRef.X + dir.GetHorizontalOffset();
int dy = spanRef.Y + dir.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref s, dir);
r = regions[di];
}
if (r != curReg)
{
curReg = r;
cont.Add(curReg);
}
dir = dir.NextClockwise(); //rotate clockwise
}
else
{
int di = -1;
int dx = spanRef.X + dir.GetHorizontalOffset();
int dy = spanRef.Y + dir.GetVerticalOffset();
if (s.IsConnected(dir))
{
CompactCell dc = cells[dx + dy * width];
di = dc.StartIndex + CompactSpan.GetConnection(ref s, dir);
}
if (di == -1)
{
//shouldn't happen
return;
}
spanRef = new CompactSpanReference(dx, dy, di);
dir = dir.NextCounterClockwise(); //rotate counterclockwise
}
if (starti == spanRef.Index && startDir == dir)
break;
}
//remove adjacent duplicates
if (cont.Count > 1)
{
for (int j = 0; j < cont.Count;)
{
//next element
int nj = (j + 1) % cont.Count;
//adjacent duplicate found
if (cont[j] == cont[nj])
cont.RemoveAt(j);
else
j++;
}
}
}
/// <summary>
/// Initial generation of the contours
/// </summary>
/// <param name="spanReference">A referecne to the span to start walking from.</param>
/// <param name="flags">An array of flags determinining </param>
/// <param name="points">The vertices of a contour.</param>
private void WalkContour(CompactSpanReference spanReference, EdgeFlags[] flags, List<ContourVertex> points)
{
Direction dir = Direction.West;
//find the first direction that has a connection
while (!EdgeFlagsHelper.IsConnected(ref flags[spanReference.Index], dir))
dir++;
Direction startDir = dir;
int startIndex = spanReference.Index;
Area area = areas[startIndex];
//TODO make the max iterations value a variable
int iter = 0;
while (++iter < 40000)
{
// this direction is connected
if (EdgeFlagsHelper.IsConnected(ref flags[spanReference.Index], dir))
{
// choose the edge corner
bool isBorderVertex;
bool isAreaBorder = false;
int px = spanReference.X;
int py = GetCornerHeight(spanReference, dir, out isBorderVertex);
int pz = spanReference.Y;
switch (dir)
{
case Direction.West:
pz++;
break;
case Direction.North:
px++;
pz++;
break;
case Direction.East:
px++;
break;
}
RegionId r = RegionId.Null;
CompactSpan s = this[spanReference];
if (s.IsConnected(dir))
{
int dx = spanReference.X + dir.GetHorizontalOffset();
int dy = spanReference.Y + dir.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref s, dir);
r = spans[di].Region;
if (area != areas[di])
isAreaBorder = true;
}
// apply flags if neccessary
if (isBorderVertex)
r = RegionId.WithFlags(r, RegionFlags.VertexBorder);
if (isAreaBorder)
r = RegionId.WithFlags(r, RegionFlags.AreaBorder);
//save the point
points.Add(new ContourVertex(px, py, pz, r));
EdgeFlagsHelper.RemoveEdge(ref flags[spanReference.Index], dir); // remove visited edges
dir = dir.NextClockwise(); // rotate clockwise
}
else
{
//get a new cell(x, y) and span index(i)
int di = -1;
int dx = spanReference.X + dir.GetHorizontalOffset();
int dy = spanReference.Y + dir.GetVerticalOffset();
CompactSpan s = this[spanReference];
if (s.IsConnected(dir))
{
CompactCell dc = cells[dx + dy * width];
di = dc.StartIndex + CompactSpan.GetConnection(ref s, dir);
}
if (di == -1)
{
// shouldn't happen
// TODO if this shouldn't happen, this check shouldn't be necessary.
throw new InvalidOperationException("Something went wrong");
}
spanReference = new CompactSpanReference(dx, dy, di);
dir = dir.NextCounterClockwise(); // rotate counterclockwise
}
if (startIndex == spanReference.Index && startDir == dir)
break;
}
}
/// <summary>
/// Checks whether the edge from a span in a direction is a solid edge.
/// A solid edge is an edge between two regions.
