public static MeshX Subdivide(MeshX mesh, Options options)
{
if (!mesh.helpersInited)
{
mesh.InitHelpers();
}
if (!mesh.normalPerPosition)
{
mesh.MakeNormalPerPosition();
}
MeshX newMesh = new MeshX {
name = mesh.name + "/s",
content = mesh.content,
normalPerPosition = true,
};
newMesh.StartBuilding();
CheckForVertexKeys(mesh);
var newVertices = new MeshVertices {
mesh = newMesh
};
var edgeMidPositions = new Dictionary <VertexKey, Vertex>(); // position & normal
// reserve indices for new control-points: they keep indices and we need no special keys for them.
// later for control-points we set position & normal only: tangent & uv stay the same.
for (int pi = 0; pi < mesh.positions.Count; ++pi)
{
newMesh.AddPosition(default(Vertex));
}
for (int vi = 0; vi < mesh.vertexCount; ++vi)
{
Vertex v = mesh.GetVertex(vi, maskVertex);
newMesh.AddVertex(v, addPosition: false);
}
// add face-points
// "for each face, a face point is created which is the average of all the points of the face."
foreach (Face f in mesh.IterAllFaces())
{
Vertex[] vs = mesh.GetVertices(mesh.GetFaceVertexIndices(f));
Vertex v = mesh.Average(vs);
VertexKey keyF = GetFacePointKey(f);
newVertices.AddVertices(v, Pair(v, keyF));
}
// add edge-points
foreach (Edge e in mesh.IterAllEdges())
{
EdgeType type = mesh.GetEdgeType(e);
if (type == EdgeType.back)
{
continue;
}
if (type == EdgeType.boundary)
{
// "for the edges that are on the border of a hole, the edge point is just the middle of the edge."
Vertex midE = mesh.Average(
mesh.GetVertices(mesh.GetEdgeVertexIndices(e))
);
VertexKey keyE = GetEdgePointKey(e);
edgeMidPositions[keyE] = midE;
newVertices.AddVertices(midE, Pair(midE, keyE));
}
else if (type == EdgeType.solid)
{
// "for each edge, an edge point is created which is the average between the center of the edge
// and the center of the segment made with the face points of the two adjacent faces."
Edge n = mesh.GetNeighbor(e);
Vertex midE = mesh.Average(
mesh.GetVertices(mesh.GetEdgeVertexIndices(e))
);
VertexKey keyE = GetEdgePointKey(e);
edgeMidPositions[keyE] = midE;
Vertex v = mesh.Average(
new[] {
midE,
newVertices.GetVertex(GetFacePointKey(e.face)),
newVertices.GetVertex(GetFacePointKey(n.face)),
},
weights: new[] { 2f, 1f, 1f }
);
newVertices.AddVertices(v, Pair(v, keyE));
}
else // seam edge
{
Edge n = mesh.GetNeighbor(e);
Vertex midE = mesh.Average(
mesh.GetVertices(mesh.GetEdgeVertexIndices(e))
);
Vertex midN = mesh.Average(
mesh.GetVertices(mesh.GetEdgeVertexIndices(n)),
maskVertex // pos & normal already got in midE
);
VertexKey keyE = GetEdgePointKey(e);
VertexKey keyN = GetEdgePointKey(n);
edgeMidPositions[keyE] = midE;
Vertex p = mesh.Average( // pos & normal only
new[] {
midE,
newVertices.GetVertex(GetFacePointKey(e.face), maskPosition),
newVertices.GetVertex(GetFacePointKey(n.face), maskPosition),
},
maskPosition,
new[] { 2f, 1f, 1f }
);
newVertices.AddVertices(p, Pair(midE, keyE), Pair(midN, keyN));
}
}
// move control-points
for (int pi = 0; pi < mesh.positions.Count; ++pi)
{
// count edges
var edges = new List <Edge>(); // edges outcoming from the position
var boundaries = new List <Edge>();
var front = new List <Edge>();
foreach (int vi in mesh.positionVertices[pi])
{
foreach (Edge e in mesh.vertexEdges[vi])
{
edges.Add(e);
foreach (Edge edge in new[] { e, mesh.GetNextInFace(e, -1) })
{
EdgeType type = mesh.GetEdgeType(edge);
if (type == EdgeType.boundary)
{
boundaries.Add(edge);
}
else if (type != EdgeType.back)
{
front.Add(edge);
}
}
}
}
Debug.AssertFormat(boundaries.Count > 0 || (edges.Count == front.Count),
"Counting edges error: boundaries: {0}, edges {1}, front: {2}", boundaries.Count, edges.Count, front.Count);
Vertex controlPoint;
if (boundaries.Count > 0)
{
bool isCorner = edges.Count == 1;
if (options.boundaryInterpolation == Options.BoundaryInterpolation.fixBoundaries ||
options.boundaryInterpolation == Options.BoundaryInterpolation.fixCorners && isCorner)
{
controlPoint = mesh.GetPosition(pi); // keep same position
}
else
{
// "for the vertex points that are on the border of a hole, the new coordinates are calculated as follows:
// 1. in all the edges the point belongs to, only take in account the middles of the edges that are on the border of the hole
// 2. calculate the average between these points (on the hole boundary) and the old coordinates (also on the hole boundary)."
