/// <summary>
/// Use the HeightPatch data to obtain a height for a certain location.
/// </summary>
/// <param name="loc">The location</param>
/// <param name="invCellSize">Reciprocal of cell size</param>
/// <param name="cellHeight">Cell height</param>
/// <param name="hp">Height patch</param>
/// <returns>The height</returns>
private int GetHeight(Vector3 loc, float invCellSize, float cellHeight, HeightPatch hp)
{
int ix = (int)Math.Floor(loc.X * invCellSize + 0.01f);
int iz = (int)Math.Floor(loc.Z * invCellSize + 0.01f);
ix = MathHelper.Clamp(ix - hp.X, 0, hp.Width - 1);
iz = MathHelper.Clamp(iz - hp.Y, 0, hp.Length - 1);
int h;
if (!hp.TryGetHeight(ix, iz, out h))
{
//go in counterclockwise direction starting from west, ending in northwest
int[] off =
{
-1, 0,
-1, -1,
0, -1,
1, -1,
1, 0,
1, 1,
0, 1,
-1, 1
};
float dmin = float.MaxValue;
for (int i = 0; i < 8; i++)
{
int nx = ix + off[i * 2 + 0];
int nz = iz + off[i * 2 + 1];
if (nx < 0 || nz < 0 || nx >= hp.Width || nz >= hp.Length)
continue;
int nh;
if (!hp.TryGetHeight(nx, nz, out nh))
continue;
float d = Math.Abs(nh * cellHeight - loc.Y);
if (d < dmin)
{
h = nh;
dmin = d;
}
}
}
return h;
}
/// <summary>
/// Initializes a new instance of the <see cref="PolyMeshDetail"/> class.
/// </summary>
/// <remarks>
/// <see cref="PolyMeshDetail"/> uses a <see cref="CompactHeightfield"/> to add in details to a
/// <see cref="PolyMesh"/>. This detail is triangulated into a new mesh and can be used to approximate height in the walkable
/// areas of a scene.
/// </remarks>
/// <param name="mesh">The <see cref="PolyMesh"/>.</param>
/// <param name="compactField">The <see cref="CompactHeightfield"/> used to add height detail.</param>
/// <param name="sampleDist">The sampling distance.</param>
/// <param name="sampleMaxError">The maximum sampling error allowed.</param>
public PolyMeshDetail(PolyMesh mesh, CompactHeightfield compactField, float sampleDist, float sampleMaxError)
{
if (mesh.VertCount == 0 || mesh.PolyCount == 0)
return;
Vector3 origin = mesh.Bounds.Min;
int maxhw = 0, maxhh = 0;
BBox2i[] bounds = new BBox2i[mesh.PolyCount];
Vector3[] poly = new Vector3[mesh.NumVertsPerPoly];
var storedVertices = new List<Vector3>();
var storedTriangles = new List<TriangleData>();
//find max size for polygon area
for (int i = 0; i < mesh.PolyCount; i++)
{
var p = mesh.Polys[i];
int xmin = compactField.Width;
int xmax = 0;
int zmin = compactField.Length;
int zmax = 0;
for (int j = 0; j < mesh.NumVertsPerPoly; j++)
{
var pj = p.Vertices[j];
if (pj == PolyMesh.NullId)
break;
var v = mesh.Verts[pj];
xmin = Math.Min(xmin, v.X);
xmax = Math.Max(xmax, v.X);
zmin = Math.Min(zmin, v.Z);
zmax = Math.Max(zmax, v.Z);
}
xmin = Math.Max(0, xmin - 1);
xmax = Math.Min(compactField.Width, xmax + 1);
zmin = Math.Max(0, zmin - 1);
zmax = Math.Min(compactField.Length, zmax + 1);
if (xmin >= xmax || zmin >= zmax)
continue;
maxhw = Math.Max(maxhw, xmax - xmin);
maxhh = Math.Max(maxhh, zmax - zmin);
bounds[i] = new BBox2i(xmin, zmin, xmax, zmax);
}
HeightPatch hp = new HeightPatch(0, 0, maxhw, maxhh);
this.meshes = new MeshData[mesh.PolyCount];
for (int i = 0; i < mesh.PolyCount; i++)
{
var p = mesh.Polys[i];
//store polygon vertices for processing
int npoly = 0;
for (int j = 0; j < mesh.NumVertsPerPoly; j++)
{
int pvi = p.Vertices[j];
if (pvi == PolyMesh.NullId)
break;
PolyVertex pv = mesh.Verts[pvi];
Vector3 v = new Vector3(pv.X, pv.Y, pv.Z);
v.X *= mesh.CellSize;
v.Y *= mesh.CellHeight;
v.Z *= mesh.CellSize;
poly[j] = v;
npoly++;
}
//get height data from area of polygon
BBox2i bound = bounds[i];
