// E = average of two neighboring face points and original endpoints
//
// Compute P' F = average F of all n face points for faces touching P
// R = average R of all n edge midpoints for edges touching P
// F + 2R + (n-3)P P = old point location
// P' = ----------------
// n -> F weight is 1/n
// -> R weight is 2/n
// F 2R (n-3)P -> P weight is (n-3)/n
// P' = - + -- + ------
// n n n
//
// For each corner in the old polygon, add one quad
// (centroid, previous edge 'edge point', corner, next edge 'edge midpoint')
public CatmullClarkGeometryOperation(Geometry src)
{
Source = src;
// (n-3)P
// Make initial P's with ------
// n
foreach (Point oldPoint in Source.Points)
{
float n = (float)oldPoint.Corners.Count;
float weight = (n - 3.0f) / n;
MakeNewPointFromPoint(weight, oldPoint);
}
// Make edge points
// "average of two neighboring face points and original endpoints"
// Add midpoint (R) to each new end points
// R = average R of all n edge midpoints for edges touching P
// 2R we add both edge end points with weight 1 so total edge weight is 2
// --
// n
foreach (var kvp in Source.Edges)
{
Edge oldEdge = kvp.Key;
Point newPoint = MakeNewPointFromEdge(oldEdge); // these get weights 1 + 1
foreach (Polygon oldPolygon in kvp.Value)
{
float weight = 1.0f / (float)oldPolygon.Corners.Count;
AddPolygonCentroid(newPoint, weight, oldPolygon);
}
Point newPointA = pointOldToNew[oldEdge.A];
Point newPointB = pointOldToNew[oldEdge.B];
float nA = (float)(oldEdge.A.Corners.Count);
float nB = (float)(oldEdge.B.Corners.Count);
float weightA = 1.0f / nA;
float weightB = 1.0f / nB;
AddPointSource(newPointA, weightA, oldEdge.A);
AddPointSource(newPointA, weightA, oldEdge.B);
AddPointSource(newPointB, weightB, oldEdge.A);
AddPointSource(newPointB, weightB, oldEdge.B);
}
foreach (Polygon oldPolygon in Source.Polygons)
{
// Make centroid point
MakeNewPointFromPolygonCentroid(oldPolygon);
// Add polygon centroids (F) to all corners' point sources
// F = average F of all n face points for faces touching P
// F <- because F is average of all centroids, it adds extra /n
// ---
// n
foreach (Corner oldCorner in oldPolygon.Corners)
{
Point oldPoint = oldCorner.Point;
Point newPoint = pointOldToNew[oldPoint];
float pointWeight = 1.0f / (float)(oldPoint.Corners.Count);
float cornerWeight = 1.0f / (float)(oldPolygon.Corners.Count);
AddPolygonCentroid(newPoint, pointWeight * pointWeight * cornerWeight, oldPolygon);
}
}
// Subdivide polygons, clone (and corners);
for (uint polygonIndex = 0; polygonIndex < src.Polygons.Count; ++polygonIndex)
{
Polygon oldPolygon = Source.Polygons[(int)polygonIndex];
for (int i = 0; i < oldPolygon.Corners.Count; ++i) // Corner oldCorner in oldPolygon.Corners)
{
Corner oldCorner = oldPolygon.Corners[i];
Corner previousCorner = oldPolygon.Corners[(oldPolygon.Corners.Count + i - 1) % oldPolygon.Corners.Count];
Corner nextCorner = oldPolygon.Corners[(i + 1) % oldPolygon.Corners.Count];
Edge previousEdge = new Edge(previousCorner.Point, oldCorner.Point);
Edge nextEdge = new Edge(oldCorner.Point, nextCorner.Point);
Polygon newPolygon = MakeNewPolygonFromPolygon(oldPolygon);
MakeNewCornerFromPolygonCentroid(newPolygon, oldPolygon);
MakeNewCornerFromEdgePoint(newPolygon, previousEdge);
MakeNewCornerFromCorner(newPolygon, oldCorner);
MakeNewCornerFromEdgePoint(newPolygon, nextEdge);
}
}
Destination.BuildEdges();
// TODO can we map some edges to old edges? yes. Do it.
InterpolateAllAttributeMaps();
}
public TruncateGeometryOperation(Geometry src, bool close)
{
Source = src;
// Pass 1: Create truncated versions of old polygons
foreach (Polygon oldPolygon in Source.Polygons)
{
Polygon newPolygon = MakeNewPolygonFromPolygon(oldPolygon);
double n1 = (double)(oldPolygon.Corners.Count);
double n2 = (double)(2 * oldPolygon.Corners.Count);
float ratio = (float)(System.Math.Tan(System.Math.PI / n2) / System.Math.Tan(System.Math.PI / n1));
float t = 0.5f - 0.5f * ratio;
// Pass 1A: Create truncated corners
for (int i = 0; i < oldPolygon.Corners.Count; ++i)
{
Corner oldCorner = oldPolygon.Corners[i];
Corner nextCorner = oldPolygon.Corners[(i + 1) % oldPolygon.Corners.Count];
UpdateTruncatedEdge(newPolygon, oldCorner, nextCorner, t);
}
// Pass 1B: Collect open edges from new polygon to per point dictionary
// Note the order of points in new edge is important in this case.
for (int i = 0; i < newPolygon.Corners.Count; i += 2)
{
Corner newCorner = newPolygon.Corners[i];
Corner previousCorner = newPolygon.Corners[(i + newPolygon.Corners.Count - 1) % newPolygon.Corners.Count];
Point newPoint = newCorner.Point;
Point previousPoint = previousCorner.Point;
Point oldPoint = newPointToOld[newPoint];
Edge newEdge = new Edge(newPoint, previousPoint);
if (oldPointToOpenEdges.ContainsKey(oldPoint) == false)
{
oldPointToOpenEdges[oldPoint] = new List <Edge>();
}
oldPointToOpenEdges[oldPoint].Add(newEdge);
}
}
// Pass 2: Connect open edges
if (close)
{
foreach (Point oldPoint in src.Points)
{
if (oldPointToOpenEdges.ContainsKey(oldPoint) == false)
{
continue;
}
if (oldPointToOpenEdges[oldPoint].Count < 3)
{
continue;
}
Polygon newPolygon = Destination.MakePolygon();
// TODO This polygon has no sources.. inherit average of surrounding polygons?
Edge edge = oldPointToOpenEdges[oldPoint].First();
Edge startEdge = edge;
// TODO MUSTFIX This loop does not terminate for some geometries
// such as tetrahemihexahedron
do
{
bool nextEdgeFound = false;
int edgeIndex = 0;
foreach (Edge nextEdge in oldPointToOpenEdges[oldPoint])
{
++edgeIndex;
if (nextEdge.A == edge.B)
{
Point newPoint = edge.A;
Corner newCorner = newPolygon.MakeCorner(newPoint);
DistributeCornerSources(newCorner, 1.0f, newPoint);
edge = nextEdge;
nextEdgeFound = true;
break;
}
}
/* This can happen */
if (nextEdgeFound == false)
{
break;
}
}while(edge.Equals(startEdge) == false);
if (newPolygon.Corners.Count < 3)
{
Destination.RemovePolygon(newPolygon);
}
}
}
Destination.BuildEdges();
InterpolateAllAttributeMaps();
}