Vertex[] vs = new Vertex[boundaries.Count + 1];
vs[0] = mesh.GetPosition(pi);
for (int e = 0; e < boundaries.Count; ++e)
{
vs[e + 1] = edgeMidPositions[GetEdgePointKey(boundaries[e])];
}
controlPoint = mesh.Average(vs, maskPosition);
}
}
else
{
// "for each vertex point, its coordinates are updated from (new_coords):
// the old coordinates (P),
// the average of the face points of the faces the point belongs to (F),
// the average of the centers of edges the point belongs to (R),
// how many faces a point belongs to (n), then use this formula:
// (F + 2R + (n-3)P) / n"
// edge-midpoints
Vertex[] ms = new Vertex[front.Count];
for (int e = 0; e < front.Count; ++e)
{
ms[e] = edgeMidPositions[GetEdgePointKey(front[e])];
}
Vertex edgeMidAverage = mesh.Average(ms, maskPosition);
// face-points
Vertex[] fs = new Vertex[edges.Count];
for (int e = 0; e < edges.Count; ++e)
{
fs[e] = newVertices.GetVertex(GetFacePointKey(edges[e].face), maskPosition);
}
Vertex faceAverage = mesh.Average(fs, maskPosition);
// new control-point
controlPoint = mesh.Average(
new[] {
faceAverage,
edgeMidAverage,
mesh.GetPosition(pi)
},
maskPosition,
new[] { 1f, 2f, edges.Count - 3f }
);
}
// set moved control-point position to reserved index
newMesh.SetPosition(pi, controlPoint);
}
// add 4 new quads per face
// eis[i]
// fis[i].----.----.fis[i+1]
// | |
// eis[i-1]. ci. .
// | |
// .____.____.
newMesh.submeshes = new Submesh[mesh.submeshes.Length];
for (int si = 0; si < mesh.submeshes.Length; ++si)
{
int[][] faces = mesh.submeshes[si].faces;
// get new face count
int faceCount = 0;
foreach (int[] face in faces)
{
faceCount += face.Length;
}
newMesh.submeshes[si].faces = new int[faceCount][];
// fill faces
int faceIndex = 0;
for (int fi = 0; fi < faces.Length; ++fi)
{
int[] fis = faces[fi];
int edgeCount = fis.Length; // 3 or 4
//
Face f = new Face {
submesh = si, index = fi
};
int ci = newVertices.vertexIndices[GetFacePointKey(f)]; // face-point index
//
int[] eis = new int[edgeCount]; // edge-point indices
for (int i = 0; i < edgeCount; ++i)
{
Edge e = new Edge {
face = f, index = i
};
// get neighbor for solid back edges
if (mesh.GetEdgeType(e) == EdgeType.back) //!!! here should be some EdgeType.backOfSeam or EdgeType.backOfSolid
{
Edge n = mesh.GetNeighbor(e);
if (mesh.GetEdgeType(n) == EdgeType.solid)
{
e = n;
}
}
eis[i] = newVertices.vertexIndices[GetEdgePointKey(e)];
}
//
for (int i = 0; i < edgeCount; ++i)
{
int[] q = new int[4]; // new faces are always quads
int s = edgeCount == 4 ? i : 0; // shift indices (+ i) to keep quad orientation
q[(0 + s) % 4] = fis[i];
q[(1 + s) % 4] = eis[i];
q[(2 + s) % 4] = ci;
q[(3 + s) % 4] = eis[(i - 1 + edgeCount) % edgeCount];
newMesh.submeshes[si].faces[faceIndex++] = q;
}
}
}
newMesh.FinishBuilding();
return(newMesh);
}
public Vertex GetVertex(VertexKey key, VertexContent mask = VertexContent.full)
{
return(mesh.GetVertex(vertexIndices[key], mask));
}