hp.Resize(bound.Min.X, bound.Min.Y, bound.Max.X - bound.Min.X, bound.Max.Y - bound.Min.Y);
GetHeightData(compactField, p, npoly, mesh.Verts, mesh.BorderSize, hp);
List<Vector3> tempVerts = new List<Vector3>();
List<TriangleData> tempTris = new List<TriangleData>(128);
List<EdgeInfo> edges = new List<EdgeInfo>(16);
List<SamplingData> samples = new List<SamplingData>(128);
BuildPolyDetail(poly, npoly, sampleDist, sampleMaxError, compactField, hp, tempVerts, tempTris, edges, samples);
//more detail verts
for (int j = 0; j < tempVerts.Count; j++)
{
Vector3 tv = tempVerts[j];
Vector3 v;
v.X = tv.X + origin.X;
v.Y = tv.Y + origin.Y + compactField.CellHeight;
v.Z = tv.Z + origin.Z;
tempVerts[j] = v;
}
for (int j = 0; j < npoly; j++)
{
Vector3 po = poly[j];
po.X += origin.X;
po.Y += origin.Y;
po.Z += origin.Z;
poly[j] = po;
}
//save data
this.meshes[i].VertexIndex = storedVertices.Count;
this.meshes[i].VertexCount = tempVerts.Count;
this.meshes[i].TriangleIndex = storedTriangles.Count;
this.meshes[i].TriangleCount = tempTris.Count;
//store vertices
storedVertices.AddRange(tempVerts);
//store triangles
for (int j = 0; j < tempTris.Count; j++)
{
storedTriangles.Add(new TriangleData(tempTris[j], tempVerts, poly, npoly));
}
}
this.verts = storedVertices.ToArray();
this.tris = storedTriangles.ToArray();
}
/// <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);
}
}
/// <summary>
/// Generate the PolyMeshDetail using the PolyMesh and HeightPatch
/// </summary>
/// <param name="polyMeshVerts">PolyMesh Vertex data</param>
/// <param name="numMeshVerts">Number of PolyMesh vertices</param>
/// <param name="sampleDist">Sampling distance</param>
/// <param name="sampleMaxError">Maximum sampling error</param>
/// <param name="compactField">THe compactHeightfield</param>
/// <param name="hp">The heightPatch</param>
/// <param name="verts">Detail verts</param>
/// <param name="tris">Detail triangles</param>
/// <param name="edges">The edge array</param>
/// <param name="samples">The samples array</param>
private void BuildPolyDetail(Vector3[] polyMeshVerts, int numMeshVerts, float sampleDist, float sampleMaxError, CompactHeightfield compactField, HeightPatch hp, List<Vector3> verts, List<TriangleData> tris, List<EdgeInfo> edges, List<SamplingData> samples)
{
const int MAX_VERTS = 127;
const int MAX_TRIS = 255;
const int MAX_VERTS_PER_EDGE = 32;
Vector3[] edge = new Vector3[MAX_VERTS_PER_EDGE + 1];
List<int> hull = new List<int>(MAX_VERTS);
//fill up vertex array
for (int i = 0; i < numMeshVerts; ++i)
verts.Add(polyMeshVerts[i]);
float cs = compactField.CellSize;
float ics = 1.0f / cs;
float minExtent = PolyMinExtent(polyMeshVerts);
//tessellate outlines
if (sampleDist > 0)
{
for (int i = 0, j = verts.Count - 1; i < verts.Count; j = i++)
{
Vector3 vi = verts[i];
Vector3 vj = verts[j];
bool swapped = false;
//make sure order is correct, otherwise swap data
if (Math.Abs(vj.X - vi.X) < 1E-06f)
{
if (vj.Z > vi.Z)
{
Vector3 temp = vj;
vj = vi;
vi = temp;
swapped = true;
}
}
else if (vj.X > vi.X)
{
Vector3 temp = vj;
vj = vi;
vi = temp;
swapped = true;
}
//create samples along the edge
Vector3 dv;
Vector3.Subtract(ref vi, ref vj, out dv);
float d = (float)Math.Sqrt(dv.X * dv.X + dv.Z * dv.Z);
int nn = 1 + (int)Math.Floor(d / sampleDist);
if (nn >= MAX_VERTS_PER_EDGE)
nn = MAX_VERTS_PER_EDGE - 1;
if (verts.Count + nn >= MAX_VERTS)
nn = MAX_VERTS - 1 - verts.Count;
for (int k = 0; k <= nn; k++)
{
float u = (float)k / (float)nn;
Vector3 pos;
Vector3 tmp;
Vector3.Multiply(ref dv, u, out tmp);
Vector3.Add(ref vj, ref tmp, out pos);