/// </summary>
/// <param name="regions">The region ID array.</param>
/// <param name="spanRef">A reference to the span connected to the edge.</param>
/// <param name="dir">The direction of the edge.</param>
/// <returns>A value indicating whether the described edge is solid.</returns>
private bool IsSolidEdge(RegionId[] regions, ref CompactSpanReference spanRef, Direction dir)
{
CompactSpan s = spans[spanRef.Index];
RegionId r = RegionId.Null;
if (s.IsConnected(dir))
{
int dx = spanRef.X + dir.GetHorizontalOffset();
int dy = spanRef.Y + dir.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref s, dir);
r = regions[di];
}
if (r == regions[spanRef.Index])
return false;
return true;
}
/// <summary>
/// Helper method for WalkContour function
/// </summary>
/// <param name="sr">The span to get the corner height for.</param>
/// <param name="dir">The direction to get the corner height from.</param>
/// <param name="isBorderVertex">Determine whether the vertex is a border or not.</param>
/// <returns>The corner height.</returns>
private int GetCornerHeight(CompactSpanReference sr, Direction dir, out bool isBorderVertex)
{
isBorderVertex = false;
CompactSpan s = this[sr];
int cornerHeight = s.Minimum;
Direction dirp = dir.NextClockwise(); //new clockwise direction
RegionId[] cornerRegs = new RegionId[4];
Area[] cornerAreas = new Area[4];
//combine region and area codes in order to prevent border vertices, which are in between two areas, to be removed
cornerRegs[0] = s.Region;
cornerAreas[0] = areas[sr.Index];
if (s.IsConnected(dir))
{
//get neighbor span
int dx = sr.X + dir.GetHorizontalOffset();
int dy = sr.Y + dir.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref s, dir);
CompactSpan ds = spans[di];
cornerHeight = Math.Max(cornerHeight, ds.Minimum);
cornerRegs[1] = spans[di].Region;
cornerAreas[1] = areas[di];
//get neighbor of neighbor's span
if (ds.IsConnected(dirp))
{
int dx2 = dx + dirp.GetHorizontalOffset();
int dy2 = dy + dirp.GetVerticalOffset();
int di2 = cells[dx2 + dy2 * width].StartIndex + CompactSpan.GetConnection(ref ds, dirp);
CompactSpan ds2 = spans[di2];
cornerHeight = Math.Max(cornerHeight, ds2.Minimum);
cornerRegs[2] = ds2.Region;
cornerAreas[2] = areas[di2];
}
}
//get neighbor span
if (s.IsConnected(dirp))
{
int dx = sr.X + dirp.GetHorizontalOffset();
int dy = sr.Y + dirp.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref s, dirp);
CompactSpan ds = spans[di];
cornerHeight = Math.Max(cornerHeight, ds.Minimum);
cornerRegs[3] = ds.Region;
cornerAreas[3] = areas[di];
//get neighbor of neighbor's span
if (ds.IsConnected(dir))
{
int dx2 = dx + dir.GetHorizontalOffset();
int dy2 = dy + dir.GetVerticalOffset();
int di2 = cells[dx2 + dy2 * width].StartIndex + CompactSpan.GetConnection(ref ds, dir);
CompactSpan ds2 = spans[di2];
cornerHeight = Math.Max(cornerHeight, ds2.Minimum);
cornerRegs[2] = ds2.Region;
cornerAreas[2] = areas[di2];
}
}
//check if vertex is special edge vertex
//if so, these vertices will be removed later
for (int j = 0; j < 4; j++)
{
int a = j;
int b = (j + 1) % 4;
int c = (j + 2) % 4;
int d = (j + 3) % 4;
RegionId ra = cornerRegs[a], rb = cornerRegs[b], rc = cornerRegs[c], rd = cornerRegs[d];
Area aa = cornerAreas[a], ab = cornerAreas[b], ac = cornerAreas[c], ad = cornerAreas[d];
//the vertex is a border vertex if:
//two same exterior cells in a row followed by two interior cells and none of the regions are out of bounds
bool twoSameExteriors = RegionId.HasFlags(ra, RegionFlags.Border) && RegionId.HasFlags(rb, RegionFlags.Border) && (ra == rb && aa == ab);
bool twoSameInteriors = !(RegionId.HasFlags(rc, RegionFlags.Border) || RegionId.HasFlags(rd, RegionFlags.Border));
bool intsSameArea = ac == ad;
bool noZeros = ra != 0 && rb != 0 && rc != 0 && rd != 0 && aa != 0 && ab != 0 && ac != 0 && ad != 0;
if (twoSameExteriors && twoSameInteriors && intsSameArea && noZeros)
{
isBorderVertex = true;
break;
}
}
return cornerHeight;
}
/// <summary>
/// Floods the regions at a certain level
/// </summary>
/// <param name="regions">source region</param>
/// <param name="floodDistances">source distances</param>
/// <param name="regionIndex">region id</param>
/// <param name="level">current level</param>
/// <param name="start">A reference to the starting span.</param>
/// <returns>Always true.</returns>
private bool FloodRegion(RegionId[] regions, int[] floodDistances, int regionIndex, int level, ref CompactSpanReference start)
{
//TODO this method should always return true, make it not return a bool?
//flood fill mark region
Stack<CompactSpanReference> stack = new Stack<CompactSpanReference>();
stack.Push(start);
Area area = areas[start.Index];
regions[start.Index] = new RegionId(regionIndex);
floodDistances[start.Index] = 0;
int lev = level >= 2 ? level - 2 : 0;
int count = 0;
while (stack.Count > 0)
{
CompactSpanReference cell = stack.Pop();
CompactSpan cs = spans[cell.Index];
//check if any of the neighbors already have a valid reigon set
RegionId ar = RegionId.Null;
for (var dir = Direction.West; dir <= Direction.South; dir++)
{
//8 connected
if (cs.IsConnected(dir))
{
int dx = cell.X + dir.GetHorizontalOffset();
int dy = cell.Y + dir.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref cs, dir);
if (areas[di] != area)
continue;
RegionId nr = regions[di];
if (RegionId.HasFlags(nr, RegionFlags.Border)) //skip borders
continue;
if (nr != 0 && nr != regionIndex)
{
ar = nr;
break;
}
CompactSpan ds = spans[di];
Direction dir2 = dir.NextClockwise();
if (ds.IsConnected(dir2))
{
int dx2 = dx + dir2.GetHorizontalOffset();
int dy2 = dy + dir2.GetVerticalOffset();
int di2 = cells[dx2 + dy2 * width].StartIndex + CompactSpan.GetConnection(ref ds, dir2);
if (areas[di2] != area)
continue;
RegionId nr2 = regions[di2];
if (nr2 != 0 && nr2 != regionIndex)
{
ar = nr2;
break;
}
}
}
}
if (ar != 0)
{
regions[cell.Index] = RegionId.Null;
continue;
}
count++;
//expand neighbors
for (var dir = Direction.West; dir <= Direction.South; dir++)
{
if (cs.IsConnected(dir))
{
int dx = cell.X + dir.GetHorizontalOffset();
int dy = cell.Y + dir.GetVerticalOffset();
int di = cells[dx + dy * width].StartIndex + CompactSpan.GetConnection(ref cs, dir);
if (areas[di] != area)
continue;
if (distances[di] >= lev && regions[di] == 0)
{
regions[di] = new RegionId(regionIndex);
floodDistances[di] = 0;
stack.Push(new CompactSpanReference(dx, dy, di));
}
}
}
}
return count > 0;
}
/// <summary>
/// Discards regions that are too small.
/// </summary>
/// <param name="regionIds">region data</param>
/// <param name="minRegionArea">The minimum area a region can have</param>
/// <param name="mergeRegionSize">The size of the regions after merging</param>
/// <param name="maxRegionId">determines the number of regions available</param>
/// <returns>The reduced number of regions.</returns>
private int FilterSmallRegions(RegionId[] regionIds, int minRegionArea, int mergeRegionSize, int maxRegionId)
{
int numRegions = maxRegionId + 1;
Region[] regions = new Region[numRegions];
//construct regions
for (int i = 0; i < numRegions; i++)
regions[i] = new Region(i);
//find edge of a region and find connections around a contour
for (int y = 0; y < length; y++)
{
for (int x = 0; x < width; x++)
{
CompactCell c = cells[x + y * width];
for (int i = c.StartIndex, end = c.StartIndex + c.Count; i < end; i++)
{
CompactSpanReference spanRef = new CompactSpanReference(x, y, i);
//HACK since the border region flag makes r negative, I changed r == 0 to r <= 0. Figure out exactly what maxRegionId's purpose is and see if Region.IsBorderOrNull is all we need.
int r = (int)regionIds[i];
if (r <= 0 || (int)r >= numRegions)
continue;
Region reg = regions[(int)r];
reg.SpanCount++;
//update floors
for (int j = c.StartIndex; j < end; j++)
{
if (i == j) continue;
RegionId floorId = regionIds[j];
if (floorId == 0 || (int)floorId >= numRegions)
continue;
reg.AddUniqueFloorRegion(floorId);
}
//have found contour
if (reg.Connections.Count > 0)
continue;
reg.AreaType = areas[i];
//check if this cell is next to a border
for (var dir = Direction.West; dir <= Direction.South; dir++)
{
if (IsSolidEdge(regionIds, ref spanRef, dir))
{
//The cell is at a border.