pos.Y = GetHeight(pos, ics, compactField.CellHeight, hp) * compactField.CellHeight;
edge[k] = pos;
}
//simplify samples
int[] idx = new int[MAX_VERTS_PER_EDGE];
idx[0] = 0;
idx[1] = nn;
int nidx = 2;
for (int k = 0; k < nidx - 1;)
{
int a = idx[k];
int b = idx[k + 1];
Vector3 va = edge[a];
Vector3 vb = edge[b];
//find maximum deviation along segment
float maxd = 0;
int maxi = -1;
for (int m = a + 1; m < b; m++)
{
float dev = Distance.PointToSegmentSquared(ref edge[m], ref va, ref vb);
if (dev > maxd)
{
maxd = dev;
maxi = m;
}
}
if (maxi != -1 && maxd > (sampleMaxError * sampleMaxError))
{
//shift data to the right
for (int m = nidx; m > k; m--)
idx[m] = idx[m - 1];
//set new value
idx[k + 1] = maxi;
nidx++;
}
else
{
k++;
}
}
hull.Add(j);
//add new vertices
if (swapped)
{
for (int k = nidx - 2; k > 0; k--)
{
hull.Add(verts.Count);
verts.Add(edge[idx[k]]);
}
}
else
{
for (int k = 1; k < nidx - 1; k++)
{
hull.Add(verts.Count);
verts.Add(edge[idx[k]]);
}
}
}
}
//tesselate base mesh
edges.Clear();
tris.Clear();
if (minExtent < sampleDist * 2)
{
TriangulateHull(verts, hull, tris);
return;
}
TriangulateHull(verts, hull, tris);
if (tris.Count == 0)
{
Console.WriteLine("Can't triangulate polygon, adding default data.");
return;
}
if (sampleDist > 0)
{
//create sample locations
BBox3 bounds = new BBox3();
bounds.Min = polyMeshVerts[0];
bounds.Max = polyMeshVerts[0];
for (int i = 1; i < numMeshVerts; i++)
{
Vector3Extensions.ComponentMin(ref bounds.Min, ref polyMeshVerts[i], out bounds.Min);
Vector3Extensions.ComponentMax(ref bounds.Max, ref polyMeshVerts[i], out bounds.Max);
}
int x0 = (int)Math.Floor(bounds.Min.X / sampleDist);
int x1 = (int)Math.Ceiling(bounds.Max.X / sampleDist);
int z0 = (int)Math.Floor(bounds.Min.Z / sampleDist);
int z1 = (int)Math.Ceiling(bounds.Max.Z / sampleDist);
samples.Clear();
for (int z = z0; z < z1; z++)
{
for (int x = x0; x < x1; x++)
{
Vector3 pt = new Vector3(x * sampleDist, (bounds.Max.Y + bounds.Min.Y) * 0.5f, z * sampleDist);
//make sure samples aren't too close to edge
if (Distance.PointToPolygonSquared(pt, polyMeshVerts, numMeshVerts) > -sampleDist * 0.5f)
continue;
SamplingData sd = new SamplingData(x, GetHeight(pt, ics, compactField.CellHeight, hp), z, false);
samples.Add(sd);
}
}
//added samples
for (int iter = 0; iter < samples.Count; iter++)
{
if (verts.Count >= MAX_VERTS)
break;
//find sample with most error
Vector3 bestPt = Vector3.Zero;
float bestDistance = 0;
int bestIndex = -1;
for (int i = 0; i < samples.Count; i++)
{
SamplingData sd = samples[i];
if (sd.IsSampled)
continue;
//jitter sample location to remove effects of bad triangulation
Vector3 pt;
pt.X = sd.X * sampleDist + GetJitterX(i) * compactField.CellSize * 0.1f;
pt.Y = sd.Y * compactField.CellHeight;
pt.Z = sd.Z * sampleDist + GetJitterY(i) * compactField.CellSize * 0.1f;
float d = DistanceToTriMesh(pt, verts, tris);
if (d < 0)
continue;
if (d > bestDistance)
{
bestDistance = d;
bestIndex = i;
bestPt = pt;
}
}
if (bestDistance <= sampleMaxError || bestIndex == -1)
break;
SamplingData bsd = samples[bestIndex];
bsd.IsSampled = true;
samples[bestIndex] = bsd;
verts.Add(bestPt);
//create new triangulation
edges.Clear();
tris.Clear();
DelaunayHull(verts, hull, tris, edges);
}
}
int ntris = tris.Count;
if (ntris > MAX_TRIS)
{
//TODO we're using lists... let the user have super detailed meshes?
//Perhaps just a warning saying there's a lot of tris?
//tris.RemoveRange(MAX_TRIS + 1, tris.Count - MAX_TRIS);
//Console.WriteLine("WARNING: shrinking number of triangles.");
}
}
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));
}
}
}