//Walk around contour to find all neighbors
WalkContour(regionIds, spanRef, dir, reg.Connections);
break;
}
}
}
}
}
//Remove too small regions
Stack<RegionId> stack = new Stack<RegionId>();
List<RegionId> trace = new List<RegionId>();
for (int i = 0; i < numRegions; i++)
{
Region reg = regions[i];
if (reg.IsBorderOrNull || reg.SpanCount == 0 || reg.Visited)
continue;
//count the total size of all connected regions
//also keep track of the regions connections to a tile border
bool connectsToBorder = false;
int spanCount = 0;
stack.Clear();
trace.Clear();
reg.Visited = true;
stack.Push(reg.Id);
while (stack.Count > 0)
{
//pop
RegionId ri = stack.Pop();
Region creg = regions[(int)ri];
spanCount += creg.SpanCount;
trace.Add(ri);
for (int j = 0; j < creg.Connections.Count; j++)
{
if (RegionId.HasFlags(creg.Connections[j], RegionFlags.Border))
{
connectsToBorder = true;
continue;
}
Region neiReg = regions[(int)creg.Connections[j]];
if (neiReg.Visited || neiReg.IsBorderOrNull)
continue;
//visit
stack.Push(neiReg.Id);
neiReg.Visited = true;
}
}
//if the accumulated region size is too small, remove it
//do not remove areas which connect to tile borders as their size can't be estimated correctly
//and removing them can potentially remove necessary areas
if (spanCount < minRegionArea && !connectsToBorder)
{
//kill all visited regions
for (int j = 0; j < trace.Count; j++)
{
int index = (int)trace[j];
regions[index].SpanCount = 0;
regions[index].Id = RegionId.Null;
}
}
}
//Merge too small regions to neighbor regions
int mergeCount = 0;
do
{
mergeCount = 0;
for (int i = 0; i < numRegions; i++)
{
Region reg = regions[i];
if (reg.IsBorderOrNull || reg.SpanCount == 0)
continue;
//check to see if region should be merged
if (reg.SpanCount > mergeRegionSize && reg.IsConnectedToBorder())
continue;
//small region with more than one connection or region which is not connected to border at all
//find smallest neighbor that connects to this one
int smallest = int.MaxValue;
RegionId mergeId = reg.Id;
for (int j = 0; j < reg.Connections.Count; j++)
{
if (RegionId.HasFlags(reg.Connections[j], RegionFlags.Border))
continue;
Region mreg = regions[(int)reg.Connections[j]];
if (mreg.IsBorderOrNull)
continue;
if (mreg.SpanCount < smallest && reg.CanMergeWith(mreg) && mreg.CanMergeWith(reg))
{
smallest = mreg.SpanCount;
mergeId = mreg.Id;
}
}
//found new id
if (mergeId != reg.Id)
{
RegionId oldId = reg.Id;
Region target = regions[(int)mergeId];
//merge regions
if (target.MergeWithRegion(reg))
{
//fix regions pointing to current region
for (int j = 0; j < numRegions; j++)
{
if (regions[j].IsBorderOrNull)
continue;
//if another regions was already merged into current region
//change the nid of the previous region too
if (regions[j].Id == oldId)
regions[j].Id = mergeId;
//replace current region with new one if current region is neighbor
regions[j].ReplaceNeighbour(oldId, mergeId);
}
mergeCount++;
}
}
}
}
while (mergeCount > 0);
//Compress region ids
for (int i = 0; i < numRegions; i++)
{
regions[i].Remap = false;
if (regions[i].IsBorderOrNull)
continue;
regions[i].Remap = true;
}
int regIdGen = 0;
for (int i = 0; i < numRegions; i++)
{
if (!regions[i].Remap)
continue;
RegionId oldId = regions[i].Id;
RegionId newId = new RegionId(++regIdGen);
for (int j = i; j < numRegions; j++)
{
if (regions[j].Id == oldId)
{
regions[j].Id = newId;
regions[j].Remap = false;
}
}
}
//Remap regions
for (int i = 0; i < spans.Length; i++)
{
if (!RegionId.HasFlags(regionIds[i], RegionFlags.Border))
regionIds[i] = regions[(int)regionIds[i]].Id;
}
return regIdGen;
}
/// <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);
}